import { defineConfig } from 'vite';
import react from '@vitejs/plugin-react';
import path from 'path';

const ADMIN_BUNDLE_BANNER =
  '/*! LLMagnet AI SEO Optimizer — compiled admin bundle (Vite). Human-readable TypeScript/React source ships in this plugin under src/. Rebuild: npm ci && npm run build. See readme.txt → Source code. */';

/**
 * Dedicated build pass for the Gutenberg editor entry (adoption plan F2.2,
 * Phase E Lane E1). Run AFTER the main build:
 *
 *   vite build && vite build --config vite.editor.config.ts
 *
 * Why a separate config instead of another input in vite.config.ts:
 * the editor bundle must reuse the editor's own React (window.React /
 * window.ReactDOM / window.ReactJSXRuntime, provided by the `react`,
 * `react-dom` and `react-jsx-runtime` core script handles) instead of
 * bundling a duplicate copy. Rollup `external`/aliases are build-global —
 * they cannot be scoped to one entry — and aliasing react to the window
 * shims in the main config would break every other entry (the plugin's
 * admin pages bundle their own React and don't load wp deps). A second
 * tiny build pass is the only way to externalize React per-entry.
 *
 * Output lands next to the main build (emptyOutDir: false): js/editor.js.
 * The @wordpress/* aliases mirror vite.config.ts (Phase 0.5 shims).
 */
export default defineConfig(({ mode }) => ({
  base: './',
  plugins: [
    react(),
    {
      name: 'banner-css-chunks',
      generateBundle(_options, bundle) {
        const banner = `${ADMIN_BUNDLE_BANNER}\n`;
        for (const file of Object.values(bundle)) {
          if (file.type === 'chunk' && typeof file.code === 'string') {
            const without = file.code.split(ADMIN_BUNDLE_BANNER).join('');
            file.code = banner + without.replace(/^\n+/, '');
          }
          if (
            file.type === 'asset' &&
            file.fileName.endsWith('.css') &&
            typeof file.source === 'string' &&
            !file.source.startsWith(ADMIN_BUNDLE_BANNER)
          ) {
            file.source = banner + file.source;
          }
        }
      },
    },
  ],
  resolve: {
    alias: [
      // WordPress-bundled React — keep the editor bundle duplicate-free.
      // Exact-match regexes so `react-dom/client` / `react/jsx-runtime`
      // don't get mangled by the bare `react` / `react-dom` entries.
      { find: /^react$/, replacement: path.resolve(__dirname, './src/wp-externals/react.ts') },
      { find: /^react\/jsx-runtime$/, replacement: path.resolve(__dirname, './src/wp-externals/react-jsx-runtime.ts') },
      { find: /^react\/jsx-dev-runtime$/, replacement: path.resolve(__dirname, './src/wp-externals/react-jsx-runtime.ts') },
      { find: /^react-dom$/, replacement: path.resolve(__dirname, './src/wp-externals/react-dom.ts') },
      { find: /^react-dom\/client$/, replacement: path.resolve(__dirname, './src/wp-externals/react-dom-client.ts') },
      // @wordpress/* → window.wp.* shims (same set as vite.config.ts).
      { find: '@wordpress/plugins', replacement: path.resolve(__dirname, './src/wp-externals/plugins.ts') },
      { find: '@wordpress/data', replacement: path.resolve(__dirname, './src/wp-externals/data.ts') },
      { find: '@wordpress/components', replacement: path.resolve(__dirname, './src/wp-externals/components.ts') },
      { find: '@wordpress/edit-post', replacement: path.resolve(__dirname, './src/wp-externals/edit-post.ts') },
      { find: '@wordpress/editor', replacement: path.resolve(__dirname, './src/wp-externals/editor.ts') },
      { find: '@wordpress/core-data', replacement: path.resolve(__dirname, './src/wp-externals/core-data.ts') },
      { find: '@wordpress/element', replacement: path.resolve(__dirname, './src/wp-externals/element.ts') },
      { find: '@wordpress/i18n', replacement: path.resolve(__dirname, './src/wp-externals/i18n.ts') },
      { find: '@wordpress/api-fetch', replacement: path.resolve(__dirname, './src/wp-externals/api-fetch.ts') },
      { find: '@', replacement: path.resolve(__dirname, './src') },
    ],
  },
  build: {
    outDir: 'assets/react-build',
    // The main vite.config.ts build owns (and empties) the output dir;
    // this pass only adds js/editor.js next to it.
    emptyOutDir: false,
    sourcemap: mode === 'development',
    rollupOptions: {
      input: {
        editor: path.resolve(__dirname, 'src/editor-main.tsx'),
      },
      output: {
        banner: `${ADMIN_BUNDLE_BANNER}\n`,
        entryFileNames: 'js/[name].js',
        chunkFileNames: 'js/[name]-[hash].js',
        assetFileNames: ({ name }) => {
          if (/\.(css)$/.test(name ?? '')) {
            return 'css/[name][extname]';
          }
          return 'assets/[name]-[hash][extname]';
        },
      },
    },
  },
}));