tam_worktree/

git.rs

use anyhow::{bail, Context, Result};
use std::path::{Path, PathBuf};
use std::process::Command;

/// Check that git is available.
pub fn check_git_available() -> Result<()> {
    Command::new("git")
        .arg("--version")
        .output()
        .context("git is not installed or not in PATH")?;
    Ok(())
}

/// Run a git command in the given directory and return stdout.
fn git(dir: &Path, args: &[&str]) -> Result<String> {
    let output = Command::new("git")
        .args(args)
        .current_dir(dir)
        .output()
        .context("git is not installed or not in PATH")?;

    if !output.status.success() {
        let stderr = String::from_utf8_lossy(&output.stderr);
        bail!("git {} failed: {}", args.join(" "), stderr.trim());
    }

    Ok(String::from_utf8_lossy(&output.stdout).trim().to_string())
}

/// Resolve the toplevel of the current working tree (the checkout root).
/// For the main repo this is the repo root; for a worktree it's the worktree directory.
pub fn toplevel(dir: &Path) -> Result<PathBuf> {
    let tl = git(dir, &["rev-parse", "--show-toplevel"])?;
    Ok(PathBuf::from(tl))
}

/// Resolve the main repository root (the common dir for worktrees).
pub fn repo_root(dir: &Path) -> Result<PathBuf> {
    let common_dir = git(dir, &["rev-parse", "--git-common-dir"])?;
    let git_common = PathBuf::from(&common_dir);

    // git-common-dir returns the .git dir; we want its parent
    let root = if git_common.is_absolute() {
        git_common
            .parent()
            .map(|p| p.to_path_buf())
            .unwrap_or(git_common)
    } else {
        let abs = dir.join(&git_common);
        abs.canonicalize()?
            .parent()
            .map(|p| p.to_path_buf())
            .unwrap_or(abs)
    };

    Ok(root)
}

/// Run `git fetch --quiet`.
pub fn fetch(dir: &Path) -> Result<()> {
    // fetch may fail if there's no remote, that's ok
    let _ = git(dir, &["fetch", "--quiet"]);
    Ok(())
}

/// Check if a local branch exists.
pub fn local_branch_exists(dir: &Path, name: &str) -> Result<bool> {
    let result = git(
        dir,
        &["show-ref", "--verify", &format!("refs/heads/{}", name)],
    );
    Ok(result.is_ok())
}

/// Check if a remote tracking branch exists (origin/<name>).
pub fn remote_branch_exists(dir: &Path, name: &str) -> Result<bool> {
    let result = git(
        dir,
        &[
            "show-ref",
            "--verify",
            &format!("refs/remotes/origin/{}", name),
        ],
    );
    Ok(result.is_ok())
}

/// Detect the default branch via origin/HEAD, falling back to main then master.
pub fn default_branch(dir: &Path) -> Result<String> {
    // Try origin/HEAD
    if let Ok(output) = git(dir, &["symbolic-ref", "refs/remotes/origin/HEAD"]) {
        if let Some(branch) = output.strip_prefix("refs/remotes/origin/") {
            return Ok(branch.to_string());
        }
    }

    // Fallback: check if main exists
    if remote_branch_exists(dir, "main")? || local_branch_exists(dir, "main")? {
        return Ok("main".to_string());
    }

    // Fallback: check if master exists
    if remote_branch_exists(dir, "master")? || local_branch_exists(dir, "master")? {
        return Ok("master".to_string());
    }

    bail!("could not detect default branch")
}

/// Add a worktree.
pub fn worktree_add(dir: &Path, target: &Path, branch: &str) -> Result<()> {
    git(dir, &["worktree", "add", &target.to_string_lossy(), branch])?;
    Ok(())
}

/// Add a worktree with a new branch.
pub fn worktree_add_new_branch(
    dir: &Path,
    target: &Path,
    branch: &str,
    start_point: &str,
) -> Result<()> {
    git(
        dir,
        &[
            "worktree",
            "add",
            "-b",
            branch,
            &target.to_string_lossy(),
            start_point,
        ],
    )?;
    Ok(())
}

/// Remove a worktree.
pub fn worktree_remove(dir: &Path, target: &Path) -> Result<()> {
    git(dir, &["worktree", "remove", &target.to_string_lossy()])?;
    Ok(())
}

/// Force-remove a worktree (allows dirty/locked worktrees).
pub fn worktree_remove_force(dir: &Path, target: &Path) -> Result<()> {
    git(
        dir,
        &["worktree", "remove", "--force", &target.to_string_lossy()],
    )?;
    Ok(())
}

/// Delete a local branch with `git branch -d` (safe delete).
pub fn delete_branch(dir: &Path, name: &str) -> Result<()> {
    git(dir, &["branch", "-d", name])?;
    Ok(())
}

/// List worktrees. Returns list of worktree paths.
pub fn worktree_list(dir: &Path) -> Result<Vec<PathBuf>> {
    let output = git(dir, &["worktree", "list", "--porcelain"])?;
    let paths = output
        .lines()
        .filter_map(|line| line.strip_prefix("worktree "))
        .map(PathBuf::from)
        .collect();
    Ok(paths)
}

#[cfg(test)]
mod tests {
    use super::*;
    use std::fs;
    use tempfile::TempDir;

    /// Create a real git repo with an initial commit.
    fn init_repo(path: &Path) {
        fs::create_dir_all(path).unwrap();
        git(path, &["init"]).unwrap();
        git(path, &["config", "user.email", "test@test.com"]).unwrap();
        git(path, &["config", "user.name", "Test"]).unwrap();
        // Create initial commit so we have a branch
        fs::write(path.join("README.md"), "# test").unwrap();
        git(path, &["add", "."]).unwrap();
        git(path, &["commit", "-m", "init"]).unwrap();
    }

    #[test]
    fn test_repo_root_regular_repo() {
        let tmp = TempDir::new().unwrap();
        let repo = tmp.path().join("myrepo");
        init_repo(&repo);

        let root = repo_root(&repo).unwrap();
        assert_eq!(root.canonicalize().unwrap(), repo.canonicalize().unwrap());
    }

    #[test]
    fn test_repo_root_from_worktree() {
        let tmp = TempDir::new().unwrap();
        let repo = tmp.path().join("myrepo");
        init_repo(&repo);

        let wt_path = tmp.path().join("myrepo--feature");
        git(
            &repo,
            &[
                "worktree",
                "add",
                "-b",
                "feature",
                &wt_path.to_string_lossy(),
            ],
        )
        .unwrap();

        let root = repo_root(&wt_path).unwrap();
        assert_eq!(root.canonicalize().unwrap(), repo.canonicalize().unwrap());
    }

    #[test]
    fn test_local_branch_exists() {
        let tmp = TempDir::new().unwrap();
        let repo = tmp.path().join("repo");
        init_repo(&repo);

        // The default branch (main or master) should exist
        let default = git(&repo, &["branch", "--show-current"]).unwrap();
        assert!(local_branch_exists(&repo, &default).unwrap());
        assert!(!local_branch_exists(&repo, "nonexistent-branch").unwrap());
    }

    #[test]
    fn test_local_branch_exists_after_create() {
        let tmp = TempDir::new().unwrap();
        let repo = tmp.path().join("repo");
        init_repo(&repo);

        git(&repo, &["branch", "feature-x"]).unwrap();
        assert!(local_branch_exists(&repo, "feature-x").unwrap());
    }

    #[test]
    fn test_default_branch_fallback_to_main() {
        let tmp = TempDir::new().unwrap();
        let repo = tmp.path().join("repo");
        init_repo(&repo);
        // Ensure we're on main
        let _ = git(&repo, &["branch", "-M", "main"]);

        let branch = default_branch(&repo).unwrap();
        assert!(branch == "main" || branch == "master");
    }

    #[test]
    fn test_worktree_add_and_list() {
        let tmp = TempDir::new().unwrap();
        let repo = tmp.path().join("repo");
        init_repo(&repo);

        let wt_path = tmp.path().join("repo--feature");
        worktree_add_new_branch(&repo, &wt_path, "feature", "HEAD").unwrap();

        let worktrees = worktree_list(&repo).unwrap();
        assert!(worktrees.len() >= 2); // main + the new worktree
        let wt_canonical = wt_path.canonicalize().unwrap();
        assert!(
            worktrees
                .iter()
                .any(|p| p.canonicalize().unwrap_or_default() == wt_canonical),
            "worktree list should contain the new worktree"
        );
    }

    #[test]
    fn test_worktree_add_existing_branch() {
        let tmp = TempDir::new().unwrap();
        let repo = tmp.path().join("repo");
        init_repo(&repo);

        git(&repo, &["branch", "existing-branch"]).unwrap();

        let wt_path = tmp.path().join("repo--existing");
        worktree_add(&repo, &wt_path, "existing-branch").unwrap();

        assert!(wt_path.exists());
        let worktrees = worktree_list(&repo).unwrap();
        assert!(worktrees.len() >= 2);
    }

    #[test]
    fn test_worktree_remove() {
        let tmp = TempDir::new().unwrap();
        let repo = tmp.path().join("repo");
        init_repo(&repo);

        let wt_path = tmp.path().join("repo--feature");
        worktree_add_new_branch(&repo, &wt_path, "feature", "HEAD").unwrap();
        assert!(wt_path.exists());

        worktree_remove(&repo, &wt_path).unwrap();
        assert!(!wt_path.exists());
    }

    #[test]
    fn test_fetch_no_remote() {
        let tmp = TempDir::new().unwrap();
        let repo = tmp.path().join("repo");
        init_repo(&repo);

        // Should not error even without a remote
        fetch(&repo).unwrap();
    }
}