From 01ad0fb31d77c32c5fb3434d543943848bb9938c Mon Sep 17 00:00:00 2001
From: Alexis Sellier <alexis@radicle.xyz>
Date: Thu, 24 Nov 2022 13:36:35 +0100
Subject: [PATCH] cob: Split generic code from automerge-specific

---
 radicle-cli/src/commands/issue.rs             |   4 +-
 radicle-cli/src/commands/merge.rs             |   4 +-
 radicle-cli/src/commands/patch/common.rs      |   2 +-
 radicle-cli/src/commands/patch/create.rs      |   5 +-
 radicle-cli/src/commands/patch/list.rs        |   4 +-
 radicle-cli/src/commands/review.rs            |   4 +-
 radicle-cli/src/terminal/io.rs                |   2 +-
 radicle-crdt/src/thread.rs                    |   2 +-
 radicle/src/cob.rs                            |  11 +-
 radicle/src/cob/automerge.rs                  |  10 +
 radicle/src/cob/{ => automerge}/doc.rs        |   2 +-
 radicle/src/cob/automerge/issue.rs            | 682 ++++++++++++++
 radicle/src/cob/{ => automerge}/label.rs      |  11 +-
 radicle/src/cob/automerge/patch.rs            | 835 +++++++++++++++++
 radicle/src/cob/automerge/shared.rs           | 185 ++++
 radicle/src/cob/{ => automerge}/store.rs      |  20 +-
 .../src/cob/{ => automerge}/transaction.rs    |   2 +-
 radicle/src/cob/{ => automerge}/value.rs      |  20 +
 radicle/src/cob/common.rs                     | 223 +++++
 radicle/src/cob/issue.rs                      | 681 +-------------
 radicle/src/cob/patch.rs                      | 849 +-----------------
 radicle/src/cob/shared.rs                     | 394 --------
 22 files changed, 1992 insertions(+), 1960 deletions(-)
 create mode 100644 radicle/src/cob/automerge.rs
 rename radicle/src/cob/{ => automerge}/doc.rs (99%)
 create mode 100644 radicle/src/cob/automerge/issue.rs
 rename radicle/src/cob/{ => automerge}/label.rs (93%)
 create mode 100644 radicle/src/cob/automerge/patch.rs
 create mode 100644 radicle/src/cob/automerge/shared.rs
 rename radicle/src/cob/{ => automerge}/store.rs (90%)
 rename radicle/src/cob/{ => automerge}/transaction.rs (97%)
 rename radicle/src/cob/{ => automerge}/value.rs (78%)
 create mode 100644 radicle/src/cob/common.rs
 delete mode 100644 radicle/src/cob/shared.rs

diff --git a/radicle-cli/src/commands/issue.rs b/radicle-cli/src/commands/issue.rs
index afac4bbd..102523ee 100644
--- a/radicle-cli/src/commands/issue.rs
+++ b/radicle-cli/src/commands/issue.rs
@@ -7,9 +7,9 @@ use anyhow::{anyhow, Context as _};
 use crate::terminal as term;
 use crate::terminal::args::{Args, Error, Help};
 
+use radicle::cob::automerge::store::Store;
+use radicle::cob::common::{Label, Reaction};
 use radicle::cob::issue::{CloseReason, IssueId, State};
-use radicle::cob::shared::{Label, Reaction};
-use radicle::cob::store::Store;
 use radicle::storage::WriteStorage;
 
 pub const HELP: Help = Help {
diff --git a/radicle-cli/src/commands/merge.rs b/radicle-cli/src/commands/merge.rs
index 0f381ba3..81d21548 100644
--- a/radicle-cli/src/commands/merge.rs
+++ b/radicle-cli/src/commands/merge.rs
@@ -7,7 +7,7 @@ use anyhow::{anyhow, Context};
 
 use crate::terminal as term;
 use crate::terminal::args::{Args, Error, Help};
-use radicle::cob;
+use radicle::cob::automerge;
 use radicle::cob::patch::RevisionIx;
 use radicle::cob::patch::{Patch, PatchId};
 use radicle::git;
@@ -141,7 +141,7 @@ pub fn run(options: Options, ctx: impl term::Context) -> anyhow::Result<()> {
         .project_of(profile.id())
         .context(format!("couldn't load project {} from local state", id))?;
     let repository = profile.storage.repository(id)?;
-    let cobs = cob::Store::open(*profile.id(), &repository)?;
+    let cobs = automerge::Store::open(*profile.id(), &repository)?;
     let patches = cobs.patches();
 
     if repo.head_detached()? {
diff --git a/radicle-cli/src/commands/patch/common.rs b/radicle-cli/src/commands/patch/common.rs
index d8f1d982..48178096 100644
--- a/radicle-cli/src/commands/patch/common.rs
+++ b/radicle-cli/src/commands/patch/common.rs
@@ -1,4 +1,4 @@
-use radicle::cob::patch::{MergeTarget, Patch, PatchId, PatchStore};
+use radicle::cob::automerge::patch::{MergeTarget, Patch, PatchId, PatchStore};
 use radicle::git;
 use radicle::git::raw::Oid;
 use radicle::prelude::*;
diff --git a/radicle-cli/src/commands/patch/create.rs b/radicle-cli/src/commands/patch/create.rs
index 68579db9..eefe4d8f 100644
--- a/radicle-cli/src/commands/patch/create.rs
+++ b/radicle-cli/src/commands/patch/create.rs
@@ -2,7 +2,8 @@ use std::path::Path;
 
 use anyhow::{anyhow, Context};
 
-use radicle::cob::patch::{MergeTarget, Patch, PatchId, PatchStore};
+use radicle::cob::automerge;
+use radicle::cob::automerge::patch::{MergeTarget, Patch, PatchId, PatchStore};
 use radicle::git;
 use radicle::git::raw::Oid;
 use radicle::prelude::*;
@@ -51,7 +52,7 @@ pub fn run(
     ));
 
     let signer = term::signer(profile)?;
-    let cobs = radicle::cob::Store::open(profile.public_key, storage)?;
+    let cobs = automerge::Store::open(profile.public_key, storage)?;
     let patches = cobs.patches();
 
     // `HEAD`; This is what we are proposing as a patch.
diff --git a/radicle-cli/src/commands/patch/list.rs b/radicle-cli/src/commands/patch/list.rs
index a1866700..3e321653 100644
--- a/radicle-cli/src/commands/patch/list.rs
+++ b/radicle-cli/src/commands/patch/list.rs
@@ -1,4 +1,4 @@
-use radicle::cob;
+use radicle::cob::automerge;
 use radicle::cob::patch::{Patch, PatchId, Verdict};
 use radicle::git;
 use radicle::prelude::*;
@@ -22,7 +22,7 @@ pub fn run(
     }
 
     let me = *profile.id();
-    let cobs = cob::Store::open(*profile.id(), storage)?;
+    let cobs = automerge::Store::open(*profile.id(), storage)?;
     let patches = cobs.patches();
     let proposed = patches.proposed()?;
 
diff --git a/radicle-cli/src/commands/review.rs b/radicle-cli/src/commands/review.rs
index 50b0c7d8..34c79bf3 100644
--- a/radicle-cli/src/commands/review.rs
+++ b/radicle-cli/src/commands/review.rs
@@ -4,7 +4,7 @@ use std::str::FromStr;
 use anyhow::{anyhow, Context};
 
 use radicle::cob;
-use radicle::cob::patch::{PatchId, RevisionIx, Verdict};
+use radicle::cob::automerge::patch::{PatchId, RevisionIx, Verdict};
 use radicle::prelude::*;
 use radicle::rad;
 
@@ -138,7 +138,7 @@ pub fn run(options: Options, ctx: impl term::Context) -> anyhow::Result<()> {
     let _project = repository
         .project_of(profile.id())
         .context(format!("couldn't load project {} from local state", id))?;
-    let cobs = cob::Store::open(*profile.id(), &repository)?;
+    let cobs = cob::automerge::Store::open(*profile.id(), &repository)?;
     let patches = cobs.patches();
 
     let patch_id = options.id;
diff --git a/radicle-cli/src/terminal/io.rs b/radicle-cli/src/terminal/io.rs
index 86832245..da7f17a4 100644
--- a/radicle-cli/src/terminal/io.rs
+++ b/radicle-cli/src/terminal/io.rs
@@ -3,8 +3,8 @@ use std::str::FromStr;
 
 use dialoguer::{console::style, console::Style, theme::ColorfulTheme, Input, Password};
 
+use radicle::cob::common::CommentId;
 use radicle::cob::issue::Issue;
-use radicle::cob::shared::CommentId;
 use radicle::crypto::ssh::keystore::Passphrase;
 use radicle::crypto::Signer;
 use radicle::profile::env::RAD_PASSPHRASE;
diff --git a/radicle-crdt/src/thread.rs b/radicle-crdt/src/thread.rs
index aa46ac15..8419c31a 100644
--- a/radicle-crdt/src/thread.rs
+++ b/radicle-crdt/src/thread.rs
@@ -3,7 +3,7 @@ use std::ops::Deref;
 
 use serde::{Deserialize, Serialize};
 
-use radicle::cob::shared::Reaction;
+use radicle::cob::common::Reaction;
 use radicle::cob::Timestamp;
 use radicle::crypto::{PublicKey, Signature, Signer};
 use radicle::hash;
diff --git a/radicle/src/cob.rs b/radicle/src/cob.rs
index 27291e6d..fde7ed9c 100644
--- a/radicle/src/cob.rs
+++ b/radicle/src/cob.rs
@@ -1,18 +1,13 @@
-pub mod doc;
+pub mod automerge;
+pub mod common;
 pub mod issue;
-pub mod label;
 pub mod patch;
-pub mod shared;
-pub mod store;
-pub mod transaction;
-pub mod value;
 
 pub use cob::{
     identity, object::collaboration::error, CollaborativeObject, Contents, Create, Entry, History,
     HistoryType, ObjectId, TypeName, Update,
 };
-pub use shared::Timestamp;
-pub use store::Store;
+pub use common::*;
 
 use radicle_cob as cob;
 use radicle_git_ext::Oid;
diff --git a/radicle/src/cob/automerge.rs b/radicle/src/cob/automerge.rs
new file mode 100644
index 00000000..476e5a13
--- /dev/null
+++ b/radicle/src/cob/automerge.rs
@@ -0,0 +1,10 @@
+pub mod doc;
+pub mod issue;
+pub mod label;
+pub mod patch;
+pub mod shared;
+pub mod store;
+pub mod transaction;
+pub mod value;
+
+pub use store::Store;
diff --git a/radicle/src/cob/doc.rs b/radicle/src/cob/automerge/doc.rs
similarity index 99%
rename from radicle/src/cob/doc.rs
rename to radicle/src/cob/automerge/doc.rs
index 44b52e4f..a8b1524d 100644
--- a/radicle/src/cob/doc.rs
+++ b/radicle/src/cob/automerge/doc.rs
@@ -6,7 +6,7 @@ use std::str::FromStr;
 
 use automerge::{Automerge, AutomergeError, ObjType};
 
-use crate::cob::value::{FromValue, ValueError};
+use crate::cob::automerge::value::{FromValue, ValueError};
 
 /// Error decoding a document.
 #[derive(thiserror::Error, Debug)]
diff --git a/radicle/src/cob/automerge/issue.rs b/radicle/src/cob/automerge/issue.rs
new file mode 100644
index 00000000..6479b39d
--- /dev/null
+++ b/radicle/src/cob/automerge/issue.rs
@@ -0,0 +1,682 @@
+#![allow(clippy::large_enum_variant)]
+use std::collections::HashSet;
+use std::convert::TryFrom;
+use std::ops::ControlFlow;
+
+use automerge::{Automerge, ObjType, ScalarValue, Value};
+
+use crate::cob::automerge::doc::{Document, DocumentError};
+use crate::cob::automerge::shared;
+use crate::cob::automerge::shared::*;
+use crate::cob::automerge::store::{Error, Store};
+use crate::cob::automerge::transaction::{Transaction, TransactionError};
+use crate::cob::automerge::value::{FromValue, ValueError};
+use crate::cob::common::*;
+use crate::cob::issue::*;
+use crate::cob::{Contents, History, ObjectId, Timestamp, TypeName};
+use crate::prelude::*;
+
+impl From<State> for ScalarValue {
+    fn from(state: State) -> Self {
+        match state {
+            State::Open => ScalarValue::from("open"),
+            State::Closed {
+                reason: CloseReason::Solved,
+            } => ScalarValue::from("solved"),
+            State::Closed {
+                reason: CloseReason::Other,
+            } => ScalarValue::from("closed"),
+        }
+    }
+}
+
+impl<'a> FromValue<'a> for State {
+    fn from_value(value: Value) -> Result<Self, ValueError> {
+        let state = value.to_str().ok_or(ValueError::InvalidType)?;
+
+        match state {
+            "open" => Ok(Self::Open),
+            "closed" => Ok(Self::Closed {
+                reason: CloseReason::Other,
+            }),
+            "solved" => Ok(Self::Closed {
+                reason: CloseReason::Solved,
+            }),
+            _ => Err(ValueError::InvalidValue(value.to_string())),
+        }
+    }
+}
+
+impl FromHistory for Issue {
+    fn type_name() -> &'static TypeName {
+        &TYPENAME
+    }
+
+    fn from_history(history: &History) -> Result<Self, Error> {
+        let doc = history.traverse(Automerge::new(), |mut doc, entry| {
+            let bytes = entry.contents();
+            match automerge::Change::from_bytes(bytes.clone()) {
+                Ok(change) => {
+                    doc.apply_changes([change]).ok();
+                }
+                Err(_err) => {
+                    // Ignore
+                }
+            }
+            ControlFlow::Continue(doc)
+        });
+        let issue = Issue::try_from(doc)?;
+
+        Ok(issue)
+    }
+}
+
+impl TryFrom<&History> for Issue {
+    type Error = Error;
+
+    fn try_from(history: &History) -> Result<Self, Self::Error> {
+        Issue::from_history(history)
+    }
+}
+
+impl TryFrom<Automerge> for Issue {
+    type Error = DocumentError;
+
+    fn try_from(doc: Automerge) -> Result<Self, Self::Error> {
+        let doc = Document::new(&doc);
+        let obj_id = doc.get_id(automerge::ObjId::Root, "issue")?;
+        let title = doc.get(&obj_id, "title")?;
+        let comment_id = doc.get_id(&obj_id, "comment")?;
+        let author = doc.get(&obj_id, "author").map(Author::new)?;
+        let state = doc.get(&obj_id, "state")?;
+        let timestamp = doc.get(&obj_id, "timestamp")?;
+
+        let comment = shared::lookup::comment(doc, &comment_id)?;
+        let discussion: Discussion = doc.list(&obj_id, "discussion", shared::lookup::thread)?;
+        let labels: HashSet<Label> = doc.keys(&obj_id, "labels")?;
+
+        Ok(Self {
+            title,
+            state,
+            author,
+            comment,
+            discussion,
+            labels,
+            timestamp,
+        })
+    }
+}
+
+pub struct IssueStore<'a> {
+    store: Store<'a, Issue>,
+}
+
+impl<'a> IssueStore<'a> {
+    /// Create a new issue store.
+    pub fn new(store: Store<'a, Issue>) -> Self {
+        Self { store }
+    }
+
+    /// Get an issue by id.
+    pub fn get(&self, id: &ObjectId) -> Result<Option<Issue>, Error> {
+        self.store.get(id)
+    }
+
+    /// Create an issue.
+    pub fn create<G: Signer>(
+        &self,
+        title: &str,
+        description: &str,
+        labels: &[Label],
+        signer: &G,
+    ) -> Result<IssueId, Error> {
+        let author = self.store.author();
+        let timestamp = Timestamp::now();
+        let contents = events::create(&author, title, description, timestamp, labels)?;
+        let cob = self.store.create("Create issue", contents, signer)?;
+
+        Ok(*cob.id())
+    }
+
+    /// Remove an issue.
+    pub fn remove<G: Signer>(&self, _issue_id: &IssueId, _signer: &G) -> Result<(), Error> {
+        todo!()
+    }
+
+    /// Comment on an issue.
+    pub fn comment<G: Signer>(
+        &self,
+        issue_id: &IssueId,
+        body: &str,
+        signer: &G,
+    ) -> Result<(), Error> {
+        let author = self.store.author();
+        let mut issue = self.store.get_raw(issue_id)?;
+        let timestamp = Timestamp::now();
+        let changes = events::comment(&mut issue, &author, body, timestamp)?;
+
+        self.store
+            .update(*issue_id, "Add comment", changes, signer)?;
+
+        Ok(())
+    }
+
+    /// Life-cycle an issue, eg. open or close it.
+    pub fn lifecycle<G: Signer>(
+        &self,
+        issue_id: &IssueId,
+        state: State,
+        signer: &G,
+    ) -> Result<(), Error> {
+        let author = self.store.author();
+        let mut issue = self.store.get_raw(issue_id)?;
+        let changes = events::lifecycle(&mut issue, &author, state)?;
+
+        self.store.update(*issue_id, "Lifecycle", changes, signer)?;
+
+        Ok(())
+    }
+
+    /// Label an issue.
+    pub fn label<G: Signer>(
+        &self,
+        issue_id: &IssueId,
+        labels: &[Label],
+        signer: &G,
+    ) -> Result<(), Error> {
+        let author = self.store.author();
+        let mut issue = self.store.get_raw(issue_id)?;
+        let changes = events::label(&mut issue, &author, labels)?;
+
+        self.store.update(*issue_id, "Add label", changes, signer)?;
+
+        Ok(())
+    }
+
+    /// React to an issue comment.
+    pub fn react<G: Signer>(
+        &self,
+        issue_id: &IssueId,
+        comment_id: CommentId,
+        reaction: Reaction,
+        signer: &G,
+    ) -> Result<(), Error> {
+        let author = self.store.author();
+        let mut issue = self.store.get_raw(issue_id)?;
+        let changes = events::react(&mut issue, comment_id, &author, &[reaction])?;
+
+        self.store.update(*issue_id, "React", changes, signer)?;
+
+        Ok(())
+    }
+
+    /// Reply to an issue comment.
+    pub fn reply<G: Signer>(
+        &self,
+        issue_id: &IssueId,
+        comment_id: CommentId,
+        reply: &str,
+        signer: &G,
+    ) -> Result<(), Error> {
+        let author = self.store.author();
+        let mut issue = self.store.get_raw(issue_id)?;
+        let changes = events::reply(&mut issue, comment_id, &author, reply, Timestamp::now())?;
+
+        self.store.update(*issue_id, "Reply", changes, signer)?;
+
+        Ok(())
+    }
+
+    /// Get all issues, sorted by time.
+    pub fn all(&self) -> Result<Vec<(IssueId, Issue)>, Error> {
+        let mut issues = self.store.list()?;
+        issues.sort_by_key(|(_, i)| i.timestamp);
+
+        Ok(issues)
+    }
+
+    /// Get the issue count.
+    pub fn count(&self) -> Result<usize, Error> {
+        let issues = self.store.list()?;
+
+        Ok(issues.len())
+    }
+}
+
+/// Issue events.
+mod events {
+    use super::*;
+    use automerge::{
+        transaction::{CommitOptions, Transactable},
+        ObjId,
+    };
+
+    pub fn create(
+        author: &Author,
+        title: &str,
+        description: &str,
+        timestamp: Timestamp,
+        labels: &[Label],
+    ) -> Result<Contents, TransactionError> {
+        let title = title.trim();
+        if title.is_empty() {
+            return Err(TransactionError::InvalidValue("title"));
+        }
+
+        let mut doc = Automerge::new();
+        let _issue = doc
+            .transact_with::<_, _, TransactionError, _, ()>(
+                |_| CommitOptions::default().with_message("Create issue".to_owned()),
+                |tx| {
+                    let issue = tx.put_object(ObjId::Root, "issue", ObjType::Map)?;
+
+                    tx.put(&issue, "title", title)?;
+                    tx.put(&issue, "author", author)?;
+                    tx.put(&issue, "state", State::Open)?;
+                    tx.put(&issue, "timestamp", timestamp)?;
+                    tx.put_object(&issue, "discussion", ObjType::List)?;
+
+                    let labels_id = tx.put_object(&issue, "labels", ObjType::Map)?;
+                    for label in labels {
+                        tx.put(&labels_id, label.name().trim(), true)?;
+                    }
+
+                    // Nb. The top-level comment doesn't have a `replies` field.
+                    let comment_id = tx.put_object(&issue, "comment", ObjType::Map)?;
+
+                    tx.put(&comment_id, "body", description.trim())?;
+                    tx.put(&comment_id, "author", author)?;
+                    tx.put(&comment_id, "timestamp", timestamp)?;
+                    tx.put_object(&comment_id, "reactions", ObjType::Map)?;
+
+                    Ok(issue)
+                },
+            )
+            .map_err(|failure| failure.error)?
+            .result;
+
+        Ok(doc.save_incremental())
+    }
+
+    pub fn comment(
+        issue: &mut Automerge,
+        author: &Author,
+        body: &str,
+        timestamp: Timestamp,
+    ) -> Result<Contents, TransactionError> {
+        let _comment = issue
+            .transact_with::<_, _, TransactionError, _, ()>(
+                |_| CommitOptions::default().with_message("Add comment".to_owned()),
+                |tx| {
+                    let mut tx = Transaction::new(tx);
+                    let (_obj, obj_id) = tx.get(ObjId::Root, "issue")?;
+                    let (_, discussion_id) = tx.get(&obj_id, "discussion")?;
+
+                    let length = tx.length(&discussion_id);
+                    let comment = tx.insert_object(&discussion_id, length, ObjType::Map)?;
+
+                    tx.put(&comment, "author", author)?;
+                    tx.put(&comment, "body", body.trim())?;
+                    tx.put(&comment, "timestamp", timestamp)?;
+                    tx.put_object(&comment, "replies", ObjType::List)?;
+                    tx.put_object(&comment, "reactions", ObjType::Map)?;
+
+                    Ok(comment)
+                },
+            )
+            .map_err(|failure| failure.error)?
+            .result;
+
+        #[allow(clippy::unwrap_used)]
+        let change = issue.get_last_local_change().unwrap().raw_bytes().to_vec();
+
+        Ok(change)
+    }
+
+    pub fn lifecycle(
+        issue: &mut Automerge,
+        author: &Author,
+        state: State,
+    ) -> Result<Contents, TransactionError> {
+        issue
+            .transact_with::<_, _, TransactionError, _, ()>(
+                |_| CommitOptions::default().with_message(state.lifecycle_message()),
+                |tx| {
+                    let mut tx = Transaction::new(tx);
+                    let (_, obj_id) = tx.get(ObjId::Root, "issue")?;
+                    tx.put(&obj_id, "state", state)?;
+                    tx.put(&obj_id, "author", author)?;
+
+                    Ok(())
+                },
+            )
+            .map_err(|failure| failure.error)?;
+
+        #[allow(clippy::unwrap_used)]
+        let change = issue.get_last_local_change().unwrap().raw_bytes().to_vec();
+
+        Ok(change)
+    }
+
+    pub fn label(
+        issue: &mut Automerge,
+        _author: &Author,
+        labels: &[Label],
+    ) -> Result<Contents, TransactionError> {
+        issue
+            .transact_with::<_, _, TransactionError, _, ()>(
+                |_| CommitOptions::default().with_message("Label issue".to_owned()),
+                |tx| {
+                    let mut tx = Transaction::new(tx);
+                    let (_, obj_id) = tx.get(ObjId::Root, "issue")?;
+                    let (_, labels_id) = tx.get(&obj_id, "labels")?;
+
+                    for label in labels {
+                        tx.put(&labels_id, label.name().trim(), true)?;
+                    }
+                    Ok(())
+                },
+            )
+            .map_err(|failure| failure.error)?;
+
+        #[allow(clippy::unwrap_used)]
+        let change = issue.get_last_local_change().unwrap().raw_bytes().to_vec();
+
+        Ok(change)
+    }
+
+    pub fn reply(
+        issue: &mut Automerge,
+        comment_id: CommentId,
+        author: &Author,
+        body: &str,
+        timestamp: Timestamp,
+    ) -> Result<Contents, TransactionError> {
+        issue
+            .transact_with::<_, _, TransactionError, _, ()>(
+                |_| CommitOptions::default().with_message("Reply".to_owned()),
+                |tx| {
+                    let mut tx = Transaction::new(tx);
+                    let (_, obj_id) = tx.get(ObjId::Root, "issue")?;
+                    let (_, discussion_id) = tx.get(&obj_id, "discussion")?;
+                    let (_, comment_id) = tx.get(&discussion_id, usize::from(comment_id))?;
+                    let (_, replies_id) = tx.get(&comment_id, "replies")?;
+
+                    let length = tx.length(&replies_id);
+                    let reply = tx.insert_object(&replies_id, length, ObjType::Map)?;
+
+                    // Nb. Replies don't themselves have replies.
+                    tx.put(&reply, "author", author)?;
+                    tx.put(&reply, "body", body.trim())?;
+                    tx.put(&reply, "timestamp", timestamp)?;
+                    tx.put_object(&reply, "reactions", ObjType::Map)?;
+
+                    Ok(())
+                },
+            )
+            .map_err(|failure| failure.error)?;
+
+        #[allow(clippy::unwrap_used)]
+        let change = issue.get_last_local_change().unwrap().raw_bytes().to_vec();
+
+        Ok(change)
+    }
+
+    pub fn react(
+        issue: &mut Automerge,
+        comment_id: CommentId,
+        author: &Author,
+        reactions: &[Reaction],
+    ) -> Result<Contents, TransactionError> {
+        issue
+            .transact_with::<_, _, TransactionError, _, ()>(
+                |_| CommitOptions::default().with_message("React".to_owned()),
+                |tx| {
+                    let mut tx = Transaction::new(tx);
+                    let (_, obj_id) = tx.get(ObjId::Root, "issue")?;
+                    let (_, discussion_id) = tx.get(&obj_id, "discussion")?;
+                    let (_, comment_id) = if comment_id == CommentId::root() {
+                        tx.get(&obj_id, "comment")?
+                    } else {
+                        tx.get(&discussion_id, usize::from(comment_id) - 1)?
+                    };
+                    let (_, reactions_id) = tx.get(&comment_id, "reactions")?;
+
+                    for reaction in reactions {
+                        let key = reaction.emoji.to_string();
+                        let reaction_id = if let Some((_, reaction_id)) =
+                            tx.try_get(&reactions_id, key)?
+                        {
+                            reaction_id
+                        } else {
+                            tx.put_object(&reactions_id, reaction.emoji.to_string(), ObjType::Map)?
+                        };
+                        tx.put(&reaction_id, author.id.to_human(), true)?;
+                    }
+
+                    Ok(())
+                },
+            )
+            .map_err(|failure| failure.error)?;
+
+        #[allow(clippy::unwrap_used)]
+        let change = issue.get_last_local_change().unwrap().raw_bytes().to_vec();
+
+        Ok(change)
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use super::*;
+    use crate::test;
+
+    #[test]
+    fn test_issue_create_and_get() {
+        let tmp = tempfile::tempdir().unwrap();
+        let (_, signer, project) = test::setup::context(&tmp);
+        let store = Store::open(*signer.public_key(), &project).unwrap();
+        let issues = store.issues();
+        let timestamp = Timestamp::now();
+        let issue_id = issues
+            .create("My first issue", "Blah blah blah.", &[], &signer)
+            .unwrap();
+        let issue = issues.get(&issue_id).unwrap().unwrap();
+
+        assert_eq!(issue.title(), "My first issue");
+        assert_eq!(issue.author(), &store.author());
+        assert_eq!(issue.description(), "Blah blah blah.");
+        assert_eq!(issue.comments().len(), 0);
+        assert_eq!(issue.state(), State::Open);
+        assert!(issue.timestamp() >= timestamp);
+    }
+
+    #[test]
+    fn test_issue_create_and_change_state() {
+        let tmp = tempfile::tempdir().unwrap();
+        let (_, signer, project) = test::setup::context(&tmp);
+        let store = Store::open(*signer.public_key(), &project).unwrap();
+        let issues = store.issues();
+        let issue_id = issues
+            .create("My first issue", "Blah blah blah.", &[], &signer)
+            .unwrap();
+
+        issues
+            .lifecycle(
+                &issue_id,
+                State::Closed {
+                    reason: CloseReason::Other,
+                },
+                &signer,
+            )
+            .unwrap();
+
+        let issue = issues.get(&issue_id).unwrap().unwrap();
+        assert_eq!(
+            issue.state(),
+            State::Closed {
+                reason: CloseReason::Other
+            }
+        );
+
+        issues.lifecycle(&issue_id, State::Open, &signer).unwrap();
+        let issue = issues.get(&issue_id).unwrap().unwrap();
+        assert_eq!(issue.state(), State::Open);
+    }
+
+    #[test]
+    fn test_issue_react() {
+        let tmp = tempfile::tempdir().unwrap();
+        let (_, signer, project) = test::setup::context(&tmp);
+        let store = Store::open(*signer.public_key(), &project).unwrap();
+        let issues = store.issues();
+        let issue_id = issues
+            .create("My first issue", "Blah blah blah.", &[], &signer)
+            .unwrap();
+
+        let reaction = Reaction::new('🥳').unwrap();
+        issues
+            .react(&issue_id, CommentId::root(), reaction, &signer)
+            .unwrap();
+
+        let issue = issues.get(&issue_id).unwrap().unwrap();
+        let count = issue.reactions()[&reaction];
+
+        // TODO: Test multiple reactions from same author and different authors
+
+        assert_eq!(count, 1);
+    }
+
+    #[test]
+    fn test_issue_reply() {
+        let tmp = tempfile::tempdir().unwrap();
+        let (_, signer, project) = test::setup::context(&tmp);
+        let store = Store::open(*signer.public_key(), &project).unwrap();
+        let issues = store.issues();
+        let issue_id = issues
+            .create("My first issue", "Blah blah blah.", &[], &signer)
+            .unwrap();
+
+        issues.comment(&issue_id, "Ho ho ho.", &signer).unwrap();
+        issues
+            .reply(&issue_id, CommentId::root(), "Hi hi hi.", &signer)
+            .unwrap();
+        issues
+            .reply(&issue_id, CommentId::root(), "Ha ha ha.", &signer)
+            .unwrap();
+
+        let issue = issues.get(&issue_id).unwrap().unwrap();
+        let reply1 = &issue.comments()[0].replies[0];
+        let reply2 = &issue.comments()[0].replies[1];
+
+        assert_eq!(reply1.body, "Hi hi hi.");
+        assert_eq!(reply2.body, "Ha ha ha.");
+    }
+
+    #[test]
+    fn test_issue_label() {
+        let tmp = tempfile::tempdir().unwrap();
+        let (_, signer, project) = test::setup::context(&tmp);
+        let store = Store::open(*signer.public_key(), &project).unwrap();
+        let issues = store.issues();
+        let issue_id = issues
+            .create("My first issue", "Blah blah blah.", &[], &signer)
+            .unwrap();
+
+        let bug_label = Label::new("bug").unwrap();
+        let wontfix_label = Label::new("wontfix").unwrap();
+
+        issues
+            .label(&issue_id, &[bug_label.clone()], &signer)
+            .unwrap();
+        issues
+            .label(&issue_id, &[wontfix_label.clone()], &signer)
+            .unwrap();
+
+        let issue = issues.get(&issue_id).unwrap().unwrap();
+        let labels = issue.labels();
+
+        assert!(labels.contains(&bug_label));
+        assert!(labels.contains(&wontfix_label));
+    }
+
+    #[test]
+    fn test_issue_comment() {
+        let tmp = tempfile::tempdir().unwrap();
+        let (_, signer, project) = test::setup::context(&tmp);
+        let store = Store::open(*signer.public_key(), &project).unwrap();
+        let issues = store.issues();
+        let now = Timestamp::now();
+        let author = *signer.public_key();
+        let issue_id = issues
+            .create("My first issue", "Blah blah blah.", &[], &signer)
+            .unwrap();
+
+        issues.comment(&issue_id, "Ho ho ho.", &signer).unwrap();
+        issues.comment(&issue_id, "Ha ha ha.", &signer).unwrap();
+
+        let issue = issues.get(&issue_id).unwrap().unwrap();
+        let c1 = &issue.comments()[0];
+        let c2 = &issue.comments()[1];
+
+        assert_eq!(&c1.body, "Ho ho ho.");
+        assert_eq!(c1.author.id(), &author);
+        assert_eq!(&c2.body, "Ha ha ha.");
+        assert_eq!(c2.author.id(), &author);
+        assert!(c1.timestamp >= now);
+    }
+
+    #[test]
+    fn test_issue_state_serde() {
+        assert_eq!(
+            serde_json::to_value(State::Open).unwrap(),
+            serde_json::json!({ "status": "open" })
+        );
+
+        assert_eq!(
+            serde_json::to_value(State::Closed {
+                reason: CloseReason::Solved
+            })
+            .unwrap(),
+            serde_json::json!({ "status": "closed", "reason": "solved" })
+        );
+    }
+
+    #[test]
+    fn test_issue_all() {
+        let tmp = tempfile::tempdir().unwrap();
+        let (_, signer, project) = test::setup::context(&tmp);
+        let store = Store::open(*signer.public_key(), &project).unwrap();
+        let issues = store.issues();
+        let author = store.author();
+
+        let contents =
+            events::create(&author, "First", "Blah blah.", Timestamp::new(0), &[]).unwrap();
+        issues
+            .store
+            .create("Create issue", contents, &signer)
+            .unwrap();
+
+        let contents =
+            events::create(&author, "Second", "Blah blah.", Timestamp::new(1), &[]).unwrap();
+        issues
+            .store
+            .create("Create issue", contents, &signer)
+            .unwrap();
+
+        let contents =
+            events::create(&author, "Third", "Blah blah.", Timestamp::new(2), &[]).unwrap();
+        issues
+            .store
+            .create("Create issue", contents, &signer)
+            .unwrap();
+
+        let issues = issues.all().unwrap();
+        assert_eq!(issues.len(), 3);
+
+        // Issues are sorted by timestamp.
+        assert_eq!(issues[0].1.title(), "First");
+        assert_eq!(issues[1].1.title(), "Second");
+        assert_eq!(issues[2].1.title(), "Third");
+    }
+}
diff --git a/radicle/src/cob/label.rs b/radicle/src/cob/automerge/label.rs
similarity index 93%
rename from radicle/src/cob/label.rs
rename to radicle/src/cob/automerge/label.rs
index 15642f8d..59709c75 100644
--- a/radicle/src/cob/label.rs
+++ b/radicle/src/cob/automerge/label.rs
@@ -7,11 +7,12 @@ use automerge::{Automerge, ObjType};
 use once_cell::sync::Lazy;
 use serde::{Deserialize, Serialize};
 
-use crate::cob::doc::Document;
-use crate::cob::shared::*;
-use crate::cob::store::{Error, FromHistory, Store};
-use crate::cob::transaction::TransactionError;
-use crate::cob::{Contents, History, ObjectId, TypeName};
+use crate::cob::automerge::doc::Document;
+use crate::cob::automerge::shared::FromHistory;
+use crate::cob::automerge::store::{Error, Store};
+use crate::cob::automerge::transaction::TransactionError;
+use crate::cob::common::*;
+use crate::cob::{Contents, History, ObjectId, Timestamp, TypeName};
 use crate::prelude::*;
 
 pub static TYPENAME: Lazy<TypeName> =
diff --git a/radicle/src/cob/automerge/patch.rs b/radicle/src/cob/automerge/patch.rs
new file mode 100644
index 00000000..52d0421c
--- /dev/null
+++ b/radicle/src/cob/automerge/patch.rs
@@ -0,0 +1,835 @@
+#![allow(clippy::too_many_arguments)]
+use std::collections::{HashMap, HashSet};
+use std::convert::TryFrom;
+use std::ops::{ControlFlow, Deref};
+use std::sync::Arc;
+
+use automerge::transaction::Transactable;
+use automerge::{Automerge, AutomergeError, ObjType, ScalarValue, Value};
+use nonempty::NonEmpty;
+
+use crate::cob::automerge::doc::{Document, DocumentError};
+use crate::cob::automerge::shared;
+use crate::cob::automerge::shared::*;
+use crate::cob::automerge::store::{Error, Store};
+use crate::cob::automerge::transaction::{Transaction, TransactionError};
+use crate::cob::automerge::value::{FromValue, ValueError};
+use crate::cob::common::*;
+use crate::cob::{Contents, History, ObjectId, Timestamp, TypeName};
+use crate::git;
+use crate::prelude::*;
+
+// Re-export generic patch.
+pub use crate::cob::patch::*;
+
+impl TryFrom<Document<'_>> for Patch {
+    type Error = DocumentError;
+
+    fn try_from(doc: Document) -> Result<Self, Self::Error> {
+        let obj_id = doc.get_id(automerge::ObjId::Root, "patch")?;
+        let title = doc.get(&obj_id, "title")?;
+        let author = doc.get(&obj_id, "author")?;
+        let state = doc.get(&obj_id, "state")?;
+        let target = doc.get(&obj_id, "target")?;
+        let timestamp = doc.get(&obj_id, "timestamp")?;
+        let revisions = doc.list(&obj_id, "revisions", lookup::revision)?;
+        let labels: HashSet<Label> = doc.keys(&obj_id, "labels")?;
+        let revisions =
+            NonEmpty::from_vec(revisions).ok_or(DocumentError::EmptyList("revisions"))?;
+        let author: Author = Author::new(author);
+
+        Ok(Self {
+            author,
+            title,
+            state,
+            target,
+            labels,
+            revisions,
+            timestamp,
+        })
+    }
+}
+
+pub struct PatchStore<'a> {
+    store: Store<'a, Patch>,
+}
+
+impl<'a> Deref for PatchStore<'a> {
+    type Target = Store<'a, Patch>;
+
+    fn deref(&self) -> &Self::Target {
+        &self.store
+    }
+}
+
+impl<'a> PatchStore<'a> {
+    /// Create a new patch store.
+    pub fn new(store: Store<'a, Patch>) -> Self {
+        Self { store }
+    }
+
+    /// Get a patch by id.
+    pub fn get(&self, id: &ObjectId) -> Result<Option<Patch>, Error> {
+        self.store.get(id)
+    }
+
+    /// Create a patch.
+    pub fn create<G: Signer>(
+        &self,
+        title: &str,
+        description: &str,
+        target: MergeTarget,
+        base: impl Into<git::Oid>,
+        oid: impl Into<git::Oid>,
+        labels: &[Label],
+        signer: &G,
+    ) -> Result<PatchId, Error> {
+        let author = self.author();
+        let timestamp = Timestamp::now();
+        let revision = Revision::new(
+            author.clone(),
+            base.into(),
+            oid.into(),
+            description.to_owned(),
+            timestamp,
+        );
+        let contents = events::create(&author, title, &revision, target, timestamp, labels)?;
+        let cob = self.store.create("Create patch", contents, signer)?;
+
+        Ok(*cob.id())
+    }
+
+    /// Comment on a patch.
+    pub fn comment<G: Signer>(
+        &self,
+        patch_id: &PatchId,
+        revision_ix: RevisionIx,
+        body: &str,
+        signer: &G,
+    ) -> Result<(), Error> {
+        let author = self.author();
+        let mut patch = self.store.get_raw(patch_id)?;
+        let timestamp = Timestamp::now();
+        let changes = events::comment(&mut patch, revision_ix, &author, body, timestamp)?;
+
+        self.store
+            .update(*patch_id, "Add comment", changes, signer)?;
+
+        Ok(())
+    }
+
+    /// Update a patch with new code. Creates a new revision.
+    pub fn update<G: Signer>(
+        &self,
+        patch_id: &PatchId,
+        comment: impl ToString,
+        base: impl Into<git::Oid>,
+        oid: impl Into<git::Oid>,
+        signer: &G,
+    ) -> Result<RevisionIx, Error> {
+        let author = self.author();
+        let timestamp = Timestamp::now();
+        let revision = Revision::new(
+            author,
+            base.into(),
+            oid.into(),
+            comment.to_string(),
+            timestamp,
+        );
+
+        let mut patch = self.get_raw(patch_id)?;
+        let (revision_ix, changes) = events::update(&mut patch, revision)?;
+
+        self.store
+            .update(*patch_id, "Update patch", changes, signer)?;
+
+        Ok(revision_ix)
+    }
+
+    /// Reply to a patch comment.
+    pub fn reply<G: Signer>(
+        &self,
+        patch_id: &PatchId,
+        revision_ix: RevisionIx,
+        comment_id: CommentId,
+        reply: &str,
+        signer: &G,
+    ) -> Result<(), Error> {
+        let author = self.author();
+        let mut patch = self.get_raw(patch_id)?;
+        let changes = events::reply(
+            &mut patch,
+            revision_ix,
+            comment_id,
+            &author,
+            reply,
+            Timestamp::now(),
+        )?;
+
+        self.store.update(*patch_id, "Reply", changes, signer)?;
+
+        Ok(())
+    }
+
+    /// Review a patch revision.
+    pub fn review<G: Signer>(
+        &self,
+        patch_id: &PatchId,
+        revision_ix: RevisionIx,
+        verdict: Option<Verdict>,
+        comment: impl Into<String>,
+        inline: Vec<CodeComment>,
+        signer: &G,
+    ) -> Result<(), Error> {
+        let timestamp = Timestamp::now();
+        let review = Review::new(self.author(), verdict, comment, inline, timestamp);
+
+        let mut patch = self.get_raw(patch_id)?;
+        let (_, changes) = events::review(&mut patch, revision_ix, review)?;
+
+        self.store
+            .update(*patch_id, "Review patch", changes, signer)?;
+
+        Ok(())
+    }
+
+    /// Merge a patch revision.
+    pub fn merge<G: Signer>(
+        &self,
+        patch_id: &PatchId,
+        revision_ix: RevisionIx,
+        commit: git::Oid,
+        signer: &G,
+    ) -> Result<Merge, Error> {
+        let timestamp = Timestamp::now();
+        let merge = Merge {
+            node: *signer.public_key(),
+            commit,
+            timestamp,
+        };
+
+        let mut patch = self.get_raw(patch_id)?;
+        let changes = events::merge(&mut patch, revision_ix, &merge)?;
+
+        self.store
+            .update(*patch_id, "Merge revision", changes, signer)?;
+
+        Ok(merge)
+    }
+
+    /// Get the patch count.
+    pub fn count(&self) -> Result<usize, Error> {
+        let cobs = self.store.list()?;
+
+        Ok(cobs.len())
+    }
+
+    /// Get all patches for this project.
+    pub fn all(&self) -> Result<Vec<(PatchId, Patch)>, Error> {
+        let mut patches = self.store.list()?;
+        patches.sort_by_key(|(_, p)| p.timestamp);
+
+        Ok(patches)
+    }
+
+    /// Get proposed patches.
+    pub fn proposed(&self) -> Result<impl Iterator<Item = (PatchId, Patch)>, Error> {
+        let all = self.all()?;
+
+        Ok(all.into_iter().filter(|(_, p)| p.is_proposed()))
+    }
+
+    /// Get patches proposed by the given key.
+    pub fn proposed_by<'b>(
+        &'b self,
+        who: &'b PublicKey,
+    ) -> Result<impl Iterator<Item = (PatchId, Patch)> + '_, Error> {
+        Ok(self.proposed()?.filter(move |(_, p)| p.author.id() == who))
+    }
+}
+
+impl From<State> for ScalarValue {
+    fn from(state: State) -> Self {
+        match state {
+            State::Proposed => ScalarValue::from("proposed"),
+            State::Draft => ScalarValue::from("draft"),
+            State::Archived => ScalarValue::from("archived"),
+        }
+    }
+}
+
+impl<'a> FromValue<'a> for State {
+    fn from_value(value: Value<'a>) -> Result<Self, ValueError> {
+        let state = value.to_str().ok_or(ValueError::InvalidType)?;
+
+        match state {
+            "proposed" => Ok(Self::Proposed),
+            "draft" => Ok(Self::Draft),
+            "archived" => Ok(Self::Archived),
+            _ => Err(ValueError::InvalidValue(value.to_string())),
+        }
+    }
+}
+
+impl Revision {
+    /// Put this object into an automerge document.
+    fn put<'a>(
+        &self,
+        mut tx: impl AsMut<automerge::transaction::Transaction<'a>>,
+        id: &automerge::ObjId,
+    ) -> Result<(), AutomergeError> {
+        assert!(
+            self.merges.is_empty(),
+            "Cannot put revision with non-empty merges"
+        );
+        assert!(
+            self.reviews.is_empty(),
+            "Cannot put revision with non-empty reviews"
+        );
+        assert!(
+            self.discussion.is_empty(),
+            "Cannot put revision with non-empty discussion"
+        );
+        let tx = tx.as_mut();
+
+        tx.put(id, "id", self.id.to_string())?;
+        tx.put(id, "oid", self.oid.to_string())?;
+        tx.put(id, "base", self.base.to_string())?;
+
+        self.comment.put(tx, id)?;
+
+        tx.put_object(id, "discussion", ObjType::List)?;
+        tx.put_object(id, "reviews", ObjType::Map)?;
+        tx.put_object(id, "merges", ObjType::List)?;
+        tx.put(id, "timestamp", self.timestamp)?;
+
+        Ok(())
+    }
+}
+
+impl From<Verdict> for ScalarValue {
+    fn from(verdict: Verdict) -> Self {
+        #[allow(clippy::unwrap_used)]
+        let s = serde_json::to_string(&verdict).unwrap(); // Cannot fail.
+        ScalarValue::from(s)
+    }
+}
+
+impl<'a> FromValue<'a> for Verdict {
+    fn from_value(value: Value) -> Result<Self, ValueError> {
+        let verdict = value.to_str().ok_or(ValueError::InvalidType)?;
+        serde_json::from_str(verdict).map_err(|e| ValueError::Other(Arc::new(e)))
+    }
+}
+
+impl Review {
+    /// Put this object into an automerge document.
+    fn put<'a>(
+        &self,
+        mut tx: impl AsMut<automerge::transaction::Transaction<'a>>,
+        id: &automerge::ObjId,
+    ) -> Result<(), AutomergeError> {
+        assert!(
+            self.inline.is_empty(),
+            "Cannot put review with non-empty inline comments"
+        );
+        let tx = tx.as_mut();
+
+        tx.put(id, "author", &self.author)?;
+        tx.put(
+            id,
+            "verdict",
+            if let Some(v) = self.verdict {
+                v.into()
+            } else {
+                ScalarValue::Null
+            },
+        )?;
+
+        self.comment.put(tx, id)?;
+
+        tx.put_object(id, "inline", ObjType::List)?;
+        tx.put(id, "timestamp", self.timestamp)?;
+
+        Ok(())
+    }
+}
+
+impl FromHistory for Patch {
+    fn type_name() -> &'static TypeName {
+        &TYPENAME
+    }
+
+    /// Create a patch from an automerge history.
+    fn from_history(history: &History) -> Result<Self, Error> {
+        let doc = history.traverse(Automerge::new(), |mut doc, entry| {
+            let bytes = entry.contents();
+            match automerge::Change::from_bytes(bytes.clone()) {
+                Ok(change) => {
+                    doc.apply_changes([change]).ok();
+                }
+                Err(_err) => {
+                    // Ignore
+                }
+            }
+            ControlFlow::Continue(doc)
+        });
+        let patch = Patch::try_from(Document::new(&doc))?;
+
+        Ok(patch)
+    }
+}
+
+mod lookup {
+    use super::*;
+
+    pub fn revision(
+        doc: Document,
+        revision_id: &automerge::ObjId,
+    ) -> Result<Revision, DocumentError> {
+        let comment_id = doc.get_id(revision_id, "comment")?;
+        let reviews_id = doc.get_id(revision_id, "reviews")?;
+        let id = doc.get(revision_id, "id")?;
+        let base = doc.get(revision_id, "base")?;
+        let oid = doc.get(revision_id, "oid")?;
+        let timestamp = doc.get(revision_id, "timestamp")?;
+        let merges: Vec<Merge> = doc.list(revision_id, "merges", self::merge)?;
+
+        // Discussion.
+        let comment = shared::lookup::comment(doc, &comment_id)?;
+        let discussion: Discussion = doc.list(revision_id, "discussion", shared::lookup::thread)?;
+
+        // Reviews.
+        let mut reviews: HashMap<NodeId, Review> = HashMap::new();
+        for key in (*doc).keys(&reviews_id) {
+            let review_id = doc.get_id(&reviews_id, key)?;
+            let review = self::review(doc, &review_id)?;
+
+            reviews.insert(*review.author.id(), review);
+        }
+
+        Ok(Revision {
+            id,
+            base,
+            oid,
+            comment,
+            discussion,
+            reviews,
+            merges,
+            changeset: (),
+            timestamp,
+        })
+    }
+
+    pub fn merge(doc: Document, obj_id: &automerge::ObjId) -> Result<Merge, DocumentError> {
+        let node = doc.get(obj_id, "peer")?;
+        let commit = doc.get(obj_id, "commit")?;
+        let timestamp = doc.get(obj_id, "timestamp")?;
+
+        Ok(Merge {
+            node,
+            commit,
+            timestamp,
+        })
+    }
+
+    pub fn review(doc: Document, obj_id: &automerge::ObjId) -> Result<Review, DocumentError> {
+        let author = doc.get(obj_id, "author")?;
+        let verdict = doc.get(obj_id, "verdict")?;
+        let timestamp = doc.get(obj_id, "timestamp")?;
+        let comment = doc.lookup(obj_id, "comment", shared::lookup::thread)?;
+        let inline = vec![];
+
+        Ok(Review {
+            author: Author::new(author),
+            comment,
+            verdict,
+            inline,
+            timestamp,
+        })
+    }
+}
+
+/// Patch events.
+mod events {
+    use super::*;
+    use automerge::{
+        transaction::{CommitOptions, Transactable},
+        ObjId,
+    };
+
+    pub fn create(
+        author: &Author,
+        title: &str,
+        revision: &Revision,
+        target: MergeTarget,
+        timestamp: Timestamp,
+        labels: &[Label],
+    ) -> Result<Contents, TransactionError> {
+        let title = title.trim();
+        if title.is_empty() {
+            return Err(TransactionError::InvalidValue("title"));
+        }
+
+        let mut doc = Automerge::new();
+        let _patch = doc
+            .transact_with::<_, _, TransactionError, _, ()>(
+                |_| CommitOptions::default().with_message("Create patch".to_owned()),
+                |tx| {
+                    let mut tx = Transaction::new(tx);
+                    let patch_id = tx.put_object(ObjId::Root, "patch", ObjType::Map)?;
+
+                    tx.put(&patch_id, "title", title)?;
+                    tx.put(&patch_id, "author", author)?;
+                    tx.put(&patch_id, "state", State::Proposed)?;
+                    tx.put(&patch_id, "target", target)?;
+                    tx.put(&patch_id, "timestamp", timestamp)?;
+
+                    let labels_id = tx.put_object(&patch_id, "labels", ObjType::Map)?;
+                    for label in labels {
+                        tx.put(&labels_id, label.name().trim(), true)?;
+                    }
+
+                    let revisions_id = tx.put_object(&patch_id, "revisions", ObjType::List)?;
+                    let revision_id = tx.insert_object(&revisions_id, 0, ObjType::Map)?;
+
+                    revision.put(tx, &revision_id)?;
+
+                    Ok(patch_id)
+                },
+            )
+            .map_err(|failure| failure.error)?
+            .result;
+
+        Ok(doc.save_incremental())
+    }
+
+    pub fn comment(
+        patch: &mut Automerge,
+        revision_ix: RevisionIx,
+        author: &Author,
+        body: &str,
+        timestamp: Timestamp,
+    ) -> Result<Contents, TransactionError> {
+        let _comment = patch
+            .transact_with::<_, _, TransactionError, _, ()>(
+                |_| CommitOptions::default().with_message("Add comment".to_owned()),
+                |t| {
+                    let mut tx = Transaction::new(t);
+                    let (_, obj_id) = tx.get(ObjId::Root, "patch")?;
+                    let (_, revisions_id) = tx.get(&obj_id, "revisions")?;
+                    let (_, revision_id) = tx.get(&revisions_id, revision_ix)?;
+                    let (_, discussion_id) = tx.get(&revision_id, "discussion")?;
+
+                    let length = tx.length(&discussion_id);
+                    let comment = tx.insert_object(&discussion_id, length, ObjType::Map)?;
+
+                    tx.put(&comment, "author", author)?;
+                    tx.put(&comment, "body", body.trim())?;
+                    tx.put(&comment, "timestamp", timestamp)?;
+                    tx.put_object(&comment, "replies", ObjType::List)?;
+                    tx.put_object(&comment, "reactions", ObjType::Map)?;
+
+                    Ok(comment)
+                },
+            )
+            .map_err(|failure| failure.error)?
+            .result;
+
+        #[allow(clippy::unwrap_used)]
+        let change = patch.get_last_local_change().unwrap().raw_bytes().to_vec();
+
+        Ok(change)
+    }
+
+    pub fn update(
+        patch: &mut Automerge,
+        revision: Revision,
+    ) -> Result<(RevisionIx, Contents), TransactionError> {
+        let revision_ix = patch
+            .transact_with::<_, _, TransactionError, _, ()>(
+                |_| CommitOptions::default().with_message("Merge revision".to_owned()),
+                |tx| {
+                    let mut tx = Transaction::new(tx);
+                    let (_, obj_id) = tx.get(ObjId::Root, "patch")?;
+                    let (_, revisions_id) = tx.get(&obj_id, "revisions")?;
+
+                    let ix = tx.length(&revisions_id);
+                    let revision_id = tx.insert_object(&revisions_id, ix, ObjType::Map)?;
+
+                    revision.put(tx, &revision_id)?;
+
+                    Ok(ix)
+                },
+            )
+            .map_err(|failure| failure.error)?
+            .result;
+
+        #[allow(clippy::unwrap_used)]
+        let change = patch.get_last_local_change().unwrap().raw_bytes().to_vec();
+
+        Ok((revision_ix, change))
+    }
+
+    pub fn reply(
+        patch: &mut Automerge,
+        revision_ix: RevisionIx,
+        comment_id: CommentId,
+        author: &Author,
+        body: &str,
+        timestamp: Timestamp,
+    ) -> Result<Contents, TransactionError> {
+        patch
+            .transact_with::<_, _, TransactionError, _, ()>(
+                |_| CommitOptions::default().with_message("Reply".to_owned()),
+                |tx| {
+                    let mut tx = Transaction::new(tx);
+                    let (_, obj_id) = tx.get(ObjId::Root, "patch")?;
+                    let (_, revisions_id) = tx.get(&obj_id, "revisions")?;
+                    let (_, revision_id) = tx.get(&revisions_id, revision_ix)?;
+                    let (_, discussion_id) = tx.get(&revision_id, "discussion")?;
+                    let (_, comment_id) = tx.get(&discussion_id, usize::from(comment_id))?;
+                    let (_, replies_id) = tx.get(&comment_id, "replies")?;
+
+                    let length = tx.length(&replies_id);
+                    let reply = tx.insert_object(&replies_id, length, ObjType::Map)?;
+
+                    // Nb. Replies don't themselves have replies.
+                    tx.put(&reply, "author", author)?;
+                    tx.put(&reply, "body", body.trim())?;
+                    tx.put(&reply, "timestamp", timestamp)?;
+                    tx.put_object(&reply, "reactions", ObjType::Map)?;
+
+                    Ok(())
+                },
+            )
+            .map_err(|failure| failure.error)?;
+
+        #[allow(clippy::unwrap_used)]
+        let change = patch.get_last_local_change().unwrap().raw_bytes().to_vec();
+
+        Ok(change)
+    }
+
+    pub fn review(
+        patch: &mut Automerge,
+        revision_ix: RevisionIx,
+        review: Review,
+    ) -> Result<((), Contents), TransactionError> {
+        patch
+            .transact_with::<_, _, TransactionError, _, ()>(
+                |_| CommitOptions::default().with_message("Review patch".to_owned()),
+                |tx| {
+                    let mut tx = Transaction::new(tx);
+                    let (_, obj_id) = tx.get(ObjId::Root, "patch")?;
+                    let (_, revisions_id) = tx.get(&obj_id, "revisions")?;
+                    let (_, revision_id) = tx.get(&revisions_id, revision_ix)?;
+                    let (_, reviews_id) = tx.get(&revision_id, "reviews")?;
+
+                    let review_id =
+                        tx.put_object(&reviews_id, review.author.id.to_human(), ObjType::Map)?;
+
+                    review.put(tx, &review_id)?;
+
+                    Ok(())
+                },
+            )
+            .map_err(|failure| failure.error)?;
+
+        #[allow(clippy::unwrap_used)]
+        let change = patch.get_last_local_change().unwrap().raw_bytes().to_vec();
+
+        Ok(((), change))
+    }
+
+    pub fn merge(
+        patch: &mut Automerge,
+        revision_ix: RevisionIx,
+        merge: &Merge,
+    ) -> Result<Contents, TransactionError> {
+        patch
+            .transact_with::<_, _, TransactionError, _, ()>(
+                |_| CommitOptions::default().with_message("Merge revision".to_owned()),
+                |tx| {
+                    let mut tx = Transaction::new(tx);
+                    let (_, obj_id) = tx.get(ObjId::Root, "patch")?;
+                    let (_, revisions_id) = tx.get(&obj_id, "revisions")?;
+                    let (_, revision_id) = tx.get(&revisions_id, revision_ix)?;
+                    let (_, merges_id) = tx.get(&revision_id, "merges")?;
+
+                    let length = tx.length(&merges_id);
+                    let merge_id = tx.insert_object(&merges_id, length, ObjType::Map)?;
+
+                    tx.put(&merge_id, "peer", merge.node.to_string())?;
+                    tx.put(&merge_id, "commit", merge.commit.to_string())?;
+                    tx.put(&merge_id, "timestamp", merge.timestamp)?;
+
+                    Ok(())
+                },
+            )
+            .map_err(|failure| failure.error)?;
+
+        #[allow(clippy::unwrap_used)]
+        let change = patch.get_last_local_change().unwrap().raw_bytes().to_vec();
+
+        Ok(change)
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use std::str::FromStr;
+
+    use super::*;
+    use crate::test;
+
+    #[test]
+    fn test_patch_create_and_get() {
+        let tmp = tempfile::tempdir().unwrap();
+        let (_, signer, project) = test::setup::context(&tmp);
+        let store = Store::open(*signer.public_key(), &project).unwrap();
+        let patches = store.patches();
+        let author = *signer.public_key();
+        let timestamp = Timestamp::now();
+        let target = MergeTarget::Delegates;
+        let oid = git::Oid::from(git2::Oid::zero());
+        let base = git::Oid::from_str("cb18e95ada2bb38aadd8e6cef0963ce37a87add3").unwrap();
+        let patch_id = patches
+            .create(
+                "My first patch",
+                "Blah blah blah.",
+                target,
+                base,
+                oid,
+                &[],
+                &signer,
+            )
+            .unwrap();
+        let patch = patches.get(&patch_id).unwrap().unwrap();
+
+        assert_eq!(&patch.title, "My first patch");
+        assert_eq!(patch.author.id(), &author);
+        assert_eq!(patch.state, State::Proposed);
+        assert!(patch.timestamp >= timestamp);
+
+        let revision = patch.revisions.head;
+
+        assert_eq!(revision.author(), &store.author());
+        assert_eq!(revision.comment.body, "Blah blah blah.");
+        assert_eq!(revision.discussion.len(), 0);
+        assert_eq!(revision.oid, oid);
+        assert_eq!(revision.base, base);
+        assert!(revision.reviews.is_empty());
+        assert!(revision.merges.is_empty());
+    }
+
+    #[test]
+    fn test_patch_merge() {
+        let tmp = tempfile::tempdir().unwrap();
+        let (_, signer, project) = test::setup::context(&tmp);
+        let store = Store::open(*signer.public_key(), &project).unwrap();
+        let patches = store.patches();
+        let target = MergeTarget::Delegates;
+        let oid = git::Oid::from(git2::Oid::zero());
+        let base = git::Oid::from_str("cb18e95ada2bb38aadd8e6cef0963ce37a87add3").unwrap();
+        let patch_id = patches
+            .create(
+                "My first patch",
+                "Blah blah blah.",
+                target,
+                base,
+                oid,
+                &[],
+                &signer,
+            )
+            .unwrap();
+
+        let _merge = patches.merge(&patch_id, 0, base, &signer).unwrap();
+        let patch = patches.get(&patch_id).unwrap().unwrap();
+        let merges = patch.revisions.head.merges;
+
+        assert_eq!(merges.len(), 1);
+        assert_eq!(merges[0].node, *signer.public_key());
+        assert_eq!(merges[0].commit, base);
+    }
+
+    #[test]
+    fn test_patch_review() {
+        let tmp = tempfile::tempdir().unwrap();
+        let (_, signer, project) = test::setup::context(&tmp);
+        let store = Store::open(*signer.public_key(), &project).unwrap();
+        let patches = store.patches();
+        let whoami = store.author();
+        let target = MergeTarget::Delegates;
+        let base = git::Oid::from_str("cb18e95ada2bb38aadd8e6cef0963ce37a87add3").unwrap();
+        let rev_oid = git::Oid::from_str("518d5069f94c03427f694bb494ac1cd7d1339380").unwrap();
+        let patch_id = patches
+            .create(
+                "My first patch",
+                "Blah blah blah.",
+                target,
+                base,
+                rev_oid,
+                &[],
+                &signer,
+            )
+            .unwrap();
+
+        patches
+            .review(&patch_id, 0, Some(Verdict::Accept), "LGTM", vec![], &signer)
+            .unwrap();
+        let patch = patches.get(&patch_id).unwrap().unwrap();
+        let reviews = patch.revisions.head.reviews;
+        assert_eq!(reviews.len(), 1);
+
+        let review = reviews.get(whoami.id()).unwrap();
+        assert_eq!(review.author.id(), whoami.id());
+        assert_eq!(review.verdict, Some(Verdict::Accept));
+        assert_eq!(review.comment.body.as_str(), "LGTM");
+    }
+
+    #[test]
+    fn test_patch_update() {
+        let tmp = tempfile::tempdir().unwrap();
+        let (_, signer, project) = test::setup::context(&tmp);
+        let store = Store::open(*signer.public_key(), &project).unwrap();
+        let patches = store.patches();
+        let target = MergeTarget::Delegates;
+        let base = git::Oid::from_str("af08e95ada2bb38aadd8e6cef0963ce37a87add3").unwrap();
+        let rev0_oid = git::Oid::from_str("518d5069f94c03427f694bb494ac1cd7d1339380").unwrap();
+        let rev1_oid = git::Oid::from_str("cb18e95ada2bb38aadd8e6cef0963ce37a87add3").unwrap();
+        let patch_id = patches
+            .create(
+                "My first patch",
+                "Blah blah blah.",
+                target,
+                base,
+                rev0_oid,
+                &[],
+                &signer,
+            )
+            .unwrap();
+
+        let patch = patches.get(&patch_id).unwrap().unwrap();
+        assert_eq!(patch.description(), "Blah blah blah.");
+        assert_eq!(patch.version(), 0);
+
+        let revision_id = patches
+            .update(&patch_id, "I've made changes.", base, rev1_oid, &signer)
+            .unwrap();
+
+        assert_eq!(revision_id, 1);
+
+        let patch = patches.get(&patch_id).unwrap().unwrap();
+        assert_eq!(patch.description(), "I've made changes.");
+
+        assert_eq!(patch.revisions.len(), 2);
+        assert_eq!(patch.version(), 1);
+
+        let (id, revision) = patch.latest();
+
+        assert_eq!(id, 1);
+        assert_eq!(revision.oid, rev1_oid);
+        assert_eq!(revision.description(), "I've made changes.");
+    }
+}
diff --git a/radicle/src/cob/automerge/shared.rs b/radicle/src/cob/automerge/shared.rs
new file mode 100644
index 00000000..e1e4aefb
--- /dev/null
+++ b/radicle/src/cob/automerge/shared.rs
@@ -0,0 +1,185 @@
+#![allow(clippy::large_enum_variant)]
+use std::borrow::Borrow;
+use std::collections::HashMap;
+use std::str::FromStr;
+
+use automerge::transaction::Transactable;
+use automerge::{AutomergeError, ObjType, ScalarValue};
+use serde::{Deserialize, Serialize};
+
+use crate::cob::automerge::doc::{Document, DocumentError};
+use crate::cob::automerge::store::Error;
+use crate::cob::automerge::value::{FromValue, Value, ValueError};
+use crate::cob::common::*;
+use crate::cob::{History, TypeName};
+
+/// A type that can be materialized from an event history.
+/// All collaborative objects implement this trait.
+pub trait FromHistory: Sized {
+    /// The object type name.
+    fn type_name() -> &'static TypeName;
+    /// Create an object from a history.
+    fn from_history(history: &History) -> Result<Self, Error>;
+}
+
+impl<'a> FromValue<'a> for Color {
+    fn from_value(val: Value<'a>) -> Result<Self, ValueError> {
+        let color = String::from_value(val)?;
+        let color = Self::from_str(&color).map_err(|_| ValueError::InvalidValue(color))?;
+
+        Ok(color)
+    }
+}
+
+impl Serialize for Color {
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: serde::ser::Serializer,
+    {
+        let s = self.to_string();
+        serializer.serialize_str(&s)
+    }
+}
+
+impl<'a> Deserialize<'a> for Color {
+    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+    where
+        D: serde::de::Deserializer<'a>,
+    {
+        let color = String::deserialize(deserializer)?;
+        Self::from_str(&color).map_err(serde::de::Error::custom)
+    }
+}
+
+impl From<&Author> for ScalarValue {
+    fn from(author: &Author) -> Self {
+        ScalarValue::from(author.id.to_human())
+    }
+}
+
+impl Comment<()> {
+    pub(super) fn put(
+        &self,
+        tx: &mut automerge::transaction::Transaction,
+        id: &automerge::ObjId,
+    ) -> Result<(), AutomergeError> {
+        let comment_id = tx.put_object(id, "comment", ObjType::Map)?;
+
+        assert!(
+            self.reactions.is_empty(),
+            "Cannot put comment with non-empty reactions"
+        );
+
+        tx.put(&comment_id, "body", self.body.trim())?;
+        tx.put(&comment_id, "author", self.author.id().to_string())?;
+        tx.put(&comment_id, "timestamp", self.timestamp)?;
+        tx.put_object(&comment_id, "reactions", ObjType::Map)?;
+
+        Ok(())
+    }
+}
+
+impl Comment<Replies> {
+    pub(super) fn put(
+        &self,
+        tx: &mut automerge::transaction::Transaction,
+        id: &automerge::ObjId,
+    ) -> Result<(), AutomergeError> {
+        let comment_id = tx.put_object(id, "comment", ObjType::Map)?;
+
+        assert!(
+            self.reactions.is_empty(),
+            "Cannot put comment with non-empty reactions"
+        );
+        assert!(
+            self.replies.is_empty(),
+            "Cannot put comment with non-empty replies"
+        );
+
+        tx.put(&comment_id, "body", self.body.trim())?;
+        tx.put(&comment_id, "author", self.author.id().to_string())?;
+        tx.put(&comment_id, "timestamp", self.timestamp)?;
+        tx.put_object(&comment_id, "reactions", ObjType::Map)?;
+        tx.put_object(&comment_id, "replies", ObjType::List)?;
+
+        Ok(())
+    }
+}
+
+impl From<Timestamp> for ScalarValue {
+    fn from(ts: Timestamp) -> Self {
+        ScalarValue::Timestamp(ts.as_secs() as i64)
+    }
+}
+
+impl<'a> FromValue<'a> for Timestamp {
+    fn from_value(val: Value<'a>) -> Result<Self, ValueError> {
+        if let Value::Scalar(scalar) = &val {
+            if let ScalarValue::Timestamp(ts) = scalar.borrow() {
+                return Ok(Self::new(*ts as u64));
+            }
+        }
+        Err(ValueError::InvalidValue(val.to_string()))
+    }
+}
+
+pub mod lookup {
+    use super::{Author, Comment, HashMap, Reaction, Replies};
+    use super::{Document, DocumentError};
+
+    pub fn comment(doc: Document, obj_id: &automerge::ObjId) -> Result<Comment<()>, DocumentError> {
+        let author = doc.get(obj_id, "author").map(Author::new)?;
+        let body = doc.get(obj_id, "body")?;
+        let timestamp = doc.get(obj_id, "timestamp")?;
+        let reactions: HashMap<Reaction, usize> = doc.map(obj_id, "reactions", |v| *v += 1)?;
+
+        Ok(Comment {
+            author,
+            body,
+            reactions,
+            replies: (),
+            timestamp,
+        })
+    }
+
+    pub fn thread(
+        doc: Document,
+        obj_id: &automerge::ObjId,
+    ) -> Result<Comment<Replies>, DocumentError> {
+        let comment = self::comment(doc, obj_id)?;
+        let replies = doc.list(obj_id, "replies", self::comment)?;
+
+        Ok(Comment {
+            author: comment.author,
+            body: comment.body,
+            reactions: comment.reactions,
+            replies,
+            timestamp: comment.timestamp,
+        })
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use super::*;
+
+    #[test]
+    fn test_color() {
+        let c = Color::from_str("#ffccaa").unwrap();
+        assert_eq!(c.to_string(), "#ffccaa".to_owned());
+        assert_eq!(serde_json::to_string(&c).unwrap(), "\"#ffccaa\"".to_owned());
+        assert_eq!(serde_json::from_str::<'_, Color>("\"#ffccaa\"").unwrap(), c);
+
+        let c = Color::from_str("#0000aa").unwrap();
+        assert_eq!(c.to_string(), "#0000aa".to_owned());
+
+        let c = Color::from_str("#aa0000").unwrap();
+        assert_eq!(c.to_string(), "#aa0000".to_owned());
+
+        let c = Color::from_str("#00aa00").unwrap();
+        assert_eq!(c.to_string(), "#00aa00".to_owned());
+
+        Color::from_str("#aa00").unwrap_err();
+        Color::from_str("#abc").unwrap_err();
+    }
+}
diff --git a/radicle/src/cob/store.rs b/radicle/src/cob/automerge/store.rs
similarity index 90%
rename from radicle/src/cob/store.rs
rename to radicle/src/cob/automerge/store.rs
index cf3f7fa7..1bccdf64 100644
--- a/radicle/src/cob/store.rs
+++ b/radicle/src/cob/automerge/store.rs
@@ -6,12 +6,13 @@ use std::ops::ControlFlow;
 use automerge::{Automerge, AutomergeError};
 
 use crate::cob;
-use crate::cob::doc::DocumentError;
-use crate::cob::shared::Author;
-use crate::cob::transaction::TransactionError;
+use crate::cob::automerge::doc::DocumentError;
+use crate::cob::automerge::shared::FromHistory;
+use crate::cob::automerge::transaction::TransactionError;
+use crate::cob::automerge::{issue, label, patch};
+use crate::cob::common::Author;
 use crate::cob::CollaborativeObject;
-use crate::cob::{issue, label, patch};
-use crate::cob::{Contents, Create, History, HistoryType, ObjectId, TypeName, Update};
+use crate::cob::{Contents, Create, HistoryType, ObjectId, TypeName, Update};
 use crate::crypto::PublicKey;
 use crate::git;
 use crate::identity::project;
@@ -39,15 +40,6 @@ pub enum Error {
     NotFound(TypeName, ObjectId),
 }
 
-/// A type that can be materialized from an event history.
-/// All collaborative objects implement this trait.
-pub trait FromHistory: Sized {
-    /// The object type name.
-    fn type_name() -> &'static TypeName;
-    /// Create an object from a history.
-    fn from_history(history: &History) -> Result<Self, Error>;
-}
-
 /// Storage for collaborative objects of a specific type `T` in a single project.
 pub struct Store<'a, T> {
     whoami: PublicKey,
diff --git a/radicle/src/cob/transaction.rs b/radicle/src/cob/automerge/transaction.rs
similarity index 97%
rename from radicle/src/cob/transaction.rs
rename to radicle/src/cob/automerge/transaction.rs
index f7aba565..0101dc3c 100644
--- a/radicle/src/cob/transaction.rs
+++ b/radicle/src/cob/automerge/transaction.rs
@@ -3,7 +3,7 @@ use std::ops::{Deref, DerefMut};
 use automerge::transaction::Transactable;
 use automerge::AutomergeError;
 
-use crate::cob::value::Value;
+use crate::cob::automerge::value::Value;
 
 /// Wraps an automerge transaction with additional functionality.
 #[derive(Debug)]
diff --git a/radicle/src/cob/value.rs b/radicle/src/cob/automerge/value.rs
similarity index 78%
rename from radicle/src/cob/value.rs
rename to radicle/src/cob/automerge/value.rs
index ee71c234..5372335f 100644
--- a/radicle/src/cob/value.rs
+++ b/radicle/src/cob/automerge/value.rs
@@ -4,6 +4,7 @@ use std::sync::Arc;
 
 pub use automerge::{ScalarValue, Value};
 
+use crate::cob::patch::*;
 use crate::git;
 use crate::prelude::*;
 
@@ -75,3 +76,22 @@ impl<'a> FromValue<'a> for String {
         val.into_string().map_err(|_| ValueError::InvalidType)
     }
 }
+
+impl<'a> FromValue<'a> for MergeTarget {
+    fn from_value(value: Value<'a>) -> Result<Self, ValueError> {
+        let state = value.to_str().ok_or(ValueError::InvalidType)?;
+
+        match state {
+            "delegates" => Ok(Self::Delegates),
+            _ => Err(ValueError::InvalidValue(value.to_string())),
+        }
+    }
+}
+
+impl From<MergeTarget> for ScalarValue {
+    fn from(target: MergeTarget) -> Self {
+        match target {
+            MergeTarget::Delegates => ScalarValue::from("delegates"),
+        }
+    }
+}
diff --git a/radicle/src/cob/common.rs b/radicle/src/cob/common.rs
new file mode 100644
index 00000000..dde69af5
--- /dev/null
+++ b/radicle/src/cob/common.rs
@@ -0,0 +1,223 @@
+use std::collections::HashMap;
+use std::fmt;
+use std::str::FromStr;
+use std::time::{SystemTime, UNIX_EPOCH};
+
+use serde::{Deserialize, Serialize};
+
+use crate::prelude::*;
+
+/// Author.
+#[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq)]
+pub struct Author {
+    pub id: NodeId,
+}
+
+impl Author {
+    pub fn new(id: NodeId) -> Self {
+        Self { id }
+    }
+
+    pub fn id(&self) -> &NodeId {
+        &self.id
+    }
+}
+
+#[derive(Debug, Default, Copy, Clone, PartialOrd, PartialEq, Ord, Eq, Serialize, Deserialize)]
+#[serde(transparent)]
+pub struct Timestamp {
+    seconds: u64,
+}
+
+impl Timestamp {
+    pub fn new(seconds: u64) -> Self {
+        Self { seconds }
+    }
+
+    pub fn now() -> Self {
+        #[allow(clippy::unwrap_used)] // Safe because Unix was already invented!
+        let duration = SystemTime::now().duration_since(UNIX_EPOCH).unwrap();
+
+        Self {
+            seconds: duration.as_secs(),
+        }
+    }
+
+    pub fn as_secs(&self) -> u64 {
+        self.seconds
+    }
+}
+
+impl std::ops::Add<u64> for Timestamp {
+    type Output = Self;
+
+    fn add(self, rhs: u64) -> Self::Output {
+        Self {
+            seconds: self.seconds + rhs,
+        }
+    }
+}
+
+#[derive(thiserror::Error, Debug)]
+pub enum ReactionError {
+    #[error("invalid reaction")]
+    InvalidReaction,
+}
+
+#[derive(Debug, PartialEq, Eq, PartialOrd, Ord, Hash, Copy, Clone, Serialize, Deserialize)]
+#[serde(transparent)]
+pub struct Reaction {
+    pub emoji: char,
+}
+
+impl Reaction {
+    pub fn new(emoji: char) -> Result<Self, ReactionError> {
+        if emoji.is_whitespace() || emoji.is_ascii() || emoji.is_alphanumeric() {
+            return Err(ReactionError::InvalidReaction);
+        }
+        Ok(Self { emoji })
+    }
+}
+
+impl FromStr for Reaction {
+    type Err = ReactionError;
+
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        let mut chars = s.chars();
+        let first = chars.next().ok_or(ReactionError::InvalidReaction)?;
+
+        // Reactions should not consist of more than a single emoji.
+        if chars.next().is_some() {
+            return Err(ReactionError::InvalidReaction);
+        }
+        Reaction::new(first)
+    }
+}
+
+#[derive(thiserror::Error, Debug)]
+pub enum LabelError {
+    #[error("invalid label name: `{0}`")]
+    InvalidName(String),
+}
+
+#[derive(Debug, PartialEq, Eq, Hash, Clone, Serialize, Deserialize)]
+#[serde(transparent)]
+pub struct Label(String);
+
+impl Label {
+    pub fn new(name: impl Into<String>) -> Result<Self, LabelError> {
+        let name = name.into();
+
+        if name.chars().any(|c| c.is_whitespace()) || name.is_empty() {
+            return Err(LabelError::InvalidName(name));
+        }
+        Ok(Self(name))
+    }
+
+    pub fn name(&self) -> &str {
+        self.0.as_str()
+    }
+}
+
+impl FromStr for Label {
+    type Err = LabelError;
+
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        Self::new(s)
+    }
+}
+
+impl From<Label> for String {
+    fn from(Label(name): Label) -> Self {
+        name
+    }
+}
+
+/// RGB color.
+#[derive(Debug, PartialEq, Eq, Hash, Clone)]
+pub struct Color(u32);
+
+#[derive(thiserror::Error, Debug)]
+pub enum ColorConversionError {
+    #[error("invalid format: expect '#rrggbb'")]
+    InvalidFormat,
+    #[error(transparent)]
+    ParseInt(#[from] std::num::ParseIntError),
+}
+
+impl fmt::Display for Color {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(f, "#{:06x}", self.0)
+    }
+}
+
+impl FromStr for Color {
+    type Err = ColorConversionError;
+
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        let hex = s.replace('#', "").to_lowercase();
+
+        if hex.chars().count() != 6 {
+            return Err(ColorConversionError::InvalidFormat);
+        }
+
+        match u32::from_str_radix(&hex, 16) {
+            Ok(n) => Ok(Color(n)),
+            Err(e) => Err(e.into()),
+        }
+    }
+}
+
+/// A discussion thread.
+pub type Discussion = Vec<Comment<Replies>>;
+
+/// Comment replies.
+pub type Replies = Vec<Comment>;
+
+/// Local id of a comment in an issue.
+#[derive(Debug, PartialEq, Eq, PartialOrd, Ord, Copy, Clone)]
+pub struct CommentId {
+    /// Represents the index of the comment in the thread,
+    /// with `0` being the top-level comment.
+    ix: usize,
+}
+
+impl CommentId {
+    /// Root comment.
+    pub const fn root() -> Self {
+        Self { ix: 0 }
+    }
+}
+
+impl From<usize> for CommentId {
+    fn from(ix: usize) -> Self {
+        Self { ix }
+    }
+}
+
+impl From<CommentId> for usize {
+    fn from(id: CommentId) -> Self {
+        id.ix
+    }
+}
+
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct Comment<R = ()> {
+    pub author: Author,
+    pub body: String,
+    pub reactions: HashMap<Reaction, usize>,
+    pub replies: R,
+    pub timestamp: Timestamp,
+}
+
+impl<R: Default> Comment<R> {
+    pub fn new(author: Author, body: String, timestamp: Timestamp) -> Self {
+        Self {
+            author,
+            body,
+            reactions: HashMap::default(),
+            replies: R::default(),
+            timestamp,
+        }
+    }
+}
diff --git a/radicle/src/cob/issue.rs b/radicle/src/cob/issue.rs
index 3dc1f874..3a23096e 100644
--- a/radicle/src/cob/issue.rs
+++ b/radicle/src/cob/issue.rs
@@ -1,21 +1,11 @@
-#![allow(clippy::large_enum_variant)]
 use std::collections::{HashMap, HashSet};
-use std::convert::TryFrom;
-use std::ops::ControlFlow;
 use std::str::FromStr;
 
-use automerge::{Automerge, ObjType, ScalarValue, Value};
 use once_cell::sync::Lazy;
 use serde::{Deserialize, Serialize};
 
-use crate::cob::doc::{Document, DocumentError};
-use crate::cob::shared;
-use crate::cob::shared::*;
-use crate::cob::store::{Error, FromHistory, Store};
-use crate::cob::transaction::{Transaction, TransactionError};
-use crate::cob::value::{FromValue, ValueError};
-use crate::cob::{Contents, History, ObjectId, TypeName};
-use crate::prelude::*;
+use crate::cob::common::*;
+use crate::cob::{ObjectId, Timestamp, TypeName};
 
 /// Type name of an issue.
 pub static TYPENAME: Lazy<TypeName> =
@@ -43,7 +33,7 @@ pub enum State {
 }
 
 impl State {
-    fn lifecycle_message(self) -> String {
+    pub fn lifecycle_message(self) -> String {
         match self {
             State::Open => "Open issue".to_owned(),
             State::Closed { .. } => "Close issue".to_owned(),
@@ -51,37 +41,6 @@ impl State {
     }
 }
 
-impl From<State> for ScalarValue {
-    fn from(state: State) -> Self {
-        match state {
-            State::Open => ScalarValue::from("open"),
-            State::Closed {
-                reason: CloseReason::Solved,
-            } => ScalarValue::from("solved"),
-            State::Closed {
-                reason: CloseReason::Other,
-            } => ScalarValue::from("closed"),
-        }
-    }
-}
-
-impl<'a> FromValue<'a> for State {
-    fn from_value(value: Value) -> Result<Self, ValueError> {
-        let state = value.to_str().ok_or(ValueError::InvalidType)?;
-
-        match state {
-            "open" => Ok(Self::Open),
-            "closed" => Ok(Self::Closed {
-                reason: CloseReason::Other,
-            }),
-            "solved" => Ok(Self::Closed {
-                reason: CloseReason::Solved,
-            }),
-            _ => Err(ValueError::InvalidValue(value.to_string())),
-        }
-    }
-}
-
 /// An issue or "ticket".
 #[derive(Debug, Clone, Serialize, Deserialize)]
 pub struct Issue {
@@ -127,637 +86,3 @@ impl Issue {
         self.timestamp
     }
 }
-
-impl FromHistory for Issue {
-    fn type_name() -> &'static TypeName {
-        &TYPENAME
-    }
-
-    fn from_history(history: &History) -> Result<Self, Error> {
-        let doc = history.traverse(Automerge::new(), |mut doc, entry| {
-            let bytes = entry.contents();
-            match automerge::Change::from_bytes(bytes.clone()) {
-                Ok(change) => {
-                    doc.apply_changes([change]).ok();
-                }
-                Err(_err) => {
-                    // Ignore
-                }
-            }
-            ControlFlow::Continue(doc)
-        });
-        let issue = Issue::try_from(doc)?;
-
-        Ok(issue)
-    }
-}
-
-impl TryFrom<&History> for Issue {
-    type Error = Error;
-
-    fn try_from(history: &History) -> Result<Self, Self::Error> {
-        Issue::from_history(history)
-    }
-}
-
-impl TryFrom<Automerge> for Issue {
-    type Error = DocumentError;
-
-    fn try_from(doc: Automerge) -> Result<Self, Self::Error> {
-        let doc = Document::new(&doc);
-        let obj_id = doc.get_id(automerge::ObjId::Root, "issue")?;
-        let title = doc.get(&obj_id, "title")?;
-        let comment_id = doc.get_id(&obj_id, "comment")?;
-        let author = doc.get(&obj_id, "author").map(Author::new)?;
-        let state = doc.get(&obj_id, "state")?;
-        let timestamp = doc.get(&obj_id, "timestamp")?;
-
-        let comment = shared::lookup::comment(doc, &comment_id)?;
-        let discussion: Discussion = doc.list(&obj_id, "discussion", shared::lookup::thread)?;
-        let labels: HashSet<Label> = doc.keys(&obj_id, "labels")?;
-
-        Ok(Self {
-            title,
-            state,
-            author,
-            comment,
-            discussion,
-            labels,
-            timestamp,
-        })
-    }
-}
-
-pub struct IssueStore<'a> {
-    store: Store<'a, Issue>,
-}
-
-impl<'a> IssueStore<'a> {
-    /// Create a new issue store.
-    pub fn new(store: Store<'a, Issue>) -> Self {
-        Self { store }
-    }
-
-    /// Get an issue by id.
-    pub fn get(&self, id: &ObjectId) -> Result<Option<Issue>, Error> {
-        self.store.get(id)
-    }
-
-    /// Create an issue.
-    pub fn create<G: Signer>(
-        &self,
-        title: &str,
-        description: &str,
-        labels: &[Label],
-        signer: &G,
-    ) -> Result<IssueId, Error> {
-        let author = self.store.author();
-        let timestamp = Timestamp::now();
-        let contents = events::create(&author, title, description, timestamp, labels)?;
-        let cob = self.store.create("Create issue", contents, signer)?;
-
-        Ok(*cob.id())
-    }
-
-    /// Remove an issue.
-    pub fn remove<G: Signer>(&self, _issue_id: &IssueId, _signer: &G) -> Result<(), Error> {
-        todo!()
-    }
-
-    /// Comment on an issue.
-    pub fn comment<G: Signer>(
-        &self,
-        issue_id: &IssueId,
-        body: &str,
-        signer: &G,
-    ) -> Result<(), Error> {
-        let author = self.store.author();
-        let mut issue = self.store.get_raw(issue_id)?;
-        let timestamp = Timestamp::now();
-        let changes = events::comment(&mut issue, &author, body, timestamp)?;
-
-        self.store
-            .update(*issue_id, "Add comment", changes, signer)?;
-
-        Ok(())
-    }
-
-    /// Life-cycle an issue, eg. open or close it.
-    pub fn lifecycle<G: Signer>(
-        &self,
-        issue_id: &IssueId,
-        state: State,
-        signer: &G,
-    ) -> Result<(), Error> {
-        let author = self.store.author();
-        let mut issue = self.store.get_raw(issue_id)?;
-        let changes = events::lifecycle(&mut issue, &author, state)?;
-
-        self.store.update(*issue_id, "Lifecycle", changes, signer)?;
-
-        Ok(())
-    }
-
-    /// Label an issue.
-    pub fn label<G: Signer>(
-        &self,
-        issue_id: &IssueId,
-        labels: &[Label],
-        signer: &G,
-    ) -> Result<(), Error> {
-        let author = self.store.author();
-        let mut issue = self.store.get_raw(issue_id)?;
-        let changes = events::label(&mut issue, &author, labels)?;
-
-        self.store.update(*issue_id, "Add label", changes, signer)?;
-
-        Ok(())
-    }
-
-    /// React to an issue comment.
-    pub fn react<G: Signer>(
-        &self,
-        issue_id: &IssueId,
-        comment_id: CommentId,
-        reaction: Reaction,
-        signer: &G,
-    ) -> Result<(), Error> {
-        let author = self.store.author();
-        let mut issue = self.store.get_raw(issue_id)?;
-        let changes = events::react(&mut issue, comment_id, &author, &[reaction])?;
-
-        self.store.update(*issue_id, "React", changes, signer)?;
-
-        Ok(())
-    }
-
-    /// Reply to an issue comment.
-    pub fn reply<G: Signer>(
-        &self,
-        issue_id: &IssueId,
-        comment_id: CommentId,
-        reply: &str,
-        signer: &G,
-    ) -> Result<(), Error> {
-        let author = self.store.author();
-        let mut issue = self.store.get_raw(issue_id)?;
-        let changes = events::reply(&mut issue, comment_id, &author, reply, Timestamp::now())?;
-
-        self.store.update(*issue_id, "Reply", changes, signer)?;
-
-        Ok(())
-    }
-
-    /// Get all issues, sorted by time.
-    pub fn all(&self) -> Result<Vec<(IssueId, Issue)>, Error> {
-        let mut issues = self.store.list()?;
-        issues.sort_by_key(|(_, i)| i.timestamp);
-
-        Ok(issues)
-    }
-
-    /// Get the issue count.
-    pub fn count(&self) -> Result<usize, Error> {
-        let issues = self.store.list()?;
-
-        Ok(issues.len())
-    }
-}
-
-/// Issue events.
-mod events {
-    use super::*;
-    use automerge::{
-        transaction::{CommitOptions, Transactable},
-        ObjId,
-    };
-
-    pub fn create(
-        author: &Author,
-        title: &str,
-        description: &str,
-        timestamp: Timestamp,
-        labels: &[Label],
-    ) -> Result<Contents, TransactionError> {
-        let title = title.trim();
-        if title.is_empty() {
-            return Err(TransactionError::InvalidValue("title"));
-        }
-
-        let mut doc = Automerge::new();
-        let _issue = doc
-            .transact_with::<_, _, TransactionError, _, ()>(
-                |_| CommitOptions::default().with_message("Create issue".to_owned()),
-                |tx| {
-                    let issue = tx.put_object(ObjId::Root, "issue", ObjType::Map)?;
-
-                    tx.put(&issue, "title", title)?;
-                    tx.put(&issue, "author", author)?;
-                    tx.put(&issue, "state", State::Open)?;
-                    tx.put(&issue, "timestamp", timestamp)?;
-                    tx.put_object(&issue, "discussion", ObjType::List)?;
-
-                    let labels_id = tx.put_object(&issue, "labels", ObjType::Map)?;
-                    for label in labels {
-                        tx.put(&labels_id, label.name().trim(), true)?;
-                    }
-
-                    // Nb. The top-level comment doesn't have a `replies` field.
-                    let comment_id = tx.put_object(&issue, "comment", ObjType::Map)?;
-
-                    tx.put(&comment_id, "body", description.trim())?;
-                    tx.put(&comment_id, "author", author)?;
-                    tx.put(&comment_id, "timestamp", timestamp)?;
-                    tx.put_object(&comment_id, "reactions", ObjType::Map)?;
-
-                    Ok(issue)
-                },
-            )
-            .map_err(|failure| failure.error)?
-            .result;
-
-        Ok(doc.save_incremental())
-    }
-
-    pub fn comment(
-        issue: &mut Automerge,
-        author: &Author,
-        body: &str,
-        timestamp: Timestamp,
-    ) -> Result<Contents, TransactionError> {
-        let _comment = issue
-            .transact_with::<_, _, TransactionError, _, ()>(
-                |_| CommitOptions::default().with_message("Add comment".to_owned()),
-                |tx| {
-                    let mut tx = Transaction::new(tx);
-                    let (_obj, obj_id) = tx.get(ObjId::Root, "issue")?;
-                    let (_, discussion_id) = tx.get(&obj_id, "discussion")?;
-
-                    let length = tx.length(&discussion_id);
-                    let comment = tx.insert_object(&discussion_id, length, ObjType::Map)?;
-
-                    tx.put(&comment, "author", author)?;
-                    tx.put(&comment, "body", body.trim())?;
-                    tx.put(&comment, "timestamp", timestamp)?;
-                    tx.put_object(&comment, "replies", ObjType::List)?;
-                    tx.put_object(&comment, "reactions", ObjType::Map)?;
-
-                    Ok(comment)
-                },
-            )
-            .map_err(|failure| failure.error)?
-            .result;
-
-        #[allow(clippy::unwrap_used)]
-        let change = issue.get_last_local_change().unwrap().raw_bytes().to_vec();
-
-        Ok(change)
-    }
-
-    pub fn lifecycle(
-        issue: &mut Automerge,
-        author: &Author,
-        state: State,
-    ) -> Result<Contents, TransactionError> {
-        issue
-            .transact_with::<_, _, TransactionError, _, ()>(
-                |_| CommitOptions::default().with_message(state.lifecycle_message()),
-                |tx| {
-                    let mut tx = Transaction::new(tx);
-                    let (_, obj_id) = tx.get(ObjId::Root, "issue")?;
-                    tx.put(&obj_id, "state", state)?;
-                    tx.put(&obj_id, "author", author)?;
-
-                    Ok(())
-                },
-            )
-            .map_err(|failure| failure.error)?;
-
-        #[allow(clippy::unwrap_used)]
-        let change = issue.get_last_local_change().unwrap().raw_bytes().to_vec();
-
-        Ok(change)
-    }
-
-    pub fn label(
-        issue: &mut Automerge,
-        _author: &Author,
-        labels: &[Label],
-    ) -> Result<Contents, TransactionError> {
-        issue
-            .transact_with::<_, _, TransactionError, _, ()>(
-                |_| CommitOptions::default().with_message("Label issue".to_owned()),
-                |tx| {
-                    let mut tx = Transaction::new(tx);
-                    let (_, obj_id) = tx.get(ObjId::Root, "issue")?;
-                    let (_, labels_id) = tx.get(&obj_id, "labels")?;
-
-                    for label in labels {
-                        tx.put(&labels_id, label.name().trim(), true)?;
-                    }
-                    Ok(())
-                },
-            )
-            .map_err(|failure| failure.error)?;
-
-        #[allow(clippy::unwrap_used)]
-        let change = issue.get_last_local_change().unwrap().raw_bytes().to_vec();
-
-        Ok(change)
-    }
-
-    pub fn reply(
-        issue: &mut Automerge,
-        comment_id: CommentId,
-        author: &Author,
-        body: &str,
-        timestamp: Timestamp,
-    ) -> Result<Contents, TransactionError> {
-        issue
-            .transact_with::<_, _, TransactionError, _, ()>(
-                |_| CommitOptions::default().with_message("Reply".to_owned()),
-                |tx| {
-                    let mut tx = Transaction::new(tx);
-                    let (_, obj_id) = tx.get(ObjId::Root, "issue")?;
-                    let (_, discussion_id) = tx.get(&obj_id, "discussion")?;
-                    let (_, comment_id) = tx.get(&discussion_id, usize::from(comment_id))?;
-                    let (_, replies_id) = tx.get(&comment_id, "replies")?;
-
-                    let length = tx.length(&replies_id);
-                    let reply = tx.insert_object(&replies_id, length, ObjType::Map)?;
-
-                    // Nb. Replies don't themselves have replies.
-                    tx.put(&reply, "author", author)?;
-                    tx.put(&reply, "body", body.trim())?;
-                    tx.put(&reply, "timestamp", timestamp)?;
-                    tx.put_object(&reply, "reactions", ObjType::Map)?;
-
-                    Ok(())
-                },
-            )
-            .map_err(|failure| failure.error)?;
-
-        #[allow(clippy::unwrap_used)]
-        let change = issue.get_last_local_change().unwrap().raw_bytes().to_vec();
-
-        Ok(change)
-    }
-
-    pub fn react(
-        issue: &mut Automerge,
-        comment_id: CommentId,
-        author: &Author,
-        reactions: &[Reaction],
-    ) -> Result<Contents, TransactionError> {
-        issue
-            .transact_with::<_, _, TransactionError, _, ()>(
-                |_| CommitOptions::default().with_message("React".to_owned()),
-                |tx| {
-                    let mut tx = Transaction::new(tx);
-                    let (_, obj_id) = tx.get(ObjId::Root, "issue")?;
-                    let (_, discussion_id) = tx.get(&obj_id, "discussion")?;
-                    let (_, comment_id) = if comment_id == CommentId::root() {
-                        tx.get(&obj_id, "comment")?
-                    } else {
-                        tx.get(&discussion_id, usize::from(comment_id) - 1)?
-                    };
-                    let (_, reactions_id) = tx.get(&comment_id, "reactions")?;
-
-                    for reaction in reactions {
-                        let key = reaction.emoji.to_string();
-                        let reaction_id = if let Some((_, reaction_id)) =
-                            tx.try_get(&reactions_id, key)?
-                        {
-                            reaction_id
-                        } else {
-                            tx.put_object(&reactions_id, reaction.emoji.to_string(), ObjType::Map)?
-                        };
-                        tx.put(&reaction_id, author.id.to_human(), true)?;
-                    }
-
-                    Ok(())
-                },
-            )
-            .map_err(|failure| failure.error)?;
-
-        #[allow(clippy::unwrap_used)]
-        let change = issue.get_last_local_change().unwrap().raw_bytes().to_vec();
-
-        Ok(change)
-    }
-}
-
-#[cfg(test)]
-mod test {
-    use super::*;
-    use crate::test;
-
-    #[test]
-    fn test_issue_create_and_get() {
-        let tmp = tempfile::tempdir().unwrap();
-        let (_, signer, project) = test::setup::context(&tmp);
-        let store = Store::open(*signer.public_key(), &project).unwrap();
-        let issues = store.issues();
-        let timestamp = Timestamp::now();
-        let issue_id = issues
-            .create("My first issue", "Blah blah blah.", &[], &signer)
-            .unwrap();
-        let issue = issues.get(&issue_id).unwrap().unwrap();
-
-        assert_eq!(issue.title(), "My first issue");
-        assert_eq!(issue.author(), &store.author());
-        assert_eq!(issue.description(), "Blah blah blah.");
-        assert_eq!(issue.comments().len(), 0);
-        assert_eq!(issue.state(), State::Open);
-        assert!(issue.timestamp() >= timestamp);
-    }
-
-    #[test]
-    fn test_issue_create_and_change_state() {
-        let tmp = tempfile::tempdir().unwrap();
-        let (_, signer, project) = test::setup::context(&tmp);
-        let store = Store::open(*signer.public_key(), &project).unwrap();
-        let issues = store.issues();
-        let issue_id = issues
-            .create("My first issue", "Blah blah blah.", &[], &signer)
-            .unwrap();
-
-        issues
-            .lifecycle(
-                &issue_id,
-                State::Closed {
-                    reason: CloseReason::Other,
-                },
-                &signer,
-            )
-            .unwrap();
-
-        let issue = issues.get(&issue_id).unwrap().unwrap();
-        assert_eq!(
-            issue.state(),
-            State::Closed {
-                reason: CloseReason::Other
-            }
-        );
-
-        issues.lifecycle(&issue_id, State::Open, &signer).unwrap();
-        let issue = issues.get(&issue_id).unwrap().unwrap();
-        assert_eq!(issue.state(), State::Open);
-    }
-
-    #[test]
-    fn test_issue_react() {
-        let tmp = tempfile::tempdir().unwrap();
-        let (_, signer, project) = test::setup::context(&tmp);
-        let store = Store::open(*signer.public_key(), &project).unwrap();
-        let issues = store.issues();
-        let issue_id = issues
-            .create("My first issue", "Blah blah blah.", &[], &signer)
-            .unwrap();
-
-        let reaction = Reaction::new('🥳').unwrap();
-        issues
-            .react(&issue_id, CommentId::root(), reaction, &signer)
-            .unwrap();
-
-        let issue = issues.get(&issue_id).unwrap().unwrap();
-        let count = issue.reactions()[&reaction];
-
-        // TODO: Test multiple reactions from same author and different authors
-
-        assert_eq!(count, 1);
-    }
-
-    #[test]
-    fn test_issue_reply() {
-        let tmp = tempfile::tempdir().unwrap();
-        let (_, signer, project) = test::setup::context(&tmp);
-        let store = Store::open(*signer.public_key(), &project).unwrap();
-        let issues = store.issues();
-        let issue_id = issues
-            .create("My first issue", "Blah blah blah.", &[], &signer)
-            .unwrap();
-
-        issues.comment(&issue_id, "Ho ho ho.", &signer).unwrap();
-        issues
-            .reply(&issue_id, CommentId::root(), "Hi hi hi.", &signer)
-            .unwrap();
-        issues
-            .reply(&issue_id, CommentId::root(), "Ha ha ha.", &signer)
-            .unwrap();
-
-        let issue = issues.get(&issue_id).unwrap().unwrap();
-        let reply1 = &issue.comments()[0].replies[0];
-        let reply2 = &issue.comments()[0].replies[1];
-
-        assert_eq!(reply1.body, "Hi hi hi.");
-        assert_eq!(reply2.body, "Ha ha ha.");
-    }
-
-    #[test]
-    fn test_issue_label() {
-        let tmp = tempfile::tempdir().unwrap();
-        let (_, signer, project) = test::setup::context(&tmp);
-        let store = Store::open(*signer.public_key(), &project).unwrap();
-        let issues = store.issues();
-        let issue_id = issues
-            .create("My first issue", "Blah blah blah.", &[], &signer)
-            .unwrap();
-
-        let bug_label = Label::new("bug").unwrap();
-        let wontfix_label = Label::new("wontfix").unwrap();
-
-        issues
-            .label(&issue_id, &[bug_label.clone()], &signer)
-            .unwrap();
-        issues
-            .label(&issue_id, &[wontfix_label.clone()], &signer)
-            .unwrap();
-
-        let issue = issues.get(&issue_id).unwrap().unwrap();
-        let labels = issue.labels();
-
-        assert!(labels.contains(&bug_label));
-        assert!(labels.contains(&wontfix_label));
-    }
-
-    #[test]
-    fn test_issue_comment() {
-        let tmp = tempfile::tempdir().unwrap();
-        let (_, signer, project) = test::setup::context(&tmp);
-        let store = Store::open(*signer.public_key(), &project).unwrap();
-        let issues = store.issues();
-        let now = Timestamp::now();
-        let author = *signer.public_key();
-        let issue_id = issues
-            .create("My first issue", "Blah blah blah.", &[], &signer)
-            .unwrap();
-
-        issues.comment(&issue_id, "Ho ho ho.", &signer).unwrap();
-        issues.comment(&issue_id, "Ha ha ha.", &signer).unwrap();
-
-        let issue = issues.get(&issue_id).unwrap().unwrap();
-        let c1 = &issue.comments()[0];
-        let c2 = &issue.comments()[1];
-
-        assert_eq!(&c1.body, "Ho ho ho.");
-        assert_eq!(c1.author.id(), &author);
-        assert_eq!(&c2.body, "Ha ha ha.");
-        assert_eq!(c2.author.id(), &author);
-        assert!(c1.timestamp >= now);
-    }
-
-    #[test]
-    fn test_issue_state_serde() {
-        assert_eq!(
-            serde_json::to_value(State::Open).unwrap(),
-            serde_json::json!({ "status": "open" })
-        );
-
-        assert_eq!(
-            serde_json::to_value(State::Closed {
-                reason: CloseReason::Solved
-            })
-            .unwrap(),
-            serde_json::json!({ "status": "closed", "reason": "solved" })
-        );
-    }
-
-    #[test]
-    fn test_issue_all() {
-        let tmp = tempfile::tempdir().unwrap();
-        let (_, signer, project) = test::setup::context(&tmp);
-        let store = Store::open(*signer.public_key(), &project).unwrap();
-        let issues = store.issues();
-        let author = store.author();
-
-        let contents =
-            events::create(&author, "First", "Blah blah.", Timestamp::new(0), &[]).unwrap();
-        issues
-            .store
-            .create("Create issue", contents, &signer)
-            .unwrap();
-
-        let contents =
-            events::create(&author, "Second", "Blah blah.", Timestamp::new(1), &[]).unwrap();
-        issues
-            .store
-            .create("Create issue", contents, &signer)
-            .unwrap();
-
-        let contents =
-            events::create(&author, "Third", "Blah blah.", Timestamp::new(2), &[]).unwrap();
-        issues
-            .store
-            .create("Create issue", contents, &signer)
-            .unwrap();
-
-        let issues = issues.all().unwrap();
-        assert_eq!(issues.len(), 3);
-
-        // Issues are sorted by timestamp.
-        assert_eq!(issues[0].1.title(), "First");
-        assert_eq!(issues[1].1.title(), "Second");
-        assert_eq!(issues[2].1.title(), "Third");
-    }
-}
diff --git a/radicle/src/cob/patch.rs b/radicle/src/cob/patch.rs
index 40c5ea7a..7dfde81b 100644
--- a/radicle/src/cob/patch.rs
+++ b/radicle/src/cob/patch.rs
@@ -1,25 +1,14 @@
-#![allow(clippy::too_many_arguments)]
 use std::collections::{HashMap, HashSet};
-use std::convert::TryFrom;
 use std::fmt;
-use std::ops::{ControlFlow, Deref, RangeInclusive};
+use std::ops::RangeInclusive;
 use std::str::FromStr;
-use std::sync::Arc;
 
-use automerge::transaction::Transactable;
-use automerge::{Automerge, AutomergeError, ObjType, ScalarValue, Value};
 use nonempty::NonEmpty;
 use once_cell::sync::Lazy;
 use serde::{Deserialize, Serialize};
 
-use crate::cob::doc::{Document, DocumentError};
-use crate::cob::shared;
-use crate::cob::shared::*;
-use crate::cob::store::Error;
-use crate::cob::store::{FromHistory, Store};
-use crate::cob::transaction::{Transaction, TransactionError};
-use crate::cob::value::{FromValue, ValueError};
-use crate::cob::{Contents, History, ObjectId, TypeName};
+use crate::cob::common::*;
+use crate::cob::{ObjectId, Timestamp, TypeName};
 use crate::git;
 use crate::prelude::*;
 
@@ -47,25 +36,6 @@ pub enum MergeTarget {
     Delegates,
 }
 
-impl From<MergeTarget> for ScalarValue {
-    fn from(target: MergeTarget) -> Self {
-        match target {
-            MergeTarget::Delegates => ScalarValue::from("delegates"),
-        }
-    }
-}
-
-impl<'a> FromValue<'a> for MergeTarget {
-    fn from_value(value: Value<'a>) -> Result<Self, ValueError> {
-        let state = value.to_str().ok_or(ValueError::InvalidType)?;
-
-        match state {
-            "delegates" => Ok(Self::Delegates),
-            _ => Err(ValueError::InvalidValue(value.to_string())),
-        }
-    }
-}
-
 /// A patch to a repository.
 #[derive(Debug, Clone, Serialize)]
 pub struct Patch<T = ()>
@@ -118,264 +88,6 @@ impl Patch {
     }
 }
 
-impl FromHistory for Patch {
-    fn type_name() -> &'static TypeName {
-        &TYPENAME
-    }
-
-    fn from_history(history: &History) -> Result<Self, Error> {
-        Patch::try_from(history)
-    }
-}
-
-impl TryFrom<Document<'_>> for Patch {
-    type Error = DocumentError;
-
-    fn try_from(doc: Document) -> Result<Self, Self::Error> {
-        let obj_id = doc.get_id(automerge::ObjId::Root, "patch")?;
-        let title = doc.get(&obj_id, "title")?;
-        let author = doc.get(&obj_id, "author")?;
-        let state = doc.get(&obj_id, "state")?;
-        let target = doc.get(&obj_id, "target")?;
-        let timestamp = doc.get(&obj_id, "timestamp")?;
-        let revisions = doc.list(&obj_id, "revisions", lookup::revision)?;
-        let labels: HashSet<Label> = doc.keys(&obj_id, "labels")?;
-        let revisions =
-            NonEmpty::from_vec(revisions).ok_or(DocumentError::EmptyList("revisions"))?;
-        let author: Author = Author::new(author);
-
-        Ok(Self {
-            author,
-            title,
-            state,
-            target,
-            labels,
-            revisions,
-            timestamp,
-        })
-    }
-}
-
-impl TryFrom<&History> for Patch {
-    type Error = Error;
-
-    fn try_from(history: &History) -> Result<Self, Self::Error> {
-        let doc = history.traverse(Automerge::new(), |mut doc, entry| {
-            let bytes = entry.contents();
-            match automerge::Change::from_bytes(bytes.clone()) {
-                Ok(change) => {
-                    doc.apply_changes([change]).ok();
-                }
-                Err(_err) => {
-                    // Ignore
-                }
-            }
-            ControlFlow::Continue(doc)
-        });
-        let patch = Patch::try_from(Document::new(&doc))?;
-
-        Ok(patch)
-    }
-}
-
-pub struct PatchStore<'a> {
-    store: Store<'a, Patch>,
-}
-
-impl<'a> Deref for PatchStore<'a> {
-    type Target = Store<'a, Patch>;
-
-    fn deref(&self) -> &Self::Target {
-        &self.store
-    }
-}
-
-impl<'a> PatchStore<'a> {
-    /// Create a new patch store.
-    pub fn new(store: Store<'a, Patch>) -> Self {
-        Self { store }
-    }
-
-    /// Get a patch by id.
-    pub fn get(&self, id: &ObjectId) -> Result<Option<Patch>, Error> {
-        self.store.get(id)
-    }
-
-    /// Create a patch.
-    pub fn create<G: Signer>(
-        &self,
-        title: &str,
-        description: &str,
-        target: MergeTarget,
-        base: impl Into<git::Oid>,
-        oid: impl Into<git::Oid>,
-        labels: &[Label],
-        signer: &G,
-    ) -> Result<PatchId, Error> {
-        let author = self.author();
-        let timestamp = Timestamp::now();
-        let revision = Revision::new(
-            author.clone(),
-            base.into(),
-            oid.into(),
-            description.to_owned(),
-            timestamp,
-        );
-        let contents = events::create(&author, title, &revision, target, timestamp, labels)?;
-        let cob = self.store.create("Create patch", contents, signer)?;
-
-        Ok(*cob.id())
-    }
-
-    /// Comment on a patch.
-    pub fn comment<G: Signer>(
-        &self,
-        patch_id: &PatchId,
-        revision_ix: RevisionIx,
-        body: &str,
-        signer: &G,
-    ) -> Result<(), Error> {
-        let author = self.author();
-        let mut patch = self.store.get_raw(patch_id)?;
-        let timestamp = Timestamp::now();
-        let changes = events::comment(&mut patch, revision_ix, &author, body, timestamp)?;
-
-        self.store
-            .update(*patch_id, "Add comment", changes, signer)?;
-
-        Ok(())
-    }
-
-    /// Update a patch with new code. Creates a new revision.
-    pub fn update<G: Signer>(
-        &self,
-        patch_id: &PatchId,
-        comment: impl ToString,
-        base: impl Into<git::Oid>,
-        oid: impl Into<git::Oid>,
-        signer: &G,
-    ) -> Result<RevisionIx, Error> {
-        let author = self.author();
-        let timestamp = Timestamp::now();
-        let revision = Revision::new(
-            author,
-            base.into(),
-            oid.into(),
-            comment.to_string(),
-            timestamp,
-        );
-
-        let mut patch = self.get_raw(patch_id)?;
-        let (revision_ix, changes) = events::update(&mut patch, revision)?;
-
-        self.store
-            .update(*patch_id, "Update patch", changes, signer)?;
-
-        Ok(revision_ix)
-    }
-
-    /// Reply to a patch comment.
-    pub fn reply<G: Signer>(
-        &self,
-        patch_id: &PatchId,
-        revision_ix: RevisionIx,
-        comment_id: CommentId,
-        reply: &str,
-        signer: &G,
-    ) -> Result<(), Error> {
-        let author = self.author();
-        let mut patch = self.get_raw(patch_id)?;
-        let changes = events::reply(
-            &mut patch,
-            revision_ix,
-            comment_id,
-            &author,
-            reply,
-            Timestamp::now(),
-        )?;
-
-        self.store.update(*patch_id, "Reply", changes, signer)?;
-
-        Ok(())
-    }
-
-    /// Review a patch revision.
-    pub fn review<G: Signer>(
-        &self,
-        patch_id: &PatchId,
-        revision_ix: RevisionIx,
-        verdict: Option<Verdict>,
-        comment: impl Into<String>,
-        inline: Vec<CodeComment>,
-        signer: &G,
-    ) -> Result<(), Error> {
-        let timestamp = Timestamp::now();
-        let review = Review::new(self.author(), verdict, comment, inline, timestamp);
-
-        let mut patch = self.get_raw(patch_id)?;
-        let (_, changes) = events::review(&mut patch, revision_ix, review)?;
-
-        self.store
-            .update(*patch_id, "Review patch", changes, signer)?;
-
-        Ok(())
-    }
-
-    /// Merge a patch revision.
-    pub fn merge<G: Signer>(
-        &self,
-        patch_id: &PatchId,
-        revision_ix: RevisionIx,
-        commit: git::Oid,
-        signer: &G,
-    ) -> Result<Merge, Error> {
-        let timestamp = Timestamp::now();
-        let merge = Merge {
-            node: *signer.public_key(),
-            commit,
-            timestamp,
-        };
-
-        let mut patch = self.get_raw(patch_id)?;
-        let changes = events::merge(&mut patch, revision_ix, &merge)?;
-
-        self.store
-            .update(*patch_id, "Merge revision", changes, signer)?;
-
-        Ok(merge)
-    }
-
-    /// Get the patch count.
-    pub fn count(&self) -> Result<usize, Error> {
-        let cobs = self.store.list()?;
-
-        Ok(cobs.len())
-    }
-
-    /// Get all patches for this project.
-    pub fn all(&self) -> Result<Vec<(PatchId, Patch)>, Error> {
-        let mut patches = self.store.list()?;
-        patches.sort_by_key(|(_, p)| p.timestamp);
-
-        Ok(patches)
-    }
-
-    /// Get proposed patches.
-    pub fn proposed(&self) -> Result<impl Iterator<Item = (PatchId, Patch)>, Error> {
-        let all = self.all()?;
-
-        Ok(all.into_iter().filter(|(_, p)| p.is_proposed()))
-    }
-
-    /// Get patches proposed by the given key.
-    pub fn proposed_by<'b>(
-        &'b self,
-        who: &'b PublicKey,
-    ) -> Result<impl Iterator<Item = (PatchId, Patch)> + '_, Error> {
-        Ok(self.proposed()?.filter(move |(_, p)| p.author.id() == who))
-    }
-}
-
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize)]
 #[serde(rename_all = "lowercase")]
 pub enum State {
@@ -384,29 +96,6 @@ pub enum State {
     Archived,
 }
 
-impl From<State> for ScalarValue {
-    fn from(state: State) -> Self {
-        match state {
-            State::Proposed => ScalarValue::from("proposed"),
-            State::Draft => ScalarValue::from("draft"),
-            State::Archived => ScalarValue::from("archived"),
-        }
-    }
-}
-
-impl<'a> FromValue<'a> for State {
-    fn from_value(value: Value<'a>) -> Result<Self, ValueError> {
-        let state = value.to_str().ok_or(ValueError::InvalidType)?;
-
-        match state {
-            "proposed" => Ok(Self::Proposed),
-            "draft" => Ok(Self::Draft),
-            "archived" => Ok(Self::Archived),
-            _ => Err(ValueError::InvalidValue(value.to_string())),
-        }
-    }
-}
-
 /// A patch revision.
 #[derive(Debug, Clone, Serialize)]
 pub struct Revision<T = ()> {
@@ -459,40 +148,6 @@ impl Revision {
     pub fn author(&self) -> &Author {
         &self.comment.author
     }
-
-    /// Put this object into an automerge document.
-    fn put<'a>(
-        &self,
-        mut tx: impl AsMut<automerge::transaction::Transaction<'a>>,
-        id: &automerge::ObjId,
-    ) -> Result<(), AutomergeError> {
-        assert!(
-            self.merges.is_empty(),
-            "Cannot put revision with non-empty merges"
-        );
-        assert!(
-            self.reviews.is_empty(),
-            "Cannot put revision with non-empty reviews"
-        );
-        assert!(
-            self.discussion.is_empty(),
-            "Cannot put revision with non-empty discussion"
-        );
-        let tx = tx.as_mut();
-
-        tx.put(id, "id", self.id.to_string())?;
-        tx.put(id, "oid", self.oid.to_string())?;
-        tx.put(id, "base", self.base.to_string())?;
-
-        self.comment.put(tx, id)?;
-
-        tx.put_object(id, "discussion", ObjType::List)?;
-        tx.put_object(id, "reviews", ObjType::Map)?;
-        tx.put_object(id, "merges", ObjType::List)?;
-        tx.put(id, "timestamp", self.timestamp)?;
-
-        Ok(())
-    }
 }
 
 /// A merged patch revision.
@@ -525,21 +180,6 @@ impl fmt::Display for Verdict {
     }
 }
 
-impl From<Verdict> for ScalarValue {
-    fn from(verdict: Verdict) -> Self {
-        #[allow(clippy::unwrap_used)]
-        let s = serde_json::to_string(&verdict).unwrap(); // Cannot fail.
-        ScalarValue::from(s)
-    }
-}
-
-impl<'a> FromValue<'a> for Verdict {
-    fn from_value(value: Value) -> Result<Self, ValueError> {
-        let verdict = value.to_str().ok_or(ValueError::InvalidType)?;
-        serde_json::from_str(verdict).map_err(|e| ValueError::Other(Arc::new(e)))
-    }
-}
-
 /// Code location, used for attaching comments.
 #[derive(Debug, Clone, Serialize, Deserialize)]
 pub struct CodeLocation {
@@ -593,487 +233,4 @@ impl Review {
             timestamp,
         }
     }
-
-    /// Put this object into an automerge document.
-    fn put<'a>(
-        &self,
-        mut tx: impl AsMut<automerge::transaction::Transaction<'a>>,
-        id: &automerge::ObjId,
-    ) -> Result<(), AutomergeError> {
-        assert!(
-            self.inline.is_empty(),
-            "Cannot put review with non-empty inline comments"
-        );
-        let tx = tx.as_mut();
-
-        tx.put(id, "author", &self.author)?;
-        tx.put(
-            id,
-            "verdict",
-            if let Some(v) = self.verdict {
-                v.into()
-            } else {
-                ScalarValue::Null
-            },
-        )?;
-
-        self.comment.put(tx, id)?;
-
-        tx.put_object(id, "inline", ObjType::List)?;
-        tx.put(id, "timestamp", self.timestamp)?;
-
-        Ok(())
-    }
-}
-
-mod lookup {
-    use super::*;
-
-    pub fn revision(
-        doc: Document,
-        revision_id: &automerge::ObjId,
-    ) -> Result<Revision, DocumentError> {
-        let comment_id = doc.get_id(revision_id, "comment")?;
-        let reviews_id = doc.get_id(revision_id, "reviews")?;
-        let id = doc.get(revision_id, "id")?;
-        let base = doc.get(revision_id, "base")?;
-        let oid = doc.get(revision_id, "oid")?;
-        let timestamp = doc.get(revision_id, "timestamp")?;
-        let merges: Vec<Merge> = doc.list(revision_id, "merges", self::merge)?;
-
-        // Discussion.
-        let comment = shared::lookup::comment(doc, &comment_id)?;
-        let discussion: Discussion = doc.list(revision_id, "discussion", shared::lookup::thread)?;
-
-        // Reviews.
-        let mut reviews: HashMap<NodeId, Review> = HashMap::new();
-        for key in (*doc).keys(&reviews_id) {
-            let review_id = doc.get_id(&reviews_id, key)?;
-            let review = self::review(doc, &review_id)?;
-
-            reviews.insert(*review.author.id(), review);
-        }
-
-        Ok(Revision {
-            id,
-            base,
-            oid,
-            comment,
-            discussion,
-            reviews,
-            merges,
-            changeset: (),
-            timestamp,
-        })
-    }
-
-    pub fn merge(doc: Document, obj_id: &automerge::ObjId) -> Result<Merge, DocumentError> {
-        let node = doc.get(obj_id, "peer")?;
-        let commit = doc.get(obj_id, "commit")?;
-        let timestamp = doc.get(obj_id, "timestamp")?;
-
-        Ok(Merge {
-            node,
-            commit,
-            timestamp,
-        })
-    }
-
-    pub fn review(doc: Document, obj_id: &automerge::ObjId) -> Result<Review, DocumentError> {
-        let author = doc.get(obj_id, "author")?;
-        let verdict = doc.get(obj_id, "verdict")?;
-        let timestamp = doc.get(obj_id, "timestamp")?;
-        let comment = doc.lookup(obj_id, "comment", shared::lookup::thread)?;
-        let inline = vec![];
-
-        Ok(Review {
-            author: Author::new(author),
-            comment,
-            verdict,
-            inline,
-            timestamp,
-        })
-    }
-}
-
-/// Patch events.
-mod events {
-    use super::*;
-    use automerge::{
-        transaction::{CommitOptions, Transactable},
-        ObjId,
-    };
-
-    pub fn create(
-        author: &Author,
-        title: &str,
-        revision: &Revision,
-        target: MergeTarget,
-        timestamp: Timestamp,
-        labels: &[Label],
-    ) -> Result<Contents, TransactionError> {
-        let title = title.trim();
-        if title.is_empty() {
-            return Err(TransactionError::InvalidValue("title"));
-        }
-
-        let mut doc = Automerge::new();
-        let _patch = doc
-            .transact_with::<_, _, TransactionError, _, ()>(
-                |_| CommitOptions::default().with_message("Create patch".to_owned()),
-                |tx| {
-                    let mut tx = Transaction::new(tx);
-                    let patch_id = tx.put_object(ObjId::Root, "patch", ObjType::Map)?;
-
-                    tx.put(&patch_id, "title", title)?;
-                    tx.put(&patch_id, "author", author)?;
-                    tx.put(&patch_id, "state", State::Proposed)?;
-                    tx.put(&patch_id, "target", target)?;
-                    tx.put(&patch_id, "timestamp", timestamp)?;
-
-                    let labels_id = tx.put_object(&patch_id, "labels", ObjType::Map)?;
-                    for label in labels {
-                        tx.put(&labels_id, label.name().trim(), true)?;
-                    }
-
-                    let revisions_id = tx.put_object(&patch_id, "revisions", ObjType::List)?;
-                    let revision_id = tx.insert_object(&revisions_id, 0, ObjType::Map)?;
-
-                    revision.put(tx, &revision_id)?;
-
-                    Ok(patch_id)
-                },
-            )
-            .map_err(|failure| failure.error)?
-            .result;
-
-        Ok(doc.save_incremental())
-    }
-
-    pub fn comment(
-        patch: &mut Automerge,
-        revision_ix: RevisionIx,
-        author: &Author,
-        body: &str,
-        timestamp: Timestamp,
-    ) -> Result<Contents, TransactionError> {
-        let _comment = patch
-            .transact_with::<_, _, TransactionError, _, ()>(
-                |_| CommitOptions::default().with_message("Add comment".to_owned()),
-                |t| {
-                    let mut tx = Transaction::new(t);
-                    let (_, obj_id) = tx.get(ObjId::Root, "patch")?;
-                    let (_, revisions_id) = tx.get(&obj_id, "revisions")?;
-                    let (_, revision_id) = tx.get(&revisions_id, revision_ix)?;
-                    let (_, discussion_id) = tx.get(&revision_id, "discussion")?;
-
-                    let length = tx.length(&discussion_id);
-                    let comment = tx.insert_object(&discussion_id, length, ObjType::Map)?;
-
-                    tx.put(&comment, "author", author)?;
-                    tx.put(&comment, "body", body.trim())?;
-                    tx.put(&comment, "timestamp", timestamp)?;
-                    tx.put_object(&comment, "replies", ObjType::List)?;
-                    tx.put_object(&comment, "reactions", ObjType::Map)?;
-
-                    Ok(comment)
-                },
-            )
-            .map_err(|failure| failure.error)?
-            .result;
-
-        #[allow(clippy::unwrap_used)]
-        let change = patch.get_last_local_change().unwrap().raw_bytes().to_vec();
-
-        Ok(change)
-    }
-
-    pub fn update(
-        patch: &mut Automerge,
-        revision: Revision,
-    ) -> Result<(RevisionIx, Contents), TransactionError> {
-        let revision_ix = patch
-            .transact_with::<_, _, TransactionError, _, ()>(
-                |_| CommitOptions::default().with_message("Merge revision".to_owned()),
-                |tx| {
-                    let mut tx = Transaction::new(tx);
-                    let (_, obj_id) = tx.get(ObjId::Root, "patch")?;
-                    let (_, revisions_id) = tx.get(&obj_id, "revisions")?;
-
-                    let ix = tx.length(&revisions_id);
-                    let revision_id = tx.insert_object(&revisions_id, ix, ObjType::Map)?;
-
-                    revision.put(tx, &revision_id)?;
-
-                    Ok(ix)
-                },
-            )
-            .map_err(|failure| failure.error)?
-            .result;
-
-        #[allow(clippy::unwrap_used)]
-        let change = patch.get_last_local_change().unwrap().raw_bytes().to_vec();
-
-        Ok((revision_ix, change))
-    }
-
-    pub fn reply(
-        patch: &mut Automerge,
-        revision_ix: RevisionIx,
-        comment_id: CommentId,
-        author: &Author,
-        body: &str,
-        timestamp: Timestamp,
-    ) -> Result<Contents, TransactionError> {
-        patch
-            .transact_with::<_, _, TransactionError, _, ()>(
-                |_| CommitOptions::default().with_message("Reply".to_owned()),
-                |tx| {
-                    let mut tx = Transaction::new(tx);
-                    let (_, obj_id) = tx.get(ObjId::Root, "patch")?;
-                    let (_, revisions_id) = tx.get(&obj_id, "revisions")?;
-                    let (_, revision_id) = tx.get(&revisions_id, revision_ix)?;
-                    let (_, discussion_id) = tx.get(&revision_id, "discussion")?;
-                    let (_, comment_id) = tx.get(&discussion_id, usize::from(comment_id))?;
-                    let (_, replies_id) = tx.get(&comment_id, "replies")?;
-
-                    let length = tx.length(&replies_id);
-                    let reply = tx.insert_object(&replies_id, length, ObjType::Map)?;
-
-                    // Nb. Replies don't themselves have replies.
-                    tx.put(&reply, "author", author)?;
-                    tx.put(&reply, "body", body.trim())?;
-                    tx.put(&reply, "timestamp", timestamp)?;
-                    tx.put_object(&reply, "reactions", ObjType::Map)?;
-
-                    Ok(())
-                },
-            )
-            .map_err(|failure| failure.error)?;
-
-        #[allow(clippy::unwrap_used)]
-        let change = patch.get_last_local_change().unwrap().raw_bytes().to_vec();
-
-        Ok(change)
-    }
-
-    pub fn review(
-        patch: &mut Automerge,
-        revision_ix: RevisionIx,
-        review: Review,
-    ) -> Result<((), Contents), TransactionError> {
-        patch
-            .transact_with::<_, _, TransactionError, _, ()>(
-                |_| CommitOptions::default().with_message("Review patch".to_owned()),
-                |tx| {
-                    let mut tx = Transaction::new(tx);
-                    let (_, obj_id) = tx.get(ObjId::Root, "patch")?;
-                    let (_, revisions_id) = tx.get(&obj_id, "revisions")?;
-                    let (_, revision_id) = tx.get(&revisions_id, revision_ix)?;
-                    let (_, reviews_id) = tx.get(&revision_id, "reviews")?;
-
-                    let review_id =
-                        tx.put_object(&reviews_id, review.author.id.to_human(), ObjType::Map)?;
-
-                    review.put(tx, &review_id)?;
-
-                    Ok(())
-                },
-            )
-            .map_err(|failure| failure.error)?;
-
-        #[allow(clippy::unwrap_used)]
-        let change = patch.get_last_local_change().unwrap().raw_bytes().to_vec();
-
-        Ok(((), change))
-    }
-
-    pub fn merge(
-        patch: &mut Automerge,
-        revision_ix: RevisionIx,
-        merge: &Merge,
-    ) -> Result<Contents, TransactionError> {
-        patch
-            .transact_with::<_, _, TransactionError, _, ()>(
-                |_| CommitOptions::default().with_message("Merge revision".to_owned()),
-                |tx| {
-                    let mut tx = Transaction::new(tx);
-                    let (_, obj_id) = tx.get(ObjId::Root, "patch")?;
-                    let (_, revisions_id) = tx.get(&obj_id, "revisions")?;
-                    let (_, revision_id) = tx.get(&revisions_id, revision_ix)?;
-                    let (_, merges_id) = tx.get(&revision_id, "merges")?;
-
-                    let length = tx.length(&merges_id);
-                    let merge_id = tx.insert_object(&merges_id, length, ObjType::Map)?;
-
-                    tx.put(&merge_id, "peer", merge.node.to_string())?;
-                    tx.put(&merge_id, "commit", merge.commit.to_string())?;
-                    tx.put(&merge_id, "timestamp", merge.timestamp)?;
-
-                    Ok(())
-                },
-            )
-            .map_err(|failure| failure.error)?;
-
-        #[allow(clippy::unwrap_used)]
-        let change = patch.get_last_local_change().unwrap().raw_bytes().to_vec();
-
-        Ok(change)
-    }
-}
-
-#[cfg(test)]
-mod test {
-    use super::*;
-    use crate::test;
-
-    #[test]
-    fn test_patch_create_and_get() {
-        let tmp = tempfile::tempdir().unwrap();
-        let (_, signer, project) = test::setup::context(&tmp);
-        let store = Store::open(*signer.public_key(), &project).unwrap();
-        let patches = store.patches();
-        let author = *signer.public_key();
-        let timestamp = Timestamp::now();
-        let target = MergeTarget::Delegates;
-        let oid = git::Oid::from(git2::Oid::zero());
-        let base = git::Oid::from_str("cb18e95ada2bb38aadd8e6cef0963ce37a87add3").unwrap();
-        let patch_id = patches
-            .create(
-                "My first patch",
-                "Blah blah blah.",
-                target,
-                base,
-                oid,
-                &[],
-                &signer,
-            )
-            .unwrap();
-        let patch = patches.get(&patch_id).unwrap().unwrap();
-
-        assert_eq!(&patch.title, "My first patch");
-        assert_eq!(patch.author.id(), &author);
-        assert_eq!(patch.state, State::Proposed);
-        assert!(patch.timestamp >= timestamp);
-
-        let revision = patch.revisions.head;
-
-        assert_eq!(revision.author(), &store.author());
-        assert_eq!(revision.comment.body, "Blah blah blah.");
-        assert_eq!(revision.discussion.len(), 0);
-        assert_eq!(revision.oid, oid);
-        assert_eq!(revision.base, base);
-        assert!(revision.reviews.is_empty());
-        assert!(revision.merges.is_empty());
-    }
-
-    #[test]
-    fn test_patch_merge() {
-        let tmp = tempfile::tempdir().unwrap();
-        let (_, signer, project) = test::setup::context(&tmp);
-        let store = Store::open(*signer.public_key(), &project).unwrap();
-        let patches = store.patches();
-        let target = MergeTarget::Delegates;
-        let oid = git::Oid::from(git2::Oid::zero());
-        let base = git::Oid::from_str("cb18e95ada2bb38aadd8e6cef0963ce37a87add3").unwrap();
-        let patch_id = patches
-            .create(
-                "My first patch",
-                "Blah blah blah.",
-                target,
-                base,
-                oid,
-                &[],
-                &signer,
-            )
-            .unwrap();
-
-        let _merge = patches.merge(&patch_id, 0, base, &signer).unwrap();
-        let patch = patches.get(&patch_id).unwrap().unwrap();
-        let merges = patch.revisions.head.merges;
-
-        assert_eq!(merges.len(), 1);
-        assert_eq!(merges[0].node, *signer.public_key());
-        assert_eq!(merges[0].commit, base);
-    }
-
-    #[test]
-    fn test_patch_review() {
-        let tmp = tempfile::tempdir().unwrap();
-        let (_, signer, project) = test::setup::context(&tmp);
-        let store = Store::open(*signer.public_key(), &project).unwrap();
-        let patches = store.patches();
-        let whoami = store.author();
-        let target = MergeTarget::Delegates;
-        let base = git::Oid::from_str("cb18e95ada2bb38aadd8e6cef0963ce37a87add3").unwrap();
-        let rev_oid = git::Oid::from_str("518d5069f94c03427f694bb494ac1cd7d1339380").unwrap();
-        let patch_id = patches
-            .create(
-                "My first patch",
-                "Blah blah blah.",
-                target,
-                base,
-                rev_oid,
-                &[],
-                &signer,
-            )
-            .unwrap();
-
-        patches
-            .review(&patch_id, 0, Some(Verdict::Accept), "LGTM", vec![], &signer)
-            .unwrap();
-        let patch = patches.get(&patch_id).unwrap().unwrap();
-        let reviews = patch.revisions.head.reviews;
-        assert_eq!(reviews.len(), 1);
-
-        let review = reviews.get(whoami.id()).unwrap();
-        assert_eq!(review.author.id(), whoami.id());
-        assert_eq!(review.verdict, Some(Verdict::Accept));
-        assert_eq!(review.comment.body.as_str(), "LGTM");
-    }
-
-    #[test]
-    fn test_patch_update() {
-        let tmp = tempfile::tempdir().unwrap();
-        let (_, signer, project) = test::setup::context(&tmp);
-        let store = Store::open(*signer.public_key(), &project).unwrap();
-        let patches = store.patches();
-        let target = MergeTarget::Delegates;
-        let base = git::Oid::from_str("af08e95ada2bb38aadd8e6cef0963ce37a87add3").unwrap();
-        let rev0_oid = git::Oid::from_str("518d5069f94c03427f694bb494ac1cd7d1339380").unwrap();
-        let rev1_oid = git::Oid::from_str("cb18e95ada2bb38aadd8e6cef0963ce37a87add3").unwrap();
-        let patch_id = patches
-            .create(
-                "My first patch",
-                "Blah blah blah.",
-                target,
-                base,
-                rev0_oid,
-                &[],
-                &signer,
-            )
-            .unwrap();
-
-        let patch = patches.get(&patch_id).unwrap().unwrap();
-        assert_eq!(patch.description(), "Blah blah blah.");
-        assert_eq!(patch.version(), 0);
-
-        let revision_id = patches
-            .update(&patch_id, "I've made changes.", base, rev1_oid, &signer)
-            .unwrap();
-
-        assert_eq!(revision_id, 1);
-
-        let patch = patches.get(&patch_id).unwrap().unwrap();
-        assert_eq!(patch.description(), "I've made changes.");
-
-        assert_eq!(patch.revisions.len(), 2);
-        assert_eq!(patch.version(), 1);
-
-        let (id, revision) = patch.latest();
-
-        assert_eq!(id, 1);
-        assert_eq!(revision.oid, rev1_oid);
-        assert_eq!(revision.description(), "I've made changes.");
-    }
 }
diff --git a/radicle/src/cob/shared.rs b/radicle/src/cob/shared.rs
deleted file mode 100644
index 47ced735..00000000
--- a/radicle/src/cob/shared.rs
+++ /dev/null
@@ -1,394 +0,0 @@
-#![allow(clippy::large_enum_variant)]
-use std::borrow::Borrow;
-use std::collections::HashMap;
-use std::fmt;
-use std::hash::Hash;
-use std::str::FromStr;
-use std::time::{SystemTime, UNIX_EPOCH};
-
-use automerge::transaction::Transactable;
-use automerge::{AutomergeError, ObjType, ScalarValue};
-use serde::{Deserialize, Serialize};
-
-use crate::cob::doc::{Document, DocumentError};
-use crate::cob::value::{FromValue, Value, ValueError};
-use crate::prelude::*;
-
-/// A discussion thread.
-pub type Discussion = Vec<Comment<Replies>>;
-
-#[derive(thiserror::Error, Debug)]
-pub enum ReactionError {
-    #[error("invalid reaction")]
-    InvalidReaction,
-}
-
-#[derive(Debug, PartialEq, Eq, PartialOrd, Ord, Hash, Copy, Clone, Serialize, Deserialize)]
-#[serde(transparent)]
-pub struct Reaction {
-    pub emoji: char,
-}
-
-impl Reaction {
-    pub fn new(emoji: char) -> Result<Self, ReactionError> {
-        if emoji.is_whitespace() || emoji.is_ascii() || emoji.is_alphanumeric() {
-            return Err(ReactionError::InvalidReaction);
-        }
-        Ok(Self { emoji })
-    }
-}
-
-impl FromStr for Reaction {
-    type Err = ReactionError;
-
-    fn from_str(s: &str) -> Result<Self, Self::Err> {
-        let mut chars = s.chars();
-        let first = chars.next().ok_or(ReactionError::InvalidReaction)?;
-
-        // Reactions should not consist of more than a single emoji.
-        if chars.next().is_some() {
-            return Err(ReactionError::InvalidReaction);
-        }
-        Reaction::new(first)
-    }
-}
-
-#[derive(thiserror::Error, Debug)]
-pub enum LabelError {
-    #[error("invalid label name: `{0}`")]
-    InvalidName(String),
-}
-
-#[derive(Debug, PartialEq, Eq, Hash, Clone, Serialize, Deserialize)]
-#[serde(transparent)]
-pub struct Label(String);
-
-impl Label {
-    pub fn new(name: impl Into<String>) -> Result<Self, LabelError> {
-        let name = name.into();
-
-        if name.chars().any(|c| c.is_whitespace()) || name.is_empty() {
-            return Err(LabelError::InvalidName(name));
-        }
-        Ok(Self(name))
-    }
-
-    pub fn name(&self) -> &str {
-        self.0.as_str()
-    }
-}
-
-impl FromStr for Label {
-    type Err = LabelError;
-
-    fn from_str(s: &str) -> Result<Self, Self::Err> {
-        Self::new(s)
-    }
-}
-
-impl From<Label> for String {
-    fn from(Label(name): Label) -> Self {
-        name
-    }
-}
-
-/// RGB color.
-#[derive(Debug, PartialEq, Eq, Hash, Clone)]
-pub struct Color(u32);
-
-#[derive(thiserror::Error, Debug)]
-pub enum ColorConversionError {
-    #[error("invalid format: expect '#rrggbb'")]
-    InvalidFormat,
-    #[error(transparent)]
-    ParseInt(#[from] std::num::ParseIntError),
-}
-
-impl fmt::Display for Color {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        write!(f, "#{:06x}", self.0)
-    }
-}
-
-impl FromStr for Color {
-    type Err = ColorConversionError;
-
-    fn from_str(s: &str) -> Result<Self, Self::Err> {
-        let hex = s.replace('#', "").to_lowercase();
-
-        if hex.chars().count() != 6 {
-            return Err(ColorConversionError::InvalidFormat);
-        }
-
-        match u32::from_str_radix(&hex, 16) {
-            Ok(n) => Ok(Color(n)),
-            Err(e) => Err(e.into()),
-        }
-    }
-}
-
-impl<'a> FromValue<'a> for Color {
-    fn from_value(val: Value<'a>) -> Result<Self, ValueError> {
-        let color = String::from_value(val)?;
-        let color = Self::from_str(&color).map_err(|_| ValueError::InvalidValue(color))?;
-
-        Ok(color)
-    }
-}
-
-impl Serialize for Color {
-    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
-    where
-        S: serde::ser::Serializer,
-    {
-        let s = self.to_string();
-        serializer.serialize_str(&s)
-    }
-}
-
-impl<'a> Deserialize<'a> for Color {
-    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
-    where
-        D: serde::de::Deserializer<'a>,
-    {
-        let color = String::deserialize(deserializer)?;
-        Self::from_str(&color).map_err(serde::de::Error::custom)
-    }
-}
-
-/// Author.
-#[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq)]
-pub struct Author {
-    pub id: NodeId,
-}
-
-impl Author {
-    pub fn new(id: NodeId) -> Self {
-        Self { id }
-    }
-
-    pub fn id(&self) -> &NodeId {
-        &self.id
-    }
-}
-
-impl From<&Author> for ScalarValue {
-    fn from(author: &Author) -> Self {
-        ScalarValue::from(author.id.to_human())
-    }
-}
-
-/// Local id of a comment in an issue.
-#[derive(Debug, PartialEq, Eq, PartialOrd, Ord, Copy, Clone)]
-pub struct CommentId {
-    /// Represents the index of the comment in the thread,
-    /// with `0` being the top-level comment.
-    ix: usize,
-}
-
-impl CommentId {
-    /// Root comment.
-    pub const fn root() -> Self {
-        Self { ix: 0 }
-    }
-}
-
-impl From<usize> for CommentId {
-    fn from(ix: usize) -> Self {
-        Self { ix }
-    }
-}
-
-impl From<CommentId> for usize {
-    fn from(id: CommentId) -> Self {
-        id.ix
-    }
-}
-
-/// Comment replies.
-pub type Replies = Vec<Comment>;
-
-#[derive(Debug, Clone, Serialize, Deserialize)]
-pub struct Comment<R = ()> {
-    pub author: Author,
-    pub body: String,
-    pub reactions: HashMap<Reaction, usize>,
-    pub replies: R,
-    pub timestamp: Timestamp,
-}
-
-impl<R: Default> Comment<R> {
-    pub fn new(author: Author, body: String, timestamp: Timestamp) -> Self {
-        Self {
-            author,
-            body,
-            reactions: HashMap::default(),
-            replies: R::default(),
-            timestamp,
-        }
-    }
-}
-
-impl Comment<()> {
-    pub(super) fn put(
-        &self,
-        tx: &mut automerge::transaction::Transaction,
-        id: &automerge::ObjId,
-    ) -> Result<(), AutomergeError> {
-        let comment_id = tx.put_object(id, "comment", ObjType::Map)?;
-
-        assert!(
-            self.reactions.is_empty(),
-            "Cannot put comment with non-empty reactions"
-        );
-
-        tx.put(&comment_id, "body", self.body.trim())?;
-        tx.put(&comment_id, "author", self.author.id().to_string())?;
-        tx.put(&comment_id, "timestamp", self.timestamp)?;
-        tx.put_object(&comment_id, "reactions", ObjType::Map)?;
-
-        Ok(())
-    }
-}
-
-impl Comment<Replies> {
-    pub(super) fn put(
-        &self,
-        tx: &mut automerge::transaction::Transaction,
-        id: &automerge::ObjId,
-    ) -> Result<(), AutomergeError> {
-        let comment_id = tx.put_object(id, "comment", ObjType::Map)?;
-
-        assert!(
-            self.reactions.is_empty(),
-            "Cannot put comment with non-empty reactions"
-        );
-        assert!(
-            self.replies.is_empty(),
-            "Cannot put comment with non-empty replies"
-        );
-
-        tx.put(&comment_id, "body", self.body.trim())?;
-        tx.put(&comment_id, "author", self.author.id().to_string())?;
-        tx.put(&comment_id, "timestamp", self.timestamp)?;
-        tx.put_object(&comment_id, "reactions", ObjType::Map)?;
-        tx.put_object(&comment_id, "replies", ObjType::List)?;
-
-        Ok(())
-    }
-}
-
-#[derive(Debug, Default, Copy, Clone, PartialOrd, PartialEq, Ord, Eq, Serialize, Deserialize)]
-#[serde(transparent)]
-pub struct Timestamp {
-    seconds: u64,
-}
-
-impl Timestamp {
-    pub fn new(seconds: u64) -> Self {
-        Self { seconds }
-    }
-
-    pub fn now() -> Self {
-        #[allow(clippy::unwrap_used)] // Safe because Unix was already invented!
-        let duration = SystemTime::now().duration_since(UNIX_EPOCH).unwrap();
-
-        Self {
-            seconds: duration.as_secs(),
-        }
-    }
-
-    pub fn as_secs(&self) -> u64 {
-        self.seconds
-    }
-}
-
-impl std::ops::Add<u64> for Timestamp {
-    type Output = Self;
-
-    fn add(self, rhs: u64) -> Self::Output {
-        Self {
-            seconds: self.seconds + rhs,
-        }
-    }
-}
-
-impl From<Timestamp> for ScalarValue {
-    fn from(ts: Timestamp) -> Self {
-        ScalarValue::Timestamp(ts.seconds as i64)
-    }
-}
-
-impl<'a> FromValue<'a> for Timestamp {
-    fn from_value(val: Value<'a>) -> Result<Self, ValueError> {
-        if let Value::Scalar(scalar) = &val {
-            if let ScalarValue::Timestamp(ts) = scalar.borrow() {
-                return Ok(Self {
-                    seconds: *ts as u64,
-                });
-            }
-        }
-        Err(ValueError::InvalidValue(val.to_string()))
-    }
-}
-
-pub mod lookup {
-    use super::{Author, Comment, HashMap, Reaction, Replies};
-    use super::{Document, DocumentError};
-
-    pub fn comment(doc: Document, obj_id: &automerge::ObjId) -> Result<Comment<()>, DocumentError> {
-        let author = doc.get(obj_id, "author").map(Author::new)?;
-        let body = doc.get(obj_id, "body")?;
-        let timestamp = doc.get(obj_id, "timestamp")?;
-        let reactions: HashMap<Reaction, usize> = doc.map(obj_id, "reactions", |v| *v += 1)?;
-
-        Ok(Comment {
-            author,
-            body,
-            reactions,
-            replies: (),
-            timestamp,
-        })
-    }
-
-    pub fn thread(
-        doc: Document,
-        obj_id: &automerge::ObjId,
-    ) -> Result<Comment<Replies>, DocumentError> {
-        let comment = self::comment(doc, obj_id)?;
-        let replies = doc.list(obj_id, "replies", self::comment)?;
-
-        Ok(Comment {
-            author: comment.author,
-            body: comment.body,
-            reactions: comment.reactions,
-            replies,
-            timestamp: comment.timestamp,
-        })
-    }
-}
-
-#[cfg(test)]
-mod test {
-    use super::*;
-
-    #[test]
-    fn test_color() {
-        let c = Color::from_str("#ffccaa").unwrap();
-        assert_eq!(c.to_string(), "#ffccaa".to_owned());
-        assert_eq!(serde_json::to_string(&c).unwrap(), "\"#ffccaa\"".to_owned());
-        assert_eq!(serde_json::from_str::<'_, Color>("\"#ffccaa\"").unwrap(), c);
-
-        let c = Color::from_str("#0000aa").unwrap();
-        assert_eq!(c.to_string(), "#0000aa".to_owned());
-
-        let c = Color::from_str("#aa0000").unwrap();
-        assert_eq!(c.to_string(), "#aa0000".to_owned());
-
-        let c = Color::from_str("#00aa00").unwrap();
-        assert_eq!(c.to_string(), "#00aa00".to_owned());
-
-        Color::from_str("#aa00").unwrap_err();
-        Color::from_str("#abc").unwrap_err();
-    }
-}