using AutoMapper;
using DocumentOperator.Application.Common.DTOs;
using DocumentOperator.Application.Common.Interfaces;
using MediatR;

namespace DocumentOperator.Application.CheckPdfAttachments.Queries;

/// <summary>
/// Query for checking PDF attachments (supports both byte array and Base64 input)
/// </summary>
public record CheckPdfAttachmentsQuery : IRequest<AttachmentCheckResult>
{
    /// <summary>
    /// PDF as byte array (direct upload via multipart/form-data)
    /// </summary>
    public byte[]? PdfBytes { get; init; }

    /// <summary>
    /// PDF as Base64 string (for API clients using application/json)
    /// </summary>
    public string? Base64Pdf { get; init; }
}

/// <summary>
/// Handler for CheckPdfAttachmentsQuery
/// Orchestrates PDF attachment checking using IPdfProcessor and AutoMapper
/// </summary>
public class CheckPdfAttachmentsQueryHandler(IPdfProcessor PdfProcessor, IMapper Mapper)
    : IRequestHandler<CheckPdfAttachmentsQuery, AttachmentCheckResult>
{
    /// <summary>
    /// Checks PDF attachments and returns detailed metadata
    /// </summary>
    public async Task<AttachmentCheckResult> Handle(CheckPdfAttachmentsQuery request, CancellationToken cancellationToken)
    {
        // Use byte[] if available, otherwise convert Base64
        byte[] pdfBytes = request.PdfBytes ?? Convert.FromBase64String(request.Base64Pdf!);

        // Convert to stream for IPdfProcessor
        using var pdfStream = new MemoryStream(pdfBytes);

        // Call DevExpress service (exceptions propagate naturally)
        var attachmentInfo = await PdfProcessor.CheckAttachmentsAsync(pdfStream);

        // Map DTO to response DTO using AutoMapper
        return Mapper.Map<AttachmentCheckResult>(attachmentInfo);
    }
}