// Builds the installable Excalidraw plugin. Unlike draw.io (which vendors a
// standalone webapp) Excalidraw is an npm React component: esbuild bundles the
// controller + React + Excalidraw into plugin.js, and its font/worker assets
// are copied from node_modules into `excalidraw-assets/` so the runtime loads
// them from the plugin's own asset path (EXCALIDRAW_ASSET_PATH) — nothing ever
// talks to excalidraw.com, and the sandbox CSP pins every request to self.
import { createRequire } from 'node:module';
import {
  existsSync,
  mkdirSync,
  readFileSync,
  readdirSync,
  rmSync,
  statSync,
  writeFileSync,
} from 'node:fs';
import { dirname, join, relative } from 'node:path';
import { fileURLToPath } from 'node:url';

import { build } from 'esbuild';
import { zipSync } from 'fflate';

import { thirdPartyNotices } from '../third-party-licenses.mjs';

const root = dirname(fileURLToPath(import.meta.url));
const manifest = JSON.parse(readFileSync(join(root, 'manifest.json'), 'utf8'));
const require = createRequire(import.meta.url);

// --- 1. Locate Excalidraw's prebuilt font/worker assets --------------------
// The package's `exports` map hides ./package.json, so resolve the main entry
// and walk up to the package root instead.
function packageRootOf(specifier) {
  let dir = dirname(require.resolve(specifier));
  while (dir !== dirname(dir)) {
    const pj = join(dir, 'package.json');
    if (existsSync(pj)) {
      try {
        if (JSON.parse(readFileSync(pj, 'utf8')).name === specifier) return dir;
      } catch {
        // keep walking up
      }
    }
    dir = dirname(dir);
  }
  throw new Error(`package root not found for ${specifier}`);
}
const excalidrawPkg = packageRootOf('@excalidraw/excalidraw');
const prodDir = join(excalidrawPkg, 'dist', 'prod');
if (!existsSync(prodDir)) {
  throw new Error(`Excalidraw prod build not found at ${prodDir}. Check the dist layout.`);
}
// Runtime assets loaded relative to EXCALIDRAW_ASSET_PATH (set to the plugin's
// asset base in plugin.tsx): fonts render the sketch, locales translate the
// editor UI, data holds font metadata. Copied to the ZIP root so the sandbox
// CSP (self only) can serve them.
const ASSET_SUBDIRS = ['fonts', 'locales', 'data'];

/** Recursively collect files below `dir` (absolute), keyed by path relative to
 * it, each prefixed with `prefix`. */
function collect(dir, prefix) {
  const files = {};
  for (const name of readdirSync(dir)) {
    const abs = join(dir, name);
    const rel = `${prefix}${name}`;
    if (statSync(abs).isDirectory()) Object.assign(files, collect(abs, `${rel}/`));
    else files[rel] = readFileSync(abs);
  }
  return files;
}
const assetFiles = {};
for (const sub of ASSET_SUBDIRS) {
  const dir = join(prodDir, sub);
  if (existsSync(dir)) Object.assign(assetFiles, collect(dir, `${sub}/`));
}

// --- 2. Bundle the plugin controller (React + Excalidraw) ------------------
mkdirSync(join(root, 'dist'), { recursive: true });
const buildResult = await build({
  entryPoints: [join(root, 'src/plugin.tsx')],
  bundle: true,
  format: 'esm',
  platform: 'browser',
  // Excalidraw's `exports` gate index.js / index.css behind `production` /
  // `development` conditions (no `default`); select the production build.
  conditions: ['production'],
  outfile: join(root, 'dist/plugin.js'),
  minify: true,
  jsx: 'automatic',
  loader: { '.css': 'text', '.woff2': 'dataurl', '.ttf': 'dataurl', '.svg': 'text' },
  define: {
    'process.env.NODE_ENV': '"production"',
    'process.env.IS_PREACT': '"false"',
  },
  metafile: true,
});

// --- 3. Pack the ZIP --------------------------------------------------------
const files = {
  'manifest.json': readFileSync(join(root, 'manifest.json')),
  'plugin.js': readFileSync(join(root, 'dist/plugin.js')),
};
for (const name of readdirSync(join(root, 'i18n'))) {
  files[`i18n/${name}`] = readFileSync(join(root, 'i18n', name));
}
// Asset paths already carry their subdir prefix (fonts/…, locales/…, data/…)
// and sit at the ZIP root so they resolve under EXCALIDRAW_ASSET_PATH.
Object.assign(files, assetFiles);

// License texts for the redistributed material (issue #345): bundled npm
// packages come from the metafile; the shipped fonts have no license files
// upstream at all, so the texts are curated in licenses/ (see FONT-NOTICES.md)
// — @excalidraw/excalidraw ships no LICENSE file either, hence the committed
// MIT text instead of the metafile fallback line.
for (const name of readdirSync(join(root, 'licenses'))) {
  files[`licenses/${name}`] = readFileSync(join(root, 'licenses', name));
}
files['licenses/THIRD-PARTY-NOTICES.txt'] = Buffer.from(
  thirdPartyNotices(buildResult.metafile, [
    {
      title: 'Excalidraw (bundled into plugin.js)',
      license: 'MIT',
      note: 'Full license text in licenses/excalidraw-MIT.txt.',
    },
    {
      title: 'Fonts (shipped under fonts/)',
      license: 'OFL-1.1 and MIT, per family',
      note: 'Attribution table in licenses/FONT-NOTICES.md; per-font license texts alongside it.',
    },
  ]),
);

const target = join(root, 'dist', `${manifest.id}-${manifest.version}.zip`);
rmSync(target, { force: true });
writeFileSync(target, zipSync(files, { level: 6 }));
const unpacked = Object.values(files).reduce((sum, bytes) => sum + bytes.length, 0);
console.log(
  `wrote ${relative(process.cwd(), target)} ` +
    `(zip ${(statSync(target).size / 1024 / 1024).toFixed(1)} MiB, ` +
    `unpacked ${(unpacked / 1024 / 1024).toFixed(1)} MiB, ` +
    `${Object.keys(files).length} files)`,
);