import { app, BrowserWindow, dialog, ipcMain } from 'electron';
import { createServer, IncomingMessage, ServerResponse } from 'http';
import next from 'next';
import path from 'path';
import fs from 'fs';
import net from 'net';

// ─── Types ───────────────────────────────────────────────────────────────────

interface AppConfig {
  recentProjects: RecentProject[];
  lastActiveProjectPath?: string;
}

interface RecentProject {
  name: string;
  path: string;
  lastOpenedAt: string;
  novelType: string;
}

// ─── Globals ─────────────────────────────────────────────────────────────────

const isDev = process.env.NODE_ENV === 'development' || !app.isPackaged;

// 开发模式下直接连接已运行的 Next.js dev server，不自己启动
let nextApp: ReturnType<typeof next> | null = null;
let handle: ((req: IncomingMessage, res: ServerResponse) => void) | null = null;

if (!isDev) {
  nextApp = next({ dev: false, dir: path.join(__dirname, '..') });
  handle = nextApp.getRequestHandler();
}

let httpServer: ReturnType<typeof createServer> | null = null;
let mainWindow: BrowserWindow | null = null;

// ─── Port Discovery ───────────────────────────────────────────────────────────

function findAvailablePort(startPort: number): Promise<number> {
  return new Promise((resolve, reject) => {
    const server = net.createServer();
    server.listen(startPort, '127.0.0.1', () => {
      const address = server.address();
      const port = typeof address === 'object' && address ? address.port : startPort;
      server.close(() => resolve(port));
    });
    server.on('error', () => {
      // Port in use, try next one
      findAvailablePort(startPort + 1).then(resolve).catch(reject);
    });
  });
}

// ─── App Config (userData) ────────────────────────────────────────────────────

function getAppConfigPath(): string {
  return path.join(app.getPath('userData'), 'app-config.json');
}

function readAppConfig(): AppConfig {
  const configPath = getAppConfigPath();
  try {
    if (fs.existsSync(configPath)) {
      const raw = fs.readFileSync(configPath, 'utf-8');
      return JSON.parse(raw) as AppConfig;
    }
  } catch {
    // Return default config if file is missing or malformed
  }
  return { recentProjects: [] };
}

function writeAppConfig(config: AppConfig): void {
  const configPath = getAppConfigPath();
  const dir = path.dirname(configPath);
  if (!fs.existsSync(dir)) {
    fs.mkdirSync(dir, { recursive: true });
  }
  // Atomic write: write to temp file then rename
  const tmpPath = configPath + '.tmp';
  fs.writeFileSync(tmpPath, JSON.stringify(config, null, 2), 'utf-8');
  fs.renameSync(tmpPath, configPath);
}

// ─── IPC Handlers ─────────────────────────────────────────────────────────────

// Select a folder using the native OS dialog
ipcMain.handle('select-folder', async () => {
  const result = await dialog.showOpenDialog({
    properties: ['openDirectory'],
  });
  return result.canceled ? null : result.filePaths[0];
});

// Read global app config from userData
ipcMain.handle('get-app-config', () => {
  return readAppConfig();
});

// Write global app config to userData
ipcMain.handle('save-app-config', (_event, config: AppConfig) => {
  writeAppConfig(config);
  return { success: true };
});

// ─── App Startup ──────────────────────────────────────────────────────────────

async function startApp(): Promise<void> {
  let appPort = 3000;

  if (isDev) {
    // 开发模式：直接连接已运行的 Next.js dev server (localhost:3000)
    appPort = 3000;
  } else {
    // 生产模式：自己启动内嵌 Next.js 服务器
    await nextApp!.prepare();
    appPort = await findAvailablePort(3000);

    httpServer = createServer((req: IncomingMessage, res: ServerResponse) => {
      handle!(req, res);
    });

    await new Promise<void>((resolve) => {
      httpServer!.listen(appPort, '127.0.0.1', () => {
        resolve();
      });
    });
  }

  mainWindow = new BrowserWindow({
    width: 1400,
    height: 900,
    webPreferences: {
      contextIsolation: true,
      nodeIntegration: false,
      preload: path.join(__dirname, 'preload.js'),
    },
  });

  mainWindow.loadURL(`http://localhost:${appPort}/features/novel-writer`);

  mainWindow.on('closed', () => {
    mainWindow = null;
  });
}

// ─── Lifecycle ────────────────────────────────────────────────────────────────

app.whenReady().then(startApp).catch((err) => {
  console.error('Failed to start app:', err);
  app.quit();
});

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

app.on('activate', () => {
  if (mainWindow === null) {
    startApp().catch((err) => {
      console.error('Failed to restart app:', err);
    });
  }
});

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