const http = require("node:http");
const fs = require("node:fs");
const os = require("node:os");
const path = require("node:path");

// Smoke coverage for the workstation snapshot surface (issue #13).
//
// This is deliberately NOT the exhaustive matrix — that is issue #14. What is
// pinned here is the handful of decisions that would be expensive to get wrong
// and silent to regress: the routing-before-auth ordering, the narrow host id
// regex as the traversal control, 401 winning over 403, the whitelist rebuild,
// and the server-stamped freshness.

const TOKEN = "test-token";
const INGEST_TOKEN = "test-ingest-token";

let tmpDir;
let hostsDir;
let server;
let baseUrl;
let handler;

function validSnapshot() {
  return {
    hostname: "thinkpad-x1",
    uptime: 4242,
    cpu: { model: "Intel Core i7", cores: 8, loadAvg: [0.5, 0.4, 0.3], usagePercent: 12 },
    memory: { totalGB: 32, usedGB: 12.5, freeGB: 19.5, usagePercent: 39 },
    disk: { totalGB: 500, usedGB: 220, freeGB: 280, usagePercent: 44 },
  };
}

function startServer() {
  // Fresh import so module-level constants pick up the stubbed env.
  delete require.cache[require.resolve("../index.js")];
  ({ handler } = require("../index.js"));
  server = http.createServer(handler);
  return new Promise((resolve) => {
    server.listen(0, () => {
      const { port } = server.address();
      baseUrl = `http://127.0.0.1:${port}`;
      resolve();
    });
  });
}

function stopServer() {
  return new Promise((resolve) => {
    if (!server) return resolve();
    server.close(() => resolve());
  });
}

async function request(route, { method = "GET", auth, body } = {}) {
  const headers = {};
  if (auth) headers.Authorization = auth;
  if (body !== undefined) headers["Content-Type"] = "application/json";
  const res = await fetch(`${baseUrl}${route}`, { method, headers, body });
  const parsed = await res.json().catch(() => ({}));
  return { status: res.status, body: parsed };
}

function ingest(route, { auth = `Bearer ${INGEST_TOKEN}`, body = JSON.stringify(validSnapshot()) } = {}) {
  return request(route, { method: "POST", auth, body });
}

beforeEach(async () => {
  tmpDir = fs.mkdtempSync(path.join(os.tmpdir(), "vps-health-hosts-test-"));
  hostsDir = path.join(tmpDir, "hosts");

  process.env.HEALTH_TOKEN = TOKEN;
  process.env.HOSTS_INGEST_TOKEN = INGEST_TOKEN;
  process.env.HOSTS_DIR = hostsDir;
  process.env.HOSTS_ALLOWED_IDS = "thinkpad";
  delete process.env.HOSTS_STALE_SECONDS;
  process.env.REPORTS_DIR = path.join(tmpDir, "reports");
  process.env.DEFENSEURS_AGENTS_MAP_PATH = path.join(tmpDir, "agents-map.json");
  process.env.DEFENSEURS_STATUS_PATH = path.join(tmpDir, "status.json");

  await startServer();
});

afterEach(async () => {
  await stopServer();
  fs.rmSync(tmpDir, { recursive: true, force: true });
  delete process.env.HOSTS_INGEST_TOKEN;
  delete process.env.HOSTS_DIR;
  delete process.env.HOSTS_ALLOWED_IDS;
  delete process.env.HOSTS_STALE_SECONDS;
});

describe("POST /hosts/<id> — routing is the traversal control", () => {
  // Every one of these must be 404, not 400/403: the request never reaches a
  // handler. URL() normalises the traversal away, the rest fail the regex.
  const REJECTED = [
    ["dot-dot traversal", "/hosts/../../etc/passwd"],
    ["encoded traversal", "/hosts/..%2f..%2fetc%2fpasswd"],
    ["uppercase id", "/hosts/THINKPAD"],
    ["id with a slash", "/hosts/thinkpad/extra"],
    ["empty id", "/hosts/"],
  ];

  test.each(REJECTED)("404 on POST %s", async (_label, route) => {
    const { status, body } = await ingest(route);
    expect(status).toBe(404);
    expect(body.error).toBe("Not found");
  });

  test("404 on GET /hosts/thinkpad — the id route is POST-only", async () => {
    const { status } = await request("/hosts/thinkpad", { auth: `Bearer ${TOKEN}` });
    expect(status).toBe(404);
  });
});

describe("POST /hosts/<id> — auth gate", () => {
  test("401 with no Authorization header", async () => {
    const { status, body } = await ingest("/hosts/thinkpad", { auth: null });
    expect(status).toBe(401);
    expect(body.error).toBe("Unauthorized");
  });

  test("401 when presenting the read token instead of the ingest token", async () => {
    const { status } = await ingest("/hosts/thinkpad", { auth: `Bearer ${TOKEN}` });
    expect(status).toBe(401);
  });

  // 401 must win over 403 so an unauthenticated caller cannot probe the
  // allowlist for valid workstation ids.
  test("401 (not 403) on a non-allowlisted id without a token", async () => {
    const { status } = await ingest("/hosts/popos", { auth: null });
    expect(status).toBe(401);
  });

  test("403 on a well-formed id outside the allowlist", async () => {
    const { status, body } = await ingest("/hosts/popos");
    expect(status).toBe(403);
    expect(body.error).toBe("Forbidden");
  });

  test("503 when HOSTS_INGEST_TOKEN is unset (fail-closed)", async () => {
    delete process.env.HOSTS_INGEST_TOKEN;
    await stopServer();
    await startServer();
    const { status, body } = await ingest("/hosts/thinkpad");
    expect(status).toBe(503);
    expect(body.error).toBe("HOSTS_INGEST_TOKEN not configured");
  });
});

describe("POST /hosts/<id> — body handling", () => {
  test("204 and an atomically written file on a valid snapshot", async () => {
    const { status } = await ingest("/hosts/thinkpad");
    expect(status).toBe(204);
    const written = JSON.parse(fs.readFileSync(path.join(hostsDir, "thinkpad.json"), "utf-8"));
    expect(written.hostname).toBe("thinkpad-x1");
    expect(typeof written.receivedAt).toBe("string");
    // No leftover temp file next to the snapshot.
    expect(fs.readdirSync(hostsDir)).toEqual(["thinkpad.json"]);
  });

  test("the persisted object is rebuilt from the whitelist, not stored verbatim", async () => {
    const raw = `{"__proto__":{"polluted":true},"extra":"nope","receivedAt":"1999-01-01T00:00:00.000Z",${JSON.stringify(
      { ...validSnapshot(), hostname: "h".repeat(300) },
    ).slice(1)}`;
    const { status } = await ingest("/hosts/thinkpad", { body: raw });
    expect(status).toBe(204);

    const written = JSON.parse(fs.readFileSync(path.join(hostsDir, "thinkpad.json"), "utf-8"));
    expect(Object.keys(written)).toEqual([
      "id",
      "hostname",
      "uptime",
      "cpu",
      "memory",
      "disk",
      "receivedAt",
    ]);
    expect(written.extra).toBeUndefined();
    expect(written.polluted).toBeUndefined();
    expect({}.polluted).toBeUndefined();
    // Strings capped at 128 chars, timestamp stamped by the server.
    expect(written.hostname.length).toBe(128);
    expect(written.receivedAt).not.toBe("1999-01-01T00:00:00.000Z");
    expect(Date.now() - new Date(written.receivedAt).getTime()).toBeLessThan(10000);
  });

  test("400 on unparsable JSON", async () => {
    const { status } = await ingest("/hosts/thinkpad", { body: "{not json" });
    expect(status).toBe(400);
  });

  test("400 on a missing or mistyped field", async () => {
    const payload = validSnapshot();
    delete payload.memory;
    const { status, body } = await ingest("/hosts/thinkpad", { body: JSON.stringify(payload) });
    expect(status).toBe(400);
    expect(body.error).toMatch(/memory/);
    expect(fs.existsSync(path.join(hostsDir, "thinkpad.json"))).toBe(false);
  });

  test("413 past 4 KiB, and nothing is written", async () => {
    const payload = { ...validSnapshot(), padding: "x".repeat(5000) };
    let status;
    try {
      ({ status } = await ingest("/hosts/thinkpad", { body: JSON.stringify(payload) }));
    } catch {
      // The socket is destroyed right after the 413 flushes; a client that
      // loses the race sees a transport error instead. Either way the write
      // must not have happened, which is what the assertion below pins.
      status = 413;
    }
    expect(status).toBe(413);
    expect(fs.existsSync(path.join(hostsDir, "thinkpad.json"))).toBe(false);
  });
});

describe("GET /hosts", () => {
  test("401 when presenting the ingest token instead of the read token", async () => {
    const { status } = await request("/hosts", { auth: `Bearer ${INGEST_TOKEN}` });
    expect(status).toBe(401);
  });

  test("reports an allowlisted host that never checked in", async () => {
    const { status, body } = await request("/hosts", { auth: `Bearer ${TOKEN}` });
    expect(status).toBe(200);
    expect(body.staleAfterSeconds).toBe(900);
    expect(body.hosts).toHaveLength(1);
    expect(body.hosts[0]).toMatchObject({ id: "thinkpad", neverSeen: true, online: false });
  });

  test("serves the snapshot back with a server-computed freshness", async () => {
    await ingest("/hosts/thinkpad");
    const { status, body } = await request("/hosts", { auth: `Bearer ${TOKEN}` });
    expect(status).toBe(200);
    const host = body.hosts[0];
    expect(host.neverSeen).toBeUndefined();
    expect(host.hostname).toBe("thinkpad-x1");
    expect(host.ageSeconds).toBeLessThan(5);
    expect(host.online).toBe(true);
    expect(Object.keys(host.cpu)).toEqual(["model", "cores", "loadAvg", "usagePercent"]);
  });

  test("online flips to false past HOSTS_STALE_SECONDS", async () => {
    fs.mkdirSync(hostsDir, { recursive: true });
    const stale = {
      id: "thinkpad",
      ...validSnapshot(),
      receivedAt: new Date(Date.now() - 3600 * 1000).toISOString(),
    };
    fs.writeFileSync(path.join(hostsDir, "thinkpad.json"), JSON.stringify(stale));

    const { body } = await request("/hosts", { auth: `Bearer ${TOKEN}` });
    expect(body.hosts[0].online).toBe(false);
    expect(body.hosts[0].ageSeconds).toBeGreaterThan(3000);
  });

  test("degrades a corrupted snapshot instead of failing the whole response", async () => {
    fs.mkdirSync(hostsDir, { recursive: true });
    fs.writeFileSync(path.join(hostsDir, "thinkpad.json"), "{ truncated");

    const { status, body } = await request("/hosts", { auth: `Bearer ${TOKEN}` });
    expect(status).toBe(200);
    expect(body.hosts).toHaveLength(1);
    expect(body.hosts[0].neverSeen).toBe(true);
  });
});

describe("HOSTS_ALLOWED_IDS validation", () => {
  test("entries that are not valid host ids are dropped at startup", async () => {
    process.env.HOSTS_ALLOWED_IDS = "thinkpad, ../defenseurs/status ,POPOS,,popos";
    await stopServer();
    await startServer();

    const { body } = await request("/hosts", { auth: `Bearer ${TOKEN}` });
    expect(body.hosts.map((h) => h.id)).toEqual(["popos", "thinkpad"]);
  });
});