UTXOPool.js

const { UTXO } = require('./UTXO');
const { clone } = require('ramda');

class UTXOPool {
  constructor(utxos = {}) {
    this.utxos = utxos;
  }

  addUTXO(publicKey, amount) {
    if (this.utxos[publicKey]) {
      this.utxos[publicKey].amount += amount;
    } else {
      this.utxos[publicKey] = new UTXO(publicKey, amount);
    }
  }

  handleTransaction(transaction, feeReceiverPublicKey) {
    if (!this.isValidTransaction(transaction)) return;

    const inputUTXO = this.utxos[transaction.inputPublicKey];
    inputUTXO.amount -= transaction.amount;
    inputUTXO.amount -= transaction.fee;

    if (inputUTXO.amount === 0) {
      delete this.utxos[transaction.inputPublicKey];
    }

    this.addUTXO(transaction.outputPublicKey, transaction.amount);
    this.addUTXO(feeReceiverPublicKey, transaction.fee);
  }

  isValidTransaction(transaction) {
    const { inputPublicKey, amount, fee } = transaction;
    const utxo = this.utxos[inputPublicKey];
    return utxo !== undefined && utxo.amount >= (amount + fee) && amount > 0
  }

  addingTransactionErrorMessage(transaction) {
    const { inputPublicKey, amount, fee } = transaction;
    const utxo = this.utxos[inputPublicKey];
    if (utxo === undefined) {
      return "No UTXO was associated with this public key"
    }
    if (amount <= 0) {
      return "Amount has to be at least 0";
    }
    if (utxo.amount < amount + fee) {
      return `UTXO associated with this public key (${utxo.amount}) does not cover desired amount (${amount}) and fee (${fee}}`;
    }
  }

  clone() {
    return new UTXOPool(clone(this.utxos));
  }
}

module.exports = {
  UTXOPool
};