#!/usr/bin/env node

import { spawn } from "node:child_process";
import { mkdtemp, readdir, readFile, rm, writeFile } from "node:fs/promises";
import { tmpdir } from "node:os";
import { join, resolve } from "node:path";

const projectRoot = resolve(import.meta.dirname, "..");

async function readPublishedBinName() {
  const packageJsonRaw = await readFile(join(projectRoot, "package.json"), "utf8");
  const packageJson = JSON.parse(packageJsonRaw);
  const binNames = Object.keys(packageJson.bin ?? {});

  if (binNames.length !== 1) {
    throw new Error(`Expected exactly one published bin entry, found ${binNames.length}`);
  }

  return binNames[0];
}

function run(command, args, options = {}) {
  return new Promise((resolvePromise, rejectPromise) => {
    const child = spawn(command, args, {
      cwd: projectRoot,
      stdio: ["ignore", "pipe", "pipe"],
      ...options,
    });

    let stdout = "";
    let stderr = "";

    child.stdout.on("data", (chunk) => {
      stdout += chunk.toString();
    });

    child.stderr.on("data", (chunk) => {
      stderr += chunk.toString();
    });

    child.on("error", rejectPromise);
    child.on("exit", (code) => {
      if (code === 0) {
        resolvePromise({ stdout, stderr });
        return;
      }

      rejectPromise(
        new Error(
          `${command} ${args.join(" ")} failed with code ${code}\nSTDOUT:\n${stdout}\nSTDERR:\n${stderr}`,
        ),
      );
    });
  });
}

async function verifyPackagedBin() {
  const packDir = await mkdtemp(join(tmpdir(), "mcp-template-pack-"));
  const installDir = await mkdtemp(join(tmpdir(), "mcp-template-install-"));
  const binName = await readPublishedBinName();

  try {
    await run("pnpm", ["pack", "--pack-destination", packDir]);
    const tarballs = (await readdir(packDir)).filter((name) => name.endsWith(".tgz"));

    if (tarballs.length !== 1) {
      throw new Error(`Expected exactly one tarball, found ${tarballs.length}`);
    }

    const tarballPath = join(packDir, tarballs[0]);
    await writeFile(join(installDir, "package.json"), '{"name":"publish-bin-check","private":true}\n');
    await run("npm", ["install", tarballPath], { cwd: installDir });

    const startup = spawn(join(installDir, "node_modules", ".bin", binName), [], {
      cwd: installDir,
      stdio: ["ignore", "pipe", "pipe"],
    });

    const startupOutput = await new Promise((resolvePromise, rejectPromise) => {
      let stderr = "";
      const timeout = setTimeout(() => {
        startup.kill("SIGTERM");
        rejectPromise(new Error(`Timed out waiting for packaged bin to start\nSTDERR:\n${stderr}`));
      }, 10000);

      startup.stderr.on("data", (chunk) => {
        stderr += chunk.toString();
        if (stderr.includes("MCP stdio server started")) {
          clearTimeout(timeout);
          startup.kill("SIGTERM");
          resolvePromise(stderr);
        }
      });

      startup.on("error", (error) => {
        clearTimeout(timeout);
        rejectPromise(error);
      });

      startup.on("exit", (code, signal) => {
        if (signal === "SIGTERM") {
          return;
        }

        clearTimeout(timeout);
        rejectPromise(
          new Error(
            `Packaged bin exited before startup completed (code=${code}, signal=${signal})\nSTDERR:\n${stderr}`,
          ),
        );
      });
    });

    if (!String(startupOutput).includes("MCP stdio server started")) {
      throw new Error("Packaged bin did not emit the expected startup log");
    }
  } finally {
    await rm(packDir, { recursive: true, force: true });
    await rm(installDir, { recursive: true, force: true });
  }
}

await verifyPackagedBin();