go simple blockchain logics

simple-blockchain.go

package main

import (
	"crypto/sha256"
	"fmt"
	"strconv"
	"time"
)

type Block struct {
	Index        int
	Timestamp    string
	Transactions []Transaction
	Data         string
	PreviousHash string
	Hash         string
}

func calculateHash(block Block) string {
	record := strconv.Itoa(block.Index) + block.Timestamp + block.Data + block.PreviousHash
	h := sha256.New()
	h.Write([]byte(record))
	hashed := h.Sum(nil)
	return fmt.Sprintf("%x", hashed)
}

func createBlock(prevBlock Block, data string) Block {
	block := Block{
		Index: prevBlock.Index + 1, Timestamp: time.Now().String(), Data: data, PreviousHash: prevBlock.Hash,
	}
	block.Hash = calculateHash(block)
	return block
}

func createGenesisBlock() Block {
	return Block{Index: 0, Timestamp: time.Now().String(), Data: "Genesis Block", PreviousHash: "", Hash: ""}
}

func main() {
	// Create the blockchain and add the genesis block
	var blockchain []Block
	genesisBlock := createGenesisBlock()
	blockchain = append(blockchain, genesisBlock)

	previousBlock := genesisBlock

	// Add blocks to the blockchain
	numBlocks := 10
	for i := 1; i <= numBlocks; i++ {
		newData := fmt.Sprintf("Block #%d data", i)
		newBlock := createBlock(previousBlock, newData)
		blockchain = append(blockchain, newBlock)
		previousBlock = newBlock

		fmt.Printf("Block #%d has been added to the blockchain!\n", newBlock.Index)
		fmt.Printf("Hash: %s\n\n", newBlock.Hash)
	}

	// Create the blockchain and add the genesis block
	//var blockchain []Block
	//genesisBlock := createGenesisBlock()
	//blockchain = append(blockchain, genesisBlock)

	//previousBlock := genesisBlock

	// Add blocks with transactions to the blockchain
	transactions1 := []Transaction{
		{Sender: "Alice", Recipient: "Bob", Amount: 50},
		{Sender: "Bob", Recipient: "Charlie", Amount: 25},
	}

	block1 := createBlockLedger(previousBlock, transactions1)
	blockchain = append(blockchain, block1)
	previousBlock = block1

	transactions2 := []Transaction{
		{Sender: "Charlie", Recipient: "Alice", Amount: 10},
		{Sender: "Alice", Recipient: "Bob", Amount: 5},
	}

	block2 := createBlockLedger(previousBlock, transactions2)
	blockchain = append(blockchain, block2)

	// Print the blockchain ledger
	for _, block := range blockchain {
		fmt.Printf("Block #%d \n", block.Index)
		for _, tx := range block.Transactions {
			fmt.Printf("Sender: %s, Recipient: %s, Amount: %f\n", tx.Sender, tx.Recipient, tx.Amount)
		}
		fmt.Printf("Hash: %s\n\n", block.Hash)
	}
}

type Transaction struct {
	Sender    string
	Recipient string
	Amount    float64
}

func createBlockLedger(prevBlock Block, transactions []Transaction) Block {
	block := Block{
		Index:        prevBlock.Index + 1,
		Timestamp:    time.Now().String(),
		Transactions: transactions,
		PreviousHash: prevBlock.Hash,
	}
	block.Hash = calculateHash(block)
	return block
}