koring-launcher/electron/preload.ts

import electron from 'electron';
import path from 'path';
import fs from 'fs';
const { contextBridge, ipcRenderer } = electron;

const MIME_MAP: Record<string, string> = {
  '.png': 'image/png',
  '.jpg': 'image/jpeg',
  '.jpeg': 'image/jpeg',
  '.webp': 'image/webp',
  '.gif': 'image/gif',
  '.bmp': 'image/bmp',
};

function getFileAsDataUrl(filePath: string): string | null {
  try {
    const buffer = fs.readFileSync(filePath);
    const ext = path.extname(filePath).toLowerCase();
    const mime = MIME_MAP[ext] || 'image/png';
    return `data:${mime};base64,${buffer.toString('base64')}`;
  } catch {
    return null;
  }
}

contextBridge.exposeInMainWorld('electronAPI', {
  // Generic IPC
  invoke: (channel: string, ...args: unknown[]) =>
    ipcRenderer.invoke(channel, ...args),

  on: (channel: string, callback: (...args: unknown[]) => void) => {
    const handler = (_event: Electron.IpcRendererEvent, ...args: unknown[]) => callback(...args);
    ipcRenderer.on(channel, handler);
    return () => ipcRenderer.removeListener(channel, handler);
  },

  send: (channel: string, ...args: unknown[]) =>
    ipcRenderer.send(channel, ...args),

  // Window controls
  minimize: () => ipcRenderer.invoke('window:minimize'),
  maximize: () => ipcRenderer.invoke('window:maximize'),
  close: () => ipcRenderer.invoke('window:close'),
  isMaximized: () => ipcRenderer.invoke('window:isMaximized'),
  onResized: (callback: () => void) => {
    const handler = () => callback();
    ipcRenderer.on('window:resized', handler);
    return () => ipcRenderer.removeListener('window:resized', handler);
  },

  // Theme
  getTheme: () => ipcRenderer.invoke('window:getTheme'),

  // Background image — pick file, copy to userData, return base64 data URL
  pickBackgroundImage: async (): Promise<string | null> => {
    const result = await ipcRenderer.invoke('dialog:openFile', {
      filters: [{ name: '图片', extensions: ['png', 'jpg', 'jpeg', 'webp', 'gif', 'bmp'] }],
    });
    if (!result) return null;
    const { srcPath, ext } = result as { srcPath: string; ext: string };
    // Copy to userData via main process
    const destPath = await ipcRenderer.invoke('background:copyToUserData', srcPath, ext);
    if (!destPath) return null;
    return getFileAsDataUrl(destPath);
  },

  // Get cached background as base64 data URL
  getBackgroundDataUrl: async (): Promise<string | null> => {
    const filePath = await ipcRenderer.invoke('background:getCachedPath');
    if (!filePath) return null;
    return getFileAsDataUrl(filePath);
  },

  // Open external URL in system browser
  openExternal: (url: string) => ipcRenderer.invoke('shell:openExternal', url),
});