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

namespace DocumentOperator.Application.Features.Documents.ExtractSwissQrCode;

/// <summary>
/// Handles extraction of Swiss QR Code from PDF documents.
/// Uses ISwissQrCodeProcessor to extract QR code from the last page and parse it.
/// </summary>
public sealed class ExtractSwissQrCodeHandler : IRequestHandler<ExtractSwissQrCodeQuery, ExtractSwissQrCodeResult>
{
    private readonly ISwissQrCodeProcessor _qrCodeProcessor;

    public ExtractSwissQrCodeHandler(ISwissQrCodeProcessor qrCodeProcessor)
    {
        _qrCodeProcessor = qrCodeProcessor;
    }

    public async Task<ExtractSwissQrCodeResult> Handle(ExtractSwissQrCodeQuery request, CancellationToken cancellationToken)
    {
        // Convert Base64 string to byte array
        byte[] pdfBytes = request.PdfContent.ToByteArray();

        // Extract and parse Swiss QR Code from last page
        var qrCodeData = await _qrCodeProcessor.ExtractSwissQrCodeAsync(pdfBytes, cancellationToken);

        // Return references (passed through) + QR code data
        return new ExtractSwissQrCodeResult(
            References: request.References,
            QrCodeData: qrCodeData
        );
    }
}