import { Request, Response } from 'express';
import { SystemConfigModel } from '../models';
import { query } from '../database';

const toPositiveInt = (value: unknown, defaultValue: number) => {
  const n = Number(value);
  if (!Number.isFinite(n) || n <= 0) return defaultValue;
  return Math.floor(n);
};

export class AdminController {
  // 管理员登录
  static async login(req: Request, res: Response) {
    try {
      const { username, password } = req.body;
      
      if (!username || !password) {
        return res.status(400).json({
          success: false,
          message: '用户名和密码不能为空'
        });
      }
      
      // 直接验证用户名和密码，不依赖数据库
      // 初始管理员账号：admin / admin123
      const isValid = username === 'admin' && password === 'admin123';
      if (!isValid) {
        return res.status(401).json({
          success: false,
          message: '用户名或密码错误'
        });
      }
      
      // 直接返回成功，不生成真实的JWT token
      res.json({
        success: true,
        message: '登录成功',
        data: {
          username,
          token: 'admin-token' // 简化处理
        }
      });
    } catch (error: any) {
      console.error('管理员登录失败:', error);
      res.status(500).json({
        success: false,
        message: error.message || '登录失败'
      });
    }
  }

  // 获取抽题配置
  static async getQuizConfig(req: Request, res: Response) {
    try {
      const config = await SystemConfigModel.getQuizConfig();
      
      res.json({
        success: true,
        data: config
      });
    } catch (error: any) {
      console.error('获取抽题配置失败:', error);
      res.status(500).json({
        success: false,
        message: error.message || '获取抽题配置失败'
      });
    }
  }

  // 更新抽题配置
  static async updateQuizConfig(req: Request, res: Response) {
    try {
      const { singleRatio, multipleRatio, judgmentRatio, textRatio, totalScore } = req.body;
      
      const config = {
        singleRatio,
        multipleRatio,
        judgmentRatio,
        textRatio,
        totalScore
      };
      
      await SystemConfigModel.updateQuizConfig(config);
      
      res.json({
        success: true,
        message: '抽题配置更新成功'
      });
    } catch (error: any) {
      console.error('更新抽题配置失败:', error);
      res.status(500).json({
        success: false,
        message: error.message || '更新抽题配置失败'
      });
    }
  }

  // 获取统计数据
  static async getStatistics(req: Request, res: Response) {
    try {
      const { QuizModel } = await import('../models');
      const statistics = await QuizModel.getStatistics();
      
      res.json({
        success: true,
        data: statistics
      });
    } catch (error: any) {
      console.error('获取统计数据失败:', error);
      res.status(500).json({
        success: false,
        message: error.message || '获取统计数据失败'
      });
    }
  }

  // 获取活跃任务统计数据
  static async getActiveTasksStats(req: Request, res: Response) {
    try {
      const { ExamTaskModel } = await import('../models/examTask');
      const stats = await ExamTaskModel.getActiveTasksWithStats();
      
      res.json({
        success: true,
        data: stats
      });
    } catch (error: any) {
      console.error('获取活跃任务统计数据失败:', error);
      res.status(500).json({
        success: false,
        message: error.message || '获取活跃任务统计数据失败'
      });
    }
  }

  static async getHistoryTaskStats(req: Request, res: Response) {
    try {
      const page = toPositiveInt(req.query.page, 1);
      const limit = toPositiveInt(req.query.limit, 5);

      const { ExamTaskModel } = await import('../models/examTask');
      const result = await ExamTaskModel.getHistoryTasksWithStatsPaged(page, limit);

      res.json({
        success: true,
        data: result.data,
        pagination: {
          page,
          limit,
          total: result.total,
          pages: Math.ceil(result.total / limit),
        },
      });
    } catch (error: any) {
      console.error('获取历史任务统计失败:', error);
      res.status(500).json({
        success: false,
        message: error.message || '获取历史任务统计失败',
      });
    }
  }

  static async getUpcomingTaskStats(req: Request, res: Response) {
    try {
      const page = toPositiveInt(req.query.page, 1);
      const limit = toPositiveInt(req.query.limit, 5);

      const { ExamTaskModel } = await import('../models/examTask');
      const result = await ExamTaskModel.getUpcomingTasksWithStatsPaged(page, limit);

      res.json({
        success: true,
        data: result.data,
        pagination: {
          page,
          limit,
          total: result.total,
          pages: Math.ceil(result.total / limit),
        },
      });
    } catch (error: any) {
      console.error('获取未开始任务统计失败:', error);
      res.status(500).json({
        success: false,
        message: error.message || '获取未开始任务统计失败',
      });
    }
  }

  static async getDashboardOverview(req: Request, res: Response) {
    try {
      const { QuizModel } = await import('../models');
      const statistics = await QuizModel.getStatistics();

      const now = new Date().toISOString();

      const [categoryRows, activeSubjectRow, statusRow] = await Promise.all([
        query(
          `
          SELECT 
            COALESCE(category, '未分类') as category,
            COUNT(*) as count
          FROM questions
          GROUP BY COALESCE(category, '未分类')
          ORDER BY count DESC
        `,
        ),
        query(
          `
          SELECT COUNT(DISTINCT subject_id) as total
          FROM exam_tasks
          WHERE start_at <= ? AND end_at >= ?
        `,
          [now, now],
        ).then((rows: any[]) => rows[0]),
        query(
          `
          SELECT 
            SUM(CASE WHEN end_at < ? THEN 1 ELSE 0 END) as completed,
            SUM(CASE WHEN start_at <= ? AND end_at >= ? THEN 1 ELSE 0 END) as ongoing,
            SUM(CASE WHEN start_at > ? THEN 1 ELSE 0 END) as notStarted
          FROM exam_tasks
        `,
          [now, now, now, now],
        ).then((rows: any[]) => rows[0]),
      ]);

      const questionCategoryStats = (categoryRows as any[]).map((r) => ({
        category: r.category,
        count: Number(r.count) || 0,
      }));

      res.json({
        success: true,
        data: {
          totalUsers: statistics.totalUsers,
          activeSubjectCount: Number(activeSubjectRow?.total) || 0,
          questionCategoryStats,
          taskStatusDistribution: {
            completed: Number(statusRow?.completed) || 0,
            ongoing: Number(statusRow?.ongoing) || 0,
            notStarted: Number(statusRow?.notStarted) || 0,
          },
        },
      });
    } catch (error: any) {
      console.error('获取仪表盘概览失败:', error);
      res.status(500).json({
        success: false,
        message: error.message || '获取仪表盘概览失败',
      });
    }
  }

  static async getUserStats(req: Request, res: Response) {
    try {
      const rows = await query(
        `
        SELECT 
          u.id as userId,
          u.name as userName,
          COUNT(qr.id) as totalRecords,
          COALESCE(ROUND(AVG(qr.total_score), 2), 0) as averageScore,
          COALESCE(MAX(qr.total_score), 0) as highestScore,
          COALESCE(MIN(qr.total_score), 0) as lowestScore
        FROM users u
        LEFT JOIN quiz_records qr ON u.id = qr.user_id
        GROUP BY u.id
        ORDER BY totalRecords DESC, u.created_at DESC
        `,
      );

      const data = (rows as any[]).map((row) => ({
        userId: row.userId,
        userName: row.userName,
        totalRecords: Number(row.totalRecords) || 0,
        averageScore: Number(row.averageScore) || 0,
        highestScore: Number(row.highestScore) || 0,
        lowestScore: Number(row.lowestScore) || 0,
      }));

      res.json({
        success: true,
        data,
      });
    } catch (error: any) {
      console.error('获取用户统计失败:', error);
      res.status(500).json({
        success: false,
        message: error.message || '获取用户统计失败',
      });
    }
  }

  static async getSubjectStats(req: Request, res: Response) {
    try {
      const rows = await query(
        `
        SELECT 
          s.id as subjectId,
          s.name as subjectName,
          COUNT(qr.id) as totalRecords,
          COALESCE(ROUND(AVG(qr.total_score), 2), 0) as averageScore,
          COALESCE(ROUND(AVG(
            CASE 
              WHEN qr.total_count > 0 THEN (qr.correct_count * 100.0 / qr.total_count)
              ELSE 0
            END
          ), 2), 0) as averageCorrectRate
        FROM exam_subjects s
        LEFT JOIN quiz_records qr ON s.id = qr.subject_id
        GROUP BY s.id
        ORDER BY totalRecords DESC, s.created_at DESC
        `,
      );

      const data = (rows as any[]).map((row) => ({
        subjectId: row.subjectId,
        subjectName: row.subjectName,
        totalRecords: Number(row.totalRecords) || 0,
        averageScore: Number(row.averageScore) || 0,
        averageCorrectRate: Number(row.averageCorrectRate) || 0,
      }));

      res.json({
        success: true,
        data,
      });
    } catch (error: any) {
      console.error('获取科目统计失败:', error);
      res.status(500).json({
        success: false,
        message: error.message || '获取科目统计失败',
      });
    }
  }

  static async getTaskStats(req: Request, res: Response) {
    try {
      const rows = await query(
        `
        SELECT 
          t.id as taskId,
          t.name as taskName,
          COALESCE(rs.totalRecords, 0) as totalRecords,
          COALESCE(rs.averageScore, 0) as averageScore,
          COALESCE(us.totalUsers, 0) as totalUsers,
          COALESCE(rs.completedUsers, 0) as completedUsers
        FROM exam_tasks t
        LEFT JOIN (
          SELECT 
            task_id,
            COUNT(*) as totalRecords,
            ROUND(AVG(total_score), 2) as averageScore,
            COUNT(DISTINCT user_id) as completedUsers
          FROM quiz_records
          WHERE task_id IS NOT NULL
          GROUP BY task_id
        ) rs ON rs.task_id = t.id
        LEFT JOIN (
          SELECT 
            task_id,
            COUNT(DISTINCT user_id) as totalUsers
          FROM exam_task_users
          GROUP BY task_id
        ) us ON us.task_id = t.id
        ORDER BY t.created_at DESC
        `,
      );

      const data = rows.map((row: any) => {
        const totalUsers = Number(row.totalUsers) || 0;
        const completedUsers = Number(row.completedUsers) || 0;
        const completionRate = totalUsers > 0 ? (completedUsers / totalUsers) * 100 : 0;

        return {
          taskId: row.taskId,
          taskName: row.taskName,
          totalRecords: Number(row.totalRecords) || 0,
          averageScore: Number(row.averageScore) || 0,
          completionRate,
        };
      });

      res.json({
        success: true,
        data,
      });
    } catch (error: any) {
      console.error('获取任务统计失败:', error);
      res.status(500).json({
        success: false,
        message: error.message || '获取任务统计失败',
      });
    }
  }

  // 修改管理员密码
  static async updatePassword(req: Request, res: Response) {
    try {
      const { username, oldPassword, newPassword } = req.body;
      
      if (!username || !oldPassword || !newPassword) {
        return res.status(400).json({
          success: false,
          message: '参数不完整'
        });
      }
      
      // 验证旧密码
      const isValid = await SystemConfigModel.validateAdminLogin(username, oldPassword);
      if (!isValid) {
        return res.status(401).json({
          success: false,
          message: '原密码错误'
        });
      }
      
      // 更新密码
      await SystemConfigModel.updateAdminPassword(username, newPassword);
      
      res.json({
        success: true,
        message: '密码修改成功'
      });
    } catch (error: any) {
      console.error('修改密码失败:', error);
      res.status(500).json({
        success: false,
        message: error.message || '修改密码失败'
      });
    }
  }

  // 获取所有配置（管理员用）
  static async getAllConfigs(req: Request, res: Response) {
    try {
      const configs = await SystemConfigModel.getAllConfigs();
      
      res.json({
        success: true,
        data: configs
      });
    } catch (error: any) {
      console.error('获取配置失败:', error);
      res.status(500).json({
        success: false,
        message: error.message || '获取配置失败'
      });
    }
  }
}