package handlers

import (
	"fmt"
	"net/http"
	"sort"
	"time"

	"ezops/internal/models"

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

// BillingHandler 云账单处理器
type BillingHandler struct {
	db *gorm.DB
}

func NewBillingHandler(db *gorm.DB) *BillingHandler {
	return &BillingHandler{db: db}
}

// ListBillings 获取账单列表
func (h *BillingHandler) ListBillings(c *gin.Context) {
	var billings []models.CloudBilling

	query := h.db.Model(&models.CloudBilling{})

	// 筛选
	if provider := c.Query("provider"); provider != "" {
		query = query.Where("provider = ?", provider)
	}
	if accountName := c.Query("account_name"); accountName != "" {
		query = query.Where("account_name LIKE ?", "%"+accountName+"%")
	}
	if startDate := c.Query("start_date"); startDate != "" {
		query = query.Where("billing_date >= ?", startDate)
	}
	if endDate := c.Query("end_date"); endDate != "" {
		query = query.Where("billing_date <= ?", endDate)
	}

	// 排序
	query = query.Order("billing_date DESC, id DESC")

	// 分页
	page := 1
	pageSize := 50
	if c.Query("page") != "" {
		fmt.Sscanf(c.Query("page"), "%d", &page)
	}
	if c.Query("page_size") != "" {
		fmt.Sscanf(c.Query("page_size"), "%d", &pageSize)
	}
	if page < 1 {
		page = 1
	}
	if pageSize < 1 || pageSize > 500 {
		pageSize = 50
	}

	var total int64
	query.Count(&total)
	query.Offset((page - 1) * pageSize).Limit(pageSize).Find(&billings)

	c.JSON(http.StatusOK, models.Response{
		Code:    200,
		Message: "success",
		Data: models.ListResponse{
			List:  billings,
			Total: total,
		},
	})
}

// CreateBilling 创建账单记录
func (h *BillingHandler) CreateBilling(c *gin.Context) {
	var req models.CreateBillingRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(http.StatusBadRequest, models.Response{Code: 400, Message: err.Error()})
		return
	}

	billing := models.CloudBilling{
		CloudAccountID: req.CloudAccountID,
		AccountName:    req.AccountName,
		Provider:       req.Provider,
		BillingDate:    req.BillingDate,
		Cost:           req.Cost,
		Currency:       req.Currency,
		Service:        req.Service,
		Region:         req.Region,
		Description:    req.Description,
	}
	if billing.Currency == "" {
		billing.Currency = "CNY"
	}

	if err := h.db.Create(&billing).Error; err != nil {
		c.JSON(http.StatusInternalServerError, models.Response{Code: 500, Message: "创建失败: " + err.Error()})
		return
	}

	c.JSON(http.StatusOK, models.Response{
		Code:    200,
		Message: "创建成功",
		Data:    billing,
	})
}

// BatchCreateBillings 批量创建账单
func (h *BillingHandler) BatchCreateBillings(c *gin.Context) {
	var req struct {
		Records []models.CreateBillingRequest `json:"records" binding:"required"`
	}
	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(http.StatusBadRequest, models.Response{Code: 400, Message: err.Error()})
		return
	}

	created := 0
	for _, r := range req.Records {
		billing := models.CloudBilling{
			CloudAccountID: r.CloudAccountID,
			AccountName:    r.AccountName,
			Provider:       r.Provider,
			BillingDate:    r.BillingDate,
			Cost:           r.Cost,
			Currency:       r.Currency,
			Service:        r.Service,
			Region:         r.Region,
			Description:    r.Description,
		}
		if billing.Currency == "" {
			billing.Currency = "CNY"
		}
		if err := h.db.Create(&billing).Error; err == nil {
			created++
		}
	}

	c.JSON(http.StatusOK, models.Response{
		Code:    200,
		Message: fmt.Sprintf("成功导入 %d 条记录", created),
		Data:    gin.H{"created": created, "total": len(req.Records)},
	})
}

// DeleteBilling 删除账单记录
func (h *BillingHandler) DeleteBilling(c *gin.Context) {
	id := c.Param("id")
	if err := h.db.Delete(&models.CloudBilling{}, id).Error; err != nil {
		c.JSON(http.StatusInternalServerError, models.Response{Code: 500, Message: "删除失败"})
		return
	}
	c.JSON(http.StatusOK, models.Response{Code: 200, Message: "删除成功"})
}

// GetBillingStats 获取账单统计
func (h *BillingHandler) GetBillingStats(c *gin.Context) {
	now := time.Now()
	today := now.Format("2006-01-02")
	yesterday := now.AddDate(0, 0, -1).Format("2006-01-02")
	monthStart := now.Format("2006-01") + "-01"
	yearStart := fmt.Sprintf("%d-01-01", now.Year())

	stats := models.BillingStats{
		MonthTrend:   []models.DailyCost{},
		ProviderDist: []models.ProviderCost{},
		Alerts:       []models.BillingAlert{},
	}

	// 今日成本
	h.db.Model(&models.CloudBilling{}).Where("billing_date = ?", today).
		Select("COALESCE(SUM(cost), 0)").Scan(&stats.TodayCost)

	// 昨日成本
	h.db.Model(&models.CloudBilling{}).Where("billing_date = ?", yesterday).
		Select("COALESCE(SUM(cost), 0)").Scan(&stats.YesterdayCost)

	// 本月成本
	h.db.Model(&models.CloudBilling{}).Where("billing_date >= ?", monthStart).
		Select("COALESCE(SUM(cost), 0)").Scan(&stats.MonthCost)

	// 本年成本
	h.db.Model(&models.CloudBilling{}).Where("billing_date >= ?", yearStart).
		Select("COALESCE(SUM(cost), 0)").Scan(&stats.YearCost)

	// 近30天趋势
	type dayCost struct {
		BillingDate string
		Total       float64
	}
	var trends []dayCost
	h.db.Model(&models.CloudBilling{}).
		Select("billing_date, SUM(cost) as total").
		Where("billing_date >= ?", now.AddDate(0, 0, -29).Format("2006-01-02")).
		Group("billing_date").
		Order("billing_date ASC").
		Scan(&trends)

	for _, t := range trends {
		stats.MonthTrend = append(stats.MonthTrend, models.DailyCost{Date: t.BillingDate, Cost: t.Total})
	}

	// 本月厂商成本分布
	type provCost struct {
		Provider string
		Total    float64
	}
	var provCosts []provCost
	h.db.Model(&models.CloudBilling{}).
		Select("provider, SUM(cost) as total").
		Where("billing_date >= ?", monthStart).
		Group("provider").
		Scan(&provCosts)

	var totalProviderCost float64
	for _, p := range provCosts {
		totalProviderCost += p.Total
	}
	for _, p := range provCosts {
		percent := 0.0
		if totalProviderCost > 0 {
			percent = p.Total / totalProviderCost * 100
		}
		stats.ProviderDist = append(stats.ProviderDist, models.ProviderCost{
			Provider: p.Provider,
			Cost:     p.Total,
			Percent:  percent,
		})
	}
	sort.Slice(stats.ProviderDist, func(i, j int) bool {
		return stats.ProviderDist[i].Cost > stats.ProviderDist[j].Cost
	})

	// 检查预警规则
	h.checkBillingAlerts(&stats, now)

	c.JSON(http.StatusOK, models.Response{
		Code:    200,
		Message: "success",
		Data:    stats,
	})
}

// checkBillingAlerts 检查预警规则是否触发
func (h *BillingHandler) checkBillingAlerts(stats *models.BillingStats, now time.Time) {
	var rules []models.BillingAlertRule
	h.db.Where("enabled = ?", true).Find(&rules)

	for _, rule := range rules {
		var current float64

		if rule.Metric == "daily" {
			// 查今日该厂商/账号的成本
			q := h.db.Model(&models.CloudBilling{}).Where("billing_date = ?", now.Format("2006-01-02"))
			if rule.Provider != "" {
				q = q.Where("provider = ?", rule.Provider)
			}
			if rule.CloudAccountID != nil {
				q = q.Where("cloud_account_id = ?", *rule.CloudAccountID)
			}
			q.Select("COALESCE(SUM(cost), 0)").Scan(&current)
		} else {
			// monthly - 本月累计
			q := h.db.Model(&models.CloudBilling{}).Where("billing_date >= ?", now.Format("2006-01")+"-01")
			if rule.Provider != "" {
				q = q.Where("provider = ?", rule.Provider)
			}
			if rule.CloudAccountID != nil {
				q = q.Where("cloud_account_id = ?", *rule.CloudAccountID)
			}
			q.Select("COALESCE(SUM(cost), 0)").Scan(&current)
		}

		// 检查阈值
		triggered := false
		switch rule.Operator {
		case ">":
			triggered = current > rule.Threshold
		case ">=":
			triggered = current >= rule.Threshold
		case "<":
			triggered = current < rule.Threshold
		case "<=":
			triggered = current <= rule.Threshold
		}

		if triggered {
			providerLabel := rule.Provider
			if providerLabel == "" {
				providerLabel = "全部"
			}
			stats.Alerts = append(stats.Alerts, models.BillingAlert{
				RuleID:    rule.ID,
				RuleName:  rule.Name,
				Provider:  providerLabel,
				Current:   current,
				Threshold: rule.Threshold,
				Metric:    rule.Metric,
				Operator:  rule.Operator,
			})
		}
	}
}