package services

import (
	"encoding/json"
	"fmt"
	"platform/web/core"
	g "platform/web/globals"
	m "platform/web/models"
	q "platform/web/queries"

	"github.com/shopspring/decimal"
)

var User = &userService{}

type userService struct{}

func (s *userService) UpdateBalanceByTrade(uid int32, info *RechargeProductInfo, trade *m.Trade) (err error) {
	err = g.Redsync.WithLock(userBalanceKey(uid), func() error {
		return q.Q.Transaction(func(q *q.Query) error {

			err = updateBalance(q, uid, info)
			if err != nil {
				return err
			}

			// 生成账单
			subject, err := info.GetSubject()
			if err != nil {
				return err
			}
			amount, err := info.GetAmount()
			if err != nil {
				return err
			}
			err = q.Bill.Create(newForRecharge(uid, Bill.GenNo(), subject, amount, trade))
			if err != nil {
				return core.NewServErr("生成账单失败", err)
			}

			return nil
		})
	})
	if err != nil {
		return core.NewServErr("更新用户余额失败")
	}

	return nil
}
func updateBalance(q *q.Query, uid int32, info *RechargeProductInfo) error {
	user, err := q.User.
		Where(q.User.ID.Eq(uid)).Take()
	if err != nil {
		return core.NewServErr("查询用户失败", err)
	}

	amount, err := info.GetAmount()
	if err != nil {
		return err
	}
	balance := user.Balance.Add(amount)
	if balance.IsNegative() {
		return core.NewServErr("用户余额不足")
	}

	_, err = q.User.
		Where(q.User.ID.Eq(user.ID)).
		UpdateSimple(q.User.Balance.Value(balance))
	if err != nil {
		return core.NewServErr("更新用户余额失败", err)
	}

	return nil
}

func userBalanceKey(uid int32) string {
	return fmt.Sprintf("user:%d:balance", uid)
}

type RechargeProductInfo struct {
	Amount int `json:"amount"`
}

func (r *RechargeProductInfo) GetType() m.TradeType {
	return m.TradeTypeRecharge
}

func (r *RechargeProductInfo) GetSubject() (string, error) {
	amount, _ := r.GetAmount()
	return fmt.Sprintf("账户充值 - %s元", amount.StringFixed(2)), nil
}

func (r *RechargeProductInfo) GetAmount() (decimal.Decimal, error) {
	return decimal.NewFromInt(int64(r.Amount)).Div(decimal.NewFromInt(100)), nil
}

func (r *RechargeProductInfo) Serialize() (string, error) {
	bytes, err := json.Marshal(r)
	return string(bytes), err
}

func (r *RechargeProductInfo) Deserialize(str string) error {
	return json.Unmarshal([]byte(str), r)
}

type UserOnTradeComplete struct{}

func (u UserOnTradeComplete) Check(t m.TradeType) (ProductInfo, bool) {
	if t == m.TradeTypeRecharge {
		return &RechargeProductInfo{}, true
	}
	return nil, false
}

func (u UserOnTradeComplete) OnTradeComplete(info ProductInfo, trade *m.Trade) error {
	return User.UpdateBalanceByTrade(trade.UserID, info.(*RechargeProductInfo), trade)
}