package handlers

import (
	"ankao/internal/database"
	"ankao/internal/models"
	"encoding/json"
	"net/http"
	"time"

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

// GetWrongQuestions 获取错题列表
func GetWrongQuestions(c *gin.Context) {
	userID, exists := c.Get("user_id")
	if !exists {
		c.JSON(http.StatusUnauthorized, gin.H{
			"success": false,
			"message": "未登录",
		})
		return
	}

	db := database.GetDB()
	var wrongQuestions []models.WrongQuestion

	// 查询参数
	isMastered := c.Query("is_mastered") // "true" 或 "false"
	questionType := c.Query("type")      // 题型筛选

	query := db.Where("user_id = ?", userID).Preload("PracticeQuestion")

	// 筛选是否已掌握
	if isMastered == "true" {
		query = query.Where("is_mastered = ?", true)
	} else if isMastered == "false" {
		query = query.Where("is_mastered = ?", false)
	}

	// 按最后错误时间倒序
	if err := query.Order("last_wrong_time DESC").Find(&wrongQuestions).Error; err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{
			"success": false,
			"message": "查询失败",
		})
		return
	}

	// 转换为DTO
	dtos := make([]models.WrongQuestionDTO, 0, len(wrongQuestions))
	for _, wq := range wrongQuestions {
		// 题型筛选 - 直接比较type字段
		if questionType != "" && wq.PracticeQuestion.Type != questionType {
			continue
		}

		// 解析答案
		var wrongAnswer, correctAnswer interface{}
		json.Unmarshal([]byte(wq.WrongAnswer), &wrongAnswer)
		json.Unmarshal([]byte(wq.CorrectAnswer), &correctAnswer)

		dto := models.WrongQuestionDTO{
			ID:            wq.ID,
			QuestionID:    wq.QuestionID,
			Question:      convertToDTO(wq.PracticeQuestion),
			WrongAnswer:   wrongAnswer,
			CorrectAnswer: correctAnswer,
			WrongCount:    wq.WrongCount,
			LastWrongTime: wq.LastWrongTime,
			IsMastered:    wq.IsMastered,
		}
		dtos = append(dtos, dto)
	}

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

// GetWrongQuestionStats 获取错题统计
func GetWrongQuestionStats(c *gin.Context) {
	userID, exists := c.Get("user_id")
	if !exists {
		c.JSON(http.StatusUnauthorized, gin.H{
			"success": false,
			"message": "未登录",
		})
		return
	}

	db := database.GetDB()
	var wrongQuestions []models.WrongQuestion

	if err := db.Where("user_id = ?", userID).Preload("PracticeQuestion").Find(&wrongQuestions).Error; err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{
			"success": false,
			"message": "查询失败",
		})
		return
	}

	stats := models.WrongQuestionStats{
		TotalWrong:    len(wrongQuestions),
		Mastered:      0,
		NotMastered:   0,
		TypeStats:     make(map[string]int),
		CategoryStats: make(map[string]int),
	}

	for _, wq := range wrongQuestions {
		if wq.IsMastered {
			stats.Mastered++
		} else {
			stats.NotMastered++
		}

		// 统计题型 - 直接使用type字段
		stats.TypeStats[wq.PracticeQuestion.Type]++

		// 统计分类
		stats.CategoryStats[wq.PracticeQuestion.TypeName]++
	}

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

// MarkWrongQuestionMastered 标记错题为已掌握
func MarkWrongQuestionMastered(c *gin.Context) {
	userID, exists := c.Get("user_id")
	if !exists {
		c.JSON(http.StatusUnauthorized, gin.H{
			"success": false,
			"message": "未登录",
		})
		return
	}

	wrongQuestionID := c.Param("id")
	db := database.GetDB()

	var wrongQuestion models.WrongQuestion
	if err := db.Where("id = ? AND user_id = ?", wrongQuestionID, userID).First(&wrongQuestion).Error; err != nil {
		c.JSON(http.StatusNotFound, gin.H{
			"success": false,
			"message": "错题不存在",
		})
		return
	}

	wrongQuestion.IsMastered = true
	if err := db.Save(&wrongQuestion).Error; err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{
			"success": false,
			"message": "更新失败",
		})
		return
	}

	c.JSON(http.StatusOK, gin.H{
		"success": true,
		"message": "已标记为掌握",
	})
}

// ClearWrongQuestions 清空错题本
func ClearWrongQuestions(c *gin.Context) {
	userID, exists := c.Get("user_id")
	if !exists {
		c.JSON(http.StatusUnauthorized, gin.H{
			"success": false,
			"message": "未登录",
		})
		return
	}

	db := database.GetDB()

	// 删除用户所有错题记录
	if err := db.Where("user_id = ?", userID).Delete(&models.WrongQuestion{}).Error; err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{
			"success": false,
			"message": "清空失败",
		})
		return
	}

	c.JSON(http.StatusOK, gin.H{
		"success": true,
		"message": "错题本已清空",
	})
}

// recordWrongQuestion 记录错题（内部函数，在答题错误时调用）
func recordWrongQuestion(userID, questionID uint, userAnswer, correctAnswer interface{}) error {
	db := database.GetDB()

	// 将答案序列化为JSON
	wrongAnswerJSON, _ := json.Marshal(userAnswer)
	correctAnswerJSON, _ := json.Marshal(correctAnswer)

	// 查找是否已存在该错题
	var existingWrong models.WrongQuestion
	result := db.Where("user_id = ? AND question_id = ?", userID, questionID).First(&existingWrong)

	if result.Error == nil {
		// 已存在，更新错误次数和时间
		existingWrong.WrongCount++
		existingWrong.LastWrongTime = time.Now()
		existingWrong.WrongAnswer = string(wrongAnswerJSON)
		existingWrong.CorrectAnswer = string(correctAnswerJSON)
		existingWrong.IsMastered = false // 重新标记为未掌握
		return db.Save(&existingWrong).Error
	}

	// 不存在，创建新记录
	newWrong := models.WrongQuestion{
		UserID:        userID,
		QuestionID:    questionID,
		WrongAnswer:   string(wrongAnswerJSON),
		CorrectAnswer: string(correctAnswerJSON),
		WrongCount:    1,
		LastWrongTime: time.Now(),
		IsMastered:    false,
	}

	return db.Create(&newWrong).Error
}

// GetRandomWrongQuestion 获取随机错题进行练习
func GetRandomWrongQuestion(c *gin.Context) {
	userID, exists := c.Get("user_id")
	if !exists {
		c.JSON(http.StatusUnauthorized, gin.H{
			"success": false,
			"message": "未登录",
		})
		return
	}

	db := database.GetDB()
	var wrongQuestion models.WrongQuestion

	// 随机获取一个错题
	if err := db.Where("user_id = ?", userID).Order("RANDOM()").Preload("PracticeQuestion").First(&wrongQuestion).Error; err != nil {
		c.JSON(http.StatusNotFound, gin.H{
			"success": false,
			"message": "暂无错题",
		})
		return
	}

	// 转换为DTO返回
	dto := convertToDTO(wrongQuestion.PracticeQuestion)

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

// DeleteWrongQuestion 删除单个错题
func DeleteWrongQuestion(c *gin.Context) {
	userID, exists := c.Get("user_id")
	if !exists {
		c.JSON(http.StatusUnauthorized, gin.H{
			"success": false,
			"message": "未登录",
		})
		return
	}

	wrongQuestionID := c.Param("id")
	db := database.GetDB()

	// 删除错题（确保只能删除自己的错题）
	result := db.Where("id = ? AND user_id = ?", wrongQuestionID, userID).Delete(&models.WrongQuestion{})
	if result.Error != nil {
		c.JSON(http.StatusInternalServerError, gin.H{
			"success": false,
			"message": "删除失败",
		})
		return
	}

	if result.RowsAffected == 0 {
		c.JSON(http.StatusNotFound, gin.H{
			"success": false,
			"message": "错题不存在",
		})
		return
	}

	c.JSON(http.StatusOK, gin.H{
		"success": true,
		"message": "已删除",
	})
}