#if WINDOWS
using EnvelopeGenerator.Application.Common.Extensions;
using EnvelopeGenerator.Application.Exceptions;
using EnvelopeGenerator.Domain.Constants;
using GdPicture14;
using MediatR;

namespace EnvelopeGenerator.Application.Pdf.Behaviors;

/// <summary>
/// 
/// </summary>
public class PdfMergeBehavior : IPipelineBehavior<BurnPdfCommand, byte[]>
{
    /// <summary>
    /// 
    /// </summary>
    /// <param name="request"></param>
    /// <param name="next"></param>
    /// <param name="cancel"></param>
    /// <returns></returns>
    /// <exception cref="NotImplementedException"></exception>
    public async Task<byte[]> Handle(BurnPdfCommand request, RequestHandlerDelegate<byte[]> next, CancellationToken cancel)
    {
        var doc = await next(cancel);

        if (request.Report is null)
            throw new InvalidOperationException("The final document report could not be merged." 
                + "There may be an error related to the behavior register order." 
                + "Request details:\n" + request.ToJson(Format.Json.ForDiagnostics));

        using var oDocumentStream = new MemoryStream(doc);
        using var oReportStream = new MemoryStream(request.Report);
        using var oFinalStream = new MemoryStream();
        using var oDocumentPDF = new GdPicturePDF();
        using var oReportPDF = new GdPicturePDF();
        GdPictureStatus oStatus = GdPictureStatus.OK;

        // Load the source file into memory
        oDocumentPDF.LoadFromStream(oDocumentStream, true);

        oStatus = oDocumentPDF.GetStat();
        if (oStatus != GdPictureStatus.OK)
            throw new MergeDocumentException($"Document could not be loaded: {oStatus}." 
                + "Request details:\n" + request.ToJson(Format.Json.ForDiagnostics));

        // Load the report file into memory
        oReportPDF.LoadFromStream(oReportStream, true);
        oStatus = oReportPDF.GetStat();
        if (oStatus != GdPictureStatus.OK)
            throw new MergeDocumentException($"Report could not be loaded: {oStatus}." 
                + "Request details:\n" + request.ToJson(Format.Json.ForDiagnostics));

        // Merge the documents 
        var oMergedPDF = oDocumentPDF.Merge2Documents(oDocumentPDF, oReportPDF);
        oStatus = oMergedPDF.GetStat();
        if (oStatus != GdPictureStatus.OK)
            throw new MergeDocumentException($"Documents could not be merged: {oStatus}." 
                + "Request details:\n" + request.ToJson(Format.Json.ForDiagnostics));

        // Convert to byte
        oMergedPDF.SaveToStream(oFinalStream);
        oStatus = oDocumentPDF.GetStat();
        if (oStatus != GdPictureStatus.OK)
            throw new MergeDocumentException($"Document could not be converted to byte: {oStatus}."
                + "Request details:\n" + request.ToJson(Format.Json.ForDiagnostics));

        return oFinalStream.ToArray();
    }
}
#endif