package signx

import (
	"crypto/md5"
	"errors"
	"fmt"
	"sort"
	"strings"

	"code.yun.ink/open/utils/convx"
)

// 缺点
// 1.值必须是字符串，数组/对象这些不允许，或者需要通过一定规则转成字符串

// 签名规则
// 1.除掉不参与签名的用户参数
// 1.所有参数的key根据字典排序
// 2.根据key=val&key2=val2的格式组装字符串
// 3.后面拼接用户签名key `&key=xxxx`得道新字符串
// 4.把新字符串用md5加密并转大写的道签名的值
func GetSign(params map[string]interface{}, key string) (sign string, err error) {
	delete(params, "platform_key")
	delete(params, "sign")
	delete(params, "key")

	// 排序
	keys := make([]string, len(params))
	i := 0
	for k := range params {
		keys[i] = k
		i++
	}
	sort.Strings(keys)
	var str string
	for k, v := range keys {
		if k > 0 {
			str = str + "&"
		}
		val, err := convx.ToString(params[v])
		if err != nil {
			return "", err
		}
		str = str + v + "=" + val
	}
	str = str + "&key=" + key
	data := []byte(str)
	has := md5.Sum(data)
	md5str1 := fmt.Sprintf("%x", has) // []byte转16进制
	sign = strings.ToUpper(md5str1)
	return sign, nil
}

func VerifySign(params map[string]interface{}, key string) error {
	sign, ok := params["sign"]
	if !ok {
		return errors.New("签名参数不存在")
	}
	sitn_str, ok := sign.(string)
	if !ok {
		return errors.New("sign必须是字符串")
	}
	g_sign, err := GetSign(params, key)
	if err != nil {
		return err
	}
	if sitn_str != g_sign {
		return errors.New("验签失败")
	}

	return nil
}