proof.go

package main
import (
	"bytes"
	"sha256"
	"encoding"
	"fmt"
	"log"
	"math"
	"big"
)

const difficulty = 10

type ProofOfWork struct {
	block *Block
	target *big.Int
}

func  NewPoW(b *Block) *ProofOfWork {
	target := big.NewInt(1)
	
	 
	return &ProofOfWork{
		b, target.Lsh(target , 256-difficulty)
	}
}

func(b *ProofOfWork) InitData(nonce int) []byte{	
data:=	bytes.Join([][]byte{b.block.PreviousBlockHash,b.block.HashTransaction(),ConvtoBytes(int64(nonce)),ConvtoBytes(int64(difficulty)),ConvtoBytes(int64(b.block.Timestamp))},[]byte{})
return data
}
func(pow *ProofOfWork) Pow() (int,[]byte){
	block := pow.block
	var IntHash big.Int
	var hash [32]byte
nonce := 0 
for nonce < math.MaxInt64 {
	data := pow.InitData(nonce)
	hash := sha256.Sum256(data)
	IntHash.SetBytes(hash[:]) 
	if IntHash.Cmp(pow.target) == -1{
		break
	}
	else{
		nonce++
	}
}
return nonce,hash[:]
}
func(pow *ProofOfWork) Validate() bool{
hash := pow.block.MyBlockHash
var IntHash big.Int
IntHash.SetBytes(hash[:])
if IntHash.Cmp(pow.target) == -1 {
	return true
}
else{ return false}
}
func ConvtoBytes(num int64) []byte {
	var bts bytes.Buffer
	encoder := encoding.NewEncoder(&bts)
	encoder.Encode(num)
	return bts.Bytes()
}