import { access, cp, mkdir, mkdtemp, rm, writeFile } from "node:fs/promises";
import { constants } from "node:fs";
import os from "node:os";
import path from "node:path";
import { spawn } from "node:child_process";

const repoRoot = path.resolve(import.meta.dirname, "../..");
const litmusDir = path.join(repoRoot, "vendor", "litmus");
const binaryPath = path.join(litmusDir, "litmus");
const releaseVersion = "0.17";
const releaseUrl = `https://notroj.github.io/litmus/litmus-${releaseVersion}.tar.gz`;

async function exists(filePath: string): Promise<boolean> {
  try {
    await access(filePath, constants.F_OK);
    return true;
  } catch {
    return false;
  }
}

function run(command: string, args: string[], cwd: string): Promise<void> {
  return new Promise((resolve, reject) => {
    const child = spawn(command, args, { cwd, stdio: "inherit" });
    child.on("error", reject);
    child.on("exit", (code) => {
      if (code === 0) resolve();
      else reject(new Error(`${command} ${args.join(" ")} exited with ${code}`));
    });
  });
}

async function downloadReleaseTarball(): Promise<void> {
  const tempDir = await mkdtemp(path.join(os.tmpdir(), "dab-litmus-setup-"));
  try {
    const archivePath = path.join(tempDir, `litmus-${releaseVersion}.tar.gz`);
    const extractedDir = path.join(tempDir, `litmus-${releaseVersion}`);

    const response = await fetch(releaseUrl);
    if (!response.ok) throw new Error(`Unable to download ${releaseUrl}: ${response.status}`);
    const body = await response.arrayBuffer();
    await writeFile(archivePath, new Uint8Array(body));
    await run("tar", ["-xzf", archivePath, "-C", tempDir], repoRoot);
    await rm(litmusDir, { recursive: true, force: true });
    await mkdir(path.dirname(litmusDir), { recursive: true });
    await cp(extractedDir, litmusDir, { recursive: true });
  } finally {
    await rm(tempDir, { recursive: true, force: true });
  }
}

async function main(): Promise<void> {
  if (await exists(binaryPath)) {
    console.log(binaryPath);
    return;
  }

  await mkdir(path.dirname(litmusDir), { recursive: true });
  if (!(await exists(litmusDir))) {
    await downloadReleaseTarball();
  }

  if (!(await exists(path.join(litmusDir, "configure")))) {
    await downloadReleaseTarball();
  }
  if (await exists(path.join(litmusDir, "configure"))) {
    await run("./configure", [], litmusDir);
  }
  await run("make", [], litmusDir);

  if (!(await exists(binaryPath))) {
    throw new Error("litmus build completed, but vendor/litmus/litmus was not found");
  }

  console.log(binaryPath);
}

main().catch((error) => {
  console.error(
    "Unable to build litmus. Install git, make, a C compiler, autoconf/automake, and neon development headers.",
  );
  console.error(error instanceof Error ? error.message : String(error));
  process.exit(1);
});