Mini Blockchain Project — အပိုင်း ၂: Transaction Pool နဲ့ Mining ထည့်သွင်းခြင်း

const crypto = require('crypto');

class Transaction {
  constructor(fromAddress, toAddress, amount) {
    this.fromAddress = fromAddress;
    this.toAddress = toAddress;
    this.amount = amount;
  }
}

class Block {
  constructor(timestamp, transactions, previousHash = '') {
    this.timestamp = timestamp;
    this.transactions = transactions;
    this.previousHash = previousHash;
    this.nonce = 0;
    this.hash = this.calculateHash();
  }

  calculateHash() {
    return crypto
      .createHash('sha256')
      .update(this.previousHash + this.timestamp + JSON.stringify(this.transactions) + this.nonce)
      .digest('hex');
  }

  mineBlock(difficulty) {
    const target = Array(difficulty + 1).join('0');
    while (this.hash.substring(0, difficulty) !== target) {
      this.nonce++;
      this.hash = this.calculateHash();
    }
    console.log(`Block mined: ${this.hash} (nonce: ${this.nonce})`);
  }
}

class Blockchain {
  constructor() {
    this.chain = [new Block(Date.now(), 'Genesis Block', '0')];
    this.difficulty = 2;
    this.pendingTransactions = [];
  }

  getLatestBlock() {
    return this.chain[this.chain.length - 1];
  }

  minePendingTransactions(miningRewardAddress) {
    const block = new Block(Date.now(), this.pendingTransactions, this.getLatestBlock().hash);
    block.mineBlock(this.difficulty);
    this.chain.push(block);
    this.pendingTransactions = [new Transaction(null, miningRewardAddress, 1)];
  }

  createTransaction(transaction) {
    this.pendingTransactions.push(transaction);
  }
}

const myChain = new Blockchain();
myChain.createTransaction(new Transaction('wallet-A', 'wallet-B', 50));
myChain.minePendingTransactions('miner-address');