package handler

import (
	"encoding/json"
	"net/http"
	"sync"

	"soul-api/internal/database"
	"soul-api/internal/model"

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

var paidStatuses = []string{"paid", "completed", "success"}

// AdminDashboardStats GET /api/admin/dashboard/stats
// 轻量聚合：总用户、付费订单数、付费用户数、总营收、转化率（无订单/用户明细）
func AdminDashboardStats(c *gin.Context) {
	db := database.DB()
	var (
		totalUsers     int64
		paidOrderCount int64
		totalRevenue   float64
		paidUserCount  int64
	)
	var wg sync.WaitGroup
	wg.Add(4)
	go func() { defer wg.Done(); db.Model(&model.User{}).Count(&totalUsers) }()
	go func() { defer wg.Done(); db.Model(&model.Order{}).Where("status IN ?", paidStatuses).Count(&paidOrderCount) }()
	go func() {
		defer wg.Done()
		db.Model(&model.Order{}).Where("status IN ?", paidStatuses).
			Select("COALESCE(SUM(amount), 0)").Scan(&totalRevenue)
	}()
	go func() {
		defer wg.Done()
		db.Table("orders").Where("status IN ?", paidStatuses).
			Select("COUNT(DISTINCT user_id)").Scan(&paidUserCount)
	}()
	wg.Wait()
	conversionRate := 0.0
	if totalUsers > 0 && paidUserCount > 0 {
		conversionRate = float64(paidUserCount) / float64(totalUsers) * 100
	}
	c.JSON(http.StatusOK, gin.H{
		"success":        true,
		"totalUsers":     totalUsers,
		"paidOrderCount": paidOrderCount,
		"paidUserCount":  paidUserCount,
		"totalRevenue":   totalRevenue,
		"conversionRate": conversionRate,
	})
}

// AdminDashboardRecentOrders GET /api/admin/dashboard/recent-orders
func AdminDashboardRecentOrders(c *gin.Context) {
	db := database.DB()
	var recentOrders []model.Order
	db.Where("status IN ?", paidStatuses).Order("created_at DESC").Limit(5).Find(&recentOrders)
	c.JSON(http.StatusOK, gin.H{"success": true, "recentOrders": buildRecentOrdersOut(db, recentOrders)})
}

// AdminDashboardNewUsers GET /api/admin/dashboard/new-users
func AdminDashboardNewUsers(c *gin.Context) {
	db := database.DB()
	var newUsers []model.User
	db.Model(&model.User{}).Order("created_at DESC").Limit(10).Find(&newUsers)
	c.JSON(http.StatusOK, gin.H{"success": true, "newUsers": buildNewUsersOut(newUsers)})
}

// AdminDashboardOverview GET /api/admin/dashboard/overview
// 数据概览：总用户、付费订单数、付费用户数、总营收、转化率、最近订单、新用户
// 优化：6 组查询并行执行，减少总耗时
func AdminDashboardOverview(c *gin.Context) {
	db := database.DB()

	var (
		totalUsers     int64
		paidOrderCount int64
		totalRevenue   float64
		paidUserCount  int64
		recentOrders   []model.Order
		newUsers       []model.User
	)
	var wg sync.WaitGroup
	wg.Add(6)

	go func() {
		defer wg.Done()
		db.Model(&model.User{}).Count(&totalUsers)
	}()
	go func() {
		defer wg.Done()
		db.Model(&model.Order{}).Where("status IN ?", paidStatuses).Count(&paidOrderCount)
	}()
	go func() {
		defer wg.Done()
		db.Model(&model.Order{}).Where("status IN ?", paidStatuses).
			Select("COALESCE(SUM(amount), 0)").Scan(&totalRevenue)
	}()
	go func() {
		defer wg.Done()
		db.Table("orders").Where("status IN ?", paidStatuses).
			Select("COUNT(DISTINCT user_id)").Scan(&paidUserCount)
	}()
	go func() {
		defer wg.Done()
		db.Where("status IN ?", paidStatuses).
			Order("created_at DESC").Limit(5).Find(&recentOrders)
	}()
	go func() {
		defer wg.Done()
		db.Model(&model.User{}).Order("created_at DESC").Limit(10).Find(&newUsers)
	}()
	wg.Wait()

	conversionRate := 0.0
	if totalUsers > 0 && paidUserCount > 0 {
		conversionRate = float64(paidUserCount) / float64(totalUsers) * 100
	}

	recentOut := buildRecentOrdersOut(db, recentOrders)
	newOut := buildNewUsersOut(newUsers)

	c.JSON(http.StatusOK, gin.H{
		"success":         true,
		"totalUsers":      totalUsers,
		"paidOrderCount":  paidOrderCount,
		"paidUserCount":   paidUserCount,
		"totalRevenue":    totalRevenue,
		"conversionRate":  conversionRate,
		"recentOrders":    recentOut,
		"newUsers":        newOut,
	})
}

func dashStr(s *string) string {
	if s == nil || *s == "" {
		return ""
	}
	return *s
}

func buildRecentOrdersOut(db *gorm.DB, recentOrders []model.Order) []gin.H {
	if len(recentOrders) == 0 {
		return nil
	}
	userIDs := make(map[string]bool)
	for _, o := range recentOrders {
		if o.UserID != "" {
			userIDs[o.UserID] = true
		}
	}
	ids := make([]string, 0, len(userIDs))
	for id := range userIDs {
		ids = append(ids, id)
	}
	var users []model.User
	db.Where("id IN ?", ids).Find(&users)
	userMap := make(map[string]*model.User)
	for i := range users {
		userMap[users[i].ID] = &users[i]
	}
	out := make([]gin.H, 0, len(recentOrders))
	for _, o := range recentOrders {
		b, _ := json.Marshal(o)
		var m map[string]interface{}
		_ = json.Unmarshal(b, &m)
		if u := userMap[o.UserID]; u != nil {
			m["userNickname"] = dashStr(u.Nickname)
			m["userAvatar"] = dashStr(u.Avatar)
		} else {
			m["userNickname"] = ""
			m["userAvatar"] = ""
		}
		out = append(out, m)
	}
	return out
}

func buildNewUsersOut(newUsers []model.User) []gin.H {
	out := make([]gin.H, 0, len(newUsers))
	for _, u := range newUsers {
		out = append(out, gin.H{
			"id":           u.ID,
			"nickname":     dashStr(u.Nickname),
			"phone":        dashStr(u.Phone),
			"referralCode": dashStr(u.ReferralCode),
			"createdAt":    u.CreatedAt,
		})
	}
	return out
}