const fc = require('fast-check');

/**
 * Property-Based Tests for Admin User Management
 * Feature: overseas-appointment-backend
 * 
 * These tests verify admin user management properties using property-based testing
 * with mock data to ensure correctness across a wide range of inputs.
 */

// Mock user database to simulate storage
class MockUserDatabase {
  constructor() {
    this.users = new Map();
  }

  clear() {
    this.users.clear();
  }

  create(userData) {
    const id = Math.random().toString(36).substring(7);
    const user = {
      id,
      wechatOpenId: userData.wechatOpenId || `openid-${id}`,
      nickname: userData.nickname || null,
      realName: userData.realName || null,
      phone: userData.phone || null,
      whatsapp: userData.whatsapp || null,
      wechatId: userData.wechatId || null,
      language: userData.language || 'zh',
      balance: userData.balance || 0.00,
      status: userData.status || 'active',
      createdAt: new Date(),
      updatedAt: new Date(),
      ...userData,
    };
    this.users.set(id, user);
    return user;
  }

  findAll(options = {}) {
    let users = Array.from(this.users.values());

    // Apply filters
    if (options.where) {
      users = users.filter((user) => {
        for (const [key, value] of Object.entries(options.where)) {
          // Handle $or at the top level
          if (key === '$or' && Array.isArray(value)) {
            const matches = value.some((condition) => {
              const field = Object.keys(condition)[0];
              const fieldCondition = condition[field];
              if (fieldCondition.$like) {
                const searchTerm = fieldCondition.$like.replace(/%/g, '');
                // Check if user field exists and contains the search term
                if (!user[field]) return false;
                const userValue = String(user[field]);
                return userValue.includes(searchTerm);
              }
              return false;
            });
            if (!matches) return false;
          } else if (user[key] !== value) {
            return false;
          }
        }
        return true;
      });
    }

    // Apply pagination
    const total = users.length;
    if (options.offset !== undefined) {
      users = users.slice(options.offset);
    }
    if (options.limit !== undefined) {
      users = users.slice(0, options.limit);
    }

    return { users, total };
  }

  findById(id) {
    return this.users.get(id);
  }

  update(id, updateData) {
    const user = this.users.get(id);
    if (!user) return null;

    const updatedUser = {
      ...user,
      ...updateData,
      updatedAt: new Date(),
    };
    this.users.set(id, updatedUser);
    return updatedUser;
  }
}

describe('Admin User Management Property Tests', () => {
  let mockDb;

  beforeEach(() => {
    mockDb = new MockUserDatabase();
  });

  /**
   * **Feature: overseas-appointment-backend, Property 30: User list query capabilities**
   * **Validates: Requirements 7.1**
   * 
   * For any search term and filter criteria, the admin user list should return 
   * matching users with correct pagination.
   */
  describe('Property 30: User list query capabilities', () => {
    test('should return users matching search criteria', () => {
      fc.assert(
        fc.property(
          fc.array(
            fc.record({
              wechatOpenId: fc.uuid(),
              nickname: fc.string({ minLength: 3, maxLength: 20 }).filter(s => s.trim().length > 0),
              realName: fc.option(fc.string({ minLength: 3, maxLength: 20 }).filter(s => s.trim().length > 0), { nil: null }),
              phone: fc.option(fc.string({ minLength: 8, maxLength: 15 }).filter(s => s.trim().length > 0), { nil: null }),
              language: fc.constantFrom('zh', 'en', 'pt'),
              status: fc.constantFrom('active', 'suspended'),
            }),
            { minLength: 5, maxLength: 15 }
          ),
          fc.string({ minLength: 1, maxLength: 5 }).filter(s => s.trim().length > 0 && !s.includes('%')), // search term (exclude % wildcard)
          fc.integer({ min: 5, max: 20 }), // page size
          (usersData, searchTerm, pageSize) => {
            // Clear database before each property run
            mockDb.clear();

            // Create users
            usersData.forEach((data) => mockDb.create(data));

            // Search with the generated search term
            const result = mockDb.findAll({
              where: {
                $or: [
                  { nickname: { $like: `%${searchTerm}%` } },
                  { realName: { $like: `%${searchTerm}%` } },
                  { phone: { $like: `%${searchTerm}%` } },
                  { wechatId: { $like: `%${searchTerm}%` } },
                ],
              },
              limit: pageSize,
              offset: 0,
            });

            // All returned users should match the search criteria
            result.users.forEach((user) => {
              const matchesNickname = !!(user.nickname && user.nickname.includes(searchTerm));
              const matchesRealName = !!(user.realName && user.realName.includes(searchTerm));
              const matchesPhone = !!(user.phone && user.phone.includes(searchTerm));
              const matchesWechatId = !!(user.wechatId && user.wechatId.includes(searchTerm));
              
              expect(
                matchesNickname || matchesRealName || matchesPhone || matchesWechatId
              ).toBe(true);
            });

            // Should not exceed page size
            expect(result.users.length).toBeLessThanOrEqual(pageSize);

            return true;
          }
        ),
        { numRuns: 100 }
      );
    });

    test('should filter users by status', () => {
      fc.assert(
        fc.property(
          fc.array(
            fc.record({
              wechatOpenId: fc.uuid(),
              nickname: fc.string({ minLength: 2, maxLength: 20 }),
              status: fc.constantFrom('active', 'suspended'),
            }),
            { minLength: 10, maxLength: 20 }
          ),
          fc.constantFrom('active', 'suspended'),
          (usersData, filterStatus) => {
            // Clear database before each property run
            mockDb.clear();

            // Create users
            usersData.forEach((data) => mockDb.create(data));

            // Query with status filter
            const result = mockDb.findAll({
              where: { status: filterStatus },
            });

            // All returned users should have the filtered status
            result.users.forEach((user) => {
              expect(user.status).toBe(filterStatus);
            });

            // Count should match
            const expectedCount = usersData.filter(
              (u) => u.status === filterStatus
            ).length;
            expect(result.total).toBe(expectedCount);

            return true;
          }
        ),
        { numRuns: 100 }
      );
    });

    test('should filter users by language', () => {
      fc.assert(
        fc.property(
          fc.array(
            fc.record({
              wechatOpenId: fc.uuid(),
              nickname: fc.string({ minLength: 2, maxLength: 20 }),
              language: fc.constantFrom('zh', 'en', 'pt'),
            }),
            { minLength: 10, maxLength: 20 }
          ),
          fc.constantFrom('zh', 'en', 'pt'),
          (usersData, filterLanguage) => {
            // Clear database before each property run
            mockDb.clear();

            // Create users
            usersData.forEach((data) => mockDb.create(data));

            // Query with language filter
            const result = mockDb.findAll({
              where: { language: filterLanguage },
            });

            // All returned users should have the filtered language
            result.users.forEach((user) => {
              expect(user.language).toBe(filterLanguage);
            });

            // Count should match
            const expectedCount = usersData.filter(
              (u) => u.language === filterLanguage
            ).length;
            expect(result.total).toBe(expectedCount);

            return true;
          }
        ),
        { numRuns: 100 }
      );
    });

    test('should respect pagination limits', () => {
      fc.assert(
        fc.property(
          fc.integer({ min: 10, max: 30 }), // total users
          fc.integer({ min: 1, max: 10 }), // page size
          fc.integer({ min: 1, max: 5 }), // page number
          (totalUsers, pageSize, pageNumber) => {
            // Clear database before each property run
            mockDb.clear();

            // Create users
            const usersData = Array.from({ length: totalUsers }, (_, i) => ({
              wechatOpenId: `openid-${i}`,
              nickname: `User ${i}`,
            }));
            usersData.forEach((data) => mockDb.create(data));

            // Calculate offset
            const offset = (pageNumber - 1) * pageSize;

            // Query with pagination
            const result = mockDb.findAll({
              where: {},
              limit: pageSize,
              offset: offset,
            });

            // Should not exceed page size
            expect(result.users.length).toBeLessThanOrEqual(pageSize);

            // Total should match
            expect(result.total).toBe(totalUsers);

            // Calculate expected page count
            const totalPages = Math.ceil(totalUsers / pageSize);

            // If not the last page, should return exactly pageSize items
            if (pageNumber < totalPages) {
              expect(result.users.length).toBe(pageSize);
            }

            // If on the last page, should return remaining items
            if (pageNumber === totalPages) {
              const expectedRemaining = totalUsers - (pageNumber - 1) * pageSize;
              expect(result.users.length).toBe(expectedRemaining);
            }

            return true;
          }
        ),
        { numRuns: 100 }
      );
    });
  });

  /**
   * **Feature: overseas-appointment-backend, Property 31: User details aggregation**
   * **Validates: Requirements 7.2**
   * 
   * For any user ID, viewing user details should return complete information 
   * including profile, appointments, invitations, and balance.
   */
  describe('Property 31: User details aggregation', () => {
    test('should return complete user details with all related data', () => {
      fc.assert(
        fc.property(
          fc.record({
            wechatOpenId: fc.uuid(),
            nickname: fc.string({ minLength: 3, maxLength: 20 }),
            realName: fc.option(fc.string({ minLength: 3, maxLength: 20 }), { nil: null }),
            phone: fc.option(fc.string({ minLength: 8, maxLength: 15 }), { nil: null }),
            whatsapp: fc.option(fc.string({ minLength: 8, maxLength: 15 }), { nil: null }),
            wechatId: fc.option(fc.string({ minLength: 3, maxLength: 20 }), { nil: null }),
            language: fc.constantFrom('zh', 'en', 'pt'),
            balance: fc.float({ min: 0, max: 10000, noNaN: true }),
            status: fc.constantFrom('active', 'suspended'),
          }),
          (userData) => {
            // Clear database before each property run
            mockDb.clear();

            // Create user
            const user = mockDb.create(userData);

            // Retrieve user details
            const userDetails = mockDb.findById(user.id);

            // Should return the user
            expect(userDetails).toBeDefined();
            expect(userDetails.id).toBe(user.id);

            // Should have all profile fields
            expect(userDetails).toHaveProperty('wechatOpenId');
            expect(userDetails).toHaveProperty('nickname');
            expect(userDetails).toHaveProperty('realName');
            expect(userDetails).toHaveProperty('phone');
            expect(userDetails).toHaveProperty('whatsapp');
            expect(userDetails).toHaveProperty('wechatId');
            expect(userDetails).toHaveProperty('language');
            expect(userDetails).toHaveProperty('balance');
            expect(userDetails).toHaveProperty('status');
            expect(userDetails).toHaveProperty('createdAt');
            expect(userDetails).toHaveProperty('updatedAt');

            // Verify data matches
            expect(userDetails.wechatOpenId).toBe(userData.wechatOpenId);
            expect(userDetails.nickname).toBe(userData.nickname);
            expect(userDetails.language).toBe(userData.language);
            expect(userDetails.status).toBe(userData.status);

            return true;
          }
        ),
        { numRuns: 100 }
      );
    });

    test('should include invitation relationship when user was invited', () => {
      fc.assert(
        fc.property(
          fc.record({
            wechatOpenId: fc.uuid(),
            nickname: fc.string({ minLength: 3, maxLength: 20 }),
            language: fc.constantFrom('zh', 'en', 'pt'),
          }),
          fc.record({
            wechatOpenId: fc.uuid(),
            nickname: fc.string({ minLength: 3, maxLength: 20 }),
            language: fc.constantFrom('zh', 'en', 'pt'),
          }),
          (inviterData, inviteeData) => {
            // Clear database before each property run
            mockDb.clear();

            // Create inviter
            const inviter = mockDb.create(inviterData);

            // Create invitee with inviter reference
            const invitee = mockDb.create({
              ...inviteeData,
              invitedBy: inviter.id,
            });

            // Retrieve invitee details
            const inviteeDetails = mockDb.findById(invitee.id);

            // Should have invitedBy field
            expect(inviteeDetails.invitedBy).toBe(inviter.id);

            // In a real implementation, this would also fetch the inviter's details
            // For now, we verify the relationship is stored
            const inviterDetails = mockDb.findById(inviteeDetails.invitedBy);
            expect(inviterDetails).toBeDefined();
            expect(inviterDetails.id).toBe(inviter.id);

            return true;
          }
        ),
        { numRuns: 100 }
      );
    });

    test('should handle users without invitation relationship', () => {
      fc.assert(
        fc.property(
          fc.record({
            wechatOpenId: fc.uuid(),
            nickname: fc.string({ minLength: 3, maxLength: 20 }),
            language: fc.constantFrom('zh', 'en', 'pt'),
          }),
          (userData) => {
            // Clear database before each property run
            mockDb.clear();

            // Create user without inviter
            const user = mockDb.create(userData);

            // Retrieve user details
            const userDetails = mockDb.findById(user.id);

            // Should not have invitedBy field or it should be null/undefined
            expect(userDetails.invitedBy).toBeUndefined();

            return true;
          }
        ),
        { numRuns: 100 }
      );
    });

    test('should return consistent balance information', () => {
      fc.assert(
        fc.property(
          fc.record({
            wechatOpenId: fc.uuid(),
            nickname: fc.string({ minLength: 3, maxLength: 20 }),
            balance: fc.float({ min: 0, max: 10000, noNaN: true }),
          }),
          (userData) => {
            // Clear database before each property run
            mockDb.clear();

            // Create user with specific balance
            const user = mockDb.create(userData);

            // Retrieve user details
            const userDetails = mockDb.findById(user.id);

            // Balance should match
            expect(userDetails.balance).toBe(userData.balance);

            // Balance should be a number
            expect(typeof userDetails.balance).toBe('number');

            // Balance should not be negative
            expect(userDetails.balance).toBeGreaterThanOrEqual(0);

            return true;
          }
        ),
        { numRuns: 100 }
      );
    });
  });
});
