import { describe, it, expect, vi, beforeEach } from 'vitest';

// Mock the dependencies before importing the function
vi.mock('@/lib/prisma', () => ({
  prisma: {
    subscription: {
      findUnique: vi.fn(),
      update: vi.fn(),
    },
  },
}));

vi.mock('@/lib/stripe', () => ({
  stripe: {
    subscriptions: {
      update: vi.fn(),
    },
  },
}));

import { cancelSubscription } from '@/lib/billing/cancel-subscription';
import { prisma } from '@/lib/prisma';
import { stripe } from '@/lib/stripe';

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

  it('should return error when userId is missing', async () => {
    const result = await cancelSubscription('');
    expect(result).toEqual({ success: false, error: 'User ID is required' });
    expect(prisma.subscription.findUnique).not.toHaveBeenCalled();
  });

  it('should return error when no subscription is found in db', async () => {
    vi.mocked(prisma.subscription.findUnique).mockResolvedValue(null);

    const result = await cancelSubscription('user_123');
    expect(result).toEqual({ success: false, error: 'No active subscription found' });
    expect(prisma.subscription.findUnique).toHaveBeenCalledWith({
      where: { userId: 'user_123' },
    });
    expect(stripe.subscriptions.update).not.toHaveBeenCalled();
    expect(prisma.subscription.update).not.toHaveBeenCalled();
  });

  it('should cancel subscription in Stripe and update DB successfully', async () => {
    const mockDbSub = {
      userId: 'user_123',
      stripeSubscriptionId: 'sub_stripe_123',
      currentPeriodEnd: new Date(1702678400 * 1000),
    };
    const mockStripeSub = {
      id: 'sub_stripe_123',
      canceled_at: 1700100000,
      current_period_end: 1702678400,
    };

    vi.mocked(prisma.subscription.findUnique).mockResolvedValue(mockDbSub as any);
    vi.mocked(stripe.subscriptions.update).mockResolvedValue(mockStripeSub as any);
    vi.mocked(prisma.subscription.update).mockResolvedValue({} as any);

    const result = await cancelSubscription('user_123');
    
    expect(result).toEqual({ success: true });
    expect(stripe.subscriptions.update).toHaveBeenCalledWith('sub_stripe_123', {
      cancel_at_period_end: true,
    });
    expect(prisma.subscription.update).toHaveBeenCalledWith({
      where: { userId: 'user_123' },
      data: expect.objectContaining({
        cancelAtPeriodEnd: true,
        canceledAt: expect.any(Date),
        currentPeriodEnd: expect.any(Date),
      }),
    });
  });

  it('should support local / mock mode cancel when stripeSubscriptionId is missing', async () => {
    const mockDbSub = {
      userId: 'user_123',
      stripeSubscriptionId: null,
    };

    vi.mocked(prisma.subscription.findUnique).mockResolvedValue(mockDbSub as any);
    vi.mocked(prisma.subscription.update).mockResolvedValue({} as any);

    const result = await cancelSubscription('user_123');

    expect(result).toEqual({ success: true });
    expect(stripe.subscriptions.update).not.toHaveBeenCalled();
    expect(prisma.subscription.update).toHaveBeenCalledWith({
      where: { userId: 'user_123' },
      data: expect.objectContaining({
        cancelAtPeriodEnd: true,
        canceledAt: expect.any(Date),
      }),
    });
  });

  it('should return error when Stripe API call fails', async () => {
    const mockDbSub = {
      userId: 'user_123',
      stripeSubscriptionId: 'sub_stripe_123',
    };

    vi.mocked(prisma.subscription.findUnique).mockResolvedValue(mockDbSub as any);
    vi.mocked(stripe.subscriptions.update).mockRejectedValue(new Error('Stripe connection error'));

    const result = await cancelSubscription('user_123');

    expect(result).toEqual({ success: false, error: 'Stripe connection error' });
    expect(prisma.subscription.update).not.toHaveBeenCalled();
  });

  it('should return error when database write fails', async () => {
    const mockDbSub = {
      userId: 'user_123',
      stripeSubscriptionId: 'sub_stripe_123',
    };
    const mockStripeSub = {
      id: 'sub_stripe_123',
      canceled_at: 1700100000,
      current_period_end: 1702678400,
    };

    vi.mocked(prisma.subscription.findUnique).mockResolvedValue(mockDbSub as any);
    vi.mocked(stripe.subscriptions.update).mockResolvedValue(mockStripeSub as any);
    vi.mocked(prisma.subscription.update).mockRejectedValue(new Error('Prisma database error'));

    const result = await cancelSubscription('user_123');

    expect(result).toEqual({ success: false, error: 'Prisma database error' });
  });
});