using FruitBank.Common.Entities;

namespace Nop.Plugin.Misc.FruitBankPlugin.Services;

public interface ICustomerCreditService
{
    /// <summary>Gets the credit record for a customer, or null if none exists (= unlimited).</summary>
    Task<CustomerCredit?> GetByCustomerIdAsync(int customerId);

    /// <summary>Insert or update a customer credit record.</summary>
    Task SaveAsync(CustomerCredit entity);

    /// <summary>Delete the credit record for a customer, restoring unlimited access.</summary>
    Task DeleteAsync(CustomerCredit entity);

    /// <summary>
    /// Sum of OrderTotal for all pending/unpaid, non-cancelled orders for the customer.
    /// </summary>
    Task<decimal> GetOutstandingBalanceAsync(int customerId);

    /// <summary>
    /// CreditLimit - OutstandingBalance. Returns null if no credit record exists (= unlimited).
    /// </summary>
    Task<decimal?> GetRemainingCreditAsync(int customerId);

    /// <summary>
    /// Returns true if the customer is allowed to place a new order with the given total.
    /// Rule: no credit record = always allowed.
    /// Otherwise: OutstandingBalance + newOrderTotal must be &lt;= CreditLimit.
    /// </summary>
    Task<bool> IsOrderAllowedAsync(int customerId, decimal newOrderTotal);
}