import { spawnSync } from "node:child_process";
import { mkdir, readFile, readdir, writeFile } from "node:fs/promises";
import path from "node:path";

import { assertCiBuildEnvironment } from "./lib/build-environment.ts";
import { supplyChainDigest } from "./lib/supply-chain.ts";

assertCiBuildEnvironment(process.env);

async function filesWithin(directory: string): Promise<string[]> {
  const entries = await readdir(directory, { withFileTypes: true });
  const nested: string[][] = await Promise.all(
    entries.map((entry) => {
      const target = path.join(directory, entry.name);
      return entry.isDirectory() ? filesWithin(target) : [target];
    }),
  );
  return nested.flat().sort();
}

async function distDigest(): Promise<string> {
  const rows = await Promise.all(
    (await filesWithin("dist")).map(async (file) => ({
      path: path.relative("dist", file).replaceAll("\\", "/"),
      bytes: (await readFile(file)).byteLength,
      content: supplyChainDigest(await readFile(file)),
    })),
  );
  return supplyChainDigest(rows);
}

function build(environment: NodeJS.ProcessEnv = process.env) {
  return spawnSync("corepack", ["pnpm", "build"], {
    env: environment,
    encoding: "utf8",
    maxBuffer: 16 * 1024 * 1024,
  });
}

const deterministicEnvironment = {
  ...process.env,
  SOURCE_DATE_EPOCH: "946684800",
};
const firstBuild = build(deterministicEnvironment);
const firstDigest = firstBuild.status === 0 ? await distDigest() : "BUILD_FAILED";
const secondBuild = build(deterministicEnvironment);
const secondDigest =
  secondBuild.status === 0 ? await distDigest() : "BUILD_FAILED";
const restoreBuild = build();
const passed =
  firstBuild.status === 0 &&
  secondBuild.status === 0 &&
  restoreBuild.status === 0 &&
  firstDigest === secondDigest;

await mkdir("artifacts/release", { recursive: true });
await writeFile(
  "artifacts/release/reproducible-build.json",
  `${JSON.stringify(
    {
      schemaVersion: 1,
      sourceDateEpoch: deterministicEnvironment.SOURCE_DATE_EPOCH,
      buildId: process.env.VITE_BUILD_ID ?? "local-build",
      commitSha: process.env.VITE_COMMIT_SHA ?? "local",
      releaseId: process.env.RELEASE_ID ?? "local-release",
      runnerImage:
        process.env.CI_RUNNER_IMAGE ?? `${process.platform}-${process.arch}`,
      firstDigest,
      secondDigest,
      restored: restoreBuild.status === 0,
      status: passed ? "PASS" : "FAIL",
    },
    null,
    2,
  )}\n`,
);
if (!passed) {
  process.stderr.write(
    `Reproducible build failed: first=${firstDigest} second=${secondDigest}\n`,
  );
  process.exit(1);
}
process.stdout.write(`Reproducible build: PASS (${firstDigest})\n`);