using iText.Kernel.Pdf;
using iText.Kernel.Pdf.Canvas;

#if NETFRAMEWORK
using System.IO;
using System;
#endif

namespace EnvelopeGenerator.PdfEditor
#if NET
    ;
#elif NETFRAMEWORK
{
#endif

    public static class Extensions
    {
        #region Edit PDF document
        public static TStream Edit<TStream>(this TStream inputStream, Action<PdfDocument> edit)
            where TStream : Stream, new()
        {
            using (var outputStream = new TStream())
            {
                using (var pdfDoc = new PdfDocument(new PdfReader(inputStream), new PdfWriter(outputStream)))
                {
                    edit(pdfDoc);
                }
                return outputStream;
            }
        }

        public static byte[] Edit(this byte[] pdfBytes, Action<PdfDocument> edit)
        {
            using (var inputStream = new MemoryStream(pdfBytes))
            {
                return inputStream.Edit(edit).ToArray();
            }
        }
        #endregion

        public static byte[] Design(this byte[] pdfBytes, params (int pageIndex, Action<PdfCanvas> design)[] pageDesign)
            => pdfBytes.Edit(doc =>
            {
                foreach((int pageIndex, Action<PdfCanvas> design)  in pageDesign)
                {
                    var page = doc.GetPage(pageIndex);
                    var canvas = new PdfCanvas(page);
                    design(canvas);
                }
            });
    }
#if NETFRAMEWORK
}
#endif