EnvelopeGenerator/EnvelopeGenerator.Application/Pdf/BurnPdfCommand.cs

using DigitalData.Core.Abstraction.Application.Repository;
using EnvelopeGenerator.Application.Common.Configurations;
using EnvelopeGenerator.Application.Exceptions;
using EnvelopeGenerator.Domain.Entities;
using EnvelopeGenerator.PdfEditor;
using GdPicture14;
using MediatR;
using Microsoft.EntityFrameworkCore;

namespace EnvelopeGenerator.Application.Pdf;

/// <summary>
/// 
/// </summary>
public class BurnPdfCommand : IRequest
{
}

/// <summary>
/// 
/// </summary>
public class BurnPdfCommandHandler : IRequestHandler<BurnPdfCommand>
{
    /// <summary>
    /// 
    /// </summary>
    private readonly PDFBurnerParams _pdfBurnerParams;

    private readonly AnnotationManager _manager;

    private readonly IRepository<Signature> _signRepo;

    /// <summary>
    /// 
    /// </summary>
    /// <param name="pdfBurnerParams"></param>
    /// <param name="manager"></param>
    /// <param name="signRepo"></param>
    public BurnPdfCommandHandler(PDFBurnerParams pdfBurnerParams, AnnotationManager manager, IRepository<Signature> signRepo)
    {
        _pdfBurnerParams = pdfBurnerParams;
        _manager = manager;
        _signRepo = signRepo;
    }

    public byte[] BurnAnnotsToPDF(byte[] pSourceBuffer, List<string> pInstantJSONList, int envelopeId)
    {
        // read the elements of envelope with their annotations
        var elements = _signRepo
            .Where(sig => sig.Document.EnvelopeId == envelopeId)
            .Include(sig => sig.Annotations)
            .ToList();

        return elements.Any()
            ? BurnElementAnnotsToPDF(pSourceBuffer, elements)
            : BurnInstantJSONAnnotsToPDF(pSourceBuffer, pInstantJSONList);
    }

    /// <summary>
    /// 
    /// </summary>
    /// <param name="pSourceBuffer"></param>
    /// <param name="elements"></param>
    /// <returns></returns>
    public byte[] BurnElementAnnotsToPDF(byte[] pSourceBuffer, List<Signature> elements)
    {
        // Add background
        using (var doc = PdfEditor.Pdf.FromMemory(pSourceBuffer))
        {
            // TODO: take the length from the largest y
            pSourceBuffer = doc.Background(elements, 1.9500000000000002 * 0.93, 2.52 * 0.67)
                            .ExportStream()
                            .ToArray();

            GdPictureStatus oResult;
            using (var oSourceStream = new MemoryStream(pSourceBuffer))
            {
                // Open PDF
                oResult = _manager.InitFromStream(oSourceStream);
                if (oResult != GdPictureStatus.OK)
                    throw new BurnAnnotationException($"Could not open document for burning: [{oResult}]");

                // Imported from background (add to configuration)
                double margin = 0.2;
                double inchFactor = 72;

                // Y offset of form fields
                var keys = new[] { "position", "city", "date" }; // add to configuration
                double unitYOffsets = 0.2;

                var yOffsetsOfFF = keys
                    .Select((k, i) => new { Key = k, Value = unitYOffsets * i + 1 })
                    .ToDictionary(x => x.Key, x => x.Value);

                // Add annotations
                foreach (var element in elements)
                {
                    double frameX = element.Left - 0.7 - margin;

                    var frame = element.Annotations?.FirstOrDefault(a => a.Name == "frame");
                    double frameY = element.Top - 0.5 - margin;
                    double frameYShift = frame.Y - frameY * inchFactor;
                    double frameXShift = frame.X - frameX * inchFactor;

                    foreach (var annot in element.Annotations)
                    {
                        double yOffsetofFF;
                        if (!yOffsetsOfFF.TryGetValue(annot.Name, out yOffsetofFF))
                            yOffsetofFF = 0;

                        double y = frameY + yOffsetofFF;

                        if (annot.Type == AnnotationType.FormField)
                        {
                            AddFormFieldValue(
                                annot.X / inchFactor,
                                y,
                                annot.Width / inchFactor,
                                annot.Height / inchFactor,
                                element.Page,
                                annot.Value
                            );
                        }
                        else if (annot.Type == AnnotationType.Image)
                        {
                            AddImageAnnotation(
                                annot.X / inchFactor,
                                annot.Name == "signature" ? (annot.Y - frameYShift) / inchFactor : y,
                                annot.Width / inchFactor,
                                annot.Height / inchFactor,
                                element.Page,
                                annot.Value
                            );
                        }
                        else if (annot.Type == AnnotationType.Ink)
                        {
                            AddInkAnnotation(element.Page, annot.Value);
                        }
                    }
                }

                // Save PDF
                using (var oNewStream = new MemoryStream())
                {
                    oResult = _manager.SaveDocumentToPDF(oNewStream);
                    if (oResult != GdPictureStatus.OK)
                        throw new BurnAnnotationException($"Could not save document to stream: [{oResult}]");

                    _manager.Close();

                    return oNewStream.ToArray();
                }
            }
        }
    }

    /// <summary>
    /// 
    /// </summary>
    /// <param name="pSourceBuffer"></param>
    /// <param name="pInstantJSONList"></param>
    /// <returns></returns>
    public byte[] BurnInstantJSONAnnotsToPDF(byte[] pSourceBuffer, List<string> pInstantJSONList)
    {
        return Enumerable.Empty<byte>().ToArray();
    }

    /// <summary>
    /// 
    /// </summary>
    /// <param name="request"></param>
    /// <param name="cancellationToken"></param>
    /// <returns></returns>
    /// <exception cref="NotImplementedException"></exception>
    public Task Handle(BurnPdfCommand request, CancellationToken cancellationToken)
    {
        throw new NotImplementedException();
    }
}