Function offer_git_post_commit_hook

src/agents/mod.rs:1491–1597

If a global git `post-commit` hook is not already set up for tracedecay, interactively asks the user whether to install one. Silently succeeds if the hook is already present, if stdin is not a terminal, or if the user declines.

(tracedecay_bin: &str)

/// the hook is already present, if stdin is not a terminal, or if the user
/// declines.
pub fn offer_git_post_commit_hook(tracedecay_bin: &str) {
    let Some(home) = home_dir() else { return };

    // Determine the global hooks directory by reading core.hooksPath from
    // the global gitconfig file(s). Falls back to ~/.config/git/hooks/.
    let hooks_dir = read_global_hooks_path(&home);

    let (hooks_dir, need_set_hookspath) = match hooks_dir {
        Some(dir) => (dir, false),
        None => (home.join(".config").join("git").join("hooks"), true),
    };

    let hook_path = hooks_dir.join("post-commit");

    // Check if already installed.
    if hook_path.exists() {
        if let Ok(contents) = std::fs::read_to_string(&hook_path) {
            if contents.contains(HOOK_MARKER) {
                eprintln!("  Global git post-commit hook already contains tracedecay, skipping");
                return;
            }
        }
    }

    // Only prompt on a real terminal.
    if !atty_stdin() {
        return;
    }

    eprintln!();
    eprint!(
        "Install a global git post-commit hook to auto-run \x1b[1mtracedecay sync\x1b[0m after each commit? [y/N] "
    );

    let mut answer = String::new();
    if std::io::stdin().read_line(&mut answer).is_err() {
        return;
    }
    if !matches!(answer.trim(), "y" | "Y" | "yes" | "Yes") {
        eprintln!("  Skipped git post-commit hook");
        return;
    }

    // Create the hooks directory if needed.
    if let Err(e) = std::fs::create_dir_all(&hooks_dir) {
        eprintln!(
            "  \x1b[31m✘\x1b[0m Failed to create {}: {e}",
            hooks_dir.display()
        );
        return;
    }

    // If no global hooksPath was configured, set it in ~/.gitconfig.
    if need_set_hookspath {
        let gitconfig_path = home.join(".gitconfig");
        if let Err(msg) = set_global_hooks_path(&gitconfig_path, &hooks_dir) {
            eprintln!("  \x1b[31m✘\x1b[0m {msg} — hook not installed");
            return;