package common
  
  import (
  	"crypto/md5"
  	"encoding/hex"

  	"math/rand"
  	"strings"
  	"time"
  )
  

  func Md5V(str string) string {

  	h := md5.New()
  	h.Write([]byte(str))
  	return hex.EncodeToString(h.Sum(nil))
  }
  
  func Timex() int64 {
  	return time.Now().Unix()
  }
  
  var defaultLetters = []rune("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789")

  func RandomString(n int, allowedChars ...[]rune) string {
  	var letters []rune
  
  	if len(allowedChars) == 0 {
  		letters = defaultLetters
  	} else {
  		letters = allowedChars[0]
  	}
  
  	b := make([]rune, n)
  	for i := range b {
  		b[i] = letters[rand.Intn(len(letters))]
  	}
  
  	return string(b)
  }
  

  func RandomName(name [][]string) string {
  	idx1 := rand.Intn(len(name[0]))
  	idx2 := rand.Intn(len(name[1]))
  
  	var builder strings.Builder
  	builder.WriteString(name[0][idx1])
  	builder.WriteString(name[1][idx2])
  	return builder.String()
  }
  

  //英文字符串，第一个字符大写
  func FirstCharToUpper(key string) string {
  	first := strings.ToUpper(key[0:1])
  	str := strings.Builder{}
  	str.WriteString(first)
  	str.WriteString(key[1:])
  	return str.String()
  }