#!/usr/bin/env node
/**
 * Build CSS bundles with Lightning CSS.
 *
 * - base.min.css: resolves the @import chain in style.css into a single minified file.
 *   This eliminates ~17 sequential @import requests on every page.
 * - admin.min.css: minifies admin.css
 * - form.min.css:  bundles form-base.css + form-admin.css + filepond vendor CSS
 *
 * All other page-specific CSS files (public.css, tfe.css, repertoire.css, etc.)
 * are minified in-place as individual files.
 *
 * Output: app/public/assets/dist/
 */

import { bundleAsync } from "lightningcss";
import { readFileSync, writeFileSync, mkdirSync } from "node:fs";
import { resolve, dirname, basename } from "node:path";
import { fileURLToPath } from "node:url";

const __dirname = dirname(fileURLToPath(import.meta.url));
const root = resolve(__dirname, "..");
const cssDir = resolve(root, "app/public/assets/css");
const distDir = resolve(root, "app/public/assets/dist");

mkdirSync(distDir, { recursive: true });

const targets = {
  chrome: 115 << 16,
  firefox: 115 << 16,
  safari: 16 << 16,
};

function makeResolver() {
  return {
    resolve(specifier, from) {
      return resolve(dirname(from), specifier);
    },
    read(filePath) {
      return readFileSync(filePath, "utf8");
    },
  };
}

async function bundleCss(filename, outName) {
  const entryPath = resolve(cssDir, filename);
  const result = await bundleAsync({
    filename: entryPath,
    resolver: makeResolver(),
    minify: true,
    sourceMap: false,
    targets,
  });
  const outPath = resolve(distDir, outName);
  writeFileSync(outPath, result.code);
  const size = Buffer.byteLength(result.code, "utf8");
  console.log(`  ✓ ${outName} (${size.toLocaleString()} bytes)`);
  return size;
}

async function concatBundle(filenames, outName) {
  const parts = [];
  for (const f of filenames) {
    const fp = resolve(cssDir, f);
    parts.push(readFileSync(fp, "utf8"));
  }
  const combined = parts.join("\n");

  // Use lightningcss to minify the combined content
  const result = await bundleAsync({
    filename: resolve(cssDir, filenames[0]),
    resolver: {
      resolve() {
        throw new Error("unexpected @import in concat bundle");
      },
      read(fp) {
        if (fp === resolve(cssDir, filenames[0])) {
          return combined;
        }
        // Allow vendor CSS @imports within the combined content  
        throw new Error(`unexpected file in concat: ${fp}`);
      },
    },
    minify: true,
    sourceMap: false,
    targets,
  });

  const outPath = resolve(distDir, outName);
  writeFileSync(outPath, result.code);
  const size = Buffer.byteLength(result.code, "utf8");
  console.log(`  ✓ ${outName} (${size.toLocaleString()} bytes)`);
  return size;
}

async function main() {
  console.log("🎨 Building CSS bundles…\n");

  let total = 0;

  // 1. Base bundle: resolve style.css @import chain
  total += await bundleCss("style.css", "base.min.css");

  // 2. Admin bundle: just minify admin.css (standalone)
  total += await bundleCss("admin.css", "admin.min.css");

  // 3. Form bundle: concat + minify form-base.css + form-admin.css + filepond vendor CSS
  total += await concatBundle(
    [
      "form-base.css",
      "form-admin.css",
      "filepond.min.css",
      "filepond-plugin-image-preview.min.css",
    ],
    "form.min.css"
  );

  // 4. Individual page-specific CSS files: minify each
  const individualFiles = [
    "public.css",
    "tfe.css",
    "repertoire.css",
    "content-page.css",
    "system.css",
    "file-access.css",
  ];

  for (const f of individualFiles) {
    const outName = f.replace(/\.css$/, ".min.css");
    total += await bundleCss(f, outName);
  }

  // 5. Form-base standalone (for partage pages without FilePond)
  total += await bundleCss("form-base.css", "form-base.min.css");

  // 6. Partage bundle: form-base + filepond (for partage pages with FilePond)
  total += await concatBundle(
    [
      "form-base.css",
      "filepond.min.css",
      "filepond-plugin-image-preview.min.css",
    ],
    "partage-form.min.css"
  );

  console.log(`\n✅ CSS bundles done — ${total.toLocaleString()} bytes total\n`);
}

main().catch((err) => {
  console.error("❌ CSS build failed:", err);
  process.exit(1);
});