/**
 * Git command runner
 * @module orch/git
 */
import { execFileSync } from "child_process";

// ── Branch Helpers ───────────────────────────────────────────────────

/**
 * Get the current branch name (the branch checked out in the given directory).
 *
 * Uses `git rev-parse --abbrev-ref HEAD`. Returns the branch name or null
 * if HEAD is detached or git fails.
 *
 * @param cwd - Working directory (defaults to process.cwd())
 */
export function getCurrentBranch(cwd?: string): string | null {
	const result = runGit(["rev-parse", "--abbrev-ref", "HEAD"], cwd);
	if (!result.ok || !result.stdout.trim() || result.stdout.trim() === "HEAD") {
		return null;
	}
	return result.stdout.trim();
}

// ── Git Command Runner ───────────────────────────────────────────────

/**
 * Run a git command synchronously with consistent error handling.
 *
 * @param args - Array of git subcommand arguments (e.g. ["worktree", "add", ...])
 * @param cwd  - Working directory to run the command in (defaults to process.cwd())
 * @returns    - { ok, stdout, stderr }
 */
export function runGit(
	args: string[],
	cwd?: string,
): { ok: boolean; stdout: string; stderr: string } {
	try {
		const stdout = execFileSync("git", args, {
			encoding: "utf-8",
			timeout: 30_000,
			cwd: cwd || process.cwd(),
			stdio: ["pipe", "pipe", "pipe"],
		}).trim();
		return { ok: true, stdout, stderr: "" };
	} catch (err: unknown) {
		const e = err as { stdout?: string; stderr?: string; message?: string };
		return {
			ok: false,
			stdout: (e.stdout ?? "").toString().trim(),
			stderr: (e.stderr ?? e.message ?? "unknown error").toString().trim(),
		};
	}
}

/**
 * Run a git command with custom environment variables.
 *
 * Used by TP-169 to create commits on the orch branch without
 * modifying HEAD, via GIT_INDEX_FILE for alternate index manipulation.
 *
 * @param args  - Git command arguments
 * @param cwd   - Working directory
 * @param env   - Additional environment variables to set
 */
export function runGitWithEnv(
	args: string[],
	cwd: string,
	env: Record<string, string>,
): { ok: boolean; stdout: string; stderr: string } {
	try {
		const stdout = execFileSync("git", args, {
			encoding: "utf-8",
			timeout: 30_000,
			cwd,
			stdio: ["pipe", "pipe", "pipe"],
			env: { ...process.env, ...env },
		}).trim();
		return { ok: true, stdout, stderr: "" };
	} catch (err: unknown) {
		const e = err as { stdout?: string; stderr?: string; message?: string };
		return {
			ok: false,
			stdout: (e.stdout ?? "").toString().trim(),
			stderr: (e.stderr ?? e.message ?? "unknown error").toString().trim(),
		};
	}
}