//! Radicle node profile.
//!
//!   $RAD_HOME/                                 # Radicle home
//!     storage/                                 # Storage root
//!       zEQNunJUqkNahQ8VvQYuWZZV7EJB/          # Project git repository
//!       ...                                    # More projects...
//!     keys/
//!       radicle                                # Secret key (PKCS 8)
//!       radicle.pub                            # Public key (PKCS 8)
//!     node/
//!       radicle.sock                           # Node control socket
//!
use std::io;
use std::path::{Path, PathBuf};

use thiserror::Error;

use crate::crypto::ssh::agent::{Agent, AgentSigner};
use crate::crypto::ssh::keystore::Keystore;
use crate::crypto::PublicKey;
use crate::node;
use crate::storage::git::transport;
use crate::storage::git::Storage;

/// Environment variables used by radicle.
pub mod env {
    pub use std::env::*;

    /// Path to the radicle home folder.
    pub const RAD_HOME: &str = "RAD_HOME";
    /// Path to the radicle node socket file.
    pub const RAD_SOCKET: &str = "RAD_SOCKET";
    /// Passphrase for the encrypted radicle secret key.
    pub const RAD_PASSPHRASE: &str = "RAD_PASSPHRASE";
}

#[derive(Debug, Error)]
pub enum Error {
    #[error(transparent)]
    Io(#[from] io::Error),
    #[error(transparent)]
    Keystore(#[from] crate::crypto::ssh::keystore::Error),
    #[error("no profile found at the filepath '{0}'")]
    NotFound(PathBuf),
    #[error("error connecting to ssh-agent: {0}")]
    Agent(#[from] crate::crypto::ssh::agent::Error),
    #[error("profile key `{0}` is not registered with ssh-agent")]
    KeyNotRegistered(PublicKey),
}

#[derive(Debug, Clone)]
pub struct Profile {
    pub home: PathBuf,
    pub storage: Storage,
    pub keystore: Keystore,
    pub public_key: PublicKey,
}

impl Profile {
    pub fn init(home: impl AsRef<Path>, passphrase: &str) -> Result<Self, Error> {
        let home = home.as_ref().to_path_buf();
        let storage = Storage::open(home.join("storage"))?;
        let keystore = Keystore::new(&home.join("keys"));
        let public_key = keystore.init("radicle", passphrase)?;

        transport::local::register(storage.clone());

        Ok(Profile {
            home,
            storage,
            keystore,
            public_key,
        })
    }

    pub fn load() -> Result<Self, Error> {
        let home = self::home()?;
        let storage = Storage::open(home.join("storage"))?;
        let keystore = Keystore::new(&home.join("keys"));
        let public_key = keystore
            .public_key()?
            .ok_or_else(|| Error::NotFound(home.clone()))?;

        transport::local::register(storage.clone());

        Ok(Profile {
            home,
            storage,
            keystore,
            public_key,
        })
    }

    pub fn id(&self) -> &PublicKey {
        &self.public_key
    }

    pub fn signer(&self) -> Result<AgentSigner, Error> {
        match Agent::connect() {
            Ok(agent) => {
                let signer = agent.signer(self.public_key);
                if signer.is_ready()? {
                    Ok(signer)
                } else {
                    Err(Error::KeyNotRegistered(self.public_key))
                }
            }
            Err(err) => Err(err.into()),
        }
    }

    /// Return the path to the keys folder.
    pub fn keys(&self) -> PathBuf {
        self.home.join("keys")
    }

    /// Get the path to the radicle node socket.
    pub fn node(&self) -> PathBuf {
        env::var_os(env::RAD_SOCKET)
            .map(PathBuf::from)
            .unwrap_or_else(|| self.home.join("node").join(node::DEFAULT_SOCKET_NAME))
    }

    /// Get `Paths` of profile
    pub fn paths(&self) -> Paths {
        Paths { home: &self.home }
    }
}

/// Get the path to the radicle home folder.
pub fn home() -> Result<PathBuf, io::Error> {
    if let Some(home) = env::var_os(env::RAD_HOME) {
        Ok(PathBuf::from(home))
    } else if let Some(home) = env::var_os("HOME") {
        Ok(PathBuf::from(home).join(".radicle"))
    } else {
        Err(io::Error::new(
            io::ErrorKind::NotFound,
            "Neither `RAD_HOME` nor `HOME` are set",
        ))
    }
}

#[derive(Debug, Clone)]
pub struct Paths<'a> {
    home: &'a Path,
}

impl<'a> Paths<'a> {
    pub fn new(home: &'a Path) -> Self {
        Self { home }
    }

    pub fn storage(&self) -> PathBuf {
        self.home.join("storage")
    }

    pub fn keys(&self) -> PathBuf {
        self.home.join("keys")
    }

    pub fn node(&self) -> PathBuf {
        self.home.join("node")
    }
}