Transaction_System

import hashlib
import time
import json
from cryptography.hazmat.backends import default_backend
from cryptography.hazmat.primitives import serialization, hashes
from cryptography.hazmat.primitives.asymmetric import rsa, padding

class Transaction:
    def __init__(self, sender, recipient, amount):
        self.sender = sender
        self.recipient = recipient
        self.amount = amount
        self.timestamp = int(time.time())

    def to_dict(self):
        return {
            "sender": self.sender,
            "recipient": self.recipient,
            "amount": self.amount,
            "timestamp": self.timestamp,
        }

    def sign_transaction(self, private_key):
        signer = private_key.signer(padding.PSS(mgf=padding.MGF1(hashes.SHA256()), salt_length=padding.PSS.MAX_LENGTH), hashes.SHA256())
        data = json.dumps(self.to_dict(), sort_keys=True)
        signer.update(data.encode())
        return signer.finalize()

class Wallet:
    def __init__(self):
        self.private_key = rsa.generate_private_key(
            public_exponent=65537,
            key_size=2048,
            backend=default_backend()
        )
        self.public_key = self.private_key.public_key()

    def get_balance(self, blockchain):
        balance = 0
        for block in blockchain.chain:
            for tx in block.data:
                if tx.sender == self.public_key:
                    balance -= tx.amount
                if tx.recipient == self.public_key:
                    balance += tx.amount
        return balance

def main():
    blockchain = Blockchain()

    # Create two wallets
    wallet1 = Wallet()
    wallet2 = Wallet()

    # Wallet 1 sends 10 coins to Wallet 2
    transaction1 = Transaction(wallet1.public_key, wallet2.public_key, 10)
    transaction1.signature = transaction1.sign_transaction(wallet1.private_key)

    # Add transactions to a block and mine it
    block1 = Block(1, blockchain.get_latest_block().hash, int(time.time()), [transaction1])
    blockchain.add_block(block1)

    # Wallet 1 checks its balance
    balance_wallet1 = wallet1.get_balance(blockchain)
    print(f"Wallet 1 Balance: {balance_wallet1}")

    # Wallet 2 checks its balance
    balance_wallet2 = wallet2.get_balance(blockchain)
    print(f"Wallet 2 Balance: {balance_wallet2}")

if __name__ == "__main__":
    main()