using MediatR;
using EnvelopeGenerator.Application.Common.Dto;
using DigitalData.Core.Exceptions;

namespace EnvelopeGenerator.Application.Envelopes.Queries;

/// <summary>
/// Repräsentiert eine Abfrage für Umschläge.
/// </summary>
public record ReadSingleEnvelopeDocResultQuery() : IRequest<byte[]>
{
    /// <summary>
    /// 
    /// </summary>
    public ReadSingleEnvelopeQuery Envelope { get; set; } = null!;
}

/// <summary>
/// Verarbeitet <see cref="ReadEnvelopeQuery"/> und liefert passende <see cref="EnvelopeDto"/>-Ergebnisse.
/// </summary>
public class ReadSingleEnvelopeDocResultQueryHandler : IRequestHandler<ReadSingleEnvelopeDocResultQuery, byte[]>
{
    private readonly IMediator _mediator;

    /// <summary>
    /// 
    /// </summary>
    /// <param name="mediator"></param>
    public ReadSingleEnvelopeDocResultQueryHandler(IMediator mediator)
    {
        _mediator = mediator;
    }

    /// <summary>
    /// 
    /// </summary>
    /// <param name="request"></param>
    /// <param name="cancellationToken"></param>
    /// <returns></returns>
    public async Task<byte[]> Handle(ReadSingleEnvelopeDocResultQuery request, CancellationToken cancellationToken)
    {
        request.Envelope.IncludeDocResult = true;
        var result = await _mediator.Send(request.Envelope, cancellationToken);
        return result.DocResult is byte[] docResult && docResult.Length > 0 
            ? docResult 
            : throw new NotFoundException($"Document for Envelope with ID {request.Envelope.Id} not found");
    }
}