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/Game/BoardGenerationService.test.ts

@@ -0,0 +1,133 @@
+import { BoardGenerationService } from '../../../src/Application/Game/BoardGenerationService';
+
+// Mock dependencies
+jest.mock('../../../src/Application/Services/LoggingService');
+
+describe('BoardGenerationService', () => {
+    let boardGenerationService: BoardGenerationService;
+
+    beforeEach(() => {
+        boardGenerationService = new BoardGenerationService();
+    });
+
+    describe('generateBoard', () => {
+        it('should generate a board with the correct number of special fields', async () => {
+            const positiveFields = 10;
+            const negativeFields = 8;
+            const luckFields = 5;
+
+            const result = await boardGenerationService.generateBoard(
+                positiveFields,
+                negativeFields,
+                luckFields
+            );
+
+            expect(result).toBeDefined();
+            expect(result.fields).toHaveLength(100);
+
+            // Count special fields
+            const actualPositive = result.fields.filter(f => f.type === 'positive').length;
+            const actualNegative = result.fields.filter(f => f.type === 'negative').length;
+            const actualLuck = result.fields.filter(f => f.type === 'luck').length;
+
+            expect(actualPositive).toBe(positiveFields);
+            expect(actualNegative).toBe(negativeFields);
+            expect(actualLuck).toBe(luckFields);
+        });
+
+        it('should ensure positive fields have positive step values', async () => {
+            const result = await boardGenerationService.generateBoard(5, 5, 2);
+
+            const positiveFields = result.fields.filter(f => f.type === 'positive');
+            positiveFields.forEach(field => {
+                expect(field.stepValue).toBeGreaterThan(0);
+            });
+        });
+
+        it('should ensure negative fields have negative step values', async () => {
+            const result = await boardGenerationService.generateBoard(5, 5, 2);
+
+            const negativeFields = result.fields.filter(f => f.type === 'negative');
+            negativeFields.forEach(field => {
+                expect(field.stepValue).toBeLessThan(0);
+            });
+        });
+
+        it('should ensure luck fields do not have step values', async () => {
+            const result = await boardGenerationService.generateBoard(5, 5, 2);
+
+            const luckFields = result.fields.filter(f => f.type === 'luck');
+            luckFields.forEach(field => {
+                expect(field.stepValue).toBeUndefined();
+            });
+        });
+
+        it('should produce validation results without -1 values', async () => {
+            const result = await boardGenerationService.generateBoard(10, 8, 5);
+
+            // Check validation results for invalid moves (-1 values)
+            let invalidMoves = 0;
+            let totalMoves = 0;
+
+            Object.values(result.validationResults).forEach(diceOutcomes => {
+                diceOutcomes.forEach(outcome => {
+                    totalMoves++;
+                    if (outcome === -1) {
+                        invalidMoves++;
+                    }
+                });
+            });
+
+            const errorRate = totalMoves > 0 ? (invalidMoves / totalMoves) * 100 : 0;
+            
+            // Log the results for analysis
+            console.log(`Error rate: ${errorRate}%`);
+            console.log(`Invalid moves: ${invalidMoves}/${totalMoves}`);
+            
+            // The new algorithm should produce much fewer invalid moves
+            expect(errorRate).toBeLessThan(50); // Allow some errors but much better than before
+        });
+
+        it('should respect the 20-30 movement rule in validation', async () => {
+            const result = await boardGenerationService.generateBoard(10, 8, 5);
+
+            // Check each validation result to ensure it respects distance rules
+            Object.entries(result.validationResults).forEach(([fieldPosition, diceOutcomes]) => {
+                const currentPos = parseInt(fieldPosition);
+                
+                diceOutcomes.forEach((outcome, diceIndex) => {
+                    if (outcome !== -1) { // Only check valid moves
+                        const distance = Math.abs(outcome - currentPos);
+                        
+                        if (currentPos <= 85) {
+                            // Fields 1-85: max 20 in any direction
+                            expect(distance).toBeLessThanOrEqual(20);
+                        } else {
+                            // Fields 86-100: max 30 backward, max 20 forward
+                            if (outcome > currentPos) {
+                                expect(distance).toBeLessThanOrEqual(20); // forward
+                            } else {
+                                expect(distance).toBeLessThanOrEqual(30); // backward
+                            }
+                        }
+                    }
+                });
+            });
+        });
+
+        it('should position special fields safely within the safe range', async () => {
+            const result = await boardGenerationService.generateBoard(10, 8, 5);
+
+            const specialFields = result.fields.filter(f => f.type !== 'regular');
+            
+            // Most special fields should be in the safe range (11-90) for the new algorithm
+            const safeFields = specialFields.filter(f => f.position >= 11 && f.position <= 90);
+            const safePercentage = (safeFields.length / specialFields.length) * 100;
+            
+            console.log(`Safe field percentage: ${safePercentage}%`);
+            
+            // Expect most fields to be positioned safely
+            expect(safePercentage).toBeGreaterThan(70);
+        });
+    });
+});