package coupon

import (
	"crypto/md5"
	"encoding/hex"
	"encoding/json"
	"errors"
	"log"
	"strconv"
	"strings"
	"time"

	"git.tetele.net/tgo/crypter"

	"github.com/golang/protobuf/proto"
)

type AvailableReqArg struct {
	Dbname       string `json:"dbname"`
	UserCouponId string `json:"user_coupon_id"`
	UserId       string `json:"user_id"`
	ProductId    string `json:"product_id"`
}

type AvailableRes struct {
	Available bool   `json:"available"`
	Money     string `json:"money"`
	Name      string `json:"name"`
}

type UseReqArg struct {
	Dbname       string `json:"dbname"`
	UserCouponId string `json:"user_coupon_id"`
	OrderSn      string `json:"order_sn"`
}

type UseRes struct {
	Success bool
}

/**
 * 优惠券是否可用
 * @param data {"user_id":"","product_id":"","coupon_id":""}
 * @param return is_available,name,money,error
 */
func IsAvailable(dbname, user_id, product_id, user_coupon_id string, url ...string) (*AvailableRes, error) {

	var coupon_rpc_url string = "127.0.0.1:7972"
	if len(url) > 0 && url[0] != "" {
		coupon_rpc_url = url[0]
	}
	conn, _, err := DialCouponService("tcp", coupon_rpc_url)
	if err != nil {
		return nil, err
	}
	defer conn.Close()

	arg := AvailableReqArg{dbname, user_coupon_id, user_id, product_id}

	data_json, err := json.Marshal(arg)
	if err != nil {
		return nil, err
	}
	now_int64 := time.Now().Unix()

	encryData := crypter.DesEn(string(data_json), "conaapon")

	now := strconv.FormatInt(now_int64, 10)

	sign := Sign(encryData, now)

	req := &CouponRequest{proto.String(encryData), proto.String(now), proto.String(sign), nil}

	res := &CouponResponse{}

	err = conn.IsAvailable(req, res)

	if err != nil {
		log.Println("coupon rpc error:", err)
		return nil, err
	}

	res_data := res.GetData()

	if res_data != "" {

		time_int64, err := strconv.ParseInt(res.GetTime(), 10, 64)
		if err != nil {
			return nil, err
		}

		now_int64 = time.Now().Unix()

		if now_int64-time_int64 > 10 || time_int64-now_int64 > 10 {
			//时间误差前后10秒，返回
			return nil, errors.New("返回时间错误")
		}

		check_sign := CheckSign(res.GetSign(), res_data, res.GetTime())
		if !check_sign {
			return nil, errors.New("返回数据签名错误")
		}

		//解密
		res_data_de := crypter.DesDe(res_data, "conaapon")

		var res_arr AvailableRes

		err = json.Unmarshal([]byte(res_data_de), &res_arr)

		if err != nil {
			return nil, err
		}
		return &res_arr, nil
	}

	return nil, nil
}

/**
 * 使用优惠券
 * @param data {"user_coupon_id":"","order_sn":""}
 * @param return is_available,name,money,error
 */
func Use(dbname, user_coupon_id, order_sn string, url ...string) (*UseRes, error) {

	var coupon_rpc_url string = "127.0.0.1:7972"
	if len(url) > 0 && url[0] != "" {
		coupon_rpc_url = url[0]
	}
	conn, _, err := DialCouponService("tcp", coupon_rpc_url)
	if err != nil {
		return nil, err
	}
	defer conn.Close()

	arg := UseReqArg{dbname, user_coupon_id, order_sn}

	data_json, err := json.Marshal(arg)
	if err != nil {
		return nil, err
	}
	now_int64 := time.Now().Unix()

	encryData := crypter.DesEn(string(data_json), "conaapon")

	now := strconv.FormatInt(now_int64, 10)

	sign := Sign(encryData, now)

	req := &CouponRequest{proto.String(encryData), proto.String(now), proto.String(sign), nil}

	res := &CouponResponse{}

	err = conn.Use(req, res)

	if err != nil {
		log.Println("coupon rpc error:", err)
		return nil, err
	}

	res_data := res.GetData()

	if res_data != "" {

		time_int64, err := strconv.ParseInt(res.GetTime(), 10, 64)
		if err != nil {
			return nil, err
		}

		now_int64 = time.Now().Unix()

		if now_int64-time_int64 > 10 || time_int64-now_int64 > 10 {
			//时间误差前后10秒，返回
			return nil, errors.New("返回时间错误")
		}

		check_sign := CheckSign(res.GetSign(), res_data, res.GetTime())
		if !check_sign {
			return nil, errors.New("返回数据签名错误")
		}

		//解密
		res_data_de := crypter.DesDe(res_data, "conaapon")

		var res_arr UseRes

		err = json.Unmarshal([]byte(res_data_de), &res_arr)

		if err != nil {
			return nil, err
		}
		return &res_arr, nil
	}

	return nil, nil
}

/**
 * 签名
 */
func Sign(data string, salt string) string {

	var build strings.Builder

	build.WriteString(data)
	build.WriteString(salt)
	build.WriteString("cou$%po87n")

	data_str := build.String()

	h := md5.New()
	h.Write([]byte(data_str))             // 需要加密的字符串
	return hex.EncodeToString(h.Sum(nil)) // 输出加密结果

}

/**
 * 验证签名
 */
func CheckSign(sign_str, data, salt string) bool {
	sign := Sign(data, salt)
	if strings.Compare(sign_str, sign) > -1 {
		return true
	}
	return false
}