package handler

import (
	"strconv"
	"time"

	"github.com/Nanqipro/YunQue-Tech-Projects/ai_english_learning/serve/internal/common"
	"github.com/Nanqipro/YunQue-Tech-Projects/ai_english_learning/serve/internal/services"
	"github.com/gin-gonic/gin"
)

// StudyPlanHandler 学习计划处理器
type StudyPlanHandler struct {
	studyPlanService *services.StudyPlanService
}

func NewStudyPlanHandler(studyPlanService *services.StudyPlanService) *StudyPlanHandler {
	return &StudyPlanHandler{studyPlanService: studyPlanService}
}

// CreateStudyPlan 创建学习计划
// POST /api/v1/study-plans
func (h *StudyPlanHandler) CreateStudyPlan(c *gin.Context) {
	userID := c.GetInt64("user_id")
	
	var req struct {
		PlanName    string  `json:"plan_name" binding:"required,min=1,max=200"`
		Description *string `json:"description"`
		DailyGoal   int     `json:"daily_goal" binding:"required,min=1,max=200"`
		BookID      *string `json:"book_id"`
		StartDate   string  `json:"start_date" binding:"required"` // YYYY-MM-DD
		EndDate     *string `json:"end_date"`                      // YYYY-MM-DD
		RemindTime  *string `json:"remind_time"`                   // HH:mm
		RemindDays  *string `json:"remind_days"`                   // "1,2,3,4,5" 表示周一到周五
	}
	
	if err := c.ShouldBindJSON(&req); err != nil {
		common.ErrorResponse(c, 400, "参数错误: "+err.Error())
		return
	}
	
	// 解析日期
	startDate, err := time.Parse("2006-01-02", req.StartDate)
	if err != nil {
		common.ErrorResponse(c, 400, "开始日期格式错误")
		return
	}
	
	var endDate *time.Time
	if req.EndDate != nil {
		parsedEndDate, err := time.Parse("2006-01-02", *req.EndDate)
		if err != nil {
			common.ErrorResponse(c, 400, "结束日期格式错误")
			return
		}
		endDate = &parsedEndDate
	}
	
	plan, err := h.studyPlanService.CreateStudyPlan(
		userID,
		req.PlanName,
		req.Description,
		req.DailyGoal,
		req.BookID,
		startDate,
		endDate,
		req.RemindTime,
		req.RemindDays,
	)
	
	if err != nil {
		common.ErrorResponse(c, 500, "创建学习计划失败: "+err.Error())
		return
	}
	
	common.SuccessResponse(c, plan)
}

// GetUserStudyPlans 获取用户的学习计划列表
// GET /api/v1/study-plans
func (h *StudyPlanHandler) GetUserStudyPlans(c *gin.Context) {
	userID := c.GetInt64("user_id")
	status := c.DefaultQuery("status", "all") // all, active, paused, completed, cancelled
	
	plans, err := h.studyPlanService.GetUserStudyPlans(userID, status)
	if err != nil {
		common.ErrorResponse(c, 500, "获取学习计划失败: "+err.Error())
		return
	}
	
	common.SuccessResponse(c, gin.H{
		"plans": plans,
		"total": len(plans),
	})
}

// GetStudyPlanByID 获取学习计划详情
// GET /api/v1/study-plans/:id
func (h *StudyPlanHandler) GetStudyPlanByID(c *gin.Context) {
	userID := c.GetInt64("user_id")
	planIDStr := c.Param("id")
	
	planID, err := strconv.ParseInt(planIDStr, 10, 64)
	if err != nil {
		common.ErrorResponse(c, 400, "无效的计划ID")
		return
	}
	
	plan, err := h.studyPlanService.GetStudyPlanByID(planID, userID)
	if err != nil {
		common.ErrorResponse(c, 404, "学习计划不存在")
		return
	}
	
	common.SuccessResponse(c, plan)
}

// UpdateStudyPlan 更新学习计划
// PUT /api/v1/study-plans/:id
func (h *StudyPlanHandler) UpdateStudyPlan(c *gin.Context) {
	userID := c.GetInt64("user_id")
	planIDStr := c.Param("id")
	
	planID, err := strconv.ParseInt(planIDStr, 10, 64)
	if err != nil {
		common.ErrorResponse(c, 400, "无效的计划ID")
		return
	}
	
	var updates map[string]interface{}
	if err := c.ShouldBindJSON(&updates); err != nil {
		common.ErrorResponse(c, 400, "参数错误: "+err.Error())
		return
	}
	
	plan, err := h.studyPlanService.UpdateStudyPlan(planID, userID, updates)
	if err != nil {
		common.ErrorResponse(c, 500, "更新学习计划失败: "+err.Error())
		return
	}
	
	common.SuccessResponse(c, plan)
}

// DeleteStudyPlan 删除学习计划
// DELETE /api/v1/study-plans/:id
func (h *StudyPlanHandler) DeleteStudyPlan(c *gin.Context) {
	userID := c.GetInt64("user_id")
	planIDStr := c.Param("id")
	
	planID, err := strconv.ParseInt(planIDStr, 10, 64)
	if err != nil {
		common.ErrorResponse(c, 400, "无效的计划ID")
		return
	}
	
	err = h.studyPlanService.DeleteStudyPlan(planID, userID)
	if err != nil {
		common.ErrorResponse(c, 500, "删除学习计划失败: "+err.Error())
		return
	}
	
	common.SuccessResponse(c, gin.H{
		"message": "学习计划已删除",
	})
}

// UpdatePlanStatus 更新计划状态
// PATCH /api/v1/study-plans/:id/status
func (h *StudyPlanHandler) UpdatePlanStatus(c *gin.Context) {
	userID := c.GetInt64("user_id")
	planIDStr := c.Param("id")
	
	planID, err := strconv.ParseInt(planIDStr, 10, 64)
	if err != nil {
		common.ErrorResponse(c, 400, "无效的计划ID")
		return
	}
	
	var req struct {
		Status string `json:"status" binding:"required,oneof=active paused completed cancelled"`
	}
	
	if err := c.ShouldBindJSON(&req); err != nil {
		common.ErrorResponse(c, 400, "参数错误: "+err.Error())
		return
	}
	
	err = h.studyPlanService.UpdatePlanStatus(planID, userID, req.Status)
	if err != nil {
		common.ErrorResponse(c, 500, "更新状态失败: "+err.Error())
		return
	}
	
	common.SuccessResponse(c, gin.H{
		"message": "状态更新成功",
		"status":  req.Status,
	})
}

// RecordStudyProgress 记录学习进度
// POST /api/v1/study-plans/:id/progress
func (h *StudyPlanHandler) RecordStudyProgress(c *gin.Context) {
	userID := c.GetInt64("user_id")
	planIDStr := c.Param("id")
	
	planID, err := strconv.ParseInt(planIDStr, 10, 64)
	if err != nil {
		common.ErrorResponse(c, 400, "无效的计划ID")
		return
	}
	
	var req struct {
		WordsStudied  int `json:"words_studied" binding:"required,min=1"`
		StudyDuration int `json:"study_duration"` // 学习时长(分钟)
	}
	
	if err := c.ShouldBindJSON(&req); err != nil {
		common.ErrorResponse(c, 400, "参数错误: "+err.Error())
		return
	}
	
	err = h.studyPlanService.RecordStudyProgress(planID, userID, req.WordsStudied, req.StudyDuration)
	if err != nil {
		common.ErrorResponse(c, 500, "记录进度失败: "+err.Error())
		return
	}
	
	common.SuccessResponse(c, gin.H{
		"message": "进度记录成功",
	})
}

// GetStudyPlanStatistics 获取学习计划统计
// GET /api/v1/study-plans/:id/statistics
func (h *StudyPlanHandler) GetStudyPlanStatistics(c *gin.Context) {
	userID := c.GetInt64("user_id")
	planIDStr := c.Param("id")
	
	planID, err := strconv.ParseInt(planIDStr, 10, 64)
	if err != nil {
		common.ErrorResponse(c, 400, "无效的计划ID")
		return
	}
	
	stats, err := h.studyPlanService.GetStudyPlanStatistics(planID, userID)
	if err != nil {
		common.ErrorResponse(c, 500, "获取统计信息失败: "+err.Error())
		return
	}
	
	common.SuccessResponse(c, stats)
}

// GetTodayStudyPlans 获取今日需要执行的学习计划
// GET /api/v1/study-plans/today
func (h *StudyPlanHandler) GetTodayStudyPlans(c *gin.Context) {
	userID := c.GetInt64("user_id")
	
	plans, err := h.studyPlanService.GetTodayStudyPlans(userID)
	if err != nil {
		common.ErrorResponse(c, 500, "获取今日计划失败: "+err.Error())
		return
	}
	
	common.SuccessResponse(c, gin.H{
		"plans": plans,
		"total": len(plans),
	})
}