Design a Bank Account OOP Simulation with Transfers, Payments, and Merges

Problem Statement

Design a simple banking system that manages Account objects. Your system should support the following operations while maintaining data integrity:

1. deposit(amount): Adds funds to an account.
2. withdraw(amount): Removes funds, ensuring the balance never drops below zero.
3. transfer(target_account, amount): Moves funds from the current account to a target account. This must be atomic.
4. merge(other_account): Moves the entire balance of other_account into the current account, then closes the other_account (setting its balance to 0 and marking it as inactive).

Requirements

• Ensure thread safety for concurrent operations.
• Prevent illegal states, such as transferring money to a closed account or attempting to merge an account into itself.
• Implement a unique account_id for every account instance.

Expected Interface

class Account:
    def __init__(self, account_id, initial_balance=0.0):
        # Initialize account properties
        pass

    def deposit(self, amount):
        # Logic to add funds
        pass

    def withdraw(self, amount):
        # Logic to subtract funds (must return False if insufficient funds)
        pass

    def transfer(self, target_account, amount):
        # Logic to move funds to target_account
        pass

    def merge(self, other_account):
        # Move all funds from other_account to self and close other_account
        pass

Example

acc1 = Account("A", 100)
acc2 = Account("B", 50)

acc1.transfer(acc2, 30)
# acc1 balance: 70, acc2 balance: 80

acc1.merge(acc2)
# acc1 balance: 150, acc2 balance: 0, acc2 status: inactive

Edge Cases

• Transferring more money than available.
• Attempting to merge an account that is already closed.
• Thread-safety during simultaneous operations on the same two accounts.