const { app, BrowserWindow, ipcMain, shell } = require('electron');
const path = require('path');
const fs = require('fs');
const os = require('os');
const axios = require('axios');
const https = require('https');
const { spawn } = require('child_process');
const http = require('http');

let mainWindow;
let activeProxyProcesses = new Map(); // Track active camera proxy processes
let cookieServer = null;
const COOKIE_SERVER_PORT = 18247;
const COOKIE_SERVER_TOKEN = 'apt-local-bridge-token';

// Sanitize strings before embedding in batch files to prevent command injection
function sanitizeBatchInput(input) {
  if (typeof input !== 'string') return '';
  // Remove characters that have special meaning in batch/cmd: & | < > ^ % " ` !
  return input.replace(/[&|<>^%"`!]/g, '');
}

function startCookieServer() {
  cookieServer = http.createServer((req, res) => {
    // CORS headers — only allow Chrome extension origins
    const origin = req.headers.origin || '';
    if (origin.startsWith('chrome-extension://')) {
      res.setHeader('Access-Control-Allow-Origin', origin);
    }
    res.setHeader('Access-Control-Allow-Methods', 'POST, OPTIONS');
    res.setHeader('Access-Control-Allow-Headers', 'Content-Type, X-APT-Token');

    // Handle preflight
    if (req.method === 'OPTIONS') {
      res.writeHead(204);
      res.end();
      return;
    }

    // Only accept POST /cookie
    if (req.method !== 'POST' || req.url !== '/cookie') {
      res.writeHead(404, { 'Content-Type': 'application/json' });
      res.end(JSON.stringify({ success: false, message: 'Not found' }));
      return;
    }

    // Verify shared token
    if (req.headers['x-apt-token'] !== COOKIE_SERVER_TOKEN) {
      res.writeHead(403, { 'Content-Type': 'application/json' });
      res.end(JSON.stringify({ success: false, message: 'Forbidden' }));
      return;
    }

    // Read body with 64KB size limit
    let body = '';
    let bodySize = 0;
    const MAX_BODY_SIZE = 65536;

    req.on('data', (chunk) => {
      bodySize += chunk.length;
      if (bodySize > MAX_BODY_SIZE) {
        res.writeHead(413, { 'Content-Type': 'application/json' });
        res.end(JSON.stringify({ success: false, message: 'Payload too large' }));
        req.destroy();
        return;
      }
      body += chunk;
    });

    req.on('end', () => {
      try {
        const data = JSON.parse(body);
        const { deploymentUrl, cookieValue } = data;

        if (!deploymentUrl || !cookieValue) {
          res.writeHead(400, { 'Content-Type': 'application/json' });
          res.end(JSON.stringify({ success: false, message: 'Missing deploymentUrl or cookieValue' }));
          return;
        }

        // Validate types and lengths
        if (typeof deploymentUrl !== 'string' || typeof cookieValue !== 'string' ||
            deploymentUrl.length > 512 || cookieValue.length > 4096) {
          res.writeHead(400, { 'Content-Type': 'application/json' });
          res.end(JSON.stringify({ success: false, message: 'Invalid parameter types or lengths' }));
          return;
        }

        // Validate deployment URL is an Alta domain
        try {
          const parsed = new URL(deploymentUrl);
          const isAltaDomain = parsed.hostname.endsWith('.avasecurity.com') ||
                               parsed.hostname.endsWith('.avigilon.com');
          if (!isAltaDomain || parsed.protocol !== 'https:') {
            res.writeHead(400, { 'Content-Type': 'application/json' });
            res.end(JSON.stringify({ success: false, message: 'Invalid deployment URL domain' }));
            return;
          }
        } catch {
          res.writeHead(400, { 'Content-Type': 'application/json' });
          res.end(JSON.stringify({ success: false, message: 'Invalid deployment URL' }));
          return;
        }

        if (mainWindow && !mainWindow.isDestroyed()) {
          const cookies = ['va=' + cookieValue];
          mainWindow.webContents.send('extension-cookie-received', {
            deploymentUrl: deploymentUrl.replace(/\/$/, ''),
            cookies,
            cookieValue
          });
          res.writeHead(200, { 'Content-Type': 'application/json' });
          res.end(JSON.stringify({ success: true, message: 'Cookie received' }));
        } else {
          res.writeHead(503, { 'Content-Type': 'application/json' });
          res.end(JSON.stringify({ success: false, message: 'Application window not available' }));
        }
      } catch (e) {
        res.writeHead(400, { 'Content-Type': 'application/json' });
        res.end(JSON.stringify({ success: false, message: 'Invalid JSON' }));
      }
    });
  });

  cookieServer.listen(COOKIE_SERVER_PORT, '127.0.0.1', () => {
    console.log(`Cookie server listening on http://127.0.0.1:${COOKIE_SERVER_PORT}`);
  });

  cookieServer.on('error', (err) => {
    if (err.code === 'EADDRINUSE') {
      console.error(`Cookie server error: Port ${COOKIE_SERVER_PORT} is already in use`);
    } else {
      console.error('Cookie server error:', err.message);
    }
  });
}

function createWindow() {
  mainWindow = new BrowserWindow({
    width: 1400,
    height: 900,
    webPreferences: {
      nodeIntegration: false,
      contextIsolation: true,
      preload: path.join(__dirname, 'preload.js')
    },
    icon: path.join(__dirname, 'assets', 'icon.png'), // Optional icon
    title: 'Alta Video Camera Proxy with API'
  });

  mainWindow.loadFile('index.html');

  // Open DevTools in development
  if (process.argv.includes('--dev')) {
    mainWindow.webContents.openDevTools();
  }
}

app.whenReady().then(() => {
  createWindow();
  startCookieServer();
});

app.on('before-quit', () => {
  if (cookieServer) {
    cookieServer.close();
  }
});

app.on('window-all-closed', () => {
  if (process.platform !== 'darwin') {
    app.quit();
  }
});

app.on('activate', () => {
  if (BrowserWindow.getAllWindows().length === 0) {
    createWindow();
  }
});

// IPC handlers for API communication
ipcMain.handle('api-get-devices', async (event, { deploymentUrl, cookies }) => {
  try {
    const devicesUrl = `${deploymentUrl}/api/v1/devices`;
    
    // Create axios instance with cookies
    const axiosInstance = axios.create({
      timeout: 10000,
      headers: {
        'Cookie': cookies ? cookies.join('; ') : ''
      }
    });

    const response = await axiosInstance.get(devicesUrl);
    
    return {
      success: true,
      devices: response.data,
      message: `Found ${response.data.length} devices`
    };
  } catch (error) {
    console.error('Get devices error:', error);
    return {
      success: false,
      message: error.response?.data?.message || error.message || 'Failed to get devices'
    };
  }
});

ipcMain.handle('api-get-auth-info', async (event, { deploymentUrl, cookies }) => {
  try {
    const authUrl = `${deploymentUrl}/api/v1/auth`;
    
    const axiosInstance = axios.create({
      timeout: 10000,
      headers: {
        'Cookie': cookies ? cookies.join('; ') : ''
      }
    });

    const response = await axiosInstance.get(authUrl);
    
    return {
      success: true,
      authInfo: response.data
    };
  } catch (error) {
    console.error('Get auth info error:', error);
    return {
      success: false,
      message: error.response?.data?.message || error.message || 'Failed to get auth info'
    };
  }
});

// Cookie-based camera proxy functionality
ipcMain.handle('camera-proxy-cookie-launch', async (event, { deploymentUrl, cookieKey, deviceUuid }) => {
  try {
    // Path to the cookie-based camera proxy executable
    const proxyExePath = path.join(__dirname, 'aware-cam-proxy.exe');
    
    // Check if the executable exists
    if (!fs.existsSync(proxyExePath)) {
      return {
        success: false,
        message: 'Cookie-based camera proxy executable not found. Please ensure aware-cam-proxy.exe is in the application directory.'
      };
    }
    
    // Extract the domain from the deployment URL
    let domain = deploymentUrl;
    if (domain.startsWith('https://')) {
      domain = domain.substring(8);
    } else if (domain.startsWith('http://')) {
      domain = domain.substring(7);
    }
    // Remove trailing path segments
    domain = domain.split('/')[0];

    // Sanitize all inputs before embedding in batch file
    const safeDomain = sanitizeBatchInput(domain);
    const safeDeviceUuid = sanitizeBatchInput(deviceUuid);
    const safeCookieKey = sanitizeBatchInput(cookieKey);

    if (!safeDomain || !safeDeviceUuid || !safeCookieKey) {
      return {
        success: false,
        message: 'Invalid characters detected in connection parameters.'
      };
    }

    // Create a batch file to launch the cookie-based camera proxy
    const truncatedKey = safeCookieKey.length > 20 ? safeCookieKey.substring(0, 20) + '...' : safeCookieKey;
    const batchContent = `@echo off
title APT-Proxy-${safeDeviceUuid}
echo Launching Alta Video Camera Proxy (Cookie Method)...
echo Domain: ${safeDomain}
echo Device UUID: ${safeDeviceUuid}
echo Cookie Key: ${truncatedKey}
echo.
"${proxyExePath}" -a "${safeDomain}" -d "${safeDeviceUuid}" -k "${safeCookieKey}"
echo.
echo Cookie-based camera proxy has finished. Press any key to close this window.
pause >nul`;
    
    const tempDir = os.tmpdir();
    const batchPath = path.join(tempDir, `cookie-proxy-${Date.now()}.bat`);
    
    // Write the batch file
    fs.writeFileSync(batchPath, batchContent);
    
    console.log('Launching cookie-based camera proxy via batch file:', batchPath);
    console.log('Command will be: aware-cam-proxy.exe -a', safeDomain, '-d', safeDeviceUuid, '-k [REDACTED]');

    // Launch the batch file in a new command prompt window with unique title
    const windowTitle = `APT-Proxy-${safeDeviceUuid}`;
    const cmdProcess = spawn('cmd', ['/c', 'start', `"${windowTitle}"`, 'cmd', '/c', batchPath], {
      detached: true,
      stdio: 'ignore'
    });

    // Store the process information for later termination
    const processInfo = {
      process: cmdProcess,
      batchPath: batchPath,
      deviceUuid: safeDeviceUuid,
      startTime: Date.now(),
      cookieKey: truncatedKey,
      domain: safeDomain,
      windowTitle: windowTitle, // Store window title for targeted cleanup
      type: 'cookie' // Mark as cookie-based proxy
    };

    activeProxyProcesses.set(cmdProcess.pid, processInfo);
    
    // Clean up the batch file after a delay
    setTimeout(() => {
      try {
        if (fs.existsSync(batchPath)) {
          fs.unlinkSync(batchPath);
        }
      } catch (error) {
        console.log('Could not clean up cookie proxy batch file:', error.message);
      }
    }, 60000); // Clean up after 1 minute
    
    cmdProcess.unref(); // Allow the parent process to exit independently
    
    // Clean up process tracking when it exits
    cmdProcess.on('exit', () => {
      activeProxyProcesses.delete(cmdProcess.pid);
    });
    
    return {
      success: true,
      message: `Cookie-based camera proxy launched for ${deviceUuid}!`,
      processId: cmdProcess.pid,
      deviceUuid: deviceUuid,
      type: 'cookie'
    };
    
  } catch (error) {
    console.error('Failed to launch cookie-based camera proxy:', error);
    return {
      success: false,
      message: `Failed to launch cookie-based camera proxy: ${error.message}`
    };
  }
});

// Stop camera proxy functionality
ipcMain.handle('camera-proxy-stop', async (event, { processId }) => {
  try {
    console.log('Attempting to stop camera proxy processes...');

    return new Promise((resolve) => {
      // Kill all aware-cam-proxy.exe processes by name
      const killProxy = spawn('taskkill', ['/f', '/im', 'aware-cam-proxy.exe'], {
        stdio: ['ignore', 'pipe', 'pipe']
      });

      let proxyOutput = '';
      let proxyError = '';

      killProxy.stdout.on('data', (data) => {
        proxyOutput += data.toString();
      });

      killProxy.stderr.on('data', (data) => {
        proxyError += data.toString();
      });

      killProxy.on('close', (code) => {
        // Clean up our process tracking
        activeProxyProcesses.clear();

        if (code === 0 || proxyOutput.includes('SUCCESS')) {
          console.log('Camera proxy processes terminated successfully');
          resolve({
            success: true,
            message: 'Camera proxy processes stopped successfully'
          });
        } else if (proxyError.includes('not found') || proxyError.includes('No tasks')) {
          console.log('No camera proxy processes were running');
          resolve({
            success: true,
            message: 'No camera proxy processes were running'
          });
        } else {
          resolve({
            success: true,
            message: 'Attempted to stop all camera proxy processes'
          });
        }
      });

      killProxy.on('error', (error) => {
        console.error('Error with taskkill by name:', error);
        activeProxyProcesses.clear();
        resolve({
          success: false,
          message: `Failed to stop camera proxy: ${error.message}`
        });
      });
    });

  } catch (error) {
    console.error('Failed to stop camera proxy:', error);
    return {
      success: false,
      message: `Failed to stop camera proxy: ${error.message}`
    };
  }
});

// --- Self-Update Functionality ---

// Compare semver versions: returns -1 if a < b, 0 if equal, 1 if a > b
function compareVersions(a, b) {
  // Strip pre-release tags (e.g. "1.2.3-beta.1" → "1.2.3")
  const cleanA = a.replace(/-.*$/, '');
  const cleanB = b.replace(/-.*$/, '');
  const partsA = cleanA.split('.').map(Number);
  const partsB = cleanB.split('.').map(Number);
  for (let i = 0; i < 3; i++) {
    const numA = partsA[i] || 0;
    const numB = partsB[i] || 0;
    if (numA < numB) return -1;
    if (numA > numB) return 1;
  }
  return 0;
}

// Follow HTTPS redirects and return the final response (for GitHub asset downloads)
function httpsGetFollowRedirects(url, callback, redirectCount = 0) {
  if (redirectCount >= 5) {
    return callback(null, new Error('Too many redirects'));
  }
  const parsed = new URL(url);
  if (parsed.protocol !== 'https:') {
    return callback(null, new Error('Only HTTPS URLs are allowed'));
  }
  https.get(url, { headers: { 'User-Agent': 'Alta-Proxy-Tool' } }, (res) => {
    if (res.statusCode >= 300 && res.statusCode < 400 && res.headers.location) {
      const redirectUrl = new URL(res.headers.location, url).href;
      httpsGetFollowRedirects(redirectUrl, callback, redirectCount + 1);
    } else {
      callback(res);
    }
  }).on('error', (err) => {
    callback(null, err);
  });
}

ipcMain.handle('get-current-version', async () => {
  return { success: true, version: app.getVersion() };
});

ipcMain.handle('check-for-updates', async () => {
  try {
    const response = await axios.get(
      'https://api.github.com/repos/PageZ948/Alta-Proxy-Tool/releases/latest',
      {
        timeout: 10000,
        headers: { 'User-Agent': 'Alta-Proxy-Tool', 'Accept': 'application/vnd.github.v3+json' }
      }
    );

    const release = response.data;
    const latestVersion = release.tag_name.replace(/^v/, '');
    const currentVersion = app.getVersion();

    const updateAvailable = compareVersions(currentVersion, latestVersion) < 0;

    // Find the portable .exe asset
    const exeAsset = release.assets.find(a => /AltaCameraProxy-.*-portable\.exe$/i.test(a.name));
    const downloadUrl = exeAsset ? exeAsset.browser_download_url : null;

    return {
      success: true,
      updateAvailable,
      currentVersion,
      latestVersion,
      downloadUrl,
      releaseNotes: release.body || '',
      releaseName: release.name || `v${latestVersion}`
    };
  } catch (error) {
    if (error.response && error.response.status === 404) {
      return { success: true, updateAvailable: false, currentVersion: app.getVersion(), message: 'No releases available yet' };
    }
    if (error.response && error.response.status === 403) {
      return { success: false, message: 'GitHub API rate limit exceeded. Try again later.' };
    }
    console.error('Check for updates error:', error.message);
    return { success: false, message: error.message || 'Failed to check for updates' };
  }
});

ipcMain.handle('download-and-install-update', async (event, { downloadUrl }) => {
  try {
    // Determine the path to the currently running executable
    const currentExePath = process.env.PORTABLE_EXECUTABLE_FILE || app.getPath('exe');
    const currentDir = path.dirname(currentExePath);
    const currentExeName = path.basename(currentExePath);

    // Check write permission on the app directory
    try {
      fs.accessSync(currentDir, fs.constants.W_OK);
    } catch {
      return { success: false, message: 'No write permission to the application directory. Try running as administrator.' };
    }

    const tempDir = os.tmpdir();
    const tempExePath = path.join(tempDir, `AltaCameraProxy-update-${Date.now()}.exe`);

    // Download the file with progress reporting
    await new Promise((resolve, reject) => {
      httpsGetFollowRedirects(downloadUrl, (res, err) => {
        if (err) return reject(err);
        if (res.statusCode !== 200) {
          res.resume();
          return reject(new Error(`Download failed with status ${res.statusCode}`));
        }

        const totalSize = parseInt(res.headers['content-length'], 10) || 0;
        let downloadedSize = 0;
        const fileStream = fs.createWriteStream(tempExePath);

        res.on('data', (chunk) => {
          downloadedSize += chunk.length;
          if (totalSize > 0 && mainWindow && !mainWindow.isDestroyed()) {
            const percent = Math.round((downloadedSize / totalSize) * 100);
            mainWindow.webContents.send('update-download-progress', { percent, downloadedSize, totalSize });
          }
        });

        res.pipe(fileStream);

        fileStream.on('finish', () => {
          fileStream.close();
          resolve();
        });

        fileStream.on('error', (err) => {
          fs.unlink(tempExePath, () => {});
          reject(err);
        });
      });
    });

    // Verify downloaded file size (sanity check: > 10MB for an Electron portable exe)
    const stats = fs.statSync(tempExePath);
    if (stats.size < 10 * 1024 * 1024) {
      fs.unlinkSync(tempExePath);
      return { success: false, message: 'Downloaded file is too small — update may be corrupt.' };
    }

    // Create batch script to replace the exe after this process exits
    const batchPath = path.join(tempDir, `apt-update-${Date.now()}.bat`);
    const pid = process.pid;
    const batchContent = `@echo off\r\ntitle APT-Updater\r\necho Waiting for Alta Proxy Tool to close...\r\n:waitloop\r\ntasklist /fi "PID eq ${pid}" 2>nul | find "${pid}" >nul\r\nif not errorlevel 1 (\r\n  timeout /t 1 /nobreak >nul\r\n  goto waitloop\r\n)\r\necho Applying update...\r\ncopy /y "${tempExePath}" "${path.join(currentDir, currentExeName)}"\r\nif errorlevel 1 (\r\n  echo Update failed! Could not copy new version.\r\n  pause\r\n  del "${tempExePath}" >nul 2>&1\r\n  del "%~f0" >nul 2>&1\r\n  exit /b 1\r\n)\r\necho Update complete. Launching new version...\r\nstart "" "${path.join(currentDir, currentExeName)}"\r\ndel "${tempExePath}" >nul 2>&1\r\ndel "%~f0" >nul 2>&1\r\n`;

    fs.writeFileSync(batchPath, batchContent);

    // Spawn the updater batch script detached
    let updater;
    try {
      updater = spawn('cmd', ['/c', batchPath], {
        detached: true,
        stdio: 'ignore',
        windowsHide: true
      });
      updater.unref();
    } catch (spawnError) {
      console.error('Failed to spawn updater:', spawnError);
      try { fs.unlinkSync(tempExePath); } catch {}
      try { fs.unlinkSync(batchPath); } catch {}
      return { success: false, message: 'Failed to start updater process.' };
    }

    // Quit the app after a delay to let the IPC response return to renderer
    setTimeout(() => {
      app.quit();
    }, 1500);

    return { success: true, message: 'Update is being installed. The app will restart shortly.' };
  } catch (error) {
    console.error('Download and install update error:', error);
    return { success: false, message: error.message || 'Failed to download and install update' };
  }
});