package main

import (
	"encoding/binary"
	"encoding/hex"
	"fmt"
	"hash/crc32"
	"io"
	"io/ioutil"
	"os"
	"path/filepath"
	"strconv"
)

func swab16(x uint16) uint16 {
	return (x&0x00ff)<<8 | (x&0xff00)>>8
}

func swab32(x uint32) uint32 {
	return (x&0x000000ff)<<24 | (x&0x0000ff00)<<8 | (x&0x00ff0000)>>8 | (x&0xff000000)>>24
}

func sumArr(arr []uint8) uint32 {
	sum := uint32(0)
	for _, val := range arr {
		sum += uint32(val)
	}
	return sum
}

func calChecknum(_type string, datas []byte) uint32 {
	if _type == "sum32" {
		return sumArr(datas)
	} else if _type == "crc32" {
		return crc32.ChecksumIEEE(datas)
	} else {
		print("unKown type: " + _type)
		return 0
	}
}

func getFileSize(filename string) (int64, error) {
	fileinfo, err := os.Stat(filename)
	if err != nil {
		return 0, err
	}
	size := fileinfo.Size()
	return size, nil
}

func ReadBinFile(_name string, _type string, _en string, _block int) {
	FileName := filepath.Base(_name)
	// FileType := filepath.Ext(_name)

	InputFilePath := _name
	OutputFilePath := FileName + "." + _type

	inputFile, err := os.Open(InputFilePath)
	if err != nil {
		panic(err)
	}
	defer inputFile.Close()

	outputFile, err := os.OpenFile(OutputFilePath, os.O_CREATE|os.O_APPEND|os.O_WRONLY, 0644)
	if err != nil {
		panic(err)
	}
	defer outputFile.Close()

	if _block > 0 {
		buffer := make([]byte, _block)
		for {
			n, err := inputFile.Read(buffer)
			if n > 0 {
				// 计算分片的校验和
				check := calChecknum(_type, buffer[:n])
				// 写入分片内容+分片校验和
				if _en == "big" {
					binary.Write(outputFile, binary.BigEndian, buffer[:n])
					binary.Write(outputFile, binary.BigEndian, check)
				} else {
					binary.Write(outputFile, binary.LittleEndian, buffer[:n])
					binary.Write(outputFile, binary.LittleEndian, check)
				}
			}

			if err != nil {
				if err == io.EOF {
					break // 文件读取完毕
				}
				panic(err)
			}
		}
	} else {
		data, err := ioutil.ReadAll(inputFile)
		if err != nil {
			panic(err)
		}
		// 写入全部内容
		if _en == "big" {
			binary.Write(outputFile, binary.BigEndian, data)
		} else {
			binary.Write(outputFile, binary.LittleEndian, data)
		}
	}

	// 读取文件内容到字节切片
	inputFile, err = os.Open(InputFilePath)
	if err != nil {
		panic(err)
	}
	defer inputFile.Close()
	data, err := ioutil.ReadAll(inputFile)
	if err != nil {
		panic(err)
	}

	check := calChecknum(_type, data[:])
	// 写入源文件校验码
	if _en == "big" {
		binary.Write(outputFile, binary.BigEndian, check)
	} else {
		binary.Write(outputFile, binary.LittleEndian, check)
	}

	// 大小端转换
	var networkBytes [4]byte
	if _en == "big" {
		binary.BigEndian.PutUint32(networkBytes[:], check)
	} else {
		binary.LittleEndian.PutUint32(networkBytes[:], check)
	}
	check_hex := hex.EncodeToString(networkBytes[:])

	// 打印输出内容
	size, err := getFileSize(InputFilePath)
	fmt.Println(InputFilePath, fmt.Sprintf("%d", size), _type, check_hex)

	// 关闭文件
	err = outputFile.Close()
	if err != nil {
		fmt.Println(err)
	}
	// 重命名文件
	out_name1 := FileName + "." + _type + "[" + check_hex + "]"
	err = os.Rename(OutputFilePath, out_name1)
	if err != nil {
		fmt.Println("重命名文件出错：", err)
		return
	}
}

func main() {
	// parser.add_argument("n", help="bin文件名，譬如 COAB21232D.bin")
	// parser.add_argument("-t", help="校验方式：sum32,crc32, 默认sum32")
	// parser.add_argument("-e", help="校验码大小端：little,big, 默认little")
	// parser.add_argument("-s", help="分块大小：0,1024,2048, 默认0不分块")

	// 参数解析
	// var _name = flag.String("n", "COAB21232D.bin", "bin文件名，譬如 COAB21232D.bin")
	// var _type = flag.String("-t", "sum32", "校验方式：sum32,crc32, 默认sum32")
	// var _en = flag.String("-e", "little", "校验码大小端：little,big, 默认little")
	// var _block = flag.Int("-s", 0, "代理，譬如 分块大小：0,1024,2048, 默认0不分块")
	// // 解析命令行参数
	// flag.Parse()

	_name := ""
	_type := "sum32"
	_en := "little"
	_block := 0
	for i, num := range os.Args[1:] {
		switch i {
		case 0:
			_name = num
		case 1:
			_type = num
		case 2:
			_en = num
		case 3:
			numInt, err := strconv.Atoi(num)
			if err != nil {
				// 处理转换错误
				fmt.Println("转换错误：", err)
				return
			}
			_block = numInt
		default:
			fmt.Println("未知参数")
		}
	}

	ReadBinFile(_name, _type, _en, _block)
}