package handlers

import (
	"ankao/internal/database"
	"ankao/internal/models"
	"net/http"

	"github.com/gin-gonic/gin"
)

// GetAllUsersWithStats 获取所有用户及其答题统计（仅管理员可访问）
func GetAllUsersWithStats(c *gin.Context) {
	db := database.GetDB()

	// 查询所有用户及其答题统计
	var userStats []models.UserStats

	// SQL查询：联合查询用户表和答题记录表
	query := `
		SELECT
			u.id as user_id,
			u.username,
			u.nickname,
			u.avatar,
			u.user_type,
			COALESCE(COUNT(ar.id), 0) as total_answers,
			COALESCE(SUM(CASE WHEN ar.is_correct = true THEN 1 ELSE 0 END), 0) as correct_count,
			COALESCE(SUM(CASE WHEN ar.is_correct = false THEN 1 ELSE 0 END), 0) as wrong_count,
			CASE
				WHEN COUNT(ar.id) > 0 THEN
					ROUND(CAST(CAST(SUM(CASE WHEN ar.is_correct = true THEN 1 ELSE 0 END) AS FLOAT) / COUNT(ar.id) * 100 AS NUMERIC), 2)
				ELSE 0
			END as accuracy,
			u.created_at,
			MAX(ar.answered_at) as last_answer_at
		FROM users u
		LEFT JOIN user_answer_records ar ON u.id = ar.user_id AND ar.deleted_at IS NULL
		WHERE u.deleted_at IS NULL
		GROUP BY u.id, u.username, u.nickname, u.avatar, u.user_type, u.created_at
		ORDER BY total_answers DESC, accuracy DESC
	`

	if err := db.Raw(query).Scan(&userStats).Error; err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{
			"success": false,
			"message": "获取用户统计数据失败",
			"error":   err.Error(),
		})
		return
	}

	c.JSON(http.StatusOK, gin.H{
		"success": true,
		"data":    userStats,
	})
}

// GetUserDetailStats 获取指定用户的详细统计信息
func GetUserDetailStats(c *gin.Context) {
	userID := c.Param("id")
	db := database.GetDB()

	// 查询用户基本信息
	var user models.User
	if err := db.First(&user, userID).Error; err != nil {
		c.JSON(http.StatusNotFound, gin.H{
			"success": false,
			"message": "用户不存在",
		})
		return
	}

	// 查询用户答题统计
	var stats models.UserStats
	query := `
		SELECT
			u.id as user_id,
			u.username,
			u.nickname,
			u.avatar,
			u.user_type,
			COALESCE(COUNT(ar.id), 0) as total_answers,
			COALESCE(SUM(CASE WHEN ar.is_correct = true THEN 1 ELSE 0 END), 0) as correct_count,
			COALESCE(SUM(CASE WHEN ar.is_correct = false THEN 1 ELSE 0 END), 0) as wrong_count,
			CASE
				WHEN COUNT(ar.id) > 0 THEN
					ROUND(CAST(CAST(SUM(CASE WHEN ar.is_correct = true THEN 1 ELSE 0 END) AS FLOAT) / COUNT(ar.id) * 100 AS NUMERIC), 2)
				ELSE 0
			END as accuracy,
			u.created_at,
			MAX(ar.answered_at) as last_answer_at
		FROM users u
		LEFT JOIN user_answer_records ar ON u.id = ar.user_id AND ar.deleted_at IS NULL
		WHERE u.id = ? AND u.deleted_at IS NULL
		GROUP BY u.id, u.username, u.nickname, u.avatar, u.user_type, u.created_at
	`

	if err := db.Raw(query, userID).Scan(&stats).Error; err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{
			"success": false,
			"message": "获取用户统计数据失败",
			"error":   err.Error(),
		})
		return
	}

	// 查询按题型分类的统计
	var typeStats []struct {
		QuestionType     string  `json:"question_type"`
		QuestionTypeName string  `json:"question_type_name"`
		TotalAnswers     int     `json:"total_answers"`
		CorrectCount     int     `json:"correct_count"`
		Accuracy         float64 `json:"accuracy"`
	}

	typeQuery := `
		SELECT
			pq.type as question_type,
			pq.type_name as question_type_name,
			COUNT(ar.id) as total_answers,
			SUM(CASE WHEN ar.is_correct = true THEN 1 ELSE 0 END) as correct_count,
			CASE
				WHEN COUNT(ar.id) > 0 THEN
					ROUND(CAST(CAST(SUM(CASE WHEN ar.is_correct = true THEN 1 ELSE 0 END) AS FLOAT) / COUNT(ar.id) * 100 AS NUMERIC), 2)
				ELSE 0
			END as accuracy
		FROM user_answer_records ar
		JOIN practice_questions pq ON ar.question_id = pq.id
		WHERE ar.user_id = ? AND ar.deleted_at IS NULL
		GROUP BY pq.type, pq.type_name
		ORDER BY total_answers DESC
	`

	db.Raw(typeQuery, userID).Scan(&typeStats)

	c.JSON(http.StatusOK, gin.H{
		"success": true,
		"data": gin.H{
			"user_info":  stats,
			"type_stats": typeStats,
		},
	})
}