// release/esbuild.config.mjs - Bundle the HOT-Step CPP server for portable distribution
//
// Usage: node release/esbuild.config.mjs
//
// Produces: release/staging/server/server.mjs
// - All TypeScript/JS source bundled into a single ESM file
// - better-sqlite3 marked external (native addon, can't be bundled)
// - ffmpeg-static excluded (replaced by config-based path resolution)
// - model-registry.json loaded via fs.readFileSync (not bundled inline)

import esbuild from 'esbuild';
import path from 'path';
import { fileURLToPath } from 'url';
import { builtinModules } from 'module';

const __dirname = path.dirname(fileURLToPath(import.meta.url));
const projectRoot = path.resolve(__dirname, '..');

// Build complete list of Node.js built-in modules (with and without node: prefix)
const nodeExternals = [
  ...builtinModules,
  ...builtinModules.map(m => `node:${m}`),
];

const result = await esbuild.build({
  entryPoints: [path.join(projectRoot, 'server/src/index.ts')],
  bundle: true,
  platform: 'node',
  target: 'node22',
  format: 'esm',
  outfile: path.join(projectRoot, 'release/staging/server/server.mjs'),

  // External: native addon + all Node.js built-in modules
  // Node builtins must be external because esbuild's ESM CJS-compat shim
  // can't handle dynamic require("node:events") from Express and other CJS deps.
  external: ['better-sqlite3', ...nodeExternals],

  // Plugin: redirect browser polyfill packages (with trailing slash) to Node.js
  // built-ins. e.g. require('process/') -> require('process')
  plugins: [{
    name: 'node-polyfill-redirect',
    setup(build) {
      // Match requires like 'process/', 'string_decoder/', 'events/', etc.
      build.onResolve({ filter: /^(process|string_decoder|events|buffer|stream|util|path)\/$/ }, (args) => {
        const builtin = args.path.replace(/\/$/, '');
        return { path: builtin, external: true };
      });
    },
  }],

  // Don't minify - keep readable for debugging production issues
  minify: false,
  sourcemap: false,

  // Tree-shake unused exports
  treeShaking: true,

  // CJS interop banner: provide require(), __filename, __dirname for ESM bundle.
  // Express and other CJS dependencies need require() to work inside the ESM wrapper.
  banner: {
    js: [
      '// HOT-Step CPP Server - bundled build',
      '// Generated by release/esbuild.config.mjs',
      '',
      '// CJS interop: provide require() for ESM bundle',
      'import { createRequire as __bundleCreateRequire } from "module";',
      'const require = __bundleCreateRequire(import.meta.url);',
      '',
    ].join('\n'),
  },

  // Log build stats
  logLevel: 'info',
  metafile: true,
});

// Print bundle size summary
const outputs = result.metafile?.outputs || {};
for (const [file, info] of Object.entries(outputs)) {
  const sizeKB = (info.bytes / 1024).toFixed(1);
  console.log(`  ${file}: ${sizeKB} KB`);
}

console.log('\n\u2705 Server bundle complete');