import { spawnSync } from "node:child_process";
import * as fs from "node:fs";
import * as path from "node:path";
import { tryLease } from "../../shared/file-lease.ts";

export function withHandoffWriteLock<T>(manifestPath: string, action: () => T): T {
	const requested = path.resolve(manifestPath);
	fs.mkdirSync(path.dirname(requested), { recursive: true });
	const absolute = path.join(fs.realpathSync.native(path.dirname(requested)), path.basename(requested));
	const release = tryLease(`${absolute}.write-lock`);
	if (!release) throw new Error(`Handoff is being updated or cleaned: ${absolute}. Retry after the current operation completes.`);
	try { return action(); } finally { release(); }
}

export async function withRepositoryWorktreeLock<T>(repo: string, action: () => T | Promise<T>, options: { signal?: AbortSignal; waitMs?: number } = {}): Promise<T> {
	const git = spawnSync("git", ["-C", repo, "rev-parse", "--path-format=absolute", "--git-common-dir"], { encoding: "utf-8", windowsHide: true });
	if (git.status !== 0) throw new Error(git.error?.message || git.stderr.trim() || "Cannot resolve Git common directory.");
	const lockPath = path.join(fs.realpathSync(git.stdout.trim()), "pi-subagents-worktree.lock");
	const deadline = Date.now() + (options.waitMs ?? 2_000);
	while (true) {
		options.signal?.throwIfAborted();
		const release = tryLease(lockPath);
		if (release) {
			try { return await action(); } finally { release(); }
		}
		if (Date.now() >= deadline) throw new Error("Repository worktree maintenance is busy; retry later.");
		await new Promise<void>((resolve) => setTimeout(resolve, 25));
	}
}