package statistics

import (
	"net/http"
	"strconv"
	"time"

	"task-track-backend/model"
	"task-track-backend/pkg/database"

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

// OverviewResponse 总览统计响应
type OverviewResponse struct {
	// 基本统计
	TotalTasks         int64 `json:"total_tasks"`
	TotalUsers         int64 `json:"total_users"`
	TotalOrganizations int64 `json:"total_organizations"`

	// 任务状态统计
	TasksByStatus map[string]int64 `json:"tasks_by_status"`

	// 任务优先级统计
	TasksByPriority map[string]int64 `json:"tasks_by_priority"`

	// 最近7天任务创建数
	RecentTasksCount int64 `json:"recent_tasks_count"`

	// 最近7天任务完成数
	RecentCompletedTasks int64 `json:"recent_completed_tasks"`

	// 今日任务统计
	TodayTasks struct {
		Created   int64 `json:"created"`
		Completed int64 `json:"completed"`
	} `json:"today_tasks"`

	// 本周任务统计
	WeeklyTasks struct {
		Created   int64 `json:"created"`
		Completed int64 `json:"completed"`
	} `json:"weekly_tasks"`

	// 本月任务统计
	MonthlyTasks struct {
		Created   int64 `json:"created"`
		Completed int64 `json:"completed"`
	} `json:"monthly_tasks"`
}

func (h *StatisticsHandler) GetOverview(c *gin.Context) {
	// 获取组织ID参数（可选）
	organizationIDStr := c.Query("organization_id")
	var organizationID uint
	if organizationIDStr != "" {
		if id, err := strconv.ParseUint(organizationIDStr, 10, 32); err == nil {
			organizationID = uint(id)
		}
	}

	db := database.GetDB()
	var response OverviewResponse

	// 基础查询构建器
	baseTaskQuery := db.Model(&model.Task{})
	if organizationID > 0 {
		baseTaskQuery = baseTaskQuery.Where("organization_id = ?", organizationID)
	}

	// 1. 基本统计
	// 总任务数
	if err := baseTaskQuery.Count(&response.TotalTasks).Error; err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": "获取任务统计失败"})
		return
	}

	// 总用户数
	userQuery := db.Model(&model.User{})
	if err := userQuery.Count(&response.TotalUsers).Error; err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": "获取用户统计失败"})
		return
	}

	// 总组织数
	if err := db.Model(&model.Organization{}).Count(&response.TotalOrganizations).Error; err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": "获取组织统计失败"})
		return
	}

	// 2. 任务状态统计
	var statusStats []struct {
		Status string `json:"status"`
		Count  int64  `json:"count"`
	}

	statusQuery := baseTaskQuery.Select("status, count(*) as count").Group("status")
	if err := statusQuery.Find(&statusStats).Error; err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": "获取任务状态统计失败"})
		return
	}

	response.TasksByStatus = make(map[string]int64)
	for _, stat := range statusStats {
		response.TasksByStatus[stat.Status] = stat.Count
	}

	// 3. 任务优先级统计
	var priorityStats []struct {
		Priority string `json:"priority"`
		Count    int64  `json:"count"`
	}

	priorityQuery := baseTaskQuery.Select("priority, count(*) as count").Group("priority")
	if err := priorityQuery.Find(&priorityStats).Error; err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": "获取任务优先级统计失败"})
		return
	}

	response.TasksByPriority = make(map[string]int64)
	for _, stat := range priorityStats {
		response.TasksByPriority[stat.Priority] = stat.Count
	}

	// 4. 时间范围统计
	now := time.Now()

	// 今日开始时间
	todayStart := time.Date(now.Year(), now.Month(), now.Day(), 0, 0, 0, 0, now.Location())

	// 本周开始时间（周一）
	weekStart := todayStart.AddDate(0, 0, -int(now.Weekday())+1)
	if now.Weekday() == time.Sunday {
		weekStart = weekStart.AddDate(0, 0, -7)
	}

	// 本月开始时间
	monthStart := time.Date(now.Year(), now.Month(), 1, 0, 0, 0, 0, now.Location())

	// 最近7天开始时间
	sevenDaysAgo := now.AddDate(0, 0, -7)

	// 今日任务统计
	todayTaskQuery := baseTaskQuery.Where("created_at >= ?", todayStart)
	if err := todayTaskQuery.Count(&response.TodayTasks.Created).Error; err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": "获取今日任务统计失败"})
		return
	}

	todayCompletedQuery := baseTaskQuery.Where("status = ? AND updated_at >= ?", "completed", todayStart)
	if err := todayCompletedQuery.Count(&response.TodayTasks.Completed).Error; err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": "获取今日完成任务统计失败"})
		return
	}

	// 本周任务统计
	weekTaskQuery := baseTaskQuery.Where("created_at >= ?", weekStart)
	if err := weekTaskQuery.Count(&response.WeeklyTasks.Created).Error; err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": "获取本周任务统计失败"})
		return
	}

	weekCompletedQuery := baseTaskQuery.Where("status = ? AND updated_at >= ?", "completed", weekStart)
	if err := weekCompletedQuery.Count(&response.WeeklyTasks.Completed).Error; err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": "获取本周完成任务统计失败"})
		return
	}

	// 本月任务统计
	monthTaskQuery := baseTaskQuery.Where("created_at >= ?", monthStart)
	if err := monthTaskQuery.Count(&response.MonthlyTasks.Created).Error; err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": "获取本月任务统计失败"})
		return
	}

	monthCompletedQuery := baseTaskQuery.Where("status = ? AND updated_at >= ?", "completed", monthStart)
	if err := monthCompletedQuery.Count(&response.MonthlyTasks.Completed).Error; err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": "获取本月完成任务统计失败"})
		return
	}

	// 最近7天任务统计
	recentTaskQuery := baseTaskQuery.Where("created_at >= ?", sevenDaysAgo)
	if err := recentTaskQuery.Count(&response.RecentTasksCount).Error; err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": "获取最近任务统计失败"})
		return
	}

	recentCompletedQuery := baseTaskQuery.Where("status = ? AND updated_at >= ?", "completed", sevenDaysAgo)
	if err := recentCompletedQuery.Count(&response.RecentCompletedTasks).Error; err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": "获取最近完成任务统计失败"})
		return
	}

	c.JSON(http.StatusOK, response)
}