import { describe, it, expect, afterEach, beforeEach } from "vitest";
import { mkdtempSync, rmSync } from "node:fs";
import { tmpdir } from "node:os";
import { join } from "node:path";
import { MailboxStore } from "../src/db.js";
import { buildServer } from "../src/server.js";
import type { FastifyInstance } from "fastify";

let dir: string;
let dbPath: string;
let store: MailboxStore;
let app: FastifyInstance;
let baseUrl: string;

beforeEach(async () => {
  dir = mkdtempSync(join(tmpdir(), "claude-mailbox-watch-"));
  dbPath = join(dir, "test.db");
  store = new MailboxStore(dbPath);
  app = await buildServer(
    {
      port: 0,
      bind: "127.0.0.1",
      dbPath,
      hideAfterMinutes: 0,
      deleteAfterMinutes: 0,
      sweepIntervalMinutes: 0,
    },
    store,
  );
  await app.listen({ host: "127.0.0.1", port: 0 });
  const addr = app.server.address();
  if (!addr || typeof addr === "string") throw new Error("no address");
  baseUrl = `http://127.0.0.1:${addr.port}`;
});

afterEach(async () => {
  store.rejectAllWaiters();
  await app.close();
  store.close();
  rmSync(dir, { recursive: true, force: true });
});

describe("GET /v1/watch", () => {
  it("returns 200 with one pending message when one already exists", async () => {
    store.upsertMailbox("alice");
    store.upsertMailbox("bob");
    store.send("alice", "bob", "hi bob");

    const res = await fetch(`${baseUrl}/v1/watch?name=bob&timeout=1`, {
      headers: { "X-Mailbox": "bob" },
    });
    expect(res.status).toBe(200);
    const body = (await res.json()) as { from: string; body: string; sentAt: string };
    expect(body.from).toBe("alice");
    expect(body.body).toBe("hi bob");
    expect(typeof body.sentAt).toBe("string");
  });

  it("blocks until a message arrives, then returns 200", async () => {
    store.upsertMailbox("alice");
    store.upsertMailbox("bob");

    const pending = fetch(`${baseUrl}/v1/watch?name=bob&timeout=5`, {
      headers: { "X-Mailbox": "bob" },
    });

    setTimeout(() => {
      store.send("alice", "bob", "delayed");
    }, 50);

    const res = await pending;
    expect(res.status).toBe(200);
    const body = (await res.json()) as { body: string };
    expect(body.body).toBe("delayed");
  });

  it("returns 204 on timeout with no body", async () => {
    store.upsertMailbox("bob");
    const res = await fetch(`${baseUrl}/v1/watch?name=bob&timeout=1`, {
      headers: { "X-Mailbox": "bob" },
    });
    expect(res.status).toBe(204);
    expect(await res.text()).toBe("");
  });

  it("returns 409 with { reason: 'renamed', to } when mailbox is renamed mid-wait", async () => {
    store.upsertMailbox("oldname");
    const pending = fetch(`${baseUrl}/v1/watch?name=oldname&timeout=5`, {
      headers: { "X-Mailbox": "oldname" },
    });
    setTimeout(() => store.rename("oldname", "newname"), 50);
    const res = await pending;
    expect(res.status).toBe(409);
    const body = (await res.json()) as { reason: string; to: string };
    expect(body).toEqual({ reason: "renamed", to: "newname" });
  });

  it("rejects mismatched X-Mailbox with 403", async () => {
    store.upsertMailbox("bob");
    const res = await fetch(`${baseUrl}/v1/watch?name=bob&timeout=1`, {
      headers: { "X-Mailbox": "alice" },
    });
    expect(res.status).toBe(403);
  });

  it("rejects missing X-Mailbox with 400", async () => {
    const res = await fetch(`${baseUrl}/v1/watch?name=bob&timeout=1`);
    expect(res.status).toBe(400);
  });

  it("rejects missing name with 400", async () => {
    const res = await fetch(`${baseUrl}/v1/watch?timeout=1`, {
      headers: { "X-Mailbox": "bob" },
    });
    expect(res.status).toBe(400);
  });

  it("caps timeout at 300 seconds server-side (rejects with 400 if too high)", async () => {
    store.upsertMailbox("bob");
    const res = await fetch(`${baseUrl}/v1/watch?name=bob&timeout=999`, {
      headers: { "X-Mailbox": "bob" },
    });
    expect(res.status).toBe(400);
  });

  it("client disconnect cleans up the waiter (no leak)", async () => {
    store.upsertMailbox("bob");
    const ac = new AbortController();
    const pending = fetch(`${baseUrl}/v1/watch?name=bob&timeout=5`, {
      headers: { "X-Mailbox": "bob" },
      signal: ac.signal,
    }).catch((err) => err);

    // Give the request a chance to register the waiter.
    await new Promise((r) => setTimeout(r, 50));
    ac.abort();
    await pending;

    // Wait for the server-side TCP close event to propagate and remove the waiter.
    await new Promise((r) => setTimeout(r, 100));

    // Send after abort. No one should receive it (no waiter exists).
    // It should still be queued for a future caller.
    store.upsertMailbox("alice");
    store.send("alice", "bob", "post-abort");

    // A fresh check should immediately return the queued message.
    const res = await fetch(`${baseUrl}/v1/watch?name=bob&timeout=1`, {
      headers: { "X-Mailbox": "bob" },
    });
    expect(res.status).toBe(200);
    const body = (await res.json()) as { body: string };
    expect(body.body).toBe("post-abort");
  });

  it("two clients, one message: exactly one client receives it", async () => {
    store.upsertMailbox("alice");
    store.upsertMailbox("bob");

    const r1 = fetch(`${baseUrl}/v1/watch?name=bob&timeout=2`, {
      headers: { "X-Mailbox": "bob" },
    });
    await new Promise((r) => setTimeout(r, 20));
    const r2 = fetch(`${baseUrl}/v1/watch?name=bob&timeout=2`, {
      headers: { "X-Mailbox": "bob" },
    });

    setTimeout(() => store.send("alice", "bob", "single"), 50);

    const [res1, res2] = await Promise.all([r1, r2]);
    const statuses = [res1.status, res2.status].sort();
    expect(statuses).toEqual([200, 204]);
  });
});