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

namespace FinancialApi.Domain.Entities;

public record Account(int Id, decimal Balance, string AccountType)
{
    public Account ApplyPosting(decimal amount, EntryType entryType)
    {
        if (amount <= 0)
        {
            throw new ArgumentException("Credit amount must be positive.");
        }

        var newBalance = Balance;
        if (AccountType == "Revenue")
        {
            newBalance = entryType == EntryType.Credit ? newBalance + amount : newBalance - amount;
        }
        else
        {
            newBalance = entryType == EntryType.Debit ? newBalance - amount : newBalance + amount;
        }

        if (newBalance < 0 && AccountType == "Liability")
        {
            throw new InvalidOperationException("Insufficient funds.");
        }

        return this with { Balance = newBalance };
    }

    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 };
    }
}