import { describe, it, expect } from 'vitest';
import fs from 'fs/promises';
import path from 'path';
import os from 'os';
import { ChatService } from '../src/services/chat/service.js';
import { ChatCache } from '../src/services/chat/cache.js';
import { MatrixClient, MatrixRateLimitError } from '../src/services/chat/matrix/client.js';
import { createMockLogger } from './mockLogger.js';

const creds = {
  homeserver: 'https://matrix.example.test',
  accessToken: 'tok',
  userId: '@me:example.test',
  capturedAt: Date.now(),
};

function buildService() {
  const logger = createMockLogger();
  // Fetch impl never matters here — we drive cooldowns directly via the
  // public API, which is how MatrixClient surfaces them at runtime.
  const fetchImpl = (() =>
    Promise.resolve(
      new Response('{}', { status: 200, headers: { 'content-type': 'application/json' } }),
    )) as typeof fetch;
  const matrix = new MatrixClient(creds, logger, { minRequestIntervalMs: 0, fetchImpl });
  // Point the cache at a tmp path; without this, the default falls back to
  // ./data/chat-cache.json and the test would clobber the production cache.
  const cache = new ChatCache(
    logger,
    path.join(os.tmpdir(), `chat-cache-${Date.now()}-${Math.random()}.json`),
  );
  const svc = new ChatService(matrix, logger, undefined, undefined, undefined, undefined, cache);
  return { svc, logger };
}

describe('ChatService invitation cooldown', () => {
  it('is null by default', () => {
    const { svc } = buildService();
    expect(svc.getInvitationCooldown()).toBeNull();
  });

  it('records a cooldown from a MatrixRateLimitError', () => {
    const { svc } = buildService();
    const err = new MatrixRateLimitError(
      '429',
      60_000,
      'M_LIMIT_EXCEEDED',
      'rate.invitation_limit_mature_account',
    );
    svc.setInvitationCooldown(err);
    const active = svc.getInvitationCooldown();
    expect(active).not.toBeNull();
    expect(active!.redditCode).toBe('rate.invitation_limit_mature_account');
    expect(active!.until).toBeGreaterThan(Date.now() + 50_000);
    expect(active!.reason).toMatch(/throttling new chat invitations/);
  });

  it('auto-expires once the until timestamp has passed', () => {
    const { svc } = buildService();
    const err = new MatrixRateLimitError('429', 10, 'M_LIMIT_EXCEEDED', 'rate.foo');
    svc.setInvitationCooldown(err);
    expect(svc.getInvitationCooldown()).not.toBeNull();

    // Force the clock past the cooldown window.
    const cooldown = svc.getInvitationCooldown()!;
    const realNow = Date.now;
    Date.now = () => cooldown.until + 1;
    try {
      expect(svc.getInvitationCooldown()).toBeNull();
    } finally {
      Date.now = realNow;
    }
  });

  it('startConversation short-circuits when a cooldown is active', async () => {
    const { svc } = buildService();
    svc.setInvitationCooldown(
      new MatrixRateLimitError('429', 60_000, 'M_LIMIT_EXCEEDED', 'rate.foo'),
    );
    const result = await svc.startConversation('someuser', 'hi');
    expect(result).toBeNull();
  });

  it('sendChatMessage short-circuits when a cooldown is active', async () => {
    const { svc } = buildService();
    svc.setInvitationCooldown(
      new MatrixRateLimitError('429', 60_000, 'M_LIMIT_EXCEEDED', null),
    );
    const result = await svc.sendChatMessage('!room:example.test', 'hi');
    expect(result).toBe(false);
  });

  it('persists the cooldown to disk and restores it after a fresh service load', async () => {
    const logger = createMockLogger();
    const tmpDir = await fs.mkdtemp(path.join(os.tmpdir(), 'chat-cooldown-'));
    const cacheFile = path.join(tmpDir, 'chat-cache.json');
    try {
      const matrix = new MatrixClient(creds, logger, { minRequestIntervalMs: 0 });
      const cache1 = new ChatCache(logger, cacheFile);
      const svc1 = new ChatService(matrix, logger, undefined, undefined, undefined, undefined, cache1);
      svc1.setInvitationCooldown(
        new MatrixRateLimitError('429', 120_000, 'M_LIMIT_EXCEEDED', null),
      );
      // setInvitationCooldown kicks off an async save; flush the queue.
      await cache1.save();

      const cache2 = new ChatCache(logger, cacheFile);
      const svc2 = new ChatService(matrix, logger, undefined, undefined, undefined, undefined, cache2);
      await svc2.loadCache();
      const restored = svc2.getInvitationCooldown();
      expect(restored).not.toBeNull();
      expect(restored!.until).toBeGreaterThan(Date.now() + 100_000);
    } finally {
      await fs.rm(tmpDir, { recursive: true, force: true });
    }
  });

  it('preserves on-disk chats and lastFullSyncAt when a cooldown fires before loadCache', async () => {
    const logger = createMockLogger();
    const tmpDir = await fs.mkdtemp(path.join(os.tmpdir(), 'chat-cooldown-preserve-'));
    const cacheFile = path.join(tmpDir, 'chat-cache.json');
    try {
      // Pre-seed an existing cache with a completed full sync and known chats.
      const existing = {
        version: 1,
        savedAt: Date.now() - 60_000,
        chats: [
          {
            username: 'alice',
            roomName: 'alice',
            lastMessageTime: Date.now() - 30_000,
            lastMessageSnippet: 'hi',
            isFromUs: false,
            unread: false,
            roomId: '!room:example.test',
          },
        ],
        nextBatch: 's42_1',
        lastFullSyncAt: Date.now() - 120_000,
        lastDeltaSyncAt: Date.now() - 30_000,
        cooldown: null,
      };
      await fs.writeFile(cacheFile, JSON.stringify(existing), 'utf-8');

      const matrix = new MatrixClient(creds, logger, { minRequestIntervalMs: 0 });
      const cache = new ChatCache(logger, cacheFile);
      const svc = new ChatService(matrix, logger, undefined, undefined, undefined, undefined, cache);

      // Cooldown fires before loadCache() — the in-memory chats are still [].
      svc.setInvitationCooldown(
        new MatrixRateLimitError('429', 60_000, 'M_LIMIT_EXCEEDED', null),
      );
      // Flush the async persist (read + write).
      await cache.persistCooldown();

      const raw = await fs.readFile(cacheFile, 'utf-8');
      const after = JSON.parse(raw);
      expect(after.chats).toHaveLength(1);
      expect(after.chats[0].username).toBe('alice');
      expect(after.lastFullSyncAt).toBe(existing.lastFullSyncAt);
      expect(after.nextBatch).toBe('s42_1');
      expect(after.cooldown).not.toBeNull();
      expect(after.cooldown.reason).toMatch(/M_LIMIT_EXCEEDED/);
    } finally {
      await fs.rm(tmpDir, { recursive: true, force: true });
    }
  });

  it('sendChatMessage records a cooldown when the homeserver rate-limits a reply', async () => {
    const logger = createMockLogger();
    const matrix = new MatrixClient(creds, logger, { minRequestIntervalMs: 0 });
    // Force sendTextMessage to throw a rate-limit error — simulates Reddit
    // returning M_LIMIT_EXCEEDED on a reply into an existing room.
    matrix.sendTextMessage = async () => {
      throw new MatrixRateLimitError('429', 90_000, 'M_LIMIT_EXCEEDED', null);
    };
    const cache = new ChatCache(
      logger,
      path.join(os.tmpdir(), `chat-cache-${Date.now()}-${Math.random()}.json`),
    );
    const svc = new ChatService(matrix, logger, undefined, undefined, undefined, undefined, cache);

    const result = await svc.sendChatMessage('!room:example.test', 'hi');
    expect(result).toBe(false);
    const active = svc.getInvitationCooldown();
    expect(active).not.toBeNull();
    expect(active!.until).toBeGreaterThan(Date.now() + 80_000);
  });
});