import { logger } from '../../utils/logger';
import db from '../../config/database';

export interface TestCase {
  id: string;
  name: string;
  description: string;
  testType: 'UNIT' | 'INTEGRATION' | 'E2E';
  priority: 'HIGH' | 'MEDIUM' | 'LOW';
  dependencies: string[];
  expectedResult: string;
  steps: string[];
  tags: string[];
}

export interface TestResult {
  testId: string;
  testCaseId: string;
  testCaseName: string;
  status: 'PASSED' | 'FAILED' | 'SKIPPED';
  duration: number;
  errorMessage?: string;
  stackTrace?: string;
  actualResult?: string;
  startedAt: Date;
  completedAt: Date;
}

export interface RegressionTestConfig {
  testSuite: string;
  testCases: string[];
  environment: 'DEV' | 'STAGING' | 'PRODUCTION';
  concurrency: number;
  timeout: number;
  retryCount: number;
  tags: string[];
}

export interface RegressionTestResult {
  testRunId: string;
  testSuite: string;
  startTime: Date;
  endTime: Date;
  duration: number;
  totalTests: number;
  passedTests: number;
  failedTests: number;
  skippedTests: number;
  results: TestResult[];
  success: boolean;
  summary: string;
  recommendations: string[];
  environment: string;
}

export interface TestStatistics {
  total: number;
  passed: number;
  failed: number;
  skipped: number;
  passRate: number;
  averageDuration: number;
  byTestType: Record<'UNIT' | 'INTEGRATION' | 'E2E', {
    total: number;
    passed: number;
    failed: number;
  }>;
  byPriority: Record<'HIGH' | 'MEDIUM' | 'LOW', {
    total: number;
    passed: number;
    failed: number;
  }>;
}

export default class RegressionTestService {
  static async runRegressionTest(config: RegressionTestConfig): Promise<RegressionTestResult> {
    const testRunId = this.generateTestRunId();
    const startTime = new Date();
    
    logger.info(`[RegressionTestService] Starting regression test: testRunId=${testRunId}, suite=${config.testSuite}`);

    const testCases = await this.getTestCases(config.testCases, config.tags);
    const results: TestResult[] = [];

    for (const testCase of testCases) {
      const result = await this.runTestCase(testCase, config);
      results.push(result);
    }

    const endTime = new Date();
    const duration = endTime.getTime() - startTime.getTime();
    const statistics = this.calculateStatistics(results);
    const success = statistics.failed === 0;
    const summary = this.generateSummary(statistics);
    const recommendations = this.generateRecommendations(statistics, results);

    const result: RegressionTestResult = {
      testRunId,
      testSuite: config.testSuite,
      startTime,
      endTime,
      duration,
      totalTests: testCases.length,
      passedTests: statistics.passed,
      failedTests: statistics.failed,
      skippedTests: statistics.skipped,
      results,
      success,
      summary,
      recommendations,
      environment: config.environment,
    };

    await this.saveTestResult(result);
    
    logger.info(`[RegressionTestService] Regression test completed: testRunId=${testRunId}, success=${success}, passed=${statistics.passed}/${testCases.length}`);
    return result;
  }

  private static async getTestCases(testCaseIds: string[], tags: string[]): Promise<TestCase[]> {
    // In a real implementation, this would load test cases from a test management system
    // For now, we'll generate mock test cases
    
    const mockTestCases: TestCase[] = [
      {
        id: 'test_auth_001',
        name: '用户登录测试',
        description: '测试用户登录功能',
        testType: 'INTEGRATION',
        priority: 'HIGH',
        dependencies: [],
        expectedResult: '用户成功登录',
        steps: [
          '访问登录页面',
          '输入用户名和密码',
          '点击登录按钮',
          '验证登录成功',
        ],
        tags: ['auth', 'login'],
      },
      {
        id: 'test_product_001',
        name: '商品列表测试',
        description: '测试商品列表功能',
        testType: 'E2E',
        priority: 'HIGH',
        dependencies: ['test_auth_001'],
        expectedResult: '商品列表正常显示',
        steps: [
          '登录系统',
          '访问商品列表页面',
          '验证商品列表显示',
          '测试筛选功能',
        ],
        tags: ['product', 'list'],
      },
      {
        id: 'test_order_001',
        name: '订单创建测试',
        description: '测试订单创建功能',
        testType: 'E2E',
        priority: 'HIGH',
        dependencies: ['test_product_001'],
        expectedResult: '订单创建成功',
        steps: [
          '登录系统',
          '选择商品',
          '加入购物车',
          '提交订单',
          '验证订单创建成功',
        ],
        tags: ['order', 'create'],
      },
      {
        id: 'test_payment_001',
        name: '支付功能测试',
        description: '测试支付功能',
        testType: 'INTEGRATION',
        priority: 'HIGH',
        dependencies: ['test_order_001'],
        expectedResult: '支付成功',
        steps: [
          '创建订单',
          '选择支付方式',
          '完成支付',
          '验证支付成功',
        ],
        tags: ['payment'],
      },
      {
        id: 'test_certificate_001',
        name: '证书管理测试',
        description: '测试证书管理功能',
        testType: 'INTEGRATION',
        priority: 'MEDIUM',
        dependencies: ['test_auth_001'],
        expectedResult: '证书管理功能正常',
        steps: [
          '登录系统',
          '访问证书管理页面',
          '测试证书上传',
          '测试证书查询',
        ],
        tags: ['compliance', 'certificate'],
      },
      {
        id: 'test_ad_001',
        name: '广告管理测试',
        description: '测试广告管理功能',
        testType: 'INTEGRATION',
        priority: 'MEDIUM',
        dependencies: ['test_auth_001'],
        expectedResult: '广告管理功能正常',
        steps: [
          '登录系统',
          '访问广告管理页面',
          '测试广告创建',
          '测试广告数据同步',
        ],
        tags: ['ad', 'marketing'],
      },
      {
        id: 'test_user_asset_001',
        name: '用户资产测试',
        description: '测试用户资产管理功能',
        testType: 'INTEGRATION',
        priority: 'MEDIUM',
        dependencies: ['test_auth_001'],
        expectedResult: '用户资产功能正常',
        steps: [
          '登录系统',
          '访问用户资产页面',
          '测试积分管理',
          '测试会员等级',
        ],
        tags: ['user', 'asset'],
      },
      {
        id: 'test_api_001',
        name: 'API接口测试',
        description: '测试API接口响应',
        testType: 'UNIT',
        priority: 'LOW',
        dependencies: [],
        expectedResult: 'API接口正常响应',
        steps: [
          '调用API接口',
          '验证响应状态码',
          '验证响应数据结构',
        ],
        tags: ['api', 'unit'],
      },
    ];

    if (testCaseIds.length > 0) {
      return mockTestCases.filter(tc => testCaseIds.includes(tc.id));
    }

    if (tags.length > 0) {
      return mockTestCases.filter(tc => tc.tags.some(tag => tags.includes(tag)));
    }

    return mockTestCases;
  }

  private static async runTestCase(
    testCase: TestCase,
    config: RegressionTestConfig
  ): Promise<TestResult> {
    const startedAt = new Date();
    let status: 'PASSED' | 'FAILED' | 'SKIPPED' = 'PASSED';
    let errorMessage: string | undefined;

    // Simulate test execution
    await new Promise(resolve => setTimeout(resolve, Math.random() * 1000));

    // Simulate test failures
    if (Math.random() > 0.85) {
      status = 'FAILED';
      errorMessage = `Test failed: ${testCase.name}`;
    } else if (Math.random() > 0.95) {
      status = 'SKIPPED';
    }

    const completedAt = new Date();
    const duration = completedAt.getTime() - startedAt.getTime();

    return {
      testId: this.generateTestId(),
      testCaseId: testCase.id,
      testCaseName: testCase.name,
      status,
      duration,
      errorMessage,
      startedAt,
      completedAt,
    };
  }

  private static calculateStatistics(results: TestResult[]): TestStatistics {
    const stats: TestStatistics = {
      total: results.length,
      passed: 0,
      failed: 0,
      skipped: 0,
      passRate: 0,
      averageDuration: 0,
      byTestType: {
        UNIT: { total: 0, passed: 0, failed: 0 },
        INTEGRATION: { total: 0, passed: 0, failed: 0 },
        E2E: { total: 0, passed: 0, failed: 0 },
      },
      byPriority: {
        HIGH: { total: 0, passed: 0, failed: 0 },
        MEDIUM: { total: 0, passed: 0, failed: 0 },
        LOW: { total: 0, passed: 0, failed: 0 },
      },
    };

    let totalDuration = 0;

    for (const result of results) {
      switch (result.status) {
        case 'PASSED':
          stats.passed++;
          break;
        case 'FAILED':
          stats.failed++;
          break;
        case 'SKIPPED':
          stats.skipped++;
          break;
      }

      totalDuration += result.duration;
    }

    stats.passRate = stats.total > 0 ? (stats.passed / stats.total) * 100 : 0;
    stats.averageDuration = stats.total > 0 ? totalDuration / stats.total : 0;

    return stats;
  }

  private static generateSummary(statistics: TestStatistics): string {
    const parts = [];
    parts.push(`测试完成: ${statistics.passed}/${statistics.total} 通过`);
    parts.push(`成功率: ${statistics.passRate.toFixed(2)}%`);
    
    if (statistics.failed > 0) {
      parts.push(`失败: ${statistics.failed}`);
    }
    if (statistics.skipped > 0) {
      parts.push(`跳过: ${statistics.skipped}`);
    }

    parts.push(`平均执行时间: ${(statistics.averageDuration / 1000).toFixed(2)}s`);

    if (statistics.failed === 0) {
      parts.push('所有测试通过，系统可以正常上线');
    } else {
      parts.push('存在测试失败，需要调查解决');
    }

    return parts.join('. ');
  }

  private static generateRecommendations(
    statistics: TestStatistics,
    results: TestResult[]
  ): string[] {
    const recommendations = new Set<string>();

    if (statistics.failed > 0) {
      const failedTests = results.filter(r => r.status === 'FAILED');
      recommendations.add(`调查并修复 ${failedTests.length} 个失败的测试用例`);
      
      if (failedTests.some(r => r.testCaseName.includes('HIGH'))) {
        recommendations.add('优先修复高优先级测试用例的失败');
      }
    }

    if (statistics.skipped > 0) {
      recommendations.add(`检查并执行 ${statistics.skipped} 个被跳过的测试用例`);
    }

    if (statistics.passRate < 90) {
      recommendations.add('测试通过率较低，需要加强测试覆盖');
    }

    if (statistics.averageDuration > 5000) {
      recommendations.add('测试执行时间较长，考虑优化测试效率');
    }

    if (statistics.failed === 0) {
      recommendations.add('所有测试通过，可以进行上线部署');
    }

    recommendations.add('定期运行回归测试确保系统稳定性');
    recommendations.add('更新测试用例以覆盖新功能和变更');

    return Array.from(recommendations);
  }

  private static async saveTestResult(result: RegressionTestResult): Promise<void> {
    await db('cf_regression_test').insert({
      id: result.testRunId,
      test_suite: result.testSuite,
      start_time: result.startTime,
      end_time: result.endTime,
      duration: result.duration,
      total_tests: result.totalTests,
      passed_tests: result.passedTests,
      failed_tests: result.failedTests,
      skipped_tests: result.skippedTests,
      success: result.success,
      summary: result.summary,
      recommendations: JSON.stringify(result.recommendations),
      results: JSON.stringify(result.results),
      environment: result.environment,
      created_at: new Date(),
    });
  }

  static async getTestHistory(limit: number = 10): Promise<any[]> {
    return await db('cf_regression_test')
      .orderBy('created_at', 'desc')
      .limit(limit);
  }

  static async getTestTrends(days: number = 30): Promise<any[]> {
    const cutoffDate = new Date();
    cutoffDate.setDate(cutoffDate.getDate() - days);

    const testRuns = await db('cf_regression_test')
      .where('created_at', '>=', cutoffDate)
      .orderBy('created_at');

    return testRuns.map(run => ({
      date: run.created_at,
      passRate: (run.passed_tests / run.total_tests) * 100,
      totalTests: run.total_tests,
      failedTests: run.failed_tests,
      averageDuration: run.duration / run.total_tests,
      success: run.success,
    }));
  }

  static async getFailedTests(limit: number = 10): Promise<Array<{ testCaseName: string; failureCount: number; lastFailed: Date }>> {
    const recentRuns = await db('cf_regression_test')
      .orderBy('created_at', 'desc')
      .limit(5);

    const failureCounts: Record<string, { count: number; lastFailed: Date }> = {};

    for (const run of recentRuns) {
      const results = JSON.parse(run.results);
      for (const result of results) {
        if (result.status === 'FAILED') {
          if (!failureCounts[result.testCaseName]) {
            failureCounts[result.testCaseName] = { count: 0, lastFailed: new Date(0) };
          }
          failureCounts[result.testCaseName].count++;
          const failedDate = new Date(result.completedAt);
          if (failedDate > failureCounts[result.testCaseName].lastFailed) {
            failureCounts[result.testCaseName].lastFailed = failedDate;
          }
        }
      }
    }

    return Object.entries(failureCounts)
      .map(([testCaseName, data]) => ({
        testCaseName,
        failureCount: data.count,
        lastFailed: data.lastFailed,
      }))
      .sort((a, b) => b.failureCount - a.failureCount)
      .slice(0, limit);
  }

  private static generateTestRunId(): string {
    return `regression_${Date.now()}_${Math.random().toString(36).substr(2, 9)}`;
  }

  private static generateTestId(): string {
    return `test_${Date.now()}_${Math.random().toString(36).substr(2, 9)}`;
  }
}
