path = "src/main.rs"

//! A Git remote helper for interacting with Radicle storage and notifying

//! `radicle-node`.

//!

//! Refer to <https://git-scm.com/docs/gitremote-helpers.html> for documentation

//! on Git remote helpers.

//!

//! Usage of standard streams:

//!  - Standard Error ([`eprintln`]) is used for communicating with the user.

//!  - Standard Output ([`println`]) is used for communicating with Git tooling.

mod fetch;

mod list;

mod push;

use std::path::PathBuf;

use std::process;

use std::str::FromStr;

use std::{env, fmt, io};

use thiserror::Error;

use radicle::prelude::NodeId;

use radicle::storage::git::transport::local::{Url, UrlError};

use radicle::storage::{ReadRepository, WriteStorage};

use radicle::version::Version;

use radicle::{cob, profile};

use radicle::{git, storage, Profile};

use radicle_cli::git::Rev;

use radicle_cli::terminal as cli;

pub const VERSION: Version = Version {

    name: "git-remote-rad",

    commit: env!("GIT_HEAD"),

    version: env!("RADICLE_VERSION"),

    timestamp: env!("SOURCE_DATE_EPOCH"),

};

fn main() {

    let mut args = env::args();

    if let Some(lvl) = radicle::logger::env_level() {

        let logger = radicle::logger::StderrLogger::new(lvl);

        log::set_boxed_logger(Box::new(logger))

            .expect("no other logger should have been set already");

        log::set_max_level(lvl.to_level_filter());

    }

    if args.nth(1).as_deref() == Some("--version") {

        if let Err(e) = VERSION.write(std::io::stdout()) {

            eprintln!("error: {e}");

            process::exit(1);

        };

        process::exit(0);

    }

    let profile = match radicle::Profile::load() {

        Ok(profile) => profile,

        Err(err) => {

            eprintln!("error: couldn't load profile: {err}");

            process::exit(1);

        }

    };

    if let Err(err) = run(profile) {

        eprintln!("error: {err}");

        process::exit(1);

    }

}

#[derive(Debug, Error)]

pub enum Error {

    /// Failed to parse `base`.

    #[error("failed to parse base revision: {0}")]

    Base(Box<dyn std::error::Error>),

    /// Remote repository not found (or empty).

    #[error("remote repository `{0}` not found")]

    RepositoryNotFound(PathBuf),

    /// Invalid command received.

    #[error("invalid command `{0}`")]

    InvalidCommand(String),

    /// Invalid arguments received.

    #[error("invalid arguments: {0:?}")]

    InvalidArguments(Vec<String>),

    /// Unknown push option received.

    #[error("unknown push option {0:?}")]

    UnsupportedPushOption(String),

    /// Error with the remote url.

    #[error("invalid remote url: {0}")]

    RemoteUrl(#[from] UrlError),

    /// I/O error.

    #[error("i/o error: {0}")]

    Io(#[from] io::Error),

    /// The `GIT_DIR` env var is not set.

    #[error("the `GIT_DIR` environment variable is not set")]

    NoGitDir,

    /// No parent of `GIT_DIR` was found.

    #[error("expected parent of .git but found {path:?}")]

    NoWorkingCopy { path: PathBuf },

    /// Git error.

    #[error("git: {0}")]

    Git(#[from] git::raw::Error),

    /// Invalid reference name.

    #[error("invalid ref: {0}")]

    InvalidRef(#[from] radicle::git::fmt::Error),

    /// Repository error.

    #[error(transparent)]

    Repository(#[from] radicle::storage::RepositoryError),

    /// Fetch error.

    #[error(transparent)]

    Fetch(#[from] fetch::Error),

    /// Push error.

    #[error(transparent)]

    Push(#[from] push::Error),

    /// List error.

    #[error(transparent)]

    List(#[from] list::Error),

}

/// Models values for the `verbosity` option, see

/// <https://git-scm.com/docs/gitremote-helpers#Documentation/gitremote-helpers.txt-optionverbosityn>.

#[derive(Copy, Clone, Debug)]

struct Verbosity(u8);

impl From<Verbosity> for radicle::git::Verbosity {

    /// Converts the verbosity option passed to a Git remote helper to

    /// one that can be passed to other Git commands via command line.

    /// Note that these scales are one off: While the default verbosity

    /// for remote helpers is 1, the default verbosity via command line

    /// (omitting the flag) is 0.

    /// This implementation also cuts off verbosities greater than [`i8::MAX`].

    fn from(val: Verbosity) -> Self {

        radicle::git::Verbosity::from(i8::try_from(val.0).unwrap_or(i8::MAX) - 1)

    }

}

/// The documentation on Git remote helpers, see

/// <https://git-scm.com/docs/gitremote-helpers#Documentation/gitremote-helpers.txt-optionverbosityn>

/// says: "1 is the default level of verbosity".

impl Default for Verbosity {

    fn default() -> Self {

        Self(1)

    }

}

impl FromStr for Verbosity {

    type Err = std::num::ParseIntError;

    fn from_str(s: &str) -> Result<Self, Self::Err> {

        u8::from_str(s).map(Self)

    }

}

#[derive(Debug, Default, Clone)]

pub struct Options {

    /// Don't sync after push.

    no_sync: bool,

    /// Sync debugging.

    sync_debug: bool,

    /// Enable hints.

    hints: bool,

    /// Open patch in draft mode.

    draft: bool,

    /// Patch base to use, when opening or updating a patch.

    base: Option<Rev>,

    /// Patch message.

    message: cli::patch::Message,

    verbosity: Verbosity,

}

/// Run the radicle remote helper using the given profile.

pub fn run(profile: radicle::Profile) -> Result<(), Error> {

    // Since we're going to be writing user output to `stderr`, make sure the paint

    // module is aware of that.

    cli::Paint::set_terminal(cli::TerminalFile::Stderr);

    let (remote, url): (Option<git::RefString>, Url) = {

        let args = env::args().skip(1).take(2).collect::<Vec<_>>();

        match args.as_slice() {

            [url] => (None, url.parse()?),

            [remote, url] => (git::RefString::try_from(remote.as_str()).ok(), url.parse()?),

            _ => {

                return Err(Error::InvalidArguments(args));

            }

        }

    };

    let stored = profile.storage.repository_mut(url.repo)?;

    if stored.is_empty()? {

        return Err(Error::RepositoryNotFound(stored.path().to_path_buf()));

    }

    // `GIT_DIR` is set by Git tooling, if we're in a working copy.

    let working = env::var("GIT_DIR").map(PathBuf::from);

    // Whether we should output debug logs.

    let debug = radicle::profile::env::debug();

    let stdin = io::stdin();

    let mut line = String::new();

    let mut opts = Options::default();

    if let Err(e) = radicle::io::set_file_limit(4096) {

        if debug {

            eprintln!("git-remote-rad: unable to set open file limit: {e}");

        }

    }

    loop {

        let tokens = read_line(&stdin, &mut line)?;

        if debug {

            eprintln!("git-remote-rad: {:?}", &tokens);

        }

        match tokens.as_slice() {

            ["capabilities"] => {

                println!("option");

                println!("push"); // Implies `list` command.

                println!("fetch");

                println!();

            }

            ["option", "verbosity", verbosity] => match verbosity.parse::<Verbosity>() {

                Ok(verbosity) => {

                    opts.verbosity = verbosity;

                    println!("ok");

                }

                Err(err) => {

                    println!("error {err}");

                }

            },

            ["option", "push-option", args @ ..] => {

                // Nb. Git documentation says that we can print `error <msg>` or `unsupported`

                // for options that are not supported, but this results in Git saying that

                // "push-option" itself is an unsupported option, which is not helpful or correct.

                // Hence, we just exit with an error in this case.

                push_option(args, &mut opts)?;

                println!("ok");

            }

            ["option", "progress", ..] => {

                println!("unsupported");

            }

            ["option", ..] => {

                println!("unsupported");

            }

            ["fetch", oid, refstr] => {

                let oid = git::Oid::from_str(oid)?;

                let refstr = git::RefString::try_from(*refstr)?;

                // N.b. `working` is the `.git` folder and `fetch::run`

                // requires the working directory.

                let working = dunce::canonicalize(working.map_err(|_| Error::NoGitDir)?)?;

                let working = working.parent().ok_or_else(|| Error::NoWorkingCopy {

                    path: working.clone(),

                })?;

                return fetch::run(vec![(oid, refstr)], working, stored, &stdin, opts.verbosity)

                    .map_err(Error::from);

            }

            ["push", refspec] => {

                // We have to be in a working copy to push.

                let working = working.map_err(|_| Error::NoGitDir)?;

                return push::run(

                    vec![refspec.to_string()],

                    &working,

                    // N.b. assume the default remote if there was no remote

                    remote.unwrap_or((*radicle::rad::REMOTE_NAME).clone()),

                    url,

                    &stored,

                    &profile,

                    &stdin,

                    opts,

                )

                .map_err(Error::from);

            }

            ["list"] => {

                list::for_fetch(&url, &profile, &stored)?;

            }

            ["list", "for-push"] => {

                list::for_push(&profile, &stored)?;

            }

            [] => {

                return Ok(());

            }

            _ => {

                return Err(Error::InvalidCommand(line.trim().to_owned()));

            }

        }

    }

}

/// Parse a single push option. Returns `Ok` if it was successful.

/// Note that some push options can contain spaces, eg. `patch.message="Hello World!"`,

/// hence the arguments are passed as a slice.

fn push_option(args: &[&str], opts: &mut Options) -> Result<(), Error> {

    match args {

        ["hints"] => opts.hints = true,

        ["sync"] => opts.no_sync = false,

        ["sync.debug"] => opts.sync_debug = true,

        ["no-sync"] => opts.no_sync = true,

        ["patch.draft"] => opts.draft = true,

        _ => {

            let args = args.join(" ");

            if let Some((key, val)) = args.split_once('=') {

                match key {

                    "patch.message" => {

                        opts.message.append(val);

                    }

                    "patch.base" => {

                        let base =

                            cli::args::rev(&val.into()).map_err(|e| Error::Base(e.into()))?;

                        opts.base = Some(base);

                    }

                    other => {

                        return Err(Error::UnsupportedPushOption(other.to_owned()));

                    }

                }

            } else {

                return Err(Error::UnsupportedPushOption(args.to_owned()));

            }

        }

    }

    Ok(())

}

/// Read one line from stdin, and split it into tokens.

pub(crate) fn read_line<'a>(stdin: &io::Stdin, line: &'a mut String) -> io::Result<Vec<&'a str>> {

    line.clear();

    let read = stdin.read_line(line)?;

    if read == 0 {

        return Ok(vec![]);

    }

    let line = line.trim();

    let tokens = line.split(' ').filter(|t| !t.is_empty()).collect();

    Ok(tokens)

}

/// Write a hint to the user.

pub(crate) fn hint(s: impl fmt::Display) {

    eprintln!("{}", cli::format::hint(format!("hint: {s}")));

}

/// Write a warning to the user.

pub(crate) fn warn(s: impl fmt::Display) {

    eprintln!("{}", cli::format::hint(format!("warn: {s}")));

}

/// Get the patch store.

pub(crate) fn patches<'a, R: ReadRepository + cob::Store<Namespace = NodeId>>(

    profile: &Profile,

    repo: &'a R,

) -> Result<cob::patch::Cache<cob::patch::Patches<'a, R>, cob::cache::StoreReader>, list::Error> {

    match profile.patches(repo) {

        Ok(patches) => Ok(patches),

        Err(err @ profile::Error::CobsCache(cob::cache::Error::OutOfDate)) => {

            hint(cli::cob::MIGRATION_HINT);

            Err(err.into())

        }

        Err(err) => Err(err.into()),

    }

}

/// Get the mutable patch store.

pub(crate) fn patches_mut<'a>(

    profile: &Profile,

    repo: &'a storage::git::Repository,

) -> Result<

    cob::patch::Cache<cob::patch::Patches<'a, storage::git::Repository>, cob::cache::StoreWriter>,

    push::Error,

> {

    match profile.patches_mut(repo) {

        Ok(patches) => Ok(patches),

        Err(err @ profile::Error::CobsCache(cob::cache::Error::OutOfDate)) => {

            hint(cli::cob::MIGRATION_HINT);

            Err(err.into())

        }

        Err(err) => Err(err.into()),

    }

}