import { describe, it, expect, vi, beforeEach, afterEach } from 'vitest';
import { NextRequest } from 'next/server';
import { GET } from '@/app/api/v1/control-center/conversations/route';
import { prisma } from '@/lib/db';
import * as auth from '@/lib/auth';

// Get the mocked prisma instance
const mockPrisma = vi.mocked(prisma);

// Mock the auth module
vi.mock('@/lib/auth', () => ({
  getSession: vi.fn()
}));

// Mock the conversationService through the control-center module
vi.mock('@/lib/control-center', () => ({
  conversationService: {
    listByUser: vi.fn()
  }
}));

// Import the mocked conversation service
import { conversationService } from '@/lib/control-center';
const mockConversationService = vi.mocked(conversationService);

describe('Conversations API', () => {
  beforeEach(() => {
    vi.clearAllMocks();
  });

  afterEach(() => {
    vi.resetAllMocks();
  });

  describe('GET /api/v1/control-center/conversations', () => {
    it('should return 401 when not authenticated', async () => {
      vi.mocked(auth.getSession).mockResolvedValue(null);

      const request = new NextRequest('http://localhost:3000/api/v1/control-center/conversations');
      const response = await GET(request);

      expect(response.status).toBe(401);
      const json = await response.json();
      expect(json.error).toBe('Unauthorized');
    });

    it('should return conversations for authenticated user', async () => {
      const mockUser = {
        id: 'user-123',
        email: 'test@example.com',
        role: 'user' as const,
        createdAt: new Date()
      };

      const mockConversations = [
        {
          id: 'conv-1',
          userId: 'user-123',
          title: 'First conversation',
          createdAt: new Date('2024-01-01'),
          updatedAt: new Date('2024-01-01'),
          _count: { messages: 5 }
        },
        {
          id: 'conv-2',
          userId: 'user-123',
          title: 'Second conversation',
          createdAt: new Date('2024-01-02'),
          updatedAt: new Date('2024-01-02'),
          _count: { messages: 3 }
        }
      ];

      vi.mocked(auth.getSession).mockResolvedValue({ user: mockUser });
      mockConversationService.listByUser.mockResolvedValue(mockConversations);
      mockPrisma.controlCenterConversation.count.mockResolvedValue(2);

      const request = new NextRequest('http://localhost:3000/api/v1/control-center/conversations');
      const response = await GET(request);

      expect(response.status).toBe(200);
      const json = await response.json();

      expect(json.conversations).toHaveLength(2);
      expect(json.total).toBe(2);
      expect(json.limit).toBe(20);
      expect(json.offset).toBe(0);
      expect(mockConversationService.listByUser).toHaveBeenCalledWith('user-123', 20, 0);
    });

    it('should handle pagination parameters correctly', async () => {
      const mockUser = {
        id: 'user-456',
        email: 'test@example.com',
        role: 'user' as const,
        createdAt: new Date()
      };

      vi.mocked(auth.getSession).mockResolvedValue({ user: mockUser });
      mockConversationService.listByUser.mockResolvedValue([]);
      mockPrisma.controlCenterConversation.count.mockResolvedValue(50);

      const request = new NextRequest(
        'http://localhost:3000/api/v1/control-center/conversations?limit=10&offset=20'
      );
      const response = await GET(request);

      expect(response.status).toBe(200);
      const json = await response.json();

      expect(json.limit).toBe(10);
      expect(json.offset).toBe(20);
      expect(mockConversationService.listByUser).toHaveBeenCalledWith('user-456', 10, 20);
    });

    it('should use default pagination when parameters are invalid', async () => {
      const mockUser = {
        id: 'user-789',
        email: 'test@example.com',
        role: 'user' as const,
        createdAt: new Date()
      };

      vi.mocked(auth.getSession).mockResolvedValue({ user: mockUser });
      mockConversationService.listByUser.mockResolvedValue([]);
      mockPrisma.controlCenterConversation.count.mockResolvedValue(0);

      // Invalid parameters should parse as NaN, then parseInt will return NaN
      const request = new NextRequest(
        'http://localhost:3000/api/v1/control-center/conversations?limit=invalid&offset=bad'
      );
      const response = await GET(request);

      expect(response.status).toBe(200);
      const json = await response.json();

      // parseInt('invalid') returns NaN, which is falsy, but the code uses || not ??
      // So NaN will use the default value
      expect(mockConversationService.listByUser).toHaveBeenCalledWith(
        'user-789',
        expect.any(Number),
        expect.any(Number)
      );
    });

    it('should handle empty conversation list', async () => {
      const mockUser = {
        id: 'new-user',
        email: 'new@example.com',
        role: 'user' as const,
        createdAt: new Date()
      };

      vi.mocked(auth.getSession).mockResolvedValue({ user: mockUser });
      mockConversationService.listByUser.mockResolvedValue([]);
      mockPrisma.controlCenterConversation.count.mockResolvedValue(0);

      const request = new NextRequest('http://localhost:3000/api/v1/control-center/conversations');
      const response = await GET(request);

      expect(response.status).toBe(200);
      const json = await response.json();

      expect(json.conversations).toEqual([]);
      expect(json.total).toBe(0);
    });

    it('should return 500 on database error', async () => {
      const mockUser = {
        id: 'user-error',
        email: 'error@example.com',
        role: 'user' as const,
        createdAt: new Date()
      };

      vi.mocked(auth.getSession).mockResolvedValue({ user: mockUser });
      mockConversationService.listByUser.mockRejectedValue(new Error('Database connection failed'));

      // Suppress console.error for this test
      const consoleSpy = vi.spyOn(console, 'error').mockImplementation(() => {});

      const request = new NextRequest('http://localhost:3000/api/v1/control-center/conversations');
      const response = await GET(request);

      expect(response.status).toBe(500);
      const json = await response.json();
      expect(json.error).toBe('Failed to fetch conversations');

      consoleSpy.mockRestore();
    });

    it('should count conversations correctly for the authenticated user only', async () => {
      const mockUser = {
        id: 'specific-user',
        email: 'specific@example.com',
        role: 'user' as const,
        createdAt: new Date()
      };

      vi.mocked(auth.getSession).mockResolvedValue({ user: mockUser });
      mockConversationService.listByUser.mockResolvedValue([]);
      mockPrisma.controlCenterConversation.count.mockResolvedValue(25);

      const request = new NextRequest('http://localhost:3000/api/v1/control-center/conversations');
      const response = await GET(request);

      expect(response.status).toBe(200);
      const json = await response.json();

      expect(json.total).toBe(25);
      expect(mockPrisma.controlCenterConversation.count).toHaveBeenCalledWith({
        where: { userId: 'specific-user' }
      });
    });

    it('should return conversations with message count', async () => {
      const mockUser = {
        id: 'user-with-convos',
        email: 'convos@example.com',
        role: 'user' as const,
        createdAt: new Date()
      };

      const mockConversations = [
        {
          id: 'conv-with-messages',
          userId: 'user-with-convos',
          title: 'Conversation with messages',
          createdAt: new Date(),
          updatedAt: new Date(),
          _count: { messages: 15 }
        }
      ];

      vi.mocked(auth.getSession).mockResolvedValue({ user: mockUser });
      mockConversationService.listByUser.mockResolvedValue(mockConversations);
      mockPrisma.controlCenterConversation.count.mockResolvedValue(1);

      const request = new NextRequest('http://localhost:3000/api/v1/control-center/conversations');
      const response = await GET(request);

      expect(response.status).toBe(200);
      const json = await response.json();

      expect(json.conversations[0]._count.messages).toBe(15);
    });
  });

  describe('Pagination edge cases', () => {
    it('should handle large offset beyond total count', async () => {
      const mockUser = {
        id: 'user-large-offset',
        email: 'large@example.com',
        role: 'user' as const,
        createdAt: new Date()
      };

      vi.mocked(auth.getSession).mockResolvedValue({ user: mockUser });
      mockConversationService.listByUser.mockResolvedValue([]);
      mockPrisma.controlCenterConversation.count.mockResolvedValue(5);

      const request = new NextRequest(
        'http://localhost:3000/api/v1/control-center/conversations?offset=100'
      );
      const response = await GET(request);

      expect(response.status).toBe(200);
      const json = await response.json();

      expect(json.conversations).toEqual([]);
      expect(json.total).toBe(5);
      expect(json.offset).toBe(100);
    });

    it('should handle zero limit', async () => {
      const mockUser = {
        id: 'user-zero-limit',
        email: 'zero@example.com',
        role: 'user' as const,
        createdAt: new Date()
      };

      vi.mocked(auth.getSession).mockResolvedValue({ user: mockUser });
      mockConversationService.listByUser.mockResolvedValue([]);
      mockPrisma.controlCenterConversation.count.mockResolvedValue(10);

      const request = new NextRequest(
        'http://localhost:3000/api/v1/control-center/conversations?limit=0'
      );
      const response = await GET(request);

      expect(response.status).toBe(200);
      // Note: limit=0 with parseInt returns 0, which is falsy but a valid number
      // The API should handle this, returning 0 items
    });

    it('should handle negative pagination values gracefully', async () => {
      const mockUser = {
        id: 'user-negative',
        email: 'negative@example.com',
        role: 'user' as const,
        createdAt: new Date()
      };

      vi.mocked(auth.getSession).mockResolvedValue({ user: mockUser });
      mockConversationService.listByUser.mockResolvedValue([]);
      mockPrisma.controlCenterConversation.count.mockResolvedValue(10);

      const request = new NextRequest(
        'http://localhost:3000/api/v1/control-center/conversations?limit=-5&offset=-10'
      );
      const response = await GET(request);

      // The API should still return a response (behavior depends on Prisma handling)
      expect(response.status).toBe(200);
    });
  });
});