const { app, BrowserWindow, dialog, ipcMain, Menu, nativeImage } = require('electron');
const path = require('path');
const fs = require('fs');

let mainWindow = null;
let currentFilePath = null;

function createWindow() {
  // Create the browser window
  mainWindow = new BrowserWindow({
    width: 1200,
    height: 800,
    minWidth: 800,
    minHeight: 600,
    icon: path.join(__dirname, 'assets', 'icon.ico'),
    webPreferences: {
      preload: path.join(__dirname, 'preload.js'),
      contextIsolation: true,
      nodeIntegration: false
    },
    titleBarStyle: 'default',
    show: false
  });

  // Load the index.html
  mainWindow.loadFile(path.join(__dirname, 'renderer', 'index.html'));

  // Show window when ready
  mainWindow.once('ready-to-show', () => {
    mainWindow.show();
  });

  // Build menu
  buildMenu();

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

function buildMenu() {
  const template = [
    {
      label: '文件',
      submenu: [
        {
          label: '打开文件',
          accelerator: 'CmdOrCtrl+O',
          click: () => handleOpenFile()
        },
        {
          label: '保存',
          accelerator: 'CmdOrCtrl+S',
          click: () => mainWindow.webContents.send('menu:save')
        },
        {
          label: '另存为',
          accelerator: 'CmdOrCtrl+Shift+S',
          click: () => mainWindow.webContents.send('menu:saveAs')
        },
        { type: 'separator' },
        {
          label: '退出',
          accelerator: 'CmdOrCtrl+Q',
          click: () => app.quit()
        }
      ]
    },
    {
      label: '视图',
      submenu: [
        {
          label: '编辑 + 预览',
          accelerator: 'CmdOrCtrl+1',
          click: () => mainWindow.webContents.send('menu:viewMode', 'split')
        },
        {
          label: '纯编辑',
          accelerator: 'CmdOrCtrl+2',
          click: () => mainWindow.webContents.send('menu:viewMode', 'editor')
        },
        {
          label: '纯预览',
          accelerator: 'CmdOrCtrl+3',
          click: () => mainWindow.webContents.send('menu:viewMode', 'preview')
        },
        { type: 'separator' },
        {
          label: '开发者工具',
          accelerator: 'F12',
          click: () => mainWindow.webContents.toggleDevTools()
        },
        { type: 'separator' },
        {
          label: '重新加载',
          accelerator: 'CmdOrCtrl+R',
          click: () => mainWindow.webContents.reload()
        }
      ]
    },
    {
      label: '帮助',
      submenu: [
        {
          label: '关于 MarkLite',
          click: () => {
            dialog.showMessageBox(mainWindow, {
              type: 'info',
              title: '关于 MarkLite',
              message: 'MarkLite v1.0.0',
              detail: '一款轻量级的 Markdown 阅读器。\n\n技术栈：Electron + marked.js + highlight.js'
            });
          }
        }
      ]
    }
  ];

  const menu = Menu.buildFromTemplate(template);
  Menu.setApplicationMenu(menu);
}

async function handleOpenFile() {
  const result = await dialog.showOpenDialog(mainWindow, {
    properties: ['openFile'],
    filters: [
      { name: 'Markdown 文件', extensions: ['md', 'markdown', 'txt'] },
      { name: '所有文件', extensions: ['*'] }
    ]
  });

  if (!result.canceled && result.filePaths.length > 0) {
    openFile(result.filePaths[0]);
  }
}

function openFile(filePath) {
  try {
    const content = fs.readFileSync(filePath, 'utf-8');
    currentFilePath = filePath;
    mainWindow.setTitle(`MarkLite - ${path.basename(filePath)}`);
    mainWindow.webContents.send('file:opened', { filePath, content });
  } catch (err) {
    dialog.showErrorBox('错误', `无法读取文件: ${err.message}`);
  }
}

// IPC Handlers
ipcMain.handle('dialog:openFile', async () => {
  const result = await dialog.showOpenDialog(mainWindow, {
    properties: ['openFile'],
    filters: [
      { name: 'Markdown 文件', extensions: ['md', 'markdown', 'txt'] },
      { name: '所有文件', extensions: ['*'] }
    ]
  });

  if (!result.canceled && result.filePaths.length > 0) {
    const filePath = result.filePaths[0];
    const content = fs.readFileSync(filePath, 'utf-8');
    currentFilePath = filePath;
    mainWindow.setTitle(`MarkLite - ${path.basename(filePath)}`);
    return { filePath, content };
  }
  return null;
});

ipcMain.handle('file:read', async (event, filePath) => {
  try {
    const content = fs.readFileSync(filePath, 'utf-8');
    return { success: true, content };
  } catch (err) {
    return { success: false, error: err.message };
  }
});

ipcMain.handle('file:save', async (event, { filePath, content }) => {
  try {
    if (filePath) {
      fs.writeFileSync(filePath, content, 'utf-8');
      currentFilePath = filePath;
      mainWindow.setTitle(`MarkLite - ${path.basename(filePath)}`);
      return { success: true, filePath };
    } else {
      // No file path, do save as
      const result = await dialog.showSaveDialog(mainWindow, {
        filters: [
          { name: 'Markdown 文件', extensions: ['md'] },
          { name: '文本文件', extensions: ['txt'] }
        ]
      });
      if (!result.canceled) {
        fs.writeFileSync(result.filePath, content, 'utf-8');
        currentFilePath = result.filePath;
        mainWindow.setTitle(`MarkLite - ${path.basename(result.filePath)}`);
        return { success: true, filePath: result.filePath };
      }
      return { success: false, canceled: true };
    }
  } catch (err) {
    return { success: false, error: err.message };
  }
});

ipcMain.handle('file:saveAs', async (event, { content }) => {
  try {
    const result = await dialog.showSaveDialog(mainWindow, {
      filters: [
        { name: 'Markdown 文件', extensions: ['md'] },
        { name: '文本文件', extensions: ['txt'] }
      ]
    });
    if (!result.canceled) {
      fs.writeFileSync(result.filePath, content, 'utf-8');
      currentFilePath = result.filePath;
      mainWindow.setTitle(`MarkLite - ${path.basename(result.filePath)}`);
      return { success: true, filePath: result.filePath };
    }
    return { success: false, canceled: true };
  } catch (err) {
    return { success: false, error: err.message };
  }
});

ipcMain.handle('file:getCurrentPath', () => {
  return currentFilePath;
});

// Handle file open from command line or file association
function handleFileOpen() {
  const args = process.argv.slice(1);
  if (args.length > 0 && !args[0].startsWith('--')) {
    const filePath = args[0];
    if (fs.existsSync(filePath)) {
      return filePath;
    }
  }
  return null;
}

// App lifecycle
app.whenReady().then(() => {
  createWindow();

  // Check for file passed via command line
  const fileToOpen = handleFileOpen();
  if (fileToOpen) {
    // Wait for window to be ready
    mainWindow.webContents.on('did-finish-load', () => {
      openFile(fileToOpen);
    });
  }

  // Handle macOS open-file event
  app.on('open-file', (event, filePath) => {
    event.preventDefault();
    if (mainWindow) {
      openFile(filePath);
    }
  });
});

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

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