# # Bank Account
# 
# You are given a simplified multi-threaded “bank account” implementation used by one of our infrastructure teams. The current code processes deposits concurrently but produces incorrect results.
# 
# Task
# 
# Identify the concurrency bugs in the implementation.
# 
# Explain why these bugs occur.
# 
# Fix the implementation without modifying the existing BankAccount class directly.
# 
# You may use subclassing (Python) or embedding (Go-style composition), depending on the language you choose.
# 
# Ensure your solution is thread-safe and produces the correct final balance (1200).

from threading import Lock
from concurrent.futures import ThreadPoolExecutor
import time

class BankAccount:
    def __init__(self, balance):
        self.balance = balance
        self._lock = Lock()

    def deposit(self, amount):
        while (self._lock.locked()):
            pass
        self._lock.acquire()
        new_balance = self.balance + amount  # read
        time.sleep(0.1)                      # simulate delay
        self.balance = new_balance           # write
        self._lock.release()


account = BankAccount(0)

with ThreadPoolExecutor(max_workers=2) as executor:
    futures = [
        executor.submit(account.deposit, 500),
        executor.submit(account.deposit, 700),
    ]
print(account.balance)