using Fitness_core_BE.Models;

namespace Fitness_core_BE.Interfaces
{
    public interface ICustomerInvoiceRepository
    {
        // carriedOverBalance: unpaid amount rolled forward from a prior subscription period
        // (renewal). includeOnboardingFee: false for renewals -- it's a one-time fee and would
        // otherwise re-bill every cycle.
        Task<CustomerInvoice> CreateCustomerInvoiceFromSubscription(
            Guid subscriptionId, bool chargePayment = true, decimal carriedOverBalance = 0m, bool includeOnboardingFee = true);

        // Guard-free sibling used only by the daily renewal sweep -- see the implementation for
        // why CreateCustomerInvoiceFromSubscription's idempotency guard doesn't apply here.
        Task<CustomerInvoice> CreateRenewalInvoiceAsync(
            Guid subscriptionId, decimal carriedOverBalance, CancellationToken ct = default);
        Task<CustomerInvoice?> GetInvoiceBySubscriptionIdAsync(Guid subscriptionId);
        Task<CustomerInvoice?> GetCustomerInvoiceById(Guid customerInvoiceId);
        Task<List<CustomerInvoice>> GetCustomerInvoicesByCustomerId(Guid customerId);
        Task<List<CustomerInvoice>> GetCustomerInvoicesByClientId(Guid clientId);
        Task<CustomerInvoice> UpdateCustomerInvoiceStatus(Guid customerInvoiceId, string status);

        // Renewal-approval workflow.
        Task<List<CustomerInvoice>> GetUnapprovedInvoicesByClientIdAsync(Guid clientId);

        // True when this subscription has a renewal invoice awaiting approval -- used to tell a
        // genuinely legacy "no invoice yet" subscription (safe to self-heal) apart from one whose
        // only invoices are unapproved/RolledOver right now (not safe: creating a fresh invoice
        // there would silently duplicate a renewal already in flight).
        Task<bool> HasPendingApprovalInvoiceAsync(Guid subscriptionId);
        Task<List<CustomerInvoice>> GetLatestApprovedInvoicePerCustomerAsync(Guid clientId);
        Task RepointAndRecalculateInvoiceAsync(Guid customerInvoiceId, Guid newSubscriptionId, CancellationToken ct = default);

        // Sum of each invoice's "Previous Balance" line item (0 if it has none) -- the portion of
        // Amount that's carried-forward debt rather than this cycle's own charge. Batched so list
        // endpoints (e.g. the approvals queue) don't issue one query per row.
        Task<Dictionary<Guid, decimal>> GetCarriedForwardAmountsAsync(List<Guid> invoiceIds);

        // A standalone charge on top of an existing subscription (e.g. an extra fee added
        // mid-cycle), separate from the subscription's original CreateCustomerInvoiceFromSubscription
        // invoice which is idempotent per subscription and won't pick up items added later.
        Task<CustomerInvoice> CreateSupplementalInvoiceAsync(Guid subscriptionId, string itemName, string? itemDescription, decimal amount);

        // Plan-change settlement: `amount` is the signed diff between what the new plan costs
        // and what the customer already paid toward the old one (positive = they owe more,
        // negative = they overpaid and get a credit). Nets out any of the customer's still-open
        // Credit invoices first, same as every other invoice-creation path.
        Task<CustomerInvoice> CreatePlanChangeInvoiceAsync(
            Guid subscriptionId, string itemName, decimal amount, CancellationToken ct = default);

        Task<decimal> GetApprovedPaymentTotalAsync(Guid invoiceId, CancellationToken ct = default);
    }
}