silver-octo-spoon/wolverine/a-frame-architecture/FinancialApi.Application/Account.cs

namespace FinancialApi.Application;

public record Account(int Id, decimal Balance)
{
    public Account ApplyFee(decimal amount)
    {
        if (amount <= 0)
        {
            throw new ArgumentException("Fee must be positive.");
        }
            
        if (Balance - amount < 0)
        {
            throw new InvalidOperationException("Insufficient funds.");
        }

        return this with { Balance = Balance - amount };
    }
    
    public Account Debit(decimal amount)
    {
        if (amount <= 0)
        {
            throw new ArgumentException("Debit amount must be positive.");
        }
        if (Balance - amount < 0)
        {
            throw new InvalidOperationException("Insufficient funds.");
        }
        
        return this with { Balance = Balance - amount };
    }

    public Account Credit(decimal amount)
    {
        if (amount <= 0)
        {
            throw new ArgumentException("Credit amount must be positive.");
        }
        
        return this with { Balance = Balance + amount };
    }
}