package yunda

import (
	"crypto/md5"
	"encoding/hex"
	"sort"
	"strings"
)

func BuildSign(appKey, appSecret string, params map[string]string) string {
	values := make(map[string]string, len(params)+2)
	for key, value := range params {
		values[key] = value
	}
	values["appKey"] = appKey
	values["appSecret"] = appSecret
	keys := make([]string, 0, len(values))
	for key := range values {
		keys = append(keys, key)
	}
	sort.Strings(keys)
	source := appKey
	for _, key := range keys {
		source += key + values[key]
	}
	source += appKey
	sum := md5.Sum([]byte(source))
	return strings.ToUpper(hex.EncodeToString(sum[:]))
}