import { tap, expect } from '@git.zone/tstest/tapbundle';
import { RustWatcher } from '../ts/watchers/watcher.rust.js';
import type { IWatchEvent } from '../ts/watchers/interfaces.js';
import * as path from 'path';
import * as fs from 'fs';

const TEST_DIR = path.resolve('./test/assets');
const delay = (ms: number) => new Promise<void>((r) => setTimeout(r, ms));

function waitForEvent(
  watcher: { events$: { subscribe: Function } },
  filter: (e: IWatchEvent) => boolean,
  timeoutMs = 5000
): Promise<IWatchEvent> {
  return new Promise((resolve, reject) => {
    const timeout = setTimeout(() => {
      sub.unsubscribe();
      reject(new Error(`Timeout waiting for event after ${timeoutMs}ms`));
    }, timeoutMs);
    const sub = watcher.events$.subscribe((event: IWatchEvent) => {
      if (filter(event)) {
        clearTimeout(timeout);
        sub.unsubscribe();
        resolve(event);
      }
    });
  });
}

function collectEvents(
  watcher: { events$: { subscribe: Function } },
  filter: (e: IWatchEvent) => boolean,
  durationMs: number
): Promise<IWatchEvent[]> {
  return new Promise((resolve) => {
    const events: IWatchEvent[] = [];
    const sub = watcher.events$.subscribe((event: IWatchEvent) => {
      if (filter(event)) events.push(event);
    });
    setTimeout(() => { sub.unsubscribe(); resolve(events); }, durationMs);
  });
}

let available = false;

tap.test('RustWatcher (Node): check availability', async () => {
  available = await RustWatcher.isAvailable();
  console.log(`[test] Rust binary available: ${available}`);
  if (!available) {
    console.log('[test] Skipping Rust watcher tests — binary not found');
  }
});

let watcher: RustWatcher;

tap.test('RustWatcher (Node): should create and start', async () => {
  if (!available) return;
  watcher = new RustWatcher({
    basePaths: [TEST_DIR],
    depth: 4,
    followSymlinks: false,
    debounceMs: 100,
  });
  expect(watcher.isWatching).toBeFalse();
  await watcher.start();
  expect(watcher.isWatching).toBeTrue();
  await delay(300);
});

tap.test('RustWatcher (Node): should emit initial add events', async () => {
  if (!available) return;
  // The initial scan should have emitted add events for existing files.
  // We verify by creating a file and checking it gets an add event
  const file = path.join(TEST_DIR, 'rust-node-add.txt');
  const eventPromise = waitForEvent(watcher, (e) => e.type === 'add' && e.path.includes('rust-node-add.txt'));
  await fs.promises.writeFile(file, 'rust node add test');
  const event = await eventPromise;
  expect(event.type).toEqual('add');
  expect(event.path).toInclude('rust-node-add.txt');
  await fs.promises.unlink(file);
  await delay(200);
});

tap.test('RustWatcher (Node): should detect file modification', async () => {
  if (!available) return;
  const file = path.join(TEST_DIR, 'rust-node-change.txt');
  await fs.promises.writeFile(file, 'initial');
  await delay(300);

  const eventPromise = waitForEvent(watcher, (e) => e.type === 'change' && e.path.includes('rust-node-change.txt'));
  await fs.promises.writeFile(file, 'modified');
  const event = await eventPromise;
  expect(event.type).toEqual('change');

  await fs.promises.unlink(file);
  await delay(200);
});

tap.test('RustWatcher (Node): should detect file deletion', async () => {
  if (!available) return;
  const file = path.join(TEST_DIR, 'rust-node-unlink.txt');
  await fs.promises.writeFile(file, 'to delete');
  await delay(300);

  const eventPromise = waitForEvent(watcher, (e) => e.type === 'unlink' && e.path.includes('rust-node-unlink.txt'));
  await fs.promises.unlink(file);
  const event = await eventPromise;
  expect(event.type).toEqual('unlink');
});

tap.test('RustWatcher (Node): should detect directory creation', async () => {
  if (!available) return;
  const dir = path.join(TEST_DIR, 'rust-node-subdir');
  const eventPromise = waitForEvent(watcher, (e) => e.type === 'addDir' && e.path.includes('rust-node-subdir'));
  await fs.promises.mkdir(dir, { recursive: true });
  const event = await eventPromise;
  expect(event.type).toEqual('addDir');
  await delay(200);
  await fs.promises.rmdir(dir);
  await delay(200);
});

tap.test('RustWatcher (Node): should handle rapid modifications', async () => {
  if (!available) return;
  const file = path.join(TEST_DIR, 'rust-node-rapid.txt');
  await fs.promises.writeFile(file, 'initial');
  await delay(200);

  const collector = collectEvents(watcher, (e) => e.type === 'change' && e.path.includes('rust-node-rapid.txt'), 3000);

  for (let i = 0; i < 10; i++) {
    await fs.promises.writeFile(file, `content ${i}`);
    await delay(10);
  }

  const events = await collector;
  console.log(`[test] Rapid mods: 10 writes, ${events.length} events received`);
  expect(events.length).toBeGreaterThan(0);

  await fs.promises.unlink(file);
  await delay(200);
});

tap.test('RustWatcher (Node): should not be watching after stop', async () => {
  if (!available) return;
  await watcher.stop();
  expect(watcher.isWatching).toBeFalse();
});

tap.test('RustWatcher (Node): cleanup', async () => {
  for (const name of ['rust-node-add.txt', 'rust-node-change.txt', 'rust-node-unlink.txt', 'rust-node-rapid.txt']) {
    try { await fs.promises.unlink(path.join(TEST_DIR, name)); } catch {}
  }
  try { await fs.promises.rmdir(path.join(TEST_DIR, 'rust-node-subdir')); } catch {}
});

export default tap.start();