package goku_node

import (
	"bytes"
	"math/rand"
	"runtime"
	"strings"
	"time"
)

//生成随机字符串
func GetRandomString(num int) string {
	str := "123456789abcdefghijklmnpqrstuvwxyzABCDEFGHIJKLMNPQRSTUVWXYZ"
	bytes := []byte(str)
	result := []byte{}
	r := rand.New(rand.NewSource(time.Now().UnixNano()))
	for i := 0; i < num; i++ {
		result = append(result, bytes[r.Intn(len(bytes))])
	}
	return string(result)
}

func Intercept(str, substr string) string {
	result := strings.Index(str, substr)
	var rs string
	if result != -1 {
		rs = str[:result]
	} else {
		rs = str
	}
	return rs
}
func PanicTrace(kb int) []byte {
	s := []byte("/src/runtime/panic.go")
	e := []byte("\ngoroutine ")
	line := []byte("\n")
	stack := make([]byte, kb<<10) //4KB
	length := runtime.Stack(stack, true)
	start := bytes.Index(stack, s)
	stack = stack[start:length]
	start = bytes.Index(stack, line) + 1
	stack = stack[start:]
	end := bytes.LastIndex(stack, line)
	if end != -1 {
		stack = stack[:end]
	}
	end = bytes.Index(stack, e)
	if end != -1 {
		stack = stack[:end]
	}
	stack = bytes.TrimRight(stack, "\n")
	return stack
}