package main

import (
  "encoding/binary"
  "encoding/json"
  "fmt"
  "log"
  "os"
  "strings"
  "time"

  "github.com/Shopify/sarama"
  "github.com/google/uuid"
)

const (
  DATE_TIME_PATTERN = ""
  STREAM_MAGIC   = 0xaced
  STREAM_VERSION  = 5
  TC_STRING     = 0x74
  TC_OBJECT     = 0x73
  TC_CLASSDESC   = 0x72
  SC_SERIALIZABLE  = 0x02
  TC_ENDBLOCKDATA  = 0x78
  TC_NULL      = 0x70
)

func main() {
  uuidTest()
}

func uuidTest() {
  f, _ := os.Create("uuid-go.out")
  defer f.Close()

  f.Write(ShortBytes(STREAM_MAGIC))
  f.Write(ShortBytes(STREAM_VERSION))
  f.Write([]byte{TC_OBJECT})
  f.Write([]byte{TC_CLASSDESC})

  className := "java.util.UUID"
  classNameLen := len(className)

  f.Write(ShortBytes(uint16(classNameLen)))
  f.Write([]byte(className))

  sid := -4856846361193249489

  f.Write(LongBytes(uint64(sid)))

  //flags
  f.Write([]byte{2})

  //fields length
  f.Write(ShortBytes(2))

  //field type code
  f.Write([]byte{'J'})

  f1 := "leastSigBits"
  f1Len := len(f1)

  f.Write(ShortBytes(uint16(f1Len)))
  f.Write([]byte(f1))

  //filed type code
  f.Write([]byte{'J'})

  f2 := "mostSigBits"
  f2Len := len(f2)

  f.Write(ShortBytes(uint16(f2Len)))
  f.Write([]byte(f2))

  f.Write([]byte{TC_ENDBLOCKDATA})
  f.Write([]byte{TC_NULL})

  leastSigBits := -8121893460813967576

  f.Write(LongBytes(uint64(leastSigBits)))

  mostSigBits := -8810284723775779300

  f.Write(LongBytes(uint64(mostSigBits)))

}

func ShortBytes(i uint16) []byte {
  bytes := make([]byte, 2)

  binary.BigEndian.PutUint16(bytes, i)

  return bytes
}

func LongBytes(i uint64) []byte {
  bytes := make([]byte, 8)

  binary.BigEndian.PutUint64(bytes, i)

  return bytes
}

func BigEndian() { // 大端序
  // 二进制形式：0000 0000 0000 0000 0001 0002 0003 0004
  var testInt int32 = 0x01020304 // 十六进制表示
  fmt.Printf("%d use big endian: \n", testInt)

  var testBytes []byte = make([]byte, 4)
  binary.BigEndian.PutUint32(testBytes, uint32(testInt)) //大端序模式
  fmt.Println("int32 to bytes:", testBytes)

  convInt := binary.BigEndian.Uint32(testBytes) //大端序模式的字节转为int32
  fmt.Printf("bytes to int32: %d\n\n", convInt)
}

func LittleEndian() { // 小端序
  //二进制形式： 0000 0000 0000 0000 0001 0002 0003 0004
  var testInt int32 = 0x01020304 // 16进制
  fmt.Printf("%d use little endian: \n", testInt)

  var testBytes []byte = make([]byte, 4)
  binary.LittleEndian.PutUint32(testBytes, uint32(testInt)) //小端序模式
  fmt.Println("int32 to bytes:", testBytes)

  convInt := binary.LittleEndian.Uint32(testBytes) //小端序模式的字节转换
  fmt.Printf("bytes to int32: %d\n\n", convInt)
}

func Int64ToBytes(i int64) []byte {
  var buf = make([]byte, 8)
  binary.BigEndian.PutUint64(buf, uint64(i))
  return buf
}

public class Test {

  public static void main(String[] args) throws IOException, ClassNotFoundException {
    readUUIDTest();
  }

  private static void readUUIDTest() throws IOException, ClassNotFoundException {
    try (var fis = new FileInputStream("uuid-go.out"); var is = new ObjectInputStream(fis)) {
      var uuid = is.readObject();

      System.out.print(uuid);

    }
  }
}