import { createHash } from "node:crypto";
import { readFile, writeFile } from "node:fs/promises";
import path from "node:path";

const [distributionDir, packageBaseUrl] = process.argv.slice(2);
if (!distributionDir || !packageBaseUrl) {
  throw new Error("Usage: vendor_pyodide_packages.mjs <pyodide-dir> <package-base-url>");
}

const normalize = (name) => name.toLowerCase().replace(/[-_.]+/g, "-");
const lock = JSON.parse(await readFile(path.join(distributionDir, "pyodide-lock.json"), "utf8"));
const records = lock.packages || {};
const names = new Map(Object.keys(records).map((name) => [normalize(name), name]));
const pygameKey = names.get("pygame-ce");
if (!pygameKey) throw new Error("Pinned Pyodide lock does not contain pygame-ce");

const pending = [pygameKey];
const required = new Set();
while (pending.length) {
  const name = pending.pop();
  if (required.has(name)) continue;
  required.add(name);
  for (const dependency of records[name].depends || []) {
    const dependencyKey = names.get(normalize(dependency));
    if (!dependencyKey) throw new Error(`Unknown Pyodide dependency ${dependency} required by ${name}`);
    pending.push(dependencyKey);
  }
}

const base = packageBaseUrl.endsWith("/") ? packageBaseUrl : `${packageBaseUrl}/`;
for (const name of required) {
  const record = records[name];
  if (!record.file_name) continue;
  const response = await fetch(new URL(encodeURIComponent(record.file_name), base));
  if (!response.ok) throw new Error(`Could not fetch pinned Pyodide package ${name}: HTTP ${response.status}`);
  const bytes = Buffer.from(await response.arrayBuffer());
  const digest = createHash("sha256").update(bytes).digest("hex");
  if (!record.sha256 || digest !== record.sha256) {
    throw new Error(`Pyodide package integrity check failed for ${name}`);
  }
  await writeFile(path.join(distributionDir, record.file_name), bytes, { mode: 0o644 });
  console.log(`Vendored ${name} ${record.version} (${bytes.length} bytes)`);
}