package util

import (
	"encoding/binary"
	"fmt"
	"strconv"
	"strings"
)

// IntToBytes 将一个 4 字节数字转换为 byte 数组
func IntToBytes(n int32) []byte {
	buf := make([]byte, 4)
	binary.BigEndian.PutUint32(buf, uint32(n)) // 使用 BigEndian 或 LittleEndian
	return buf
}

// Int16ToBytes 将一个 4 字节数字转换为 byte 数组
func Int16ToBytes(n uint16) []byte {
	buf := make([]byte, 2)
	binary.BigEndian.PutUint16(buf, uint16(n)) // 使用 BigEndian 或 LittleEndian
	return buf
}
func ToHexBytes(bytes []byte) string {
	var hexBytes string
	for b := range bytes {
		hexBytes = fmt.Sprint(hexBytes, strconv.FormatInt(int64(bytes[b]), 16), " ")
	}
	return strings.TrimSpace(hexBytes)
}

// CRC16-CCITT 校验算法 (多项式0x1021)
func Crc16CCITT(data []byte) uint16 {
	crc := uint16(0xFFFF)
	for _, b := range data {
		crc ^= uint16(b) << 8
		for i := 0; i < 8; i++ {
			if crc&0x8000 != 0 {
				crc = (crc << 1) ^ 0x1021
			} else {
				crc <<= 1
			}
		}
	}
	return crc
}