import { describe, it, expect, vi, beforeEach } from 'vitest';
import { NextRequest } from 'next/server';

const { mockSelect, mockInsert } = vi.hoisted(() => ({
  mockSelect: vi.fn(),
  mockInsert: vi.fn(),
}));

vi.mock('@/lib/db', () => ({ db: { select: mockSelect, insert: mockInsert } }));
vi.mock('@/lib/site-config', () => ({ isSignupsEnabled: vi.fn().mockResolvedValue(true) }));

vi.mock('bcryptjs', () => ({
  default: { hash: vi.fn().mockResolvedValue('hashed_pw'), compare: vi.fn() },
}));

import { POST } from '../route';
import bcrypt from 'bcryptjs';

const VALID_BODY = { email: 'user@example.com', name: 'Test User', password: 'securepassword123' };

function makeRequest(body: unknown) {
  return new NextRequest('http://localhost/api/auth/register', {
    method: 'POST',
    headers: { 'Content-Type': 'application/json' },
    body: JSON.stringify(body),
  });
}

function setupDefault({ existingUser = false } = {}) {
  mockSelect.mockImplementation((fields: Record<string, unknown> | undefined) => {
    if (fields && 'total' in fields) {
      // count() query — first user, so total = 0
      return { from: vi.fn().mockResolvedValue([{ total: 0 }]) };
    }
    // email duplicate check
    const rows = existingUser ? [{ id: 'existing' }] : [];
    return { from: vi.fn().mockReturnValue({ where: vi.fn().mockReturnValue({ limit: vi.fn().mockResolvedValue(rows) }) }) };
  });
  mockInsert.mockReturnValue({
    values: vi.fn().mockReturnValue({ returning: vi.fn().mockResolvedValue([{ id: 'new-user-uuid' }]) }),
  });
}

describe('POST /api/auth/register', () => {
  beforeEach(() => {
    vi.clearAllMocks();
    vi.mocked(bcrypt.hash).mockResolvedValue('hashed_pw' as never);
    setupDefault();
  });

  it('returns 400 on bad JSON', async () => {
    const req = new NextRequest('http://localhost/api/auth/register', {
      method: 'POST',
      body: '{not json',
      headers: { 'Content-Type': 'application/json' },
    });
    const res = await POST(req);
    expect(res.status).toBe(400);
  });

  it('returns 400 when email missing', async () => {
    const res = await POST(makeRequest({ name: 'Test', password: 'password123' }));
    expect(res.status).toBe(400);
  });

  it('returns 400 when email invalid', async () => {
    const res = await POST(makeRequest({ ...VALID_BODY, email: 'not-an-email' }));
    expect(res.status).toBe(400);
  });

  it('returns 400 when name missing', async () => {
    const res = await POST(makeRequest({ email: 'a@b.com', password: 'password123' }));
    expect(res.status).toBe(400);
  });

  it('returns 400 when name empty', async () => {
    const res = await POST(makeRequest({ ...VALID_BODY, name: '' }));
    expect(res.status).toBe(400);
  });

  it('returns 400 when password too short', async () => {
    const res = await POST(makeRequest({ ...VALID_BODY, password: 'short' }));
    expect(res.status).toBe(400);
  });

  it('returns 400 when password over 128 chars', async () => {
    const res = await POST(makeRequest({ ...VALID_BODY, password: 'a'.repeat(129) }));
    expect(res.status).toBe(400);
  });

  it('returns 409 when email already registered', async () => {
    setupDefault({ existingUser: true });
    const res = await POST(makeRequest(VALID_BODY));
    expect(res.status).toBe(409);
    const body = await res.json();
    expect(body.error).toMatch(/already registered/i);
  });

  it('returns 201 with userId on success', async () => {
    const res = await POST(makeRequest(VALID_BODY));
    expect(res.status).toBe(201);
    const body = await res.json();
    expect(body.userId).toBe('new-user-uuid');
  });

  it('hashes password with cost 12', async () => {
    await POST(makeRequest(VALID_BODY));
    expect(bcrypt.hash).toHaveBeenCalledWith(VALID_BODY.password, 12);
  });

  it('stores hashed password not plaintext', async () => {
    await POST(makeRequest(VALID_BODY));
    const valuesMock = vi.mocked(mockInsert).mock.results[0]?.value?.values;
    expect(valuesMock).toHaveBeenCalledWith(expect.objectContaining({ passwordHash: 'hashed_pw' }));
  });

  it('normalizes email to lowercase', async () => {
    await POST(makeRequest({ ...VALID_BODY, email: 'USER@EXAMPLE.COM' }));
    const valuesMock = vi.mocked(mockInsert).mock.results[0]?.value?.values;
    expect(valuesMock).toHaveBeenCalledWith(expect.objectContaining({ email: 'user@example.com' }));
  });
});