import { build } from "esbuild";
import fs from "node:fs";
import path from "node:path";
import url from "node:url";
import zlib from "node:zlib";

const here = path.dirname(url.fileURLToPath(import.meta.url));
const root = path.resolve(here, "..");
const entry = path.join(root, "src", "showcases", "twentyoz-core.js");
const outDir = path.join(root, "public", "work", "twentyoz-corp", "assets");
const outputFile = path.join(outDir, "core.iife.js");
const check = process.argv.includes("--check");

const result = await build({
  absWorkingDir: root,
  entryPoints: [entry],
  outfile: outputFile,
  bundle: true,
  platform: "browser",
  format: "iife",
  globalName: "TwentyozCore",
  target: ["es2020"],
  minify: true,
  treeShaking: true,
  legalComments: "eof",
  sourcemap: false,
  write: false,
});

const output = result.outputFiles?.find((item) => path.resolve(item.path) === path.resolve(outputFile));
if (!output) throw new Error("twentyoz core bundle output not found");
const generated = Buffer.from(output.contents);
const gzipBytes = zlib.gzipSync(generated, { level: 9 }).byteLength;
const maxGzipBytes = 200 * 1024;
if (gzipBytes > maxGzipBytes) {
  throw new Error(`twentyoz WebGL bundle ${gzipBytes}B gzip exceeds ${maxGzipBytes}B budget`);
}

if (check) {
  if (!fs.existsSync(outputFile)) throw new Error("twentyoz core bundle is missing; run npm run build:showcase-assets");
  const current = fs.readFileSync(outputFile);
  if (!current.equals(generated)) throw new Error("twentyoz core bundle is stale; run npm run build:showcase-assets");
} else {
  fs.mkdirSync(outDir, { recursive: true });
  fs.writeFileSync(outputFile, generated);
}

console.log(`twentyoz core ${generated.byteLength}B raw · ${gzipBytes}B gzip · budget ${maxGzipBytes}B`);