using DocumentOperator.Application.Common.Interfaces;
using FluentValidation;
using MediatR;

namespace DocumentOperator.Application.ConvertFromPdfA;

/// <summary>
/// Command to convert a PDF/A document to a standard PDF (removes PDF/A restrictions)
/// </summary>
public record ConvertFromPdfACommand : IRequest<byte[]>
{
    /// <summary>
    /// PDF/A document stream. Must be positioned at the beginning (Position = 0).
    /// </summary>
    public required Stream PdfStream { get; init; }
}

/// <summary>
/// Handler for ConvertFromPdfACommand
/// </summary>
public class ConvertFromPdfACommandHandler(IPdfProcessor pdfProcessor) 
    : IRequestHandler<ConvertFromPdfACommand, byte[]>
{
    public async Task<byte[]> Handle(ConvertFromPdfACommand request, CancellationToken cancellationToken)
    {
        return await pdfProcessor.ConvertFromPdfAAsync(request.PdfStream);
    }
}

/// <summary>
/// Validator for ConvertFromPdfACommand
/// </summary>
public class ConvertFromPdfACommandValidator : AbstractValidator<ConvertFromPdfACommand>
{
    public ConvertFromPdfACommandValidator()
    {
        RuleFor(x => x.PdfStream)
            .NotNull()
            .WithMessage("PDF stream is required");
    }
}