#!/usr/bin/env node

/**
 * Watch src/resources/ and sync changes to dist/resources/.
 *
 * Runs alongside `tsc --watch` to ensure non-TS resources (prompts, agents,
 * skills, workflow files) are kept in sync with the build output.
 *
 * This solves the `npm link` branch-drift problem: without dist/resources/,
 * `initResources()` reads from src/resources/ which changes with git branch
 * switches, causing stale extensions to be synced to ~/.sf/agent/ for ALL
 * projects using sf.
 */

import { cpSync, mkdirSync, rmSync, watch } from "node:fs";
import { resolve } from "node:path";

const __dirname = import.meta.dirname;
const src = resolve(__dirname, "..", "src", "resources");
const dest = resolve(__dirname, "..", "dist", "resources");

function sync() {
	// Remove dest first to mirror deletions from src (prevents stale files)
	rmSync(dest, { recursive: true, force: true });
	mkdirSync(dest, { recursive: true });
	cpSync(src, dest, { recursive: true, force: true });
}

// Initial sync
sync();
process.stderr.write(`[watch-resources] Initial sync done\n`);

// Watch for changes — recursive, debounced.
// fs.watch({ recursive: true }) is supported on macOS and Windows.
// On Linux (Node <20.13) it throws ERR_FEATURE_UNAVAILABLE_ON_PLATFORM.
// Fall back to polling on unsupported platforms.
let timer = null;
let fsWatcher = null;
let pollInterval = null;

const onChange = () => {
	if (timer) clearTimeout(timer);
	timer = setTimeout(() => {
		sync();
		process.stderr.write(
			`[watch-resources] Synced at ${new Date().toLocaleTimeString()}\n`,
		);
	}, 300);
};

try {
	fsWatcher = watch(src, { recursive: true }, onChange);
} catch {
	// Fallback: poll every 2s (Linux without recursive watch support)
	process.stderr.write(
		`[watch-resources] fs.watch recursive not supported, falling back to polling\n`,
	);
	pollInterval = setInterval(() => {
		try {
			sync();
		} catch {}
	}, 2000);
}

process.on("exit", () => {
	if (timer) clearTimeout(timer);
	if (fsWatcher) fsWatcher.close();
	if (pollInterval) clearInterval(pollInterval);
});

process.stderr.write(
	`[watch-resources] Watching src/resources/ → dist/resources/\n`,
);