import { createWriteStream, readdirSync, statSync, readFileSync, mkdirSync } from "fs";
import { join, relative } from "path";
import { createDeflateRaw } from "zlib";

const pkg = JSON.parse(readFileSync("package.json", "utf8"));
const version = pkg.version;

mkdirSync("artifacts", { recursive: true });

for (const browser of ["chrome", "firefox"]) {
  const distDir = `dist/${browser}`;
  const outPath = `artifacts/yt-playlist-features-${version}-${browser}.zip`;
  await writeZip(distDir, outPath);
  console.log(`Created ${outPath}`);
}

/**
 * Create a ZIP file from a directory.
 * Pure Node.js implementation — no external dependencies.
 */
async function writeZip(dir, outPath) {
  const files = collectFiles(dir);
  const stream = createWriteStream(outPath);
  const entries = [];

  let offset = 0;

  for (const filePath of files) {
    const data = readFileSync(filePath);
    const name = relative(dir, filePath).replace(/\\/g, "/");
    const nameBytes = Buffer.from(name, "utf8");
    const compressed = await deflate(data);
    const crc = crc32(data);

    const localHeader = Buffer.alloc(30);
    localHeader.writeUInt32LE(0x04034b50, 0); // signature
    localHeader.writeUInt16LE(20, 4); // version needed
    localHeader.writeUInt16LE(0, 6); // flags
    localHeader.writeUInt16LE(8, 8); // compression: deflate
    localHeader.writeUInt16LE(0, 10); // mod time
    localHeader.writeUInt16LE(0, 12); // mod date
    localHeader.writeUInt32LE(crc, 14);
    localHeader.writeUInt32LE(compressed.length, 18);
    localHeader.writeUInt32LE(data.length, 22);
    localHeader.writeUInt16LE(nameBytes.length, 26);
    localHeader.writeUInt16LE(0, 28); // extra field length

    const localHeaderOffset = offset;
    stream.write(localHeader);
    stream.write(nameBytes);
    stream.write(compressed);
    offset += localHeader.length + nameBytes.length + compressed.length;

    entries.push({ nameBytes, crc, compressed, data, localHeaderOffset });
  }

  const centralStart = offset;

  for (const entry of entries) {
    const cdHeader = Buffer.alloc(46);
    cdHeader.writeUInt32LE(0x02014b50, 0); // signature
    cdHeader.writeUInt16LE(20, 4); // version made by
    cdHeader.writeUInt16LE(20, 6); // version needed
    cdHeader.writeUInt16LE(0, 8); // flags
    cdHeader.writeUInt16LE(8, 10); // compression
    cdHeader.writeUInt16LE(0, 12); // mod time
    cdHeader.writeUInt16LE(0, 14); // mod date
    cdHeader.writeUInt32LE(entry.crc, 16);
    cdHeader.writeUInt32LE(entry.compressed.length, 20);
    cdHeader.writeUInt32LE(entry.data.length, 24);
    cdHeader.writeUInt16LE(entry.nameBytes.length, 28);
    cdHeader.writeUInt16LE(0, 30); // extra field length
    cdHeader.writeUInt16LE(0, 32); // comment length
    cdHeader.writeUInt16LE(0, 34); // disk start
    cdHeader.writeUInt16LE(0, 36); // internal attrs
    cdHeader.writeUInt32LE(0, 38); // external attrs
    cdHeader.writeUInt32LE(entry.localHeaderOffset, 42);

    stream.write(cdHeader);
    stream.write(entry.nameBytes);
    offset += cdHeader.length + entry.nameBytes.length;
  }

  const centralSize = offset - centralStart;

  const eocd = Buffer.alloc(22);
  eocd.writeUInt32LE(0x06054b50, 0); // signature
  eocd.writeUInt16LE(0, 4); // disk number
  eocd.writeUInt16LE(0, 6); // central dir disk
  eocd.writeUInt16LE(entries.length, 8);
  eocd.writeUInt16LE(entries.length, 10);
  eocd.writeUInt32LE(centralSize, 12);
  eocd.writeUInt32LE(centralStart, 16);
  eocd.writeUInt16LE(0, 20); // comment length

  stream.write(eocd);
  await new Promise((resolve) => stream.end(resolve));
}

function collectFiles(dir) {
  const results = [];
  for (const entry of readdirSync(dir)) {
    const full = join(dir, entry);
    if (statSync(full).isDirectory()) {
      results.push(...collectFiles(full));
    } else {
      results.push(full);
    }
  }
  return results.sort();
}

function deflate(data) {
  return new Promise((resolve, reject) => {
    const chunks = [];
    const deflater = createDeflateRaw();
    deflater.on("data", (chunk) => chunks.push(chunk));
    deflater.on("end", () => resolve(Buffer.concat(chunks)));
    deflater.on("error", reject);
    deflater.end(data);
  });
}

function crc32(buf) {
  let crc = 0xffffffff;
  for (let i = 0; i < buf.length; i++) {
    crc ^= buf[i];
    for (let j = 0; j < 8; j++) {
      crc = (crc >>> 1) ^ (crc & 1 ? 0xedb88320 : 0);
    }
  }
  return (crc ^ 0xffffffff) >>> 0;
}