using Distribution.Features.Invoice;
using Distribution.Infra.Authorization;
using Distribution.Infra.UoW;
using Distribution.Models;

namespace Distribution.Features.Payment;

public class PaymentService(
    IPaymentRepository repo,
    IInvoiceRepository invoiceRepo,
    IUnitOfWork uow,
    ICurrentUserService currentUser)
{
    private static PaymentResponse ToResponse(Models.Payment p) =>
        new(p.Id, p.FK_InvoiceId, p.Amount, p.Method, p.EntryMode, p.ChequeNumber, p.ChequeDate,
            p.CollectedAt, p.CollectedBy, p.RecordedBy, p.CreatedAt);

    public async Task<List<PaymentResponse>?> GetByInvoiceIdAsync(Guid invoiceId)
    {
        var invoice = await invoiceRepo.GetByIdAsync(invoiceId);
        if (invoice is null || !invoice.IsActive) return null;

        var payments = await repo.GetByInvoiceIdAsync(invoiceId);
        return payments.Select(ToResponse).ToList();
    }

    public async Task<PaymentResponse?> CreateAsync(Guid invoiceId, CreatePaymentRequest request, CancellationToken ct = default)
    {
        var invoice = await invoiceRepo.GetByIdAsync(invoiceId);
        if (invoice is null || !invoice.IsActive) return null;
        if (invoice.Status == InvoiceStatus.Finalized)
            throw new InvalidOperationException("Cannot record a payment against a finalized invoice");

        if (request.Method == PaymentMethod.Cheque &&
            (string.IsNullOrWhiteSpace(request.ChequeNumber) || request.ChequeDate is null))
            throw new InvalidOperationException("ChequeNumber and ChequeDate are required when Method is Cheque");

        var recorderId = currentUser.UserId ?? request.CollectedByUserId
            ?? throw new InvalidOperationException("CollectedByUserId is required while auth is unavailable");
        var collectedBy = request.CollectedByUserId ?? recorderId;
        var recordedBy = request.EntryMode == EntryMode.DayEndManual && collectedBy != recorderId
            ? recorderId
            : (Guid?)null;

        var payment = new Models.Payment
        {
            FK_InvoiceId = invoiceId,
            Amount = request.Amount,
            Method = request.Method,
            EntryMode = request.EntryMode,
            ChequeNumber = request.Method == PaymentMethod.Cheque ? request.ChequeNumber : null,
            ChequeDate = request.Method == PaymentMethod.Cheque ? request.ChequeDate : null,
            CollectedAt = DateTime.Now,
            CollectedBy = collectedBy,
            RecordedBy = recordedBy
        };

        await uow.BeginAsync(ct);
        try
        {
            await repo.AddAsync(payment);

            var allPayments = await repo.GetByInvoiceIdAsync(invoiceId);
            var total = allPayments.Sum(p => p.Amount) + request.Amount;

            invoice.PaymentStatus = total == 0
                ? PaymentStatus.Pending
                : total < invoice.TotalAmount
                    ? PaymentStatus.PartiallyPaid
                    : PaymentStatus.Paid;

            invoiceRepo.Update(invoice);
            await uow.CommitAsync(ct);
        }
        catch { await uow.RollbackAsync(ct); throw; }

        return ToResponse(payment);
    }
}