// 待办接口
package app

import (
	"fmt"
	"math/rand"
	"os"
	"simple-memo/global"
	"simple-memo/models"
	"simple-memo/utils"
	"time"

	"gorm.io/gorm"

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

// -------------------------- 1. 定义 Handler 接口 --------------------------
// TodoHandler 待办模块接口定义
type TodoHandler interface {
	AddTodo(c *gin.Context)    // 添加待办
	TodoList(c *gin.Context)   // 获取待办列表
	DeleteTodo(c *gin.Context) // 删除待办
	DoneTodo(c *gin.Context)   // 完成/取消完成待办
	EditTodo(c *gin.Context)   // 编辑待办
	TodoStat(c *gin.Context)   // 待办统计
}

// -------------------------- 2. 实现结构体 --------------------------
// todoHandler 接口实现结构体
type todoHandler struct {
	db *gorm.DB // 数据库依赖
}

// NewTodoHandler 创建待办处理器
func NewTodoHandler() TodoHandler {
	return &todoHandler{
		db: global.DB,
	}
}

// -------------------------- 3. 请求结构体 --------------------------
// TodoListReq 列表请求参数
type TodoListReq struct {
	Search    string `json:"search"`
	Status    string `json:"status"`
	Date      string `json:"date"`
	StartDate string `json:"start_date"`
	EndDate   string `json:"end_date"`
}

// DeleteTodoReq 删除待办请求
type DeleteTodoReq struct {
	ID uint `json:"id"`
}

// DoneTodoReq 完成待办请求
type DoneTodoReq struct {
	ID     uint `json:"id"`
	Status uint `json:"status"` // 0-取消完成 1-完成
}

// EditTodoReq 编辑待办请求（与model对齐）
type EditTodoReq struct {
	ID        uint   `json:"id"`
	Title     string `json:"title"`
	Category  string `json:"category"`
	Priority  int    `json:"priority"`
	Remark    string `json:"remark"`
	Date      string `json:"date"`
	StartTime string `json:"start_time"`
	EndTime   string `json:"end_time"`
}

// TodoStatReq 待办统计请求
type TodoStatReq struct {
	StartDate string `json:"start_date" binding:"required"` // 开始日期
	EndDate   string `json:"end_date" binding:"required"`   // 结束日期
}

// -------------------------- 4. 接口实现 --------------------------

// GetTodoListForCalendar 获取日历月份的待办列表（内部方法）
func (h *todoHandler) GetTodoListForCalendar(c *gin.Context, year, month int) []interface{} {
	userID := c.GetUint("userID")

	// 计算月份范围
	startDate := fmt.Sprintf("%d-%02d-01", year, month)
	// 计算月末
	_, lastDay := utils.GetMonthLastDay(year, month)
	endDate := fmt.Sprintf("%d-%02d-%02d", year, month, lastDay)

	var list []models.Todo
	h.db.Model(&models.Todo{}).
		Where("user_id = ? AND date BETWEEN ? AND ?", userID, startDate, endDate).
		Order("date ASC, id ASC").
		Find(&list)

	// 转换结果
	result := make([]interface{}, len(list))
	for i, v := range list {
		if v.Done == 0 && v.Date < time.Now().Format("2006-01-02") {
			v.IsOverdue = 1
		} else {
			v.IsOverdue = 0
		}
		result[i] = v
	}
	return result
}

// AddTodo 添加待办
func (h *todoHandler) AddTodo(c *gin.Context) {
	userID := c.GetUint("userID")
	var todo models.Todo

	if err := c.ShouldBindJSON(&todo); err != nil {
		utils.Fail(c, "参数解析失败")
		return
	}

	// 敏感词过滤
	todo.Title = utils.FilterSensitive(todo.Title)
	todo.Remark = utils.FilterSensitive(todo.Remark)

	// 检查每日限制（最多100个待办/天）
	today := time.Now().Format("2006-01-02")
	var todayCount int64
	if err := h.db.Model(&models.Todo{}).Where("user_id = ? AND date = ? AND deleted_at IS NULL", userID, today).Count(&todayCount).Error; err != nil {
		utils.Fail(c, "系统错误")
		return
	}
	if todayCount >= 100 {
		utils.Fail(c, "今日待办数量已达上限（100个）")
		return
	}

	todo.UserID = userID
	if err := h.db.Create(&todo).Error; err != nil {
		utils.Fail(c, "添加失败")
		return
	}

	utils.Ok(c, nil)
}

// TodoList 获取待办列表
func (h *todoHandler) TodoList(c *gin.Context) {
	userID := c.GetUint("userID")

	var req TodoListReq
	if err := c.ShouldBindJSON(&req); err != nil {
		utils.Fail(c, "参数解析失败")
		return
	}

	// 构建查询
	db := h.db.Model(&models.Todo{}).Where("user_id = ?", userID)

	// 搜索
	if req.Search != "" {
		db = db.Where("title LIKE ? OR remark LIKE ?", "%"+req.Search+"%", "%"+req.Search+"%")
	}

	// 状态筛选
	switch req.Status {
	case "undone":
		db = db.Where("done = 0")
	case "done":
		db = db.Where("done = 1")
	}

	// 日期
	now := time.Now()
	today := now.Format("2006-01-02")

	startDate := req.StartDate
	endDate := req.EndDate
	if startDate != "" && endDate != "" {
		db = db.Where("date BETWEEN ? AND ?", startDate, endDate)
	} else if startDate != "" {
		db = db.Where("date >= ?", startDate)
	} else if endDate != "" {
		db = db.Where("date <= ?", endDate)
	} else if req.Date != "" {
		db = db.Where("date = ?", req.Date)
	} else {
		db = db.Where("date = ?", today)
	}

	// 排序
	db = db.Order("date ASC, id ASC")

	// 查询
	var list []models.Todo
	if err := db.Find(&list).Error; err != nil {
		utils.Fail(c, "获取失败")
		return
	}

	// 逾期状态
	for i := range list {
		if list[i].Done == 0 && list[i].Date < today {
			list[i].IsOverdue = 1
		} else {
			list[i].IsOverdue = 0
		}
	}

	utils.Ok(c, list)
}

// DeleteTodo 删除待办
func (h *todoHandler) DeleteTodo(c *gin.Context) {
	userID := c.GetUint("userID")
	var req DeleteTodoReq

	if err := c.ShouldBindJSON(&req); err != nil {
		utils.Fail(c, "参数解析失败")
		return
	}

	// 查询待办信息（用于扣除积分）
	var todo models.Todo
	err := h.db.Where("id = ? AND user_id = ?", req.ID, userID).First(&todo).Error
	if err != nil {
		utils.Fail(c, "待办不存在")
		return
	}

	// 删除待办
	err = h.db.Where("id = ? AND user_id = ?", req.ID, userID).Delete(&models.Todo{}).Error
	if err != nil {
		utils.Fail(c, "删除失败")
		return
	}

	// 扣除今天添加时获得的积分
	growthHandler := NewGrowthHandler()
	today := time.Now().Format("2006-01-02")
	deducted := growthHandler.DeductExpInternal(userID, "task", fmt.Sprintf("%d", req.ID), today)

	utils.Ok(c, gin.H{
		"deducted_exp": deducted,
	})
}

// DoneTodo 完成/取消完成待办
func (h *todoHandler) DoneTodo(c *gin.Context) {
	userID := c.GetUint("userID")
	var req DoneTodoReq

	if err := c.ShouldBindJSON(&req); err != nil {
		utils.Fail(c, "参数解析失败")
		return
	}
	if req.Status != 0 && req.Status != 1 {
		utils.Fail(c, "参数错误")
		return
	}

	// 先查询当前状态
	var todo models.Todo
	err := h.db.Where("id = ? AND user_id = ?", req.ID, userID).First(&todo).Error
	if err != nil {
		utils.Fail(c, "待办不存在")
		return
	}

	oldDone := todo.Done

	// 更新状态
	err = h.db.Model(&models.Todo{}).
		Where("id = ? AND user_id = ?", req.ID, userID).
		Update("done", req.Status).Error
	if err != nil {
		utils.Fail(c, "操作失败")
		return
	}

	var result any
	debugMode := os.Getenv("DEBUG_MODE")
	// 只有从未完成变成完成（0→1）的时候才加积分，并且这个待办之前没有加过积分
	if oldDone == 0 && req.Status == 1 {
		// 查询是否已经给这个待办加过积分
		var count int64
		h.db.Model(&models.ExpChangeLog{}).
			Where("user_id = ? AND source = ? AND source_id = ?", userID, "task", fmt.Sprintf("%d", req.ID)).
			Count(&count)

		// 只有之前没加过积分才加
		if count == 0 {
			// ==================== 调试模式 ====================
			if debugMode == "true" {
				rand.Seed(time.Now().UnixNano())
				levelUp := rand.Intn(10) < 3        // 30%概率升级
				hasAchievement := rand.Intn(10) < 4 // 40%概率获得成就
				result = MockGrowthRewards(levelUp, hasAchievement)
			} else {
				// 生产模式：真实调用
				growthHandler := NewGrowthHandler()
				result = growthHandler.AddExpInternal(userID, "task", fmt.Sprintf("%d", req.ID), nil)
			}
			// ==================================================
		}
	}

	utils.Ok(c, gin.H{
		"success":   true,
		"growth":    result,
		"debugMode": debugMode,
		"isDebug":   debugMode == "true",
	})
}

// EditTodo 编辑待办
func (h *todoHandler) EditTodo(c *gin.Context) {
	userID := c.GetUint("userID")
	var req EditTodoReq

	if err := c.ShouldBindJSON(&req); err != nil {
		utils.Fail(c, "参数解析失败")
		return
	}

	// 敏感词过滤
	filteredTitle := utils.FilterSensitive(req.Title)
	filteredRemark := utils.FilterSensitive(req.Remark)

	data := map[string]any{
		"title":      filteredTitle,
		"remark":     filteredRemark,
		"category":   req.Category,
		"priority":   req.Priority,
		"date":       req.Date,
		"start_time": req.StartTime,
		"end_time":   req.EndTime,
	}

	err := h.db.Model(&models.Todo{}).
		Where("id = ? AND user_id = ?", req.ID, userID).
		Updates(data).Error
	if err != nil {
		utils.Fail(c, "编辑失败")
		return
	}

	utils.Ok(c, nil)
}

// TodoStat 待办统计
func (h *todoHandler) TodoStat(c *gin.Context) {
	userID := c.GetUint("userID")
	var req TodoStatReq

	if err := c.ShouldBindJSON(&req); err != nil {
		utils.Fail(c, "参数解析失败")
		return
	}

	// 总体统计
	var total, done, undone int64
	h.db.Model(&models.Todo{}).
		Where("user_id = ? AND date BETWEEN ? AND ?", userID, req.StartDate, req.EndDate).
		Count(&total)
	h.db.Model(&models.Todo{}).
		Where("user_id = ? AND date BETWEEN ? AND ? AND done = 1", userID, req.StartDate, req.EndDate).
		Count(&done)
	undone = total - done

	// 完成率
	completionRate := 0.0
	if total > 0 {
		completionRate = float64(done) / float64(total) * 100
	}

	// 按分类统计
	type CategoryStat struct {
		Total int64 `json:"total"`
		Done  int64 `json:"done"`
	}
	byCategory := make(map[string]CategoryStat)

	var categoryResults []struct {
		Category string
		Total    int64
		Done     int64
	}
	h.db.Model(&models.Todo{}).
		Select("category, COUNT(*) as total, SUM(CASE WHEN done = 1 THEN 1 ELSE 0 END) as done").
		Where("user_id = ? AND date BETWEEN ? AND ?", userID, req.StartDate, req.EndDate).
		Group("category").
		Scan(&categoryResults)

	for _, r := range categoryResults {
		byCategory[r.Category] = CategoryStat{
			Total: r.Total,
			Done:  r.Done,
		}
	}

	// 按优先级统计
	type PriorityStat struct {
		Total int64 `json:"total"`
		Done  int64 `json:"done"`
	}
	byPriority := make(map[string]PriorityStat)

	var priorityResults []struct {
		Priority int
		Total    int64
		Done     int64
	}
	h.db.Model(&models.Todo{}).
		Select("priority, COUNT(*) as total, SUM(CASE WHEN done = 1 THEN 1 ELSE 0 END) as done").
		Where("user_id = ? AND date BETWEEN ? AND ?", userID, req.StartDate, req.EndDate).
		Group("priority").
		Scan(&priorityResults)

	for _, r := range priorityResults {
		key := fmt.Sprintf("%d", r.Priority)
		byPriority[key] = PriorityStat{
			Total: r.Total,
			Done:  r.Done,
		}
	}

	utils.Ok(c, gin.H{
		"total":           total,
		"done":            done,
		"undone":          undone,
		"completion_rate": completionRate,
		"by_category":     byCategory,
		"by_priority":     byPriority,
	})
}