const path = require('path');
const fs = require('fs');
const os = require('os');
const express = require('express');
const ServiceManager = require('./service-manager');
const Patcher = require('./patcher');
const UpdateClient = require('./update-client');
const FileUpdater = require('./file-updater');
const VylaPresence = require('./discord-rpc');

function getDefaultAppData() {
  if (process.platform === 'darwin') {
    return path.join(os.homedir(), 'Library', 'Application Support', 'vyla-home', 'vyla-home-files');
  }
  if (process.platform === 'linux') {
    return path.join(os.homedir(), '.local', 'share', 'vyla-home', 'vyla-home-files');
  }
  return path.join(os.homedir(), 'AppData', 'Roaming', 'vyla-home', 'vyla-home-files');
}

const APPDATA_DIR = (process.env.APPDATA_PATH && !process.env.APPDATA_PATH.includes('com.vyla.home'))
  ? process.env.APPDATA_PATH
  : getDefaultAppData();

const LOGS_DIR = path.join(APPDATA_DIR, 'logs');
try { fs.mkdirSync(LOGS_DIR, { recursive: true }); } catch (e) { }

const debugLogPath = path.join(LOGS_DIR, 'node-debug.log');

function debugLog(msg) {
  try { fs.appendFile(debugLogPath, `[NODE] ${msg}\n`, 'utf8', () => { }); } catch (e) { }
}

debugLog("--- Node.js Process Started ---");

let serviceManager;
let updateDecisionHandler = null;

debugLog(`AppData Dir: ${APPDATA_DIR}`);

function sendToTauri(event, data) {
  debugLog(`Emitting to Tauri: [${event}] -> ${JSON.stringify(data)}`);
  process.stdout.write(JSON.stringify({ event, data }) + '\n');
}

process.stdin.resume();
require('readline').createInterface({ input: process.stdin }).on('line', (line) => {
  try {
    const msg = JSON.parse(line);
    if (msg && msg.type === 'presence') presence.report(msg.payload);
  } catch (e) { }
});
process.stdin.on('end', () => {
  debugLog('stdin closed - parent died. Self-terminating...');
  process.exit(0);
});
process.stdin.on('error', () => {
  process.exit(0);
});

process.on('uncaughtException', (err) => {
  debugLog(`CRITICAL UNCAUGHT EXCEPTION: ${err.stack || err.message}`);
  if (err.code === 'EPIPE' || err.code === 'EOF') {
    debugLog('Pipe to parent closed - parent process gone, exiting');
    process.exit(0);
  }
  try { sendToTauri('error', { message: err.message }); } catch (e) { }
});

process.on('unhandledRejection', (reason) => {
  const msg = reason && reason.stack ? reason.stack : String(reason);
  debugLog(`CRITICAL UNHANDLED REJECTION: ${msg}`);
  sendToTauri('error', { message: reason && reason.message ? reason.message : String(reason) });
});

function getEnvConfig() {
  try {
    const appPath = path.join(APPDATA_DIR, 'config/env.json');
    if (fs.existsSync(appPath)) return JSON.parse(fs.readFileSync(appPath, 'utf8'));
    return JSON.parse(fs.readFileSync(path.join(__dirname, 'config/env.json'), 'utf8'));
  } catch (e) { return {}; }
}

function getReplacementsConfig() {
  try {
    const appPath = path.join(APPDATA_DIR, 'config/replacements.json');
    if (fs.existsSync(appPath)) return JSON.parse(fs.readFileSync(appPath, 'utf8'));
    return JSON.parse(fs.readFileSync(path.join(__dirname, 'config/replacements.json'), 'utf8'));
  } catch (e) { return {}; }
}

function liveReposEnabled() {
  const cfg = getEnvConfig();
  return !!(cfg.updater && cfg.updater.liveRepos === true);
}

const updateClient = new UpdateClient(APPDATA_DIR);
const presence = new VylaPresence({ getConfig: getEnvConfig, log: debugLog });
const fileUpdater = new FileUpdater(APPDATA_DIR, updateClient);
fileUpdater.onNotice = (message) => sendToTauri('notice', { message });
let lastFilePercent = -1;
fileUpdater.onProgress = (downloaded, total) => {
  const percent = total > 0 ? Math.round((downloaded / total) * 100) : 0;
  if (percent === lastFilePercent) return;
  lastFilePercent = percent;
  sendToTauri('download-progress', { downloaded, total, percent });
};

function withTimeout(promise, ms) {
  return Promise.race([promise, new Promise((resolve) => setTimeout(() => resolve(null), ms))]);
}

function portInUse(port) {
  return new Promise((resolve) => {
    const socket = new (require('net').Socket)();
    socket.setTimeout(500);
    socket.once('connect', () => {
      socket.destroy();
      resolve(true);
    });
    socket.once('error', () => resolve(false));
    socket.once('timeout', () => {
      socket.destroy();
      resolve(false);
    });
    socket.connect(port, '127.0.0.1');
  });
}


async function start() {
  debugLog("Inside start() function");
  sendToTauri('status', { message: 'Loading core configuration files...' });

  const patcher = new Patcher(APPDATA_DIR);
  serviceManager = new ServiceManager(APPDATA_DIR, getEnvConfig());

  const sleep = (ms) => new Promise((resolve) => setTimeout(resolve, ms));

  const downloadVerified = async (name, item, dest) => {
    let lastError;
    for (let attempt = 1; attempt <= 3; attempt++) {
      fs.rmSync(dest, { force: true });
      try {
        sendToTauri('status', { message: `Downloading ${name} (attempt ${attempt}/3)...` });
        let lastPercent = -1;
        await updateClient.downloadUpdate(item, dest, (downloaded, total) => {
          const percent = total > 0 ? Math.round((downloaded / total) * 100) : 0;
          if (percent !== lastPercent) {
            lastPercent = percent;
            sendToTauri('download-progress', { downloaded, total, percent });
          }
        });
        sendToTauri('status', { message: `Verifying ${name} SHA-256...` });
        if (!patcher.verifyChecksum(dest, item.sha256)) {
          throw new Error('SHA-256 checksum verification failed.');
        }
        return;
      } catch (err) {
        lastError = err;
        fs.rmSync(dest, { force: true });
        debugLog(`Download error for ${name} on attempt ${attempt}: ${err.message}`);
        if (attempt < 3) {
          await sleep(err.retryAfterMs || 2000 * 2 ** (attempt - 1) + Math.floor(Math.random() * 500));
        }
      }
    }
    throw new Error(`Failed to download ${name} after 3 attempts: ${lastError.message}`);
  };

  const installBuild = async (release) => {
    const names = patcher.staleComponents(release);
    if (names.length === 0) return;

    const stagingDir = path.join(APPDATA_DIR, '.staging');
    fs.rmSync(stagingDir, { recursive: true, force: true });
    fs.mkdirSync(stagingDir, { recursive: true });
    const tempFiles = [];

    try {
      for (let i = 0; i < names.length; i++) {
        const name = names[i];
        const tempZip = path.join(APPDATA_DIR, `download-${name}.zip`);
        tempFiles.push(tempZip);
        await downloadVerified(name, release.components[name], tempZip);

        sendToTauri('status', { message: `Unpacking ${name}...` });
        let lastEmit = 0;
        await patcher.extractToStaging(tempZip, (file, done, total) => {
          const now = Date.now();
          if (done !== total && now - lastEmit < 40) return;
          lastEmit = now;
          sendToTauri('extract-progress', { file, done, total, percent: Math.round((done / total) * 100) });
        }, i > 0);
        fs.rmSync(tempZip, { force: true });
      }

      sendToTauri('status', { message: 'Verifying file integrity...' });
      if (!patcher.verifyStaged(stagingDir, names)) {
        throw new Error('Extraction verification failed: critical startup files missing.');
      }

      sendToTauri('status', { message: 'Replacing old version...' });
      patcher.commitStaging(stagingDir);
    } catch (err) {
      fs.rmSync(stagingDir, { recursive: true, force: true });
      for (const f of tempFiles) fs.rmSync(f, { force: true });
      throw err;
    }

    try {
      sendToTauri('status', { message: 'Applying configuration patches...' });
      patcher.applyPatches(getReplacementsConfig(), names);

      sendToTauri('status', { message: 'Migrating security credentials...' });
      patcher.bridgeCredentials(serviceManager.credentialManager);

      if (!patcher.verifyExtraction()) {
        throw new Error('Post-install verification failed.');
      }

      const current = patcher.getCurrentComponents();
      const next = {};
      for (const name of Object.keys(release.components)) {
        next[name] = names.includes(name) ? release.components[name].id : current[name];
      }
      patcher.saveCurrentVersion(release.version, release.sha256, next);
      patcher.writeIntegrity(names);
    } catch (err) {
      try { patcher.rollback(); } catch (x) { debugLog(`Rollback failed: ${x.message}`); }
      throw err;
    }

    patcher.finalizeCommit();
    if (liveReposEnabled()) fileUpdater.snapshotBase();
    serviceManager.envConfig = getEnvConfig();
    debugLog(`Update installed successfully: ${names.join(', ')}`);
  };

  try {
    if (patcher.recoverInterrupted()) {
      debugLog('Recovered from an interrupted update.');
      sendToTauri('notice', { message: 'Recovered from an interrupted update.' });
    }
    fileUpdater.recoverSdk();
    sendToTauri('status', { message: 'Inspecting local workspace and installed files...' });
    const isFirstRun = !patcher.verifyExtraction();
    const localVersion = patcher.getCurrentVersion();
    const localSha = patcher.getCurrentSha();
    debugLog(`Is First Run: ${isFirstRun}, Local Version: ${localVersion}, Local SHA: ${localSha}`);

    sendToTauri('status', { message: 'Connecting to update servers...' });
    let release = null;
    try {
      debugLog("Fetching updates from updateClient...");
      release = await updateClient.checkForUpdates(isFirstRun);
      debugLog(`Update check finished. Found: ${release ? release.version : 'None'}`);
    } catch (e) {
      debugLog(`Update check failed: ${e.message}`);
      sendToTauri('notice', { message: `Update check skipped: ${e.message}` });
    }

    const normalizeVer = (v) => (v || '').toString().replace(/^v/, '').trim();
    const parseVer = (v) => normalizeVer(v).split(/[.\-+]/).map((n) => parseInt(n, 10) || 0);
    const isNewer = (remote, local) => {
      const a = parseVer(remote);
      const b = parseVer(local);
      for (let i = 0; i < Math.max(a.length, b.length); i++) {
        const x = a[i] || 0;
        const y = b[i] || 0;
        if (x !== y) return x > y;
      }
      return false;
    };

    if (release && release.installer && process.platform === 'win32' && process.env.VYLA_DEV !== '1') {
      const appVersion = process.env.VYLA_APP_VERSION || '0.0.0';
      const tried = updateClient.readCache().selfUpdate || {};
      const recentlyTried = tried.version === release.installer.version && Date.now() - (tried.at || 0) < 10 * 60 * 1000;
      if (isNewer(release.installer.version, appVersion) && !recentlyTried) {
        try {
          const dest = path.join(APPDATA_DIR, `vyla-installer-${normalizeVer(release.installer.version)}.exe`);
          sendToTauri('status', { message: 'Downloading launcher update...' });
          await downloadVerified('launcher', release.installer, dest);
          updateClient.writeCache({ selfUpdate: { version: release.installer.version, at: Date.now() } });
          sendToTauri('status', { message: 'Removing old version and installing the latest...' });
          sendToTauri('self-update', { path: dest });
          await sleep(30000);
          sendToTauri('notice', { message: 'Launcher update did not start. Continuing on the current version.' });
        } catch (err) {
          debugLog(`Launcher update failed: ${err.message}`);
          sendToTauri('notice', { message: `Launcher update failed: ${err.message}` });
        }
      }
    }

    if (release) {
      const stale = patcher.staleComponents(release);
      const broken = stale.some((name) => !patcher.componentIntact(name));
      const sameVersion = normalizeVer(release.version) === normalizeVer(localVersion);
      const hasUpdate = stale.length > 0 && (broken || isNewer(release.version, localVersion) || sameVersion);

      if (hasUpdate) {
        debugLog(`Installing components: ${stale.join(', ')}`);
        sendToTauri('status', {
          message: isFirstRun ? 'First run detected. Preparing initial installation...' : `Updating to ${release.version}...`
        });
        try {
          await installBuild(release);
          updateClient.recordSuccess();
        } catch (err) {
          updateClient.recordFailure();
          debugLog(`Update failed: ${err.message}`);
          sendToTauri('notice', { message: `Update failed: ${err.message}` });
        }
      } else {
        debugLog("Already on the latest version.");
        sendToTauri('status', { message: 'Up to date.' });
      }
    }

    if (!patcher.verifyExtraction()) {
      debugLog("No usable install. Looking for local update-payload.zip...");
      sendToTauri('status', { message: 'Looking for local payload archive...' });
      const payloadRoots = [
        process.env.VYLA_PAYLOAD_DIR,
        __dirname,
        process.cwd(),
        path.resolve(__dirname, '..', '..', '..', '..'),
        APPDATA_DIR
      ].filter(Boolean);
      const payloadRoot = payloadRoots.find((r) => fs.existsSync(path.join(r, 'update-payload.zip')));
      const localZip = payloadRoot ? path.join(payloadRoot, 'update-payload.zip') : null;
      if (localZip) {
        sendToTauri('status', { message: 'Extracting local baseline payload...' });
        const stagingDir = await patcher.extractToStaging(localZip);
        if (!patcher.verifyStaged(stagingDir, ['frontend', 'player'])) {
          fs.rmSync(stagingDir, { recursive: true, force: true });
          throw new Error('Bundled payload is incomplete.');
        }
        patcher.commitStaging(stagingDir);

        try {
          patcher.applyPatches(getReplacementsConfig());
          patcher.bridgeCredentials(serviceManager.credentialManager);

          let ver = "1.0.0";
          let manSha = null;
          let ids = {};
          try {
            const man = JSON.parse(fs.readFileSync(path.join(payloadRoot, 'manifest.json'), 'utf8'));
            ver = man.version || ver;
            manSha = man.sha256 || null;
            ids = Object.fromEntries(Object.entries(man.components || {}).map(([k, v]) => [k, v.id]));
          } catch (e) { }

          patcher.saveCurrentVersion(ver, manSha, ids);
          patcher.writeIntegrity(['frontend', 'player']);
        } catch (e) {
          try { patcher.rollback(); } catch (x) { }
          throw e;
        }

        patcher.finalizeCommit();
        if (liveReposEnabled()) fileUpdater.snapshotBase();
        serviceManager.envConfig = getEnvConfig();
        debugLog("Local payload extracted successfully.");
      } else {
        debugLog("No local payload found!");
      }
    }

    sendToTauri('status', { message: 'Validating critical components...' });
    if (!patcher.verifyExtraction()) {
      throw new Error('No usable install and no valid signed release or bundled payload was found. Check your internet connection and relaunch, or reinstall the app.');
    }

    const liveRepos = liveReposEnabled();
    sendToTauri('status', { message: liveRepos ? 'Checking UI files and SDK...' : 'Checking SDK...' });
    const [filesCheck, sdkCheck] = await Promise.all([
      liveRepos
        ? withTimeout(fileUpdater.checkRepos().catch((e) => {
          debugLog(`Live file check failed: ${e.message}`);
          sendToTauri('notice', { message: `File check failed: ${e.message}` });
          return null;
        }), 60000)
        : Promise.resolve(null),
      withTimeout(fileUpdater.checkSdk().catch((e) => {
        debugLog(`SDK check failed: ${e.message}`);
        sendToTauri('notice', { message: `SDK check failed: ${e.message}` });
        return null;
      }), 12000)
    ]);
    if (liveRepos) {
      debugLog(`Repo check result: ${filesCheck ? `${filesCheck.changes.length} change(s)` : 'failed or timed out'}`);
    }

    if (filesCheck && (filesCheck.changes.length > 0 || filesCheck.removed.length > 0)) {
      sendToTauri('status', { message: `Updating ${filesCheck.changes.length} file(s)...` });
      try {
        await fileUpdater.applyLive(filesCheck, getReplacementsConfig(), (file, done, total) => {
          sendToTauri('extract-progress', { file, done, total, percent: Math.round((done / total) * 100) });
        });
        sendToTauri('status', { message: `Updated ${filesCheck.changes.length} file(s).` });
      } catch (e) {
        debugLog(`File update failed: ${e.message}`);
        sendToTauri('notice', { message: `File update failed: ${e.message}` });
      }
    }

    if (sdkCheck && sdkCheck.outdated) {
      sendToTauri('status', { message: `Updating SDK (${sdkCheck.latest})...` });
      try {
        await fileUpdater.installSdk(sdkCheck);
        sendToTauri('status', { message: `SDK updated to ${sdkCheck.latest}.` });
      } catch (e) {
        debugLog(`SDK install failed: ${e.message}`);
        sendToTauri('status', { message: `SDK update failed: ${e.message}` });
      }
    }

    sendToTauri('status', { message: 'Loading encrypted credentials...' });
    serviceManager.credentialManager.loadCredentials();

    const busyPorts = [];
    for (const port of [3000, 4890]) {
      if (await portInUse(port)) busyPorts.push(port);
    }
    if (busyPorts.length > 0) {
      throw new Error(`Port ${busyPorts.join(' and ')} is already in use by another program. Close it or any other running Vyla Home, then relaunch.`);
    }

    sendToTauri('status', { message: 'Starting services (player, frontend)...' });
    await serviceManager.startServices([
      { name: 'player', relativeDir: 'player', startScript: 'server.js' },
      { name: 'frontend', relativeDir: 'frontend', startScript: 'server.js' }
    ]);
    debugLog("Backend services spawn requested.");

    sendToTauri('status', { message: 'Waiting for microservices to bind...' });
    try {
      await serviceManager.waitForPorts([3000, 4890], 60000);
    } catch (e) {
      throw new Error(`${e.message}. Check logs in ${LOGS_DIR}`);
    }
    debugLog("Ports 3000 and 4890 are ready.");
    try { presence.start(); } catch (e) { debugLog(`Presence start failed: ${e.message}`); }

    sendToTauri('status', { message: 'All backend services running and healthy.' });
    debugLog("Sending READY to Tauri.");
    sendToTauri('ready', { url: 'http://127.0.0.1:4890' });

  } catch (error) {
    debugLog(`Fatal Start Error: ${error.message}`);
    sendToTauri('error', { message: error.message });
  }
}

process.on('exit', () => {
  try { presence.stop(); } catch (e) { }
  if (serviceManager) {
    serviceManager.stopAll();
  }
});

process.on('SIGINT', () => {
  process.exit(0);
});
process.on('SIGTERM', () => {
  process.exit(0);
});
process.on('SIGHUP', () => {
  process.exit(0);
});

start();