/**
 * 后台任务调试辅助工具
 * 
 * 用于在开发和测试阶段验证后台任务配置和执行情况
 */

import { logger } from '@/utils/logger';
import { NativeModules, Platform } from 'react-native';
import { BackgroundTaskManager } from './backgroundTaskManagerV2';

const NativeBackgroundModule = NativeModules.BackgroundTaskBridge;

export class BackgroundTaskDebugHelper {
  private static instance: BackgroundTaskDebugHelper;

  static getInstance(): BackgroundTaskDebugHelper {
    if (!BackgroundTaskDebugHelper.instance) {
      BackgroundTaskDebugHelper.instance = new BackgroundTaskDebugHelper();
    }
    return BackgroundTaskDebugHelper.instance;
  }

  /**
   * 执行完整的后台任务诊断
   */
  async runFullDiagnostics(): Promise<DiagnosticsReport> {
    logger.info('[BackgroundTaskDebug] ====== 开始后台任务诊断 ======');

    const report: DiagnosticsReport = {
      platform: Platform.OS,
      timestamp: new Date().toISOString(),
      checks: {},
    };

    // 1. 检查平台支持
    report.checks.platformSupport = this.checkPlatformSupport();

    // 2. 检查原生模块
    report.checks.nativeModule = await this.checkNativeModule();

    // 3. 检查后台刷新权限
    report.checks.backgroundRefresh = await this.checkBackgroundRefreshStatus();

    // 4. 检查待处理任务
    report.checks.pendingTasks = await this.checkPendingTasks();

    // 5. 检查配置
    report.checks.configuration = this.checkConfiguration();

    // 6. 检查最后执行时间
    report.checks.lastExecution = await this.checkLastExecution();

    logger.info('[BackgroundTaskDebug] ====== 诊断完成 ======');
    logger.info('[BackgroundTaskDebug] 报告:', JSON.stringify(report, null, 2));

    return report;
  }

  /**
   * 检查平台支持
   */
  private checkPlatformSupport(): CheckResult {
    const isIOS = Platform.OS === 'ios';
    return {
      status: isIOS ? 'success' : 'error',
      message: isIOS 
        ? 'iOS 平台支持后台任务' 
        : `当前平台 (${Platform.OS}) 不支持后台任务`,
      details: {
        platform: Platform.OS,
        version: Platform.Version,
      },
    };
  }

  /**
   * 检查原生模块
   */
  private async checkNativeModule(): Promise<CheckResult> {
    if (!NativeBackgroundModule) {
      return {
        status: 'error',
        message: '原生模块 BackgroundTaskBridge 不可用',
        details: {
          available: false,
        },
      };
    }

    try {
      // 尝试调用一个简单的方法来验证模块是否正常工作
      const status = await NativeBackgroundModule.backgroundRefreshStatus();
      return {
        status: 'success',
        message: '原生模块可用且正常工作',
        details: {
          available: true,
          backgroundRefreshStatus: status,
        },
      };
    } catch (error) {
      return {
        status: 'error',
        message: '原生模块存在但调用失败',
        details: {
          available: true,
          error: (error as Error).message,
        },
      };
    }
  }

  /**
   * 检查后台刷新权限状态
   */
  private async checkBackgroundRefreshStatus(): Promise<CheckResult> {
    try {
      const manager = BackgroundTaskManager.getInstance();
      const status = await manager.getStatus();
      const statusText = await manager.checkStatus();

      let resultStatus: 'success' | 'warning' | 'error';
      let message: string;

      switch (status) {
        case 'available':
          resultStatus = 'success';
          message = '后台刷新权限已启用';
          break;
        case 'denied':
          resultStatus = 'error';
          message = '后台刷新被拒绝，请在设置中启用';
          break;
        case 'restricted':
          resultStatus = 'error';
          message = '后台刷新被限制（可能是家长控制）';
          break;
        default:
          resultStatus = 'warning';
          message = `后台刷新状态未知: ${status}`;
      }

      return {
        status: resultStatus,
        message,
        details: {
          status,
          statusText,
        },
      };
    } catch (error) {
      return {
        status: 'error',
        message: '检查后台刷新状态失败',
        details: {
          error: (error as Error).message,
        },
      };
    }
  }

  /**
   * 检查待处理的任务
   */
  private async checkPendingTasks(): Promise<CheckResult> {
    try {
      const manager = BackgroundTaskManager.getInstance();
      const pendingRequests = await manager.getPendingRequests();

      return {
        status: pendingRequests.length > 0 ? 'success' : 'warning',
        message: pendingRequests.length > 0 
          ? `有 ${pendingRequests.length} 个待处理任务` 
          : '没有待处理的任务（可能需要调度）',
        details: {
          count: pendingRequests.length,
          tasks: pendingRequests,
        },
      };
    } catch (error) {
      return {
        status: 'error',
        message: '检查待处理任务失败',
        details: {
          error: (error as Error).message,
        },
      };
    }
  }

  /**
   * 检查配置
   */
  private checkConfiguration(): CheckResult {
    const config = {
      identifier: 'com.anonymous.digitalpilates.task',
      defaultDelay: 15 * 60, // 15分钟
    };

    return {
      status: 'info',
      message: '后台任务配置',
      details: config,
    };
  }

  /**
   * 检查最后执行时间
   */
  private async checkLastExecution(): Promise<CheckResult> {
    try {
      const manager = BackgroundTaskManager.getInstance();
      const lastCheckTime = await manager.getLastBackgroundCheckTime();

      if (!lastCheckTime) {
        return {
          status: 'warning',
          message: '后台任务从未执行过',
          details: {
            lastExecution: null,
          },
        };
      }

      const timeSinceLastCheck = Date.now() - lastCheckTime;
      const hoursSinceLastCheck = timeSinceLastCheck / (1000 * 60 * 60);

      return {
        status: hoursSinceLastCheck > 24 ? 'warning' : 'success',
        message: hoursSinceLastCheck > 24 
          ? `距离上次执行已超过24小时 (${hoursSinceLastCheck.toFixed(1)}小时)` 
          : `上次执行时间: ${new Date(lastCheckTime).toLocaleString()}`,
        details: {
          lastExecution: lastCheckTime,
          timeSinceLastCheck: `${hoursSinceLastCheck.toFixed(1)} 小时`,
        },
      };
    } catch (error) {
      return {
        status: 'error',
        message: '检查最后执行时间失败',
        details: {
          error: (error as Error).message,
        },
      };
    }
  }

  /**
   * 生成可读的诊断报告
   */
  generateReadableReport(report: DiagnosticsReport): string {
    let output = '\n========== 后台任务诊断报告 ==========\n';
    output += `时间: ${new Date(report.timestamp).toLocaleString()}\n`;
    output += `平台: ${report.platform}\n`;
    output += '\n';

    Object.entries(report.checks).forEach(([key, check]) => {
      const icon = check.status === 'success' ? '✅' : check.status === 'error' ? '❌' : '⚠️';
      output += `${icon} ${key}: ${check.message}\n`;
      if (check.details && Object.keys(check.details).length > 0) {
        output += `   详情: ${JSON.stringify(check.details, null, 2)}\n`;
      }
      output += '\n';
    });

    output += '=====================================\n';
    return output;
  }

  /**
   * 模拟触发后台任务（仅用于测试）
   */
  async triggerTestTask(): Promise<void> {
    logger.info('[BackgroundTaskDebug] 触发测试任务...');
    
    try {
      const manager = BackgroundTaskManager.getInstance();
      await manager.triggerTaskForTesting();
      logger.info('[BackgroundTaskDebug] ✅ 测试任务执行完成');
    } catch (error: any) {
      const errorCode = error?.code || '';
      
      if (errorCode === 'SIMULATOR_NOT_SUPPORTED') {
        logger.info('[BackgroundTaskDebug] ℹ️ 在模拟器上执行了后台任务逻辑');
        logger.info('[BackgroundTaskDebug] 模拟器不支持完整的后台任务调度');
        logger.info('[BackgroundTaskDebug] 这是正常的，请在真机上测试完整功能');
      } else {
        logger.error('[BackgroundTaskDebug] ❌ 测试任务执行失败', error);
        throw error;
      }
    }
  }
}

export interface DiagnosticsReport {
  platform: string;
  timestamp: string;
  checks: {
    [key: string]: CheckResult;
  };
}

export interface CheckResult {
  status: 'success' | 'warning' | 'error' | 'info';
  message: string;
  details?: Record<string, any>;
}