import chokidar, { FSWatcher } from 'chokidar';
import path from 'path';
import { NOTEBOOK_ROOT } from '../config/paths.js';
import { eventBus } from '../events/eventBus.js';
import { logger } from '../utils/logger.js';
import { toPosixPath } from '../../shared/utils/path.js';

let watcher: FSWatcher | null = null;

export const startWatcher = (): void => {
  if (watcher) return;

  logger.info(`Starting file watcher for: ${NOTEBOOK_ROOT}`);

  watcher = chokidar.watch(NOTEBOOK_ROOT, {
    ignored: /(^|[\/\\])\../,
    persistent: true,
    ignoreInitial: true,
  });

  const broadcast = (event: string, changedPath: string) => {
    const rel = path.relative(NOTEBOOK_ROOT, changedPath);
    if (!rel || rel.startsWith('..') || path.isAbsolute(rel)) return;
    logger.info(`File event: ${event} - ${rel}`);
    eventBus.broadcast({ event, path: toPosixPath(rel) });
  };

  watcher
    .on('add', (p) => broadcast('add', p))
    .on('change', (p) => broadcast('change', p))
    .on('unlink', (p) => broadcast('unlink', p))
    .on('addDir', (p) => broadcast('addDir', p))
    .on('unlinkDir', (p) => broadcast('unlinkDir', p))
    .on('ready', () => logger.info('File watcher ready'))
    .on('error', (err) => logger.error('File watcher error:', err));
};

export const stopWatcher = async (): Promise<void> => {
  if (watcher) {
    await watcher.close();
    watcher = null;
  }
};