import test from "node:test";
import assert from "node:assert/strict";
import fs from "node:fs";
import path from "node:path";
import http from "node:http";
import { spawn } from "node:child_process";

test("Healthcheck: test/healthcheck.js script exists and parses cleanly", () => {
  const scriptPath = path.resolve(process.cwd(), "test/healthcheck.js");
  assert.ok(fs.existsSync(scriptPath), "test/healthcheck.js must exist");

  const content = fs.readFileSync(scriptPath, "utf-8");
  assert.match(content, /127\.0\.0\.1/, "Must target IPv4 loopback 127.0.0.1 to avoid Alpine IPv6 lookup failures");
  assert.match(content, /\/healthz/, "Must target the /healthz endpoint");
});

test("Healthcheck: test/healthcheck.js succeeds when server returns 200 OK", async () => {
  const scriptPath = path.resolve(process.cwd(), "test/healthcheck.js");
  
  // Start dummy HTTP server responding 200 on /healthz
  const server = http.createServer((req, res) => {
    if (req.url === "/healthz") {
      res.writeHead(200, { "Content-Type": "application/json" });
      res.end(JSON.stringify({ status: "ok" }));
    } else {
      res.writeHead(404);
      res.end();
    }
  });

  await new Promise((resolve) => server.listen(0, "127.0.0.1", resolve));
  const port = server.address().port;

  try {
    const exitCode = await new Promise((resolve) => {
      const child = spawn(process.execPath, [scriptPath], {
        env: { ...process.env, PORT: String(port) },
      });
      child.on("close", resolve);
    });

    assert.strictEqual(exitCode, 0, "healthcheck.js must exit with code 0 on healthy endpoint");
  } finally {
    await new Promise((resolve) => server.close(resolve));
  }
});

test("Healthcheck: test/healthcheck.js fails when connection is refused or server is 500", async () => {
  const scriptPath = path.resolve(process.cwd(), "test/healthcheck.js");

  // Pick an unused high port
  const exitCodeDown = await new Promise((resolve) => {
    const child = spawn(process.execPath, [scriptPath], {
      env: { ...process.env, PORT: "59999" },
    });
    child.on("close", resolve);
  });
  assert.strictEqual(exitCodeDown, 1, "healthcheck.js must exit with code 1 when server is unreachable");

  // Test 500 status code
  const server = http.createServer((req, res) => {
    res.writeHead(500);
    res.end();
  });
  await new Promise((resolve) => server.listen(0, "127.0.0.1", resolve));
  const port = server.address().port;

  try {
    const exitCode500 = await new Promise((resolve) => {
      const child = spawn(process.execPath, [scriptPath], {
        env: { ...process.env, PORT: String(port) },
      });
      child.on("close", resolve);
    });
    assert.strictEqual(exitCode500, 1, "healthcheck.js must exit with code 1 on HTTP 500");
  } finally {
    await new Promise((resolve) => server.close(resolve));
  }
});