const { spawn } = require('child_process');
const path = require('path');
const fs = require('fs');
const http = require('http');
const { app } = require('electron');

interface ServiceProcess {
  process: ReturnType<typeof spawn> | null;
  name: string;
  port: number;
  ready: boolean;
  restartCount: number;
  lastRestartTime: number;
}

const NODE_PORT = 14890;
const LOCAL_NODE_URL = `http://127.0.0.1:${NODE_PORT}`;
const MAX_RESTARTS = 4;
const RESTART_WINDOW_MS = 2 * 60 * 1000;

const services: { node: ServiceProcess } = {
  node: {
    process: null,
    name: 'Node Server',
    port: NODE_PORT,
    ready: false,
    restartCount: 0,
    lastRestartTime: 0,
  },
};

let logFilePath = '';

function getLogPath(): string {
  if (!logFilePath) {
    try {
      logFilePath = path.join(app.getPath('userData'), 'local-services.log');
    } catch {
      logFilePath = path.join(process.cwd(), 'local-services.log');
    }
  }
  return logFilePath;
}

function log(level: string, ...args: unknown[]): void {
  const line = `[${new Date().toISOString()}] [${level}] ${args.map((item) => typeof item === 'string' ? item : JSON.stringify(item)).join(' ')}`;
  if (level === 'ERROR') {
    console.error(line);
  } else {
    console.log(line);
  }

  try {
    fs.appendFileSync(getLogPath(), line + '\n', 'utf8');
  } catch {
    // ignore logging failures
  }
}

function isPackaged(): boolean {
  return app.isPackaged;
}

function getServerDir(): string {
  if (isPackaged()) {
    return path.join((process as any).resourcesPath, 'server');
  }
  return path.resolve(__dirname, '..', '..', 'server');
}

function getPlaywrightBrowsersPath(): string | null {
  if (!isPackaged()) return null;
  const bundled = path.join((process as any).resourcesPath, 'playwright');
  return fs.existsSync(bundled) ? bundled : null;
}

function findNodeRunner(): { cmd: string; args: string[]; useElectronAsNode?: boolean } {
  const serverDir = getServerDir();
  const distEntry = path.join(serverDir, 'dist', 'app.js');
  const srcEntry = path.join(serverDir, 'src', 'app.ts');
  const isWin = process.platform === 'win32';

  if (isPackaged()) {
    return { cmd: process.execPath, args: [distEntry], useElectronAsNode: true };
  }

  if (fs.existsSync(distEntry)) {
    return { cmd: 'node', args: [distEntry] };
  }

  const tsxBin = path.join(serverDir, 'node_modules', '.bin', isWin ? 'tsx.cmd' : 'tsx');
  if (fs.existsSync(tsxBin)) {
    return { cmd: tsxBin, args: [srcEntry] };
  }

  return { cmd: isWin ? 'npx.cmd' : 'npx', args: ['tsx', srcEntry] };
}

function checkHealth(port: number): Promise<boolean> {
  return new Promise((resolve) => {
    const req = http.get(`http://127.0.0.1:${port}/api/health`, { timeout: 2500 }, (res: any) => {
      res.resume();
      resolve(res.statusCode >= 200 && res.statusCode < 500);
    });
    req.on('error', () => resolve(false));
    req.on('timeout', () => {
      req.destroy();
      resolve(false);
    });
  });
}

async function waitForService(port: number, timeoutMs = 45000): Promise<boolean> {
  const startedAt = Date.now();
  while (Date.now() - startedAt < timeoutMs) {
    if (await checkHealth(port)) {
      return true;
    }
    await new Promise((resolve) => setTimeout(resolve, 1000));
  }
  return false;
}

function shouldRestart(service: ServiceProcess): boolean {
  const now = Date.now();
  if (now - service.lastRestartTime > RESTART_WINDOW_MS) {
    service.restartCount = 0;
  }
  service.lastRestartTime = now;
  service.restartCount += 1;
  return service.restartCount <= MAX_RESTARTS;
}

function startNodeServer(): void {
  const service = services.node;
  const serverDir = getServerDir();
  const { cmd, args, useElectronAsNode } = findNodeRunner();

  const env: Record<string, string> = {
    ...(process.env as Record<string, string>),
    PORT: String(NODE_PORT),
    HOST: '127.0.0.1',
    USE_REDIS_QUEUE: 'false',
    LOCAL_NODE_ONLY_AUTOMATION: 'true',
    NODE_OPTIONS: '--max-old-space-size=512',
  };

  if (useElectronAsNode) {
    env.ELECTRON_RUN_AS_NODE = '1';
  }

  if (isPackaged()) {
    const uploadsDir = path.join(app.getPath('userData'), 'uploads');
    fs.mkdirSync(uploadsDir, { recursive: true });
    env.UPLOAD_PATH = uploadsDir;
  }

  const playwrightPath = getPlaywrightBrowsersPath();
  if (playwrightPath) {
    env.PLAYWRIGHT_BROWSERS_PATH = playwrightPath;
  }

  log('INFO', 'Starting node service', cmd, args.join(' '));
  const child = spawn(cmd, args, {
    cwd: serverDir,
    env,
    stdio: ['ignore', 'pipe', 'pipe'],
    shell: false,
    windowsHide: true,
  });

  service.process = child;
  service.ready = false;

  child.stdout?.on('data', (chunk: Buffer) => {
    const message = chunk.toString().trim();
    if (!message) return;
    log('NODE', message);
    if (message.includes('Server running') || message.includes('listening')) {
      service.ready = true;
    }
  });

  child.stderr?.on('data', (chunk: Buffer) => {
    const message = chunk.toString().trim();
    if (message) log('NODE-ERR', message);
  });

  child.on('error', (error: Error) => {
    log('ERROR', 'Node spawn error', error.message);
  });

  child.on('exit', (code: number | null, signal: string | null) => {
    log('WARN', `Node service exited code=${code} signal=${signal}`);
    service.process = null;
    service.ready = false;

    if (signal === 'SIGTERM' || signal === 'SIGINT') {
      return;
    }

    if (!shouldRestart(service)) {
      log('ERROR', 'Node service restart budget exhausted');
      return;
    }

    const backoffMs = Math.min(service.restartCount * 4000, 15000);
    log('INFO', `Restarting node service in ${backoffMs}ms`);
    setTimeout(() => startNodeServer(), backoffMs);
  });
}

async function startLocalServices(): Promise<{ nodeOk: boolean }> {
  if (!services.node.process) {
    startNodeServer();
  }

  const nodeOk = await waitForService(NODE_PORT);
  services.node.ready = nodeOk;
  return { nodeOk };
}

function stopLocalServices(): void {
  const service = services.node;
  service.ready = false;
  if (!service.process) return;

  try {
    service.process.kill('SIGTERM');
  } catch (error) {
    log('ERROR', 'Failed to stop node service', error);
  }
  service.process = null;
}

function getServiceStatus() {
  return {
    node: {
      ready: services.node.ready,
      port: services.node.port,
      restartCount: services.node.restartCount,
    },
  };
}

export {
  NODE_PORT,
  LOCAL_NODE_URL,
  startLocalServices,
  stopLocalServices,
  getServiceStatus,
  getLogPath,
};