package pcsutil

import (
	"fmt"
	"time"
	"unsafe"
)

const (
	// B byte
	B = (int64)(1 << (10 * iota))
	// KB kilobyte
	KB
	// MB megabyte
	MB
	// GB gigabyte
	GB
	// TB terabyte
	TB
	// PB petabyte
	PB
)

// ConvertFileSize 文件大小格式化输出
func ConvertFileSize(size int64, precision ...int) string {
	pint := "6"
	if len(precision) == 1 {
		pint = fmt.Sprint(precision[0])
	}
	if size <= 0 {
		return "0"
	}
	if size < KB {
		return fmt.Sprintf("%."+pint+"fB", float64(size))
	}
	if size < MB {
		return fmt.Sprintf("%."+pint+"fKB", float64(size)/float64(KB))
	}
	if size < GB {
		return fmt.Sprintf("%."+pint+"fMB", float64(size)/float64(MB))
	}
	if size < TB {
		return fmt.Sprintf("%."+pint+"fGB", float64(size)/float64(GB))
	}
	if size < PB {
		return fmt.Sprintf("%."+pint+"fTB", float64(size)/float64(TB))
	}
	return fmt.Sprintf("%."+pint+"fPB", float64(size)/float64(PB))
}

// ToString 将 []byte 转换为 string
func ToString(p []byte) string {
	return *(*string)(unsafe.Pointer(&p))
}

// ToBytes 将 string 转换为 []byte
func ToBytes(str string) []byte {
	return *(*[]byte)(unsafe.Pointer(&str))
}

// IntToBool int 类型转换为 bool
func IntToBool(i int) bool {
	return i != 0
}

// FormatTime 将 Unix 时间戳, 转换为字符串
func FormatTime(t int64) string {
	return time.Unix(t, 0).Format("2006-01-02 03:04:05")
}