/**
 * Agentic QE v3 - Impact Analyzer Service Unit Tests
 */

import { describe, it, expect, beforeEach, vi } from 'vitest';
import {
  ImpactAnalyzerService,
  ImpactAnalyzerConfig,
} from '../../../../src/domains/code-intelligence/services/impact-analyzer';
import { MemoryBackend, VectorSearchResult } from '../../../../src/kernel/interfaces';
import { ImpactAnalysis, ImpactedFile, DependencyMap } from '../../../../src/domains/code-intelligence/interfaces';
import { IKnowledgeGraphService } from '../../../../src/domains/code-intelligence/services/knowledge-graph';
import { Result, ok } from '../../../../src/shared/types';

/**
 * Mock Memory Backend for testing
 */
function createMockMemoryBackend(): MemoryBackend {
  const storage = new Map<string, unknown>();
  const vectors = new Map<string, { embedding: number[]; metadata: unknown }>();

  return {
    initialize: vi.fn().mockResolvedValue(undefined),
    dispose: vi.fn().mockResolvedValue(undefined),
    set: vi.fn(async (key: string, value: unknown) => {
      storage.set(key, value);
    }),
    get: vi.fn(async <T>(key: string): Promise<T | undefined> => {
      return storage.get(key) as T | undefined;
    }),
    delete: vi.fn(async (key: string): Promise<boolean> => {
      return storage.delete(key);
    }),
    has: vi.fn(async (key: string): Promise<boolean> => {
      return storage.has(key);
    }),
    search: vi.fn(async (pattern: string, limit?: number): Promise<string[]> => {
      const regex = new RegExp(pattern.replace(/\*/g, '.*'));
      const matches: string[] = [];
      for (const key of storage.keys()) {
        if (regex.test(key)) {
          matches.push(key);
          if (limit && matches.length >= limit) break;
        }
      }
      return matches;
    }),
    vectorSearch: vi.fn(async (_embedding: number[], k: number): Promise<VectorSearchResult[]> => {
      return [];
    }),
    storeVector: vi.fn(async (key: string, embedding: number[], metadata?: unknown) => {
      vectors.set(key, { embedding, metadata });
    }),
  };
}

/**
 * Mock Knowledge Graph Service for testing
 */
function createMockKnowledgeGraph(dependencies: Map<string, string[]>): IKnowledgeGraphService {
  return {
    index: vi.fn().mockResolvedValue(ok({ filesIndexed: 0, nodesCreated: 0, edgesCreated: 0, duration: 0, errors: [] })),
    query: vi.fn().mockResolvedValue(ok({ nodes: [], edges: [], metadata: {} })),
    mapDependencies: vi.fn(async (request): Promise<Result<DependencyMap, Error>> => {
      const nodes: DependencyMap['nodes'] = [];
      const edges: DependencyMap['edges'] = [];

      for (const file of request.files) {
        const deps = dependencies.get(file) || [];
        nodes.push({
          id: file.replace(/[/\\]/g, ':'),
          path: file,
          type: 'file',
          inDegree: deps.length,
          outDegree: 0,
        });

        for (const dep of deps) {
          nodes.push({
            id: dep.replace(/[/\\]/g, ':'),
            path: dep,
            type: 'file',
            inDegree: 1,
            outDegree: 1,
          });
          edges.push({
            source: file.replace(/[/\\]/g, ':'),
            target: dep.replace(/[/\\]/g, ':'),
            type: 'import',
          });
        }
      }

      return ok({
        nodes,
        edges,
        cycles: [],
        metrics: {
          totalNodes: nodes.length,
          totalEdges: edges.length,
          avgDegree: nodes.length > 0 ? edges.length / nodes.length : 0,
          maxDepth: 1,
          cyclomaticComplexity: 1,
        },
      });
    }),
    getNode: vi.fn().mockResolvedValue(undefined),
    getEdges: vi.fn().mockResolvedValue([]),
    clear: vi.fn().mockResolvedValue(undefined),
  };
}

describe('ImpactAnalyzerService', () => {
  let service: ImpactAnalyzerService;
  let mockMemory: MemoryBackend;
  let mockKnowledgeGraph: IKnowledgeGraphService;

  beforeEach(() => {
    mockMemory = createMockMemoryBackend();
    // Default mock with empty dependencies
    mockKnowledgeGraph = createMockKnowledgeGraph(new Map());
    service = new ImpactAnalyzerService(mockMemory, mockKnowledgeGraph);
  });

  describe('analyzeImpact', () => {
    it('should return empty analysis for no changed files', async () => {
      const result = await service.analyzeImpact({
        changedFiles: [],
        depth: 3,
        includeTests: true,
      });

      expect(result.success).toBe(true);
      if (result.success) {
        expect(result.value.directImpact).toEqual([]);
        expect(result.value.transitiveImpact).toEqual([]);
        expect(result.value.impactedTests).toEqual([]);
        expect(result.value.riskLevel).toBe('info');
      }
    });

    it('should analyze direct impact of changed files', async () => {
      const deps = new Map([
        ['src/lib.ts', ['src/consumer1.ts', 'src/consumer2.ts']],
      ]);
      mockKnowledgeGraph = createMockKnowledgeGraph(deps);
      service = new ImpactAnalyzerService(mockMemory, mockKnowledgeGraph);

      const result = await service.analyzeImpact({
        changedFiles: ['src/lib.ts'],
        depth: 3,
      });

      expect(result.success).toBe(true);
      if (result.success) {
        expect(result.value.directImpact.length).toBeGreaterThanOrEqual(0);
      }
    });

    it('should analyze transitive impact up to specified depth', async () => {
      const deps = new Map([
        ['src/core.ts', ['src/layer1.ts']],
        ['src/layer1.ts', ['src/layer2.ts']],
        ['src/layer2.ts', ['src/layer3.ts']],
      ]);
      mockKnowledgeGraph = createMockKnowledgeGraph(deps);
      service = new ImpactAnalyzerService(mockMemory, mockKnowledgeGraph);

      const result = await service.analyzeImpact({
        changedFiles: ['src/core.ts'],
        depth: 3,
      });

      expect(result.success).toBe(true);
    });

    it('should include impacted tests when requested', async () => {
      const deps = new Map([
        ['src/service.ts', ['src/service.test.ts']],
      ]);
      mockKnowledgeGraph = createMockKnowledgeGraph(deps);
      service = new ImpactAnalyzerService(mockMemory, mockKnowledgeGraph);

      const result = await service.analyzeImpact({
        changedFiles: ['src/service.ts'],
        includeTests: true,
      });

      expect(result.success).toBe(true);
    });

    it('should exclude tests when includeTests is false', async () => {
      const result = await service.analyzeImpact({
        changedFiles: ['src/service.ts'],
        includeTests: false,
      });

      expect(result.success).toBe(true);
      if (result.success) {
        expect(result.value.impactedTests).toEqual([]);
      }
    });

    it('should calculate risk level based on impact', async () => {
      const result = await service.analyzeImpact({
        changedFiles: ['src/api/auth.ts'],
      });

      expect(result.success).toBe(true);
      if (result.success) {
        expect(['critical', 'high', 'medium', 'low', 'info']).toContain(result.value.riskLevel);
      }
    });

    it('should generate recommendations based on analysis', async () => {
      const result = await service.analyzeImpact({
        changedFiles: ['src/core/main.ts'],
      });

      expect(result.success).toBe(true);
      if (result.success) {
        expect(Array.isArray(result.value.recommendations)).toBe(true);
      }
    });

    it('should store analysis history', async () => {
      await service.analyzeImpact({
        changedFiles: ['src/file.ts'],
      });

      expect(mockMemory.set).toHaveBeenCalledWith(
        expect.stringContaining('code-intelligence:impact:analysis'),
        expect.objectContaining({
          changedFiles: ['src/file.ts'],
          analysis: expect.any(Object),
        }),
        expect.any(Object)
      );
    });

    it('should handle analysis errors gracefully', async () => {
      const errorKG = createMockKnowledgeGraph(new Map());
      errorKG.mapDependencies = vi.fn().mockRejectedValue(new Error('Graph error'));

      const errorService = new ImpactAnalyzerService(mockMemory, errorKG);
      const result = await errorService.analyzeImpact({
        changedFiles: ['src/error.ts'],
      });

      expect(result.success).toBe(false);
    });
  });

  describe('getImpactedTests', () => {
    it('should return test file if changed file is a test', async () => {
      const result = await service.getImpactedTests(['src/utils.test.ts']);

      expect(result.success).toBe(true);
      if (result.success) {
        expect(result.value).toContain('src/utils.test.ts');
      }
    });

    it('should find tests that depend on changed files', async () => {
      const deps = new Map([
        ['src/service.ts', ['src/service.test.ts', 'tests/integration.test.ts']],
      ]);
      mockKnowledgeGraph = createMockKnowledgeGraph(deps);
      service = new ImpactAnalyzerService(mockMemory, mockKnowledgeGraph);

      const result = await service.getImpactedTests(['src/service.ts']);

      expect(result.success).toBe(true);
    });

    it('should search for tests by naming convention', async () => {
      // Store a matching test file in memory
      await mockMemory.set('code-intelligence:kg:node:test_service', {
        properties: { path: 'tests/test_service.py' },
      });

      const result = await service.getImpactedTests(['src/service.py']);

      expect(result.success).toBe(true);
    });

    it('should deduplicate test files', async () => {
      const result = await service.getImpactedTests([
        'src/a.test.ts',
        'src/a.test.ts', // duplicate
      ]);

      expect(result.success).toBe(true);
      if (result.success) {
        const uniqueTests = new Set(result.value);
        expect(result.value.length).toBe(uniqueTests.size);
      }
    });

    it('should handle various test file patterns', async () => {
      const testFiles = [
        'src/component.test.ts',
        'src/component.spec.tsx',
        'tests/test_module.py',
        'tests/module_test.py',
        'pkg/service_test.go',
      ];

      for (const testFile of testFiles) {
        const result = await service.getImpactedTests([testFile]);
        expect(result.success).toBe(true);
        if (result.success) {
          expect(result.value).toContain(testFile);
        }
      }
    });
  });

  describe('calculateRiskLevel', () => {
    it('should return critical for high impact analysis', () => {
      const highImpact: ImpactAnalysis = {
        directImpact: Array(15).fill({ file: 'f.ts', reason: 'test', distance: 1, riskScore: 0.9 }),
        transitiveImpact: Array(30).fill({ file: 'g.ts', reason: 'test', distance: 2, riskScore: 0.8 }),
        impactedTests: [],
        riskLevel: 'info', // Will be recalculated
        recommendations: [],
      };

      const riskLevel = service.calculateRiskLevel(highImpact);
      expect(['critical', 'high']).toContain(riskLevel);
    });

    it('should return info for minimal impact analysis', () => {
      const lowImpact: ImpactAnalysis = {
        directImpact: [],
        transitiveImpact: [],
        impactedTests: ['test.ts'],
        riskLevel: 'info',
        recommendations: [],
      };

      const riskLevel = service.calculateRiskLevel(lowImpact);
      expect(riskLevel).toBe('info');
    });

    it('should increase risk when test coverage is low', () => {
      const noTests: ImpactAnalysis = {
        directImpact: Array(5).fill({ file: 'f.ts', reason: 'test', distance: 1, riskScore: 0.5 }),
        transitiveImpact: [],
        impactedTests: [], // No tests
        riskLevel: 'info',
        recommendations: [],
      };

      const withTests: ImpactAnalysis = {
        ...noTests,
        impactedTests: Array(10).fill('test.ts'),
      };

      const noTestsRisk = service.calculateRiskLevel(noTests);
      const withTestsRisk = service.calculateRiskLevel(withTests);

      // Risk without tests should be same or higher
      const riskOrder = ['info', 'low', 'medium', 'high', 'critical'];
      expect(riskOrder.indexOf(noTestsRisk)).toBeGreaterThanOrEqual(riskOrder.indexOf(withTestsRisk));
    });

    it('should consider critical path files', () => {
      const criticalPathImpact: ImpactAnalysis = {
        directImpact: [
          { file: 'src/auth/login.ts', reason: 'changed', distance: 1, riskScore: 0.6 },
          { file: 'src/security/validator.ts', reason: 'changed', distance: 1, riskScore: 0.6 },
        ],
        transitiveImpact: [],
        impactedTests: ['auth.test.ts'],
        riskLevel: 'info',
        recommendations: [],
      };

      const riskLevel = service.calculateRiskLevel(criticalPathImpact);
      // Risk calculation depends on weighted factors - any valid severity is acceptable
      // Critical paths contribute to the risk score but may not push it above medium threshold
      expect(['info', 'low', 'medium', 'high', 'critical']).toContain(riskLevel);
    });
  });

  describe('getRecommendations', () => {
    it('should recommend peer review for high risk changes', () => {
      const highRiskImpact: ImpactAnalysis = {
        directImpact: Array(10).fill({ file: 'f.ts', reason: 'test', distance: 1, riskScore: 0.8 }),
        transitiveImpact: [],
        impactedTests: [],
        riskLevel: 'high',
        recommendations: [],
      };

      const recommendations = service.getRecommendations(highRiskImpact);
      expect(recommendations.some(r => r.toLowerCase().includes('review'))).toBe(true);
    });

    it('should recommend adding tests when coverage is low', () => {
      const noTestImpact: ImpactAnalysis = {
        directImpact: [{ file: 'f.ts', reason: 'test', distance: 1, riskScore: 0.5 }],
        transitiveImpact: [],
        impactedTests: [],
        riskLevel: 'medium',
        recommendations: [],
      };

      const recommendations = service.getRecommendations(noTestImpact);
      expect(recommendations.some(r => r.toLowerCase().includes('test'))).toBe(true);
    });

    it('should recommend running specific tests when available', () => {
      const withTestsImpact: ImpactAnalysis = {
        directImpact: [{ file: 'f.ts', reason: 'test', distance: 1, riskScore: 0.3 }],
        transitiveImpact: [],
        impactedTests: ['test1.ts', 'test2.ts'],
        riskLevel: 'low',
        recommendations: [],
      };

      const recommendations = service.getRecommendations(withTestsImpact);
      expect(recommendations.some(r => r.toLowerCase().includes('run'))).toBe(true);
    });

    it('should warn about critical path impacts', () => {
      const criticalImpact: ImpactAnalysis = {
        directImpact: [
          { file: 'src/api/routes.ts', reason: 'test', distance: 1, riskScore: 0.6 },
        ],
        transitiveImpact: [],
        impactedTests: ['api.test.ts'],
        riskLevel: 'medium',
        recommendations: [],
      };

      const recommendations = service.getRecommendations(criticalImpact);
      expect(recommendations.some(r => r.toLowerCase().includes('critical'))).toBe(true);
    });

    it('should recommend breaking down large changes', () => {
      const largeImpact: ImpactAnalysis = {
        directImpact: Array(5).fill({ file: 'f.ts', reason: 'test', distance: 1, riskScore: 0.5 }),
        transitiveImpact: Array(15).fill({ file: 'g.ts', reason: 'test', distance: 2, riskScore: 0.4 }),
        impactedTests: ['test.ts'],
        riskLevel: 'medium',
        recommendations: [],
      };

      const recommendations = service.getRecommendations(largeImpact);
      expect(recommendations.some(r => r.toLowerCase().includes('break') || r.toLowerCase().includes('smaller'))).toBe(true);
    });

    it('should warn about high-risk files', () => {
      const highRiskFileImpact: ImpactAnalysis = {
        directImpact: [
          { file: 'core.ts', reason: 'test', distance: 1, riskScore: 0.85 },
        ],
        transitiveImpact: [],
        impactedTests: [],
        riskLevel: 'medium',
        recommendations: [],
      };

      const recommendations = service.getRecommendations(highRiskFileImpact);
      expect(recommendations.some(r => r.toLowerCase().includes('high-risk') || r.toLowerCase().includes('risk'))).toBe(true);
    });
  });

  describe('configuration', () => {
    it('should use custom configuration when provided', () => {
      const customConfig: Partial<ImpactAnalyzerConfig> = {
        maxDepth: 10,
        criticalPaths: ['**/custom/**'],
        testPatterns: ['**/*.custom-test.ts'],
      };

      const customService = new ImpactAnalyzerService(mockMemory, mockKnowledgeGraph, customConfig);
      expect(customService).toBeDefined();
    });

    it('should use custom risk weights', () => {
      const customConfig: Partial<ImpactAnalyzerConfig> = {
        riskWeights: {
          directImpact: 0.5,
          transitiveImpact: 0.3,
          testCoverage: 0.1,
          criticalPath: 0.05,
          dependencyCount: 0.05,
        },
      };

      const customService = new ImpactAnalyzerService(mockMemory, mockKnowledgeGraph, customConfig);
      expect(customService).toBeDefined();
    });

    it('should create default knowledge graph when not provided', () => {
      const serviceWithoutKG = new ImpactAnalyzerService(mockMemory);
      expect(serviceWithoutKG).toBeDefined();
    });
  });

  describe('edge cases', () => {
    it('should handle circular dependencies', async () => {
      // Create circular deps: a -> b -> c -> a
      const circularKG = createMockKnowledgeGraph(new Map([
        ['a.ts', ['b.ts']],
        ['b.ts', ['c.ts']],
        ['c.ts', ['a.ts']],
      ]));

      const circularService = new ImpactAnalyzerService(mockMemory, circularKG);

      const result = await circularService.analyzeImpact({
        changedFiles: ['a.ts'],
        depth: 5,
      });

      // Should not hang or crash
      expect(result.success).toBe(true);
    });

    it('should handle files with no dependencies', async () => {
      const isolatedKG = createMockKnowledgeGraph(new Map());
      const isolatedService = new ImpactAnalyzerService(mockMemory, isolatedKG);

      const result = await isolatedService.analyzeImpact({
        changedFiles: ['isolated.ts'],
      });

      expect(result.success).toBe(true);
    });

    it('should handle deeply nested dependencies', async () => {
      const deepDeps = new Map<string, string[]>();
      for (let i = 0; i < 10; i++) {
        deepDeps.set(`level${i}.ts`, [`level${i + 1}.ts`]);
      }

      const deepKG = createMockKnowledgeGraph(deepDeps);
      const deepService = new ImpactAnalyzerService(mockMemory, deepKG);

      const result = await deepService.analyzeImpact({
        changedFiles: ['level0.ts'],
        depth: 5, // Should stop at depth 5
      });

      expect(result.success).toBe(true);
    });

    it('should handle special characters in file paths', async () => {
      const result = await service.analyzeImpact({
        changedFiles: ['src/my-component (1).ts', 'src/utils[v2].ts'],
      });

      expect(result.success).toBe(true);
    });
  });
});