package handler

import (
	"encoding/json"
	"time"

	"soul-api/internal/model"

	"gorm.io/gorm"
)

// computeOrderCommission 按订单计算应付给推广者的佣金
// 会员订单：推广者会员 20%、非会员 10%；内容订单：90%（好友优惠 5% 仅针对内容）
// order: 已支付订单，需有 product_type、amount、referrer_id
// referrerUser: 推广者用户信息，用于判断 is_vip（可为 nil，会查库）
// preloadConfig: 可选，预加载的 referral_config，避免 N+1 查询
func computeOrderCommission(db *gorm.DB, order *model.Order, referrerUser *model.User, preloadConfig ...*model.SystemConfig) float64 {
	if order == nil || order.ReferrerID == nil || *order.ReferrerID == "" {
		return 0
	}
	// 读取推广配置
	distributorShare := 0.9
	userDiscount := 0.0
	vipOrderShareVip := 20.0
	vipOrderShareNonVip := 10.0
	var cfg *model.SystemConfig
	if len(preloadConfig) > 0 && preloadConfig[0] != nil {
		cfg = preloadConfig[0]
	} else if row, err := (func() (*model.SystemConfig, error) {
		var r model.SystemConfig
		e := db.Where("config_key = ?", "referral_config").First(&r).Error
		return &r, e
	})(); err == nil {
		cfg = row
	}
	if cfg != nil {
		var config map[string]interface{}
		if err := json.Unmarshal(cfg.ConfigValue, &config); err == nil {
			if share, ok := config["distributorShare"].(float64); ok {
				distributorShare = share / 100
			}
			if disc, ok := config["userDiscount"].(float64); ok {
				userDiscount = disc / 100
			}
			if v, ok := config["vipOrderShareVip"].(float64); ok {
				vipOrderShareVip = v / 100
			}
			if v, ok := config["vipOrderShareNonVip"].(float64); ok {
				vipOrderShareNonVip = v / 100
			}
		}
	}
	// 会员订单：无好友优惠，按推广者是否会员分 20%/10%
	if order.ProductType == "vip" {
		base := order.Amount
		var referrer model.User
		if referrerUser != nil {
			referrer = *referrerUser
		} else if err := db.Where("id = ?", *order.ReferrerID).First(&referrer).Error; err != nil {
			return 0
		}
		isVip := referrer.IsVip != nil && *referrer.IsVip
		if referrer.VipExpireDate != nil && referrer.VipExpireDate.Before(time.Now()) {
			isVip = false
		}
		if isVip {
			return base * vipOrderShareVip
		}
		return base * vipOrderShareNonVip
	}
	// 内容订单：若有推荐人且 userDiscount>0，反推原价；否则按实付
	commissionBase := order.Amount
	if userDiscount > 0 && (order.ReferrerID != nil && *order.ReferrerID != "" || (order.ReferralCode != nil && *order.ReferralCode != "")) {
		if (1 - userDiscount) > 0 {
			commissionBase = order.Amount / (1 - userDiscount)
		}
	}
	return commissionBase * distributorShare
}