Backend Complete: Interface Refactoring & Service Container Enhancements

Repository Interface Optimization:
- Created IBaseRepository.ts and IPaginatedRepository.ts
- Refactored all 7 repository interfaces to extend base interfaces
- Eliminated ~200 lines of redundant code (70% reduction)
- Improved type safety and maintainability

 Dependency Injection Improvements:
- Added EmailService and GameTokenService to DIContainer
- Updated CreateUserCommandHandler constructor for DI
- Updated RequestPasswordResetCommandHandler constructor for DI
- Enhanced testability and service consistency

 Environment Configuration:
- Created comprehensive .env.example with 40+ variables
- Organized into 12 logical sections (Database, Security, Email, etc.)
- Added security guidelines and best practices
- Documented all backend environment requirements

 Documentation:
- Added comprehensive codebase review
- Created refactoring summary report
- Added frontend implementation guide

Impact: Improved code quality, reduced maintenance overhead, enhanced developer experience

SerpentRace_Backend/tests/Application/Services/JWTService.refresh.test.ts

@@ -0,0 +1,139 @@
+import { JWTService, TokenPayload } from '../../../src/Application/Services/JWTService';
+import { Request, Response } from 'express';
+import { UserState } from '../../../src/Domain/User/UserAggregate';
+
+describe('JWTService - Token Refresh Logic', () => {
+  let jwtService: JWTService;
+  let mockRequest: Partial<Request>;
+  let mockResponse: Partial<Response>;
+  let dateNowSpy: jest.SpyInstance;
+
+  beforeEach(() => {
+    jwtService = new JWTService();
+    
+    mockRequest = {
+      cookies: {}
+    };
+    
+    mockResponse = {
+      cookie: jest.fn()
+    };
+
+    // Create a fresh spy for Date.now in each test
+    dateNowSpy = jest.spyOn(Date, 'now');
+  });
+
+  afterEach(() => {
+    // Always restore Date.now after each test
+    dateNowSpy.mockRestore();
+  });
+
+  describe('shouldRefreshToken', () => {
+    it('should return true when token is 75% through its lifetime', () => {
+      // Token issued at time 100, expires at 900 (lifetime: 800)
+      // 75% of 800 = 600, so at time 700 (100 + 600), it should refresh
+      const payload: TokenPayload = {
+        userId: 'test-user',
+        authLevel: 0 as 0 | 1,
+        userStatus: UserState.VERIFIED_REGULAR,
+        orgId: 'test-org',
+        iat: 100,
+        exp: 900
+      };
+
+      // Mock current time as 700 (which is 75% through the token lifetime)
+      dateNowSpy.mockReturnValue(700 * 1000);
+
+      const result = jwtService.shouldRefreshToken(payload);
+      expect(result).toBe(true);
+    });
+
+    it('should return true when token is more than 75% through its lifetime', () => {
+      const payload: TokenPayload = {
+        userId: 'test-user',
+        authLevel: 0 as 0 | 1,
+        userStatus: UserState.VERIFIED_REGULAR,
+        orgId: 'test-org',
+        iat: 100,
+        exp: 900
+      };
+
+      // Mock current time as 750 (which is 81.25% through the token lifetime)
+      dateNowSpy.mockReturnValue(750 * 1000);
+
+      const result = jwtService.shouldRefreshToken(payload);
+      expect(result).toBe(true);
+    });
+
+    it('should return false when token is less than 75% through its lifetime', () => {
+      const payload: TokenPayload = {
+        userId: 'test-user',
+        authLevel: 0 as 0 | 1,
+        userStatus: UserState.VERIFIED_REGULAR,
+        orgId: 'test-org',
+        iat: 100,
+        exp: 900
+      };
+
+      // Mock current time as 600 (which is 62.5% through the token lifetime)
+      dateNowSpy.mockReturnValue(600 * 1000);
+
+      const result = jwtService.shouldRefreshToken(payload);
+      expect(result).toBe(false);
+    });
+
+    it('should return false when payload does not have required timestamp fields', () => {
+      const payload: TokenPayload = {
+        userId: 'test-user',
+        authLevel: 0 as 0 | 1,
+        userStatus: UserState.VERIFIED_REGULAR,
+        orgId: 'test-org'
+      };
+
+      const result = jwtService.shouldRefreshToken(payload);
+      expect(result).toBe(false);
+    });
+  });
+
+  describe('refreshIfNeeded', () => {
+    it('should return new token when refresh is needed', () => {
+      // Setup a payload that needs refresh (75% through lifetime)
+      const payload: TokenPayload = {
+        userId: 'test-user',
+        authLevel: 0 as 0 | 1,
+        userStatus: UserState.VERIFIED_REGULAR,
+        orgId: 'test-org',
+        iat: 100,
+        exp: 900
+      };
+
+      // Mock current time as 700 (75% through the token lifetime)
+      dateNowSpy.mockReturnValue(700 * 1000);
+
+      const result = jwtService.refreshIfNeeded(payload, mockResponse as Response);
+
+      expect(result).toBe(true);
+      expect(mockResponse.cookie).toHaveBeenCalled();
+    });
+
+    it('should return false when refresh is not needed', () => {
+      // Setup a payload that doesn't need refresh (less than 75% through lifetime)
+      const payload: TokenPayload = {
+        userId: 'test-user',
+        authLevel: 0 as 0 | 1,
+        userStatus: UserState.VERIFIED_REGULAR,
+        orgId: 'test-org',
+        iat: 100,
+        exp: 900
+      };
+
+      // Mock current time as 600 (62.5% through the token lifetime)
+      dateNowSpy.mockReturnValue(600 * 1000);
+
+      const result = jwtService.refreshIfNeeded(payload, mockResponse as Response);
+
+      expect(result).toBe(false);
+      expect(mockResponse.cookie).not.toHaveBeenCalled();
+    });
+  });
+});