From 171b5a45f7486515b00d9e530f730962e003170a Mon Sep 17 00:00:00 2001
From: Alexis Sellier <alexis@radicle.xyz>
Date: Sat, 26 Nov 2022 11:59:36 +0100
Subject: [PATCH] Implement issues using radicle CRDTs

Signed-off-by: Alexis Sellier <alexis@radicle.xyz>
---
 radicle-cli/src/commands/issue.rs  |  34 +-
 radicle-cli/src/terminal/io.rs     |  13 +-
 radicle/src/cob/automerge.rs       |   1 -
 radicle/src/cob/automerge/issue.rs | 682 -----------------------------
 radicle/src/cob/automerge/patch.rs |   6 +-
 radicle/src/cob/automerge/store.rs |  12 +-
 radicle/src/cob/common.rs          |  22 +-
 radicle/src/cob/issue.rs           | 601 +++++++++++++++++++++++--
 radicle/src/cob/patch.rs           |   2 +-
 radicle/src/cob/store.rs           |  52 ++-
 radicle/src/cob/thread.rs          | 110 +++--
 radicle/src/lib.rs                 |   1 +
 12 files changed, 704 insertions(+), 832 deletions(-)
 delete mode 100644 radicle/src/cob/automerge/issue.rs

diff --git a/radicle-cli/src/commands/issue.rs b/radicle-cli/src/commands/issue.rs
index 102523ee..769b87ea 100644
--- a/radicle-cli/src/commands/issue.rs
+++ b/radicle-cli/src/commands/issue.rs
@@ -7,9 +7,8 @@ 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::common::{Reaction, Tag};
+use radicle::cob::issue::{CloseReason, IssueId, Issues, Status};
 use radicle::storage::WriteStorage;
 
 pub const HELP: Help = Help {
@@ -34,7 +33,7 @@ Options
 #[derive(serde::Deserialize, serde::Serialize, Debug)]
 pub struct Metadata {
     title: String,
-    labels: Vec<Label>,
+    labels: Vec<Tag>,
 }
 
 #[derive(Debug, PartialEq, Eq)]
@@ -60,7 +59,7 @@ pub enum Operation {
     },
     State {
         id: IssueId,
-        state: State,
+        state: Status,
     },
     Delete {
         id: IssueId,
@@ -87,7 +86,7 @@ impl Args for Options {
         let mut title: Option<String> = None;
         let mut reaction: Option<Reaction> = None;
         let mut description: Option<String> = None;
-        let mut state: Option<State> = None;
+        let mut state: Option<Status> = None;
 
         while let Some(arg) = parser.next()? {
             match arg {
@@ -98,15 +97,15 @@ impl Args for Options {
                     title = Some(parser.value()?.to_string_lossy().into());
                 }
                 Long("closed") if op == Some(OperationName::State) => {
-                    state = Some(State::Closed {
+                    state = Some(Status::Closed {
                         reason: CloseReason::Other,
                     });
                 }
                 Long("open") if op == Some(OperationName::State) => {
-                    state = Some(State::Open);
+                    state = Some(Status::Open);
                 }
                 Long("solved") if op == Some(OperationName::State) => {
-                    state = Some(State::Closed {
+                    state = Some(Status::Closed {
                         reason: CloseReason::Solved,
                     });
                 }
@@ -170,23 +169,23 @@ pub fn run(options: Options, ctx: impl term::Context) -> anyhow::Result<()> {
     let storage = &profile.storage;
     let (_, id) = radicle::rad::cwd()?;
     let repo = storage.repository(id)?;
-    let cobs = Store::open(*signer.public_key(), &repo)?;
-    let issues = cobs.issues();
+    let mut issues = Issues::open(*signer.public_key(), &repo)?;
 
     match options.op {
         Operation::Create {
             title: Some(title),
             description: Some(description),
         } => {
-            issues.create(&title, &description, &[], &signer)?;
+            issues.create(title, description, &[], &signer)?;
         }
         Operation::State { id, state } => {
-            issues.lifecycle(&id, state, &signer)?;
+            let mut issue = issues.get_mut(&id)?;
+            issue.lifecycle(state, &signer)?;
         }
         Operation::React { id, reaction } => {
-            if let Some(issue) = issues.get(&id)? {
+            if let Ok(mut issue) = issues.get_mut(&id) {
                 let comment_id = term::comment_select(&issue).unwrap();
-                issues.react(&id, comment_id, reaction, &signer)?;
+                issue.react(comment_id, reaction, &signer)?;
             }
         }
         Operation::Create { title, description } => {
@@ -234,12 +233,13 @@ pub fn run(options: Options, ctx: impl term::Context) -> anyhow::Result<()> {
             }
         }
         Operation::List => {
-            for (id, issue) in issues.all()? {
+            for result in issues.all()? {
+                let (id, issue) = result?;
                 println!("{} {}", id, issue.title());
             }
         }
         Operation::Delete { id } => {
-            issues.remove(&id, &signer)?;
+            issues.remove(&id)?;
         }
     }
 
diff --git a/radicle-cli/src/terminal/io.rs b/radicle-cli/src/terminal/io.rs
index da7f17a4..340405e3 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::thread::CommentId;
 use radicle::crypto::ssh::keystore::Passphrase;
 use radicle::crypto::Signer;
 use radicle::profile::env::RAD_PASSPHRASE;
@@ -378,19 +378,20 @@ where
 pub fn comment_select(issue: &Issue) -> Option<CommentId> {
     let selection = dialoguer::Select::with_theme(&theme())
         .with_prompt("Which comment do you want to react to?")
-        .item(&issue.description().to_string())
+        .item(issue.description().unwrap_or_default())
         .items(
             &issue
                 .comments()
-                .iter()
-                .map(|p| p.body.clone())
+                .map(|(_, i)| i.body.clone())
                 .collect::<Vec<_>>(),
         )
-        .default(CommentId::root().into())
+        .default(0)
         .interact_opt()
         .unwrap();
 
-    selection.map(CommentId::from)
+    selection
+        .and_then(|n| issue.comments().nth(n))
+        .map(|(id, _)| *id)
 }
 
 pub fn markdown(content: &str) {
diff --git a/radicle/src/cob/automerge.rs b/radicle/src/cob/automerge.rs
index 476e5a13..ac384fd0 100644
--- a/radicle/src/cob/automerge.rs
+++ b/radicle/src/cob/automerge.rs
@@ -1,5 +1,4 @@
 pub mod doc;
-pub mod issue;
 pub mod label;
 pub mod patch;
 pub mod shared;
diff --git a/radicle/src/cob/automerge/issue.rs b/radicle/src/cob/automerge/issue.rs
deleted file mode 100644
index 6479b39d..00000000
--- a/radicle/src/cob/automerge/issue.rs
+++ /dev/null
@@ -1,682 +0,0 @@
-#![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/automerge/patch.rs b/radicle/src/cob/automerge/patch.rs
index 52d0421c..333d2d84 100644
--- a/radicle/src/cob/automerge/patch.rs
+++ b/radicle/src/cob/automerge/patch.rs
@@ -33,7 +33,7 @@ impl TryFrom<Document<'_>> for Patch {
         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 labels: HashSet<Tag> = doc.keys(&obj_id, "labels")?;
         let revisions =
             NonEmpty::from_vec(revisions).ok_or(DocumentError::EmptyList("revisions"))?;
         let author: Author = Author::new(author);
@@ -81,7 +81,7 @@ impl<'a> PatchStore<'a> {
         target: MergeTarget,
         base: impl Into<git::Oid>,
         oid: impl Into<git::Oid>,
-        labels: &[Label],
+        labels: &[Tag],
         signer: &G,
     ) -> Result<PatchId, Error> {
         let author = self.author();
@@ -464,7 +464,7 @@ mod events {
         revision: &Revision,
         target: MergeTarget,
         timestamp: Timestamp,
-        labels: &[Label],
+        labels: &[Tag],
     ) -> Result<Contents, TransactionError> {
         let title = title.trim();
         if title.is_empty() {
diff --git a/radicle/src/cob/automerge/store.rs b/radicle/src/cob/automerge/store.rs
index 1bccdf64..99d388b5 100644
--- a/radicle/src/cob/automerge/store.rs
+++ b/radicle/src/cob/automerge/store.rs
@@ -9,7 +9,7 @@ use crate::cob;
 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::automerge::{label, patch};
 use crate::cob::common::Author;
 use crate::cob::CollaborativeObject;
 use crate::cob::{Contents, Create, HistoryType, ObjectId, TypeName, Update};
@@ -77,16 +77,6 @@ impl<'a> Store<'a, ()> {
         })
     }
 
-    /// Return an issues store from this generic store.
-    pub fn issues(&self) -> issue::IssueStore<'_> {
-        issue::IssueStore::new(Store {
-            whoami: self.whoami,
-            project: self.project.clone(),
-            raw: self.raw,
-            witness: PhantomData,
-        })
-    }
-
     /// Return a labels store from this generic store.
     pub fn labels(&self) -> label::LabelStore<'_> {
         label::LabelStore::new(Store {
diff --git a/radicle/src/cob/common.rs b/radicle/src/cob/common.rs
index dde69af5..0883d41d 100644
--- a/radicle/src/cob/common.rs
+++ b/radicle/src/cob/common.rs
@@ -95,21 +95,21 @@ impl FromStr for Reaction {
 }
 
 #[derive(thiserror::Error, Debug)]
-pub enum LabelError {
-    #[error("invalid label name: `{0}`")]
+pub enum TagError {
+    #[error("invalid tag name: `{0}`")]
     InvalidName(String),
 }
 
-#[derive(Debug, PartialEq, Eq, Hash, Clone, Serialize, Deserialize)]
+#[derive(Debug, PartialEq, Eq, PartialOrd, Ord, Hash, Clone, Serialize, Deserialize)]
 #[serde(transparent)]
-pub struct Label(String);
+pub struct Tag(String);
 
-impl Label {
-    pub fn new(name: impl Into<String>) -> Result<Self, LabelError> {
+impl Tag {
+    pub fn new(name: impl Into<String>) -> Result<Self, TagError> {
         let name = name.into();
 
         if name.chars().any(|c| c.is_whitespace()) || name.is_empty() {
-            return Err(LabelError::InvalidName(name));
+            return Err(TagError::InvalidName(name));
         }
         Ok(Self(name))
     }
@@ -119,16 +119,16 @@ impl Label {
     }
 }
 
-impl FromStr for Label {
-    type Err = LabelError;
+impl FromStr for Tag {
+    type Err = TagError;
 
     fn from_str(s: &str) -> Result<Self, Self::Err> {
         Self::new(s)
     }
 }
 
-impl From<Label> for String {
-    fn from(Label(name): Label) -> Self {
+impl From<Tag> for String {
+    fn from(Tag(name): Tag) -> Self {
         name
     }
 }
diff --git a/radicle/src/cob/issue.rs b/radicle/src/cob/issue.rs
index 3a23096e..a281e66a 100644
--- a/radicle/src/cob/issue.rs
+++ b/radicle/src/cob/issue.rs
@@ -1,11 +1,20 @@
-use std::collections::{HashMap, HashSet};
+use std::ops::{ControlFlow, Deref};
 use std::str::FromStr;
 
 use once_cell::sync::Lazy;
+use radicle_crdt as crdt;
+use radicle_crdt::{ChangeId, LClock, LWWReg, Max, Semilattice};
 use serde::{Deserialize, Serialize};
+use thiserror::Error;
 
-use crate::cob::common::*;
-use crate::cob::{ObjectId, Timestamp, TypeName};
+use crate::cob::common::{Author, Reaction, Tag};
+use crate::cob::thread;
+use crate::cob::thread::{CommentId, Thread};
+use crate::cob::{store, ObjectId, TypeName};
+use crate::crypto::{PublicKey, Signer};
+use crate::storage::git as storage;
+
+pub type Change = crdt::Change<Action>;
 
 /// Type name of an issue.
 pub static TYPENAME: Lazy<TypeName> =
@@ -14,75 +23,589 @@ pub static TYPENAME: Lazy<TypeName> =
 /// Identifier for an issue.
 pub type IssueId = ObjectId;
 
+/// Error updating or creating issues.
+#[derive(Error, Debug)]
+pub enum Error {
+    #[error("apply failed")]
+    Apply,
+    #[error("store: {0}")]
+    Store(#[from] store::Error),
+}
+
 /// Reason why an issue was closed.
-#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize)]
+#[derive(Debug, Clone, Copy, PartialOrd, Ord, PartialEq, Eq, Serialize, Deserialize)]
 #[serde(rename_all = "lowercase")]
 pub enum CloseReason {
-    Solved,
     Other,
+    Solved,
 }
 
 /// Issue state.
-#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize)]
+#[derive(Debug, Default, Clone, Copy, PartialOrd, Ord, PartialEq, Eq, Serialize, Deserialize)]
 #[serde(rename_all = "lowercase", tag = "status")]
-pub enum State {
-    /// The issue is open.
-    Open,
+pub enum Status {
     /// The issue is closed.
     Closed { reason: CloseReason },
+    /// The issue is open.
+    #[default]
+    Open,
 }
 
-impl State {
-    pub fn lifecycle_message(self) -> String {
+impl std::fmt::Display for Status {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
         match self {
-            State::Open => "Open issue".to_owned(),
-            State::Closed { .. } => "Close issue".to_owned(),
+            Self::Closed { .. } => write!(f, "closed"),
+            Self::Open { .. } => write!(f, "open"),
         }
     }
 }
 
-/// An issue or "ticket".
-#[derive(Debug, Clone, Serialize, Deserialize)]
+impl Status {
+    pub fn lifecycle_message(self) -> String {
+        match self {
+            Status::Open => "Open issue".to_owned(),
+            Status::Closed { .. } => "Close issue".to_owned(),
+        }
+    }
+}
+
+/// Issue state. Accumulates [`Action`].
+#[derive(Debug, Clone, PartialEq, Eq)]
 pub struct Issue {
-    pub author: Author,
-    pub title: String,
-    pub state: State,
-    pub comment: Comment,
-    pub discussion: Discussion,
-    pub labels: HashSet<Label>,
-    pub timestamp: Timestamp,
+    // TODO(cloudhead): Title should bias towards shorter strings.
+    title: LWWReg<Max<String>, LClock>,
+    status: LWWReg<Max<Status>, LClock>,
+    thread: Thread,
+    clock: LClock,
+}
+
+impl Semilattice for Issue {
+    fn merge(&mut self, other: Self) {
+        self.title.merge(other.title);
+        self.status.merge(other.status);
+        self.thread.merge(other.thread);
+    }
+}
+
+impl Default for Issue {
+    fn default() -> Self {
+        Self {
+            title: Max::from(String::default()).into(),
+            status: Max::from(Status::default()).into(),
+            thread: Thread::default(),
+            clock: LClock::default(),
+        }
+    }
+}
+
+impl store::FromHistory for Issue {
+    fn type_name() -> &'static TypeName {
+        &*TYPENAME
+    }
+
+    fn from_history(history: &radicle_cob::History) -> Result<Self, store::Error> {
+        Ok(history.traverse(Self::default(), |mut acc, entry| {
+            if let Ok(change) = Change::decode(entry.contents()) {
+                if let Err(err) = acc.apply(change) {
+                    log::warn!("Error applying change to issue state: {err}");
+                    return ControlFlow::Break(acc);
+                }
+            } else {
+                return ControlFlow::Break(acc);
+            }
+            ControlFlow::Continue(acc)
+        }))
+    }
 }
 
 impl Issue {
-    pub fn author(&self) -> &Author {
-        &self.author
-    }
-
     pub fn title(&self) -> &str {
-        &self.title
+        self.title.get().as_str()
     }
 
-    pub fn state(&self) -> State {
-        self.state
+    pub fn status(&self) -> &Status {
+        self.status.get()
     }
 
-    pub fn description(&self) -> &str {
-        &self.comment.body
+    pub fn tags(&self) -> impl Iterator<Item = &Tag> {
+        self.thread.tags()
     }
 
-    pub fn reactions(&self) -> &HashMap<Reaction, usize> {
-        &self.comment.reactions
+    pub fn author(&self) -> Option<Author> {
+        self.thread
+            .comments()
+            .next()
+            .map(|((_, pk), _)| Author::new(*pk))
     }
 
-    pub fn comments(&self) -> &[Comment<Replies>] {
-        &self.discussion
+    pub fn description(&self) -> Option<&str> {
+        self.thread.comments().next().map(|(_, c)| c.body.as_str())
     }
 
-    pub fn labels(&self) -> &HashSet<Label> {
-        &self.labels
+    pub fn comments(&self) -> impl Iterator<Item = (&CommentId, &thread::Comment)> {
+        self.thread.comments().map(|(id, comment)| (id, comment))
     }
 
-    pub fn timestamp(&self) -> Timestamp {
-        self.timestamp
+    pub fn clock(&self) -> &LClock {
+        &self.clock
+    }
+
+    pub fn timeline(&self) -> Vec<Action> {
+        todo!();
+    }
+
+    pub fn apply(&mut self, change: Change) -> Result<(), Error> {
+        match change.action {
+            Action::Title { title } => {
+                self.title.set(title, change.clock);
+            }
+            Action::Lifecycle { status } => {
+                self.status.set(status, change.clock);
+            }
+            Action::Thread { action } => {
+                self.thread.apply([crdt::Change {
+                    action,
+                    author: change.author,
+                    clock: change.clock,
+                }]);
+            }
+        }
+        self.clock.merge(change.clock);
+
+        Ok(())
+    }
+}
+
+impl Deref for Issue {
+    type Target = Thread;
+
+    fn deref(&self) -> &Self::Target {
+        &self.thread
+    }
+}
+
+pub struct IssueMut<'a, 'g> {
+    id: ObjectId,
+    clock: LClock,
+    issue: Issue,
+    store: &'g mut Issues<'a>,
+}
+
+impl<'a, 'g> IssueMut<'a, 'g> {
+    /// Get the internal logical clock.
+    pub fn clock(&self) -> &LClock {
+        &self.clock
+    }
+
+    /// Lifecycle an issue.
+    pub fn lifecycle<G: Signer>(&mut self, status: Status, signer: &G) -> Result<ChangeId, Error> {
+        let clock = self.clock.tick();
+        let change = Change {
+            action: Action::Lifecycle { status },
+            author: *signer.public_key(),
+            clock,
+        };
+        self.apply("Lifecycle", change, signer)
+    }
+
+    /// Comment on an issue.
+    pub fn comment<G: Signer, S: Into<String>>(
+        &mut self,
+        body: S,
+        signer: &G,
+    ) -> Result<CommentId, Error> {
+        let author = *signer.public_key();
+        let clock = self.clock.tick();
+        let body = body.into();
+        let comment = thread::Comment::new(body, None);
+        let change = Change {
+            action: Action::from(thread::Action::Comment { comment }),
+            author,
+            clock,
+        };
+        self.apply("Comment", change, signer)
+    }
+
+    /// Tag an issue.
+    pub fn tag<G: Signer>(
+        &mut self,
+        tags: impl IntoIterator<Item = Tag>,
+        signer: &G,
+    ) -> Result<ChangeId, Error> {
+        let author = *signer.public_key();
+        let clock = self.clock.tick();
+        let tags = tags.into_iter().collect::<Vec<_>>();
+        let change = Change {
+            author,
+            action: Action::Thread {
+                action: thread::Action::Tag { tags },
+            },
+            clock,
+        };
+        self.apply("Tag", change, signer)
+    }
+
+    /// Reply to on an issue comment.
+    pub fn reply<G: Signer, S: Into<String>>(
+        &mut self,
+        parent: CommentId,
+        body: S,
+        signer: &G,
+    ) -> Result<ChangeId, Error> {
+        let author = *signer.public_key();
+        let clock = self.clock.tick();
+        let body = body.into();
+
+        assert!(self.thread.comment(&parent).is_some());
+
+        let comment = thread::Comment::new(body, Some(parent));
+        let change = Change {
+            action: Action::from(thread::Action::Comment { comment }),
+            author,
+            clock,
+        };
+        self.apply("Reply", change, signer)
+    }
+
+    /// React to an issue comment.
+    pub fn react<G: Signer>(
+        &mut self,
+        to: CommentId,
+        reaction: Reaction,
+        signer: &G,
+    ) -> Result<ChangeId, Error> {
+        let author = *signer.public_key();
+        let clock = self.clock.tick();
+        let change = Change {
+            action: Action::Thread {
+                action: thread::Action::React {
+                    to,
+                    reaction,
+                    active: true,
+                },
+            },
+            author,
+            clock,
+        };
+        self.apply("React", change, signer)
+    }
+
+    /// Apply a change to the issue.
+    pub fn apply<G: Signer>(
+        &mut self,
+        msg: &'static str,
+        change: Change,
+        signer: &G,
+    ) -> Result<ChangeId, Error> {
+        let id = change.id();
+
+        self.issue.apply(change.clone())?;
+        self.store
+            .update(self.id, msg, change, signer)
+            .map_err(|e| Error::Store(store::Error::from(e)))?;
+
+        Ok(id)
+    }
+}
+
+impl<'a, 'g> Deref for IssueMut<'a, 'g> {
+    type Target = Issue;
+
+    fn deref(&self) -> &Self::Target {
+        &self.issue
+    }
+}
+
+pub struct Issues<'a> {
+    raw: store::Store<'a, Issue>,
+}
+
+impl<'a> Deref for Issues<'a> {
+    type Target = store::Store<'a, Issue>;
+
+    fn deref(&self) -> &Self::Target {
+        &self.raw
+    }
+}
+
+impl<'a> Issues<'a> {
+    /// Open an issues store.
+    pub fn open(
+        whoami: PublicKey,
+        repository: &'a storage::Repository,
+    ) -> Result<Self, store::Error> {
+        let raw = store::Store::open(whoami, repository)?;
+
+        Ok(Self { raw })
+    }
+
+    /// Get an issue.
+    pub fn get(&self, id: &ObjectId) -> Result<Option<Issue>, store::Error> {
+        self.raw.get(id)
+    }
+
+    /// Get an issue mutably.
+    pub fn get_mut<'g>(&'g mut self, id: &ObjectId) -> Result<IssueMut<'a, 'g>, store::Error> {
+        let issue = self
+            .raw
+            .get(id)?
+            .ok_or_else(move || store::Error::NotFound(TYPENAME.clone(), *id))?;
+
+        Ok(IssueMut {
+            id: *id,
+            clock: issue.clock,
+            issue,
+            store: self,
+        })
+    }
+
+    /// Create a new issue.
+    pub fn create<'g, G: Signer>(
+        &'g mut self,
+        title: impl Into<String>,
+        description: impl Into<String>,
+        tags: &[Tag],
+        signer: &G,
+    ) -> Result<IssueMut<'a, 'g>, Error> {
+        let title = title.into();
+        let description = description.into();
+        let change = Change {
+            author: self.author().id,
+            action: Action::Title { title },
+            clock: LClock::default(),
+        };
+        let (id, issue): (_, Issue) = self.raw.create("Create issue", change, signer)?;
+        let mut issue = IssueMut {
+            id,
+            clock: issue.clock,
+            issue,
+            store: self,
+        };
+
+        issue.comment(description, signer)?;
+        issue.tag(tags.to_owned(), signer)?;
+
+        Ok(issue)
+    }
+
+    /// Remove an issue.
+    pub fn remove(&self, id: &ObjectId) -> Result<(), store::Error> {
+        self.raw.remove(id)
+    }
+}
+
+/// Issue operation.
+#[derive(Debug, PartialEq, Eq, Clone, Serialize, Deserialize)]
+pub enum Action {
+    Title { title: String },
+    Lifecycle { status: Status },
+    Thread { action: thread::Action },
+}
+
+impl From<thread::Action> for Action {
+    fn from(action: thread::Action) -> Self {
+        Self::Thread { action }
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use super::*;
+    use crate::cob::Reaction;
+    use crate::test;
+
+    #[test]
+    fn test_ordering() {
+        assert!(CloseReason::Solved > CloseReason::Other);
+        assert!(
+            Status::Open
+                > Status::Closed {
+                    reason: CloseReason::Solved
+                }
+        );
+    }
+
+    #[test]
+    fn test_issue_create_and_get() {
+        let tmp = tempfile::tempdir().unwrap();
+        let (_, signer, project) = test::setup::context(&tmp);
+        let mut issues = Issues::open(*signer.public_key(), &project).unwrap();
+        let created = issues
+            .create("My first issue", "Blah blah blah.", &[], &signer)
+            .unwrap();
+        let (id, created) = (created.id, created.issue);
+        let issue = issues.get(&id).unwrap().unwrap();
+
+        assert_eq!(issue, created);
+        assert_eq!(issue.title(), "My first issue");
+        assert_eq!(issue.author(), Some(issues.author()));
+        assert_eq!(issue.description(), Some("Blah blah blah."));
+        assert_eq!(issue.comments().count(), 1);
+        assert_eq!(issue.status(), &Status::Open);
+    }
+
+    #[test]
+    fn test_issue_create_and_change_state() {
+        let tmp = tempfile::tempdir().unwrap();
+        let (_, signer, project) = test::setup::context(&tmp);
+        let mut issues = Issues::open(*signer.public_key(), &project).unwrap();
+        let mut issue = issues
+            .create("My first issue", "Blah blah blah.", &[], &signer)
+            .unwrap();
+
+        issue
+            .lifecycle(
+                Status::Closed {
+                    reason: CloseReason::Other,
+                },
+                &signer,
+            )
+            .unwrap();
+
+        let id = issue.id;
+        let mut issue = issues.get_mut(&id).unwrap();
+        assert_eq!(
+            *issue.status(),
+            Status::Closed {
+                reason: CloseReason::Other
+            }
+        );
+
+        issue.lifecycle(Status::Open, &signer).unwrap();
+        let issue = issues.get(&id).unwrap().unwrap();
+        assert_eq!(*issue.status(), Status::Open);
+    }
+
+    #[test]
+    fn test_issue_react() {
+        let tmp = tempfile::tempdir().unwrap();
+        let (_, signer, project) = test::setup::context(&tmp);
+        let mut issues = Issues::open(*signer.public_key(), &project).unwrap();
+        let mut issue = issues
+            .create("My first issue", "Blah blah blah.", &[], &signer)
+            .unwrap();
+
+        let comment = (LClock::default(), *signer.public_key());
+        let reaction = Reaction::new('🥳').unwrap();
+        issue.react(comment, reaction, &signer).unwrap();
+
+        let id = issue.id;
+        let issue = issues.get(&id).unwrap().unwrap();
+        let (_, r) = issue.reactions(&comment).next().unwrap();
+
+        assert_eq!(r, &reaction);
+
+        // TODO: Test multiple reactions from same author and different authors
+    }
+
+    #[test]
+    fn test_issue_reply() {
+        let tmp = tempfile::tempdir().unwrap();
+        let (_, signer, project) = test::setup::context(&tmp);
+        let mut issues = Issues::open(*signer.public_key(), &project).unwrap();
+        let mut issue = issues
+            .create("My first issue", "Blah blah blah.", &[], &signer)
+            .unwrap();
+        let comment = issue.comment("Ho ho ho.", &signer).unwrap();
+
+        issue.reply(comment, "Hi hi hi.", &signer).unwrap();
+        issue.reply(comment, "Ha ha ha.", &signer).unwrap();
+
+        let id = issue.id;
+        let issue = issues.get(&id).unwrap().unwrap();
+        let (_, reply1) = &issue.replies(&comment).nth(0).unwrap();
+        let (_, reply2) = &issue.replies(&comment).nth(1).unwrap();
+
+        assert_eq!(reply1.body, "Hi hi hi.");
+        assert_eq!(reply2.body, "Ha ha ha.");
+    }
+
+    #[test]
+    fn test_issue_tag() {
+        let tmp = tempfile::tempdir().unwrap();
+        let (_, signer, project) = test::setup::context(&tmp);
+        let mut issues = Issues::open(*signer.public_key(), &project).unwrap();
+        let mut issue = issues
+            .create("My first issue", "Blah blah blah.", &[], &signer)
+            .unwrap();
+
+        let bug_tag = Tag::new("bug").unwrap();
+        let wontfix_tag = Tag::new("wontfix").unwrap();
+
+        issue.tag([bug_tag.clone()], &signer).unwrap();
+        issue.tag([wontfix_tag.clone()], &signer).unwrap();
+
+        let id = issue.id;
+        let issue = issues.get(&id).unwrap().unwrap();
+        let tags = issue.tags().cloned().collect::<Vec<_>>();
+
+        assert!(tags.contains(&bug_tag));
+        assert!(tags.contains(&wontfix_tag));
+    }
+
+    #[test]
+    fn test_issue_comment() {
+        let tmp = tempfile::tempdir().unwrap();
+        let (_, signer, project) = test::setup::context(&tmp);
+        let author = *signer.public_key();
+        let mut issues = Issues::open(*signer.public_key(), &project).unwrap();
+        let mut issue = issues
+            .create("My first issue", "Blah blah blah.", &[], &signer)
+            .unwrap();
+
+        issue.comment("Ho ho ho.", &signer).unwrap();
+        issue.comment("Ha ha ha.", &signer).unwrap();
+
+        let id = issue.id;
+        let issue = issues.get(&id).unwrap().unwrap();
+        let ((_, a0), c0) = &issue.comments().nth(0).unwrap();
+        let ((_, a1), c1) = &issue.comments().nth(1).unwrap();
+        let ((_, a2), c2) = &issue.comments().nth(2).unwrap();
+
+        assert_eq!(&c0.body, "Blah blah blah.");
+        assert_eq!(a0, &author);
+        assert_eq!(&c1.body, "Ho ho ho.");
+        assert_eq!(a1, &author);
+        assert_eq!(&c2.body, "Ha ha ha.");
+        assert_eq!(a2, &author);
+    }
+
+    #[test]
+    fn test_issue_state_serde() {
+        assert_eq!(
+            serde_json::to_value(Status::Open).unwrap(),
+            serde_json::json!({ "status": "open" })
+        );
+
+        assert_eq!(
+            serde_json::to_value(Status::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 mut issues = Issues::open(*signer.public_key(), &project).unwrap();
+
+        issues.create("First", "Blah", &[], &signer).unwrap();
+        issues.create("Second", "Blah", &[], &signer).unwrap();
+        issues.create("Third", "Blah", &[], &signer).unwrap();
+
+        let issues = issues
+            .all()
+            .unwrap()
+            .collect::<Result<Vec<_>, _>>()
+            .unwrap();
+
+        assert_eq!(issues.len(), 3);
+
+        issues.iter().find(|(_, i)| i.title() == "First").unwrap();
+        issues.iter().find(|(_, i)| i.title() == "Second").unwrap();
+        issues.iter().find(|(_, i)| i.title() == "Third").unwrap();
     }
 }
diff --git a/radicle/src/cob/patch.rs b/radicle/src/cob/patch.rs
index 7dfde81b..70e6f4a4 100644
--- a/radicle/src/cob/patch.rs
+++ b/radicle/src/cob/patch.rs
@@ -51,7 +51,7 @@ where
     /// Target this patch is meant to be merged in.
     pub target: MergeTarget,
     /// Labels associated with the patch.
-    pub labels: HashSet<Label>,
+    pub labels: HashSet<Tag>,
     /// List of patch revisions. The initial changeset is part of the
     /// first revision.
     pub revisions: NonEmpty<Revision<T>>,
diff --git a/radicle/src/cob/store.rs b/radicle/src/cob/store.rs
index f88a8114..7ebbd87a 100644
--- a/radicle/src/cob/store.rs
+++ b/radicle/src/cob/store.rs
@@ -2,10 +2,13 @@
 #![allow(clippy::large_enum_variant)]
 use std::marker::PhantomData;
 
+use radicle_crdt::Change;
+use serde::Serialize;
+
 use crate::cob;
 use crate::cob::common::Author;
 use crate::cob::CollaborativeObject;
-use crate::cob::{Contents, Create, History, HistoryType, ObjectId, TypeName, Update};
+use crate::cob::{Create, History, HistoryType, ObjectId, TypeName, Update};
 use crate::crypto::PublicKey;
 use crate::git;
 use crate::identity::project;
@@ -32,7 +35,7 @@ pub enum Error {
     Retrieve(#[from] cob::error::Retrieve),
     #[error(transparent)]
     Identity(#[from] project::IdentityError),
-    #[error("object `{1}`of type `{0}` was not found")]
+    #[error("object `{1}` of type `{0}` was not found")]
     NotFound(TypeName, ObjectId),
 }
 
@@ -62,9 +65,7 @@ impl<'a, T> Store<'a, T> {
             witness: PhantomData,
         })
     }
-}
 
-impl<'a, T> Store<'a, T> {
     /// Get this store's author.
     pub fn author(&self) -> Author {
         Author::new(self.whoami)
@@ -78,11 +79,11 @@ impl<'a, T> Store<'a, T> {
 
 impl<'a, T: FromHistory> Store<'a, T> {
     /// Update an object.
-    pub fn update<G: Signer>(
+    pub fn update<A: Serialize, G: Signer>(
         &self,
         object_id: ObjectId,
         message: &'static str,
-        changes: Contents,
+        change: Change<A>,
         signer: &G,
     ) -> Result<CollaborativeObject, cob::error::Update> {
         cob::update(
@@ -95,19 +96,19 @@ impl<'a, T: FromHistory> Store<'a, T> {
                 history_type: HistoryType::default(),
                 typename: T::type_name().clone(),
                 message: message.to_owned(),
-                changes,
+                changes: change.encode(),
             },
         )
     }
 
     /// Create an object.
-    pub fn create<G: Signer>(
+    pub fn create<A: Serialize, G: Signer>(
         &self,
         message: &'static str,
-        contents: Contents,
+        change: Change<A>,
         signer: &G,
-    ) -> Result<CollaborativeObject, cob::error::Create> {
-        cob::create(
+    ) -> Result<(ObjectId, T), Error> {
+        let cob = cob::create(
             self.raw,
             signer,
             &self.project,
@@ -116,9 +117,12 @@ impl<'a, T: FromHistory> Store<'a, T> {
                 history_type: HistoryType::default(),
                 typename: T::type_name().clone(),
                 message: message.to_owned(),
-                contents,
+                contents: change.encode(),
             },
-        )
+        )?;
+        let object = T::from_history(cob.history())?;
+
+        Ok((*cob.id(), object))
     }
 
     /// Get an object.
@@ -126,24 +130,24 @@ impl<'a, T: FromHistory> Store<'a, T> {
         let cob = cob::get(self.raw, T::type_name(), id)?;
 
         if let Some(cob) = cob {
-            let history = cob.history();
-            let obj = T::from_history(history)?;
-
+            let obj = T::from_history(cob.history())?;
             Ok(Some(obj))
         } else {
             Ok(None)
         }
     }
 
-    /// List objects.
-    pub fn list(&self) -> Result<Vec<(ObjectId, T)>, Error> {
+    /// Return all objects.
+    pub fn all(&self) -> Result<impl Iterator<Item = Result<(ObjectId, T), Error>>, Error> {
         let raw = cob::list(self.raw, T::type_name())?;
 
-        raw.into_iter()
-            .map(|o| {
-                let obj = T::from_history(o.history())?;
-                Ok::<_, Error>((*o.id(), obj))
-            })
-            .collect()
+        Ok(raw.into_iter().map(|o| {
+            let obj = T::from_history(o.history())?;
+            Ok((*o.id(), obj))
+        }))
+    }
+
+    pub fn remove(&self, _id: &ObjectId) -> Result<(), Error> {
+        todo!();
     }
 }
diff --git a/radicle/src/cob/thread.rs b/radicle/src/cob/thread.rs
index a2143730..47d22aa1 100644
--- a/radicle/src/cob/thread.rs
+++ b/radicle/src/cob/thread.rs
@@ -7,7 +7,7 @@ use once_cell::sync::Lazy;
 use radicle_crdt as crdt;
 use serde::{Deserialize, Serialize};
 
-use crate::cob::common::Reaction;
+use crate::cob::common::{Reaction, Tag};
 use crate::cob::store;
 use crate::cob::{History, TypeName};
 use crate::crypto::{PublicKey, Signer};
@@ -22,18 +22,18 @@ use crdt::{Change, ChangeId, Semilattice};
 pub static TYPENAME: Lazy<TypeName> =
     Lazy::new(|| FromStr::from_str("xyz.radicle.thread").expect("type name is valid"));
 
-/// Identifies a tag.
-pub type TagId = String;
 /// Alias for `Author`.
 pub type ActorId = PublicKey;
+/// Identifies a comment.
+pub type CommentId = ChangeId;
 
 /// A comment on a discussion thread.
 #[derive(Default, Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
 pub struct Comment {
     /// The comment body.
-    body: String,
+    pub body: String,
     /// Thread or comment this is a reply to.
-    reply_to: Option<ChangeId>,
+    pub reply_to: Option<ChangeId>,
 }
 
 impl Comment {
@@ -56,10 +56,10 @@ pub enum Action {
     Comment { comment: Comment },
     /// Redact a change. Not all changes can be redacted.
     Redact { id: ChangeId },
-    /// Add a tag to the thread.
-    Tag { tag: TagId },
-    /// Remove a tag from the thread.
-    Untag { tag: TagId },
+    /// Add tags to the thread.
+    Tag { tags: Vec<Tag> },
+    /// Remove tags from the thread.
+    Untag { tags: Vec<Tag> },
     /// React to a change.
     React {
         to: ChangeId,
@@ -72,11 +72,11 @@ pub enum Action {
 #[derive(Debug, Default, Clone, PartialEq, Eq)]
 pub struct Thread {
     /// The comments under the thread.
-    comments: BTreeMap<ChangeId, Redactable<Comment>>,
+    comments: BTreeMap<CommentId, Redactable<Comment>>,
     /// Associated tags.
-    tags: BTreeMap<TagId, LWWReg<bool, LClock>>,
+    tags: BTreeMap<Tag, LWWReg<bool, LClock>>,
     /// Reactions to changes.
-    reactions: BTreeMap<ChangeId, LWWSet<(ActorId, Reaction), LClock>>,
+    reactions: BTreeMap<CommentId, LWWSet<(ActorId, Reaction), LClock>>,
 }
 
 impl store::FromHistory for Thread {
@@ -105,7 +105,7 @@ impl Semilattice for Thread {
 }
 
 impl Deref for Thread {
-    type Target = BTreeMap<ChangeId, Redactable<Comment>>;
+    type Target = BTreeMap<CommentId, Redactable<Comment>>;
 
     fn deref(&self) -> &Self::Target {
         &self.comments
@@ -117,6 +117,39 @@ impl Thread {
         self.comments.clear();
     }
 
+    pub fn comment(&self, id: &CommentId) -> Option<&Comment> {
+        if let Some(Redactable::Present(comment)) = self.comments.get(id) {
+            Some(comment)
+        } else {
+            None
+        }
+    }
+
+    pub fn replies<'a>(
+        &'a self,
+        to: &'a CommentId,
+    ) -> impl Iterator<Item = (&CommentId, &Comment)> {
+        self.comments().filter_map(move |(id, c)| {
+            if let Some(parent) = &c.reply_to {
+                if parent == to {
+                    return Some((id, c));
+                }
+            }
+            None
+        })
+    }
+
+    pub fn reactions<'a>(
+        &'a self,
+        to: &'a CommentId,
+    ) -> impl Iterator<Item = (&ActorId, &Reaction)> {
+        self.reactions
+            .get(to)
+            .into_iter()
+            .flat_map(move |rs| rs.iter())
+            .map(|(a, r)| (a, r))
+    }
+
     pub fn apply(&mut self, changes: impl IntoIterator<Item = Change<Action>>) {
         for change in changes.into_iter() {
             let id = change.id();
@@ -140,17 +173,21 @@ impl Thread {
                         .and_modify(|e| e.merge(Redactable::Redacted))
                         .or_insert(Redactable::Redacted);
                 }
-                Action::Tag { tag } => {
-                    self.tags
-                        .entry(tag)
-                        .and_modify(|r| r.set(true, change.clock))
-                        .or_insert_with(|| LWWReg::new(true, change.clock));
+                Action::Tag { tags } => {
+                    for tag in tags {
+                        self.tags
+                            .entry(tag)
+                            .and_modify(|r| r.set(true, change.clock))
+                            .or_insert_with(|| LWWReg::new(true, change.clock));
+                    }
                 }
-                Action::Untag { tag } => {
-                    self.tags
-                        .entry(tag)
-                        .and_modify(|r| r.set(false, change.clock))
-                        .or_insert_with(|| LWWReg::new(false, change.clock));
+                Action::Untag { tags } => {
+                    for tag in tags {
+                        self.tags
+                            .entry(tag)
+                            .and_modify(|r| r.set(false, change.clock))
+                            .or_insert_with(|| LWWReg::new(false, change.clock));
+                    }
                 }
                 Action::React {
                     to,
@@ -180,7 +217,7 @@ impl Thread {
         }
     }
 
-    pub fn comments(&self) -> impl Iterator<Item = (&ChangeId, &Comment)> + '_ {
+    pub fn comments(&self) -> impl Iterator<Item = (&CommentId, &Comment)> + '_ {
         self.comments.iter().filter_map(|(id, comment)| {
             if let Redactable::Present(c) = comment {
                 Some((id, c))
@@ -190,7 +227,7 @@ impl Thread {
         })
     }
 
-    pub fn tags(&self) -> impl Iterator<Item = &TagId> + '_ {
+    pub fn tags(&self) -> impl Iterator<Item = &Tag> + '_ {
         self.tags
             .iter()
             .filter_map(|(tag, r)| if *r.get() { Some(tag) } else { None })
@@ -230,13 +267,13 @@ impl<G: Signer> Actor<G> {
     }
 
     /// Add a tag.
-    pub fn tag(&mut self, tag: TagId) -> Change<Action> {
-        self.change(Action::Tag { tag })
+    pub fn tag(&mut self, tag: Tag) -> Change<Action> {
+        self.change(Action::Tag { tags: vec![tag] })
     }
 
     /// Remove a tag.
-    pub fn untag(&mut self, tag: TagId) -> Change<Action> {
-        self.change(Action::Untag { tag })
+    pub fn untag(&mut self, tag: Tag) -> Change<Action> {
+        self.change(Action::Untag { tags: vec![tag] })
     }
 
     /// Create a new redaction.
@@ -294,7 +331,7 @@ mod tests {
         fn arbitrary(g: &mut quickcheck::Gen) -> Self {
             let rng = fastrand::Rng::with_seed(u64::arbitrary(g));
             let gen =
-                WeightedGenerator::<Action, (Vec<TagId>, Vec<Change<Action>>)>::new(rng.clone())
+                WeightedGenerator::<Action, (Vec<Tag>, Vec<Change<Action>>)>::new(rng.clone())
                     .variant(2, |_, rng| {
                         Some(Action::Comment {
                             comment: Comment {
@@ -327,19 +364,20 @@ mod tests {
                             let tag = iter::repeat_with(|| rng.alphabetic())
                                 .take(8)
                                 .collect::<String>();
+                            let tag = Tag::new(tag).unwrap();
                             tags.push(tag.clone());
                             tag
                         } else {
                             tags[rng.usize(..tags.len())].clone()
                         };
-                        Some(Action::Tag { tag })
+                        Some(Action::Tag { tags: vec![tag] })
                     })
                     .variant(2, |(tags, _), rng| {
                         if tags.is_empty() {
                             return None;
                         }
                         let tag = tags[rng.usize(..tags.len())].clone();
-                        Some(Action::Untag { tag })
+                        Some(Action::Untag { tags: vec![tag] })
                     });
 
             let mut changes = Vec::new();
@@ -381,14 +419,12 @@ mod tests {
         let mut expected = Thread::default();
         expected.apply([a1.clone(), a2.clone()]);
 
-        let created = store
-            .create("Thread created", a1.encode(), &alice.signer)
-            .unwrap();
+        let (id, _) = store.create("Thread created", a1, &alice.signer).unwrap();
         store
-            .update(*created.id(), "Thread updated", a2.encode(), &alice.signer)
+            .update(id, "Thread updated", a2, &alice.signer)
             .unwrap();
 
-        let actual = store.get(created.id()).unwrap().unwrap();
+        let actual = store.get(&id).unwrap().unwrap();
 
         assert_eq!(actual, expected);
     }
diff --git a/radicle/src/lib.rs b/radicle/src/lib.rs
index 9a211d8e..451c4e9c 100644
--- a/radicle/src/lib.rs
+++ b/radicle/src/lib.rs
@@ -1,5 +1,6 @@
 #![allow(clippy::match_like_matches_macro)]
 #![allow(clippy::explicit_auto_deref)] // TODO: This can be removed when the clippy bugs are fixed
+#![allow(clippy::iter_nth_zero)]
 #![cfg_attr(not(test), warn(clippy::unwrap_used))]
 
 pub extern crate radicle_crypto as crypto;