@masuidrive/ticket/server/src/fileWatcher.ts

Real-time ticket tracking viewer with Vite + Express

import { watch } from 'chokidar';
import { EventEmitter } from 'events';
import path from 'path';
import { createHash } from 'crypto';
import { readFile } from 'fs/promises';

export class FileWatcher extends EventEmitter {
  private watcher: any;
  private projectRoot: string;
  private fileHashes: Map<string, string> = new Map();

  constructor(projectRoot?: string) {
    super();
    this.projectRoot = projectRoot || process.cwd();
  }

  private async getFileHash(filePath: string): Promise<string | null> {
    try {
      const content = await readFile(filePath, 'utf-8');
      return createHash('sha256').update(content).digest('hex');
    } catch (error) {
      return null;
    }
  }

  watchFile(filePath: string = 'current-ticket.md'): void {
    const fullPath = path.join(this.projectRoot, filePath);
    
    // Get initial hash
    this.getFileHash(fullPath).then(hash => {
      if (hash) {
        this.fileHashes.set(filePath, hash);
      }
    });
    
    this.watcher = watch(fullPath, {
      persistent: true,
      ignoreInitial: true,
      awaitWriteFinish: {
        stabilityThreshold: 500,
        pollInterval: 100
      }
    });

    this.watcher.on('change', async () => {
      // Check if content actually changed using SHA256
      const newHash = await this.getFileHash(fullPath);
      const oldHash = this.fileHashes.get(filePath);
      
      if (newHash && newHash !== oldHash) {
        this.fileHashes.set(filePath, newHash);
        this.emit('fileChanged', filePath);
      }
    });

    this.watcher.on('add', async () => {
      const hash = await this.getFileHash(fullPath);
      if (hash) {
        this.fileHashes.set(filePath, hash);
      }
      this.emit('fileAdded', filePath);
    });

    this.watcher.on('unlink', () => {
      this.fileHashes.delete(filePath);
      this.emit('fileRemoved', filePath);
    });

    this.watcher.on('error', (error: Error) => {
      this.emit('error', error);
    });
  }

  stop(): void {
    if (this.watcher) {
      this.watcher.close();
    }
    this.fileHashes.clear();
  }
}