using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using Netca_PDFSign_COM;
using System.IO;
using System.Drawing;
using Spire.Pdf;
using System.Text;
using Spire.Pdf.Graphics;

namespace EmisTerminal
{
    public class PDFSign
    {
        public const string PDFPath = "~/Content/PrintFile";
        public static string PDFAbsolutePath 
        {
            get
            {
                return HttpContext.Current.Server.MapPath(PDFPath);
            }
        }

        static PDFSign()
        {
            if (!Directory.Exists(PDFAbsolutePath))
            {
                Directory.CreateDirectory(PDFAbsolutePath);
            }
        }

        private byte[] GetImage(string certEncoded)
        {
            if (!string.IsNullOrEmpty(certEncoded))
            {
                IUtilTool util = new UtilTool();
                byte[] imgBytes = util.GetImageFromDevicByCert(certEncoded);
                if (imgBytes == null)
                {
                    throw new Exception("找不到可用的签章图片！");
                }

                return imgBytes;
            }
            else
            {
                throw new Exception("找不到可用的外观，请确定已连接设备！");
            }
        }

        public string Sign(string targetFileName, Stream pageStream)
        {
            var pageBytes = new byte[pageStream.Length];
            var monthString = DateTime.Today.ToString("yyyy-MM");
            var monthPath = PDFAbsolutePath + @"\" + monthString;

            if (!Directory.Exists(monthPath))
            {
                Directory.CreateDirectory(monthPath);
            }
            var destFileName = "";
            var printTimes = Directory.GetFiles(monthPath).Where(x => x.Contains(targetFileName)).ToArray();
            if (printTimes.Length > 0)
            {
                destFileName = targetFileName + "(" + (printTimes.Length).ToString() + ").pdf";
            }
            else
            {
                destFileName = targetFileName + ".pdf";
            }
            var destFilePath = monthPath + @"\" + destFileName;

            pageStream.Read(pageBytes, 0, pageBytes.Length);
            ISignatureCreator creator = new SignatureCreator();
            var certEncoded = creator.SelectCert(null, 0);
            creator.SetSignPDFBytes(pageBytes, null);
            var pageCount = creator.GetPagesCount();

            var imgBytes = this.GetImage(certEncoded);
            MemoryStream ms = new MemoryStream(imgBytes);
            Image image = Image.FromStream(ms);

            PdfDocument pdf = new PdfDocument(pageStream);
            creator.SetSignCert(certEncoded, "sha-256", Const.NATCA_PASSWORD);
            for (int i = 1; i <= pageCount; i++)
            {
                try
                {
                    var position = pdf.Pages[i - 1].FindAllText().Finds.OrderByDescending(x => x.Bounds.Bottom).First().Bounds;

                    creator.SealPosition(destFilePath, i, Convert.ToInt32(Math.Floor(position.X - 20)), Convert.ToInt32(Math.Floor(position.Y - 99)), 119, 119, null, Convert.ToBase64String(imgBytes));
                }
                catch (Exception)
                {
                }
            }

            var destPath = PDFPath + "/" + monthString + "/" + destFileName;
            return destPath;
        }
    }
}