using System;
using System.Drawing;
using System.Drawing.Imaging;
using System.IO;
using System.Text;
using System.Web;
using Neo.Afx.Services.Documents;

namespace Neo.Afx.Services
{
    /// <summary>
    /// Summary description for DocumentViewer
    /// </summary>
    public class DocumentViewer : IHttpHandler
    {
        readonly DocumentsDatabase _database = new DocumentsDatabase();

        public void ProcessRequest(HttpContext context)
        {
            var isReadOnly = false;
            if(!String.IsNullOrEmpty(context.Request.QueryString["readOnly"]))
            {
                if(!bool.TryParse(context.Request.QueryString["readOnly"], out isReadOnly))
                {
                    isReadOnly = false;
                }
            }

            if(String.IsNullOrEmpty(context.Request.QueryString["documentID"]))
                return;

            long documentID;
            if(!Int64.TryParse(context.Request.QueryString["documentID"], out documentID))
            {
                return;
            }

            var docObject = _database.GetDocumentObject(documentID);
            if(docObject == null)
            {
                return;
            }

            var isDownload = true;
            if(context.Request.QueryString["download"] != null)
            {
                bool.TryParse(context.Request.QueryString["download"], out isDownload);
            }


            var isThumbnail = false;
            if (context.Request.QueryString["thumbnail"] != null)
            {
                bool.TryParse(context.Request.QueryString["thumbnail"], out isThumbnail);
            }

            var thumbnailWidth = 160;
            if (context.Request.QueryString["thumbnailWidth"] != null)
            {
                int.TryParse(context.Request.QueryString["thumbnailWidth"], out thumbnailWidth);
            }

            var thumbnailHeight = 120;
            if (context.Request.QueryString["thumbnailHeight"] != null)
            {
                int.TryParse(context.Request.QueryString["thumbnailHeight"], out thumbnailHeight);
            }


            var showPhotoDate = false;
            if (context.Request.QueryString["showPhotoDate"] != null)
            {
                bool.TryParse(context.Request.QueryString["showPhotoDate"], out showPhotoDate);
            }

            var photoDateFont = new Font("Microsoft Sans Serif", 20F, FontStyle.Regular, GraphicsUnit.Point, 0);
            var photoDateFontThumbnail = new Font("Microsoft Sans Serif", 32F, FontStyle.Regular, GraphicsUnit.Point, 0);

            try
            {
                Image.FromStream(new MemoryStream(docObject.Content));
            }
            catch (Exception)
            {
                showPhotoDate = false;
                isThumbnail = false;
            }

            if(!String.IsNullOrEmpty(docObject.Uri) && !isReadOnly)
            {
                context.Response.Redirect(docObject.Uri);
            }
            else
            {
                if (isThumbnail && showPhotoDate)
                {
                    var memoryStream = new MemoryStream(docObject.Content);
                    var fromStream = Image.FromStream(memoryStream);
                    var image = new Bitmap(fromStream.Width, fromStream.Height + 70);

                    var graphics = Graphics.FromImage(image);
                    graphics.DrawImageUnscaled(fromStream, 0, 70);
                    graphics.DrawString(GetPhotoTakenDate(fromStream), photoDateFontThumbnail, Brushes.White, new RectangleF(0, 0, fromStream.Width, 70));
                    var thumbnail = GetImageByteArray(image.GetThumbnailImage(thumbnailWidth, thumbnailHeight + (thumbnailHeight / 8), null, new IntPtr()));

                    context.Response.ClearHeaders();
                    context.Response.ClearContent();
                    if (isDownload)
                    {
                        context.Response.AddHeader("Content-Disposition", " attachment; filename=" + docObject.Name);
                    }
                    else
                    {
                        context.Response.AddHeader("Content-Disposition", " inline; filename=" + docObject.Name);
                    }
                    context.Response.AddHeader("Content-Length", thumbnail.Length.ToString());
                    context.Response.ContentType = docObject.MimeType;
                    context.Response.Charset = "UTF-8";
                    context.Response.BinaryWrite(thumbnail);
                    if (context.Response.IsClientConnected)
                    {
                        context.Response.Flush();
                        context.Response.Clear();
                    }

                }
                else if (isThumbnail)
                {
                    var memoryStream = new MemoryStream(docObject.Content);
                    var fromStream = Image.FromStream(memoryStream);
                    var thumbnailImage = fromStream.GetThumbnailImage(thumbnailWidth, thumbnailHeight, null, new IntPtr());
                    var thumbnail = GetImageByteArray(thumbnailImage);

                    context.Response.ClearHeaders();
                    context.Response.ClearContent();
                    if (isDownload)
                    {
                        context.Response.AddHeader("Content-Disposition", " attachment; filename=" + docObject.Name);
                    }
                    else
                    {
                        context.Response.AddHeader("Content-Disposition", " inline; filename=" + docObject.Name);
                    }
                    context.Response.AddHeader("Content-Length", thumbnail.Length.ToString());
                    context.Response.ContentType = docObject.MimeType;
                    context.Response.Charset = "UTF-8";
                    context.Response.BinaryWrite(thumbnail);
                    if (context.Response.IsClientConnected)
                    {
                        context.Response.Flush();
                        context.Response.Clear();
                    }
                }
                else if (showPhotoDate)
                {
                    var memoryStream = new MemoryStream(docObject.Content);
                    var fromStream = Image.FromStream(memoryStream);

                    var image = new Bitmap(fromStream.Width, fromStream.Height + 35);

                    var graphics = Graphics.FromImage(image);
                    graphics.DrawImage(fromStream, 0, 35, fromStream.Width, fromStream.Height);
                    graphics.DrawString(GetPhotoTakenDate(fromStream), photoDateFont, Brushes.White, new RectangleF(0, 0, fromStream.Width, 35));
                    var imageByteArray = GetImageByteArray(image);

                    context.Response.ClearHeaders();
                    context.Response.ClearContent();
                    if (isDownload)
                    {
                        context.Response.AddHeader("Content-Disposition", " attachment; filename=" + docObject.Name);
                    }
                    else
                    {
                        context.Response.AddHeader("Content-Disposition", " inline; filename=" + docObject.Name);
                    }
                    context.Response.AddHeader("Content-Length", imageByteArray.Length.ToString());
                    context.Response.ContentType = docObject.MimeType;
                    context.Response.Charset = "UTF-8";
                    context.Response.BinaryWrite(imageByteArray);
                    if (context.Response.IsClientConnected)
                    {
                        context.Response.Flush();
                        context.Response.Clear();
                    }
                }
                else
                {
                    context.Response.ClearHeaders();
                    context.Response.ClearContent();
                    if (isDownload)
                    {
                        context.Response.AddHeader("Content-Disposition", " attachment; filename=" + docObject.Name);
                    }
                    else
                    {
                        context.Response.AddHeader("Content-Disposition", " inline; filename=" + docObject.Name);
                    }
                    context.Response.AddHeader("Content-Length", docObject.Length.ToString());
                    context.Response.ContentType = docObject.MimeType;
                    context.Response.Charset = "UTF-8";
                    context.Response.BinaryWrite(docObject.Content);
                    if (context.Response.IsClientConnected)
                    {
                        context.Response.Flush();
                        context.Response.Clear();
                    }                    
                }
            }
            
        }

        protected string GetPhotoTakenDate(Image image)
        {
            string dateTaken;
            const int propertyTagExifDtDigitized = 0x9004;
            var img = image;
            try
            {
                var item = img.GetPropertyItem(propertyTagExifDtDigitized);
                var dataTakenTime = Encoding.ASCII.GetString(item.Value);
                dateTaken = dataTakenTime;
            }
            catch (Exception)
            {
                dateTaken = "N/A";
            }
            return "Date Taken: " + dateTaken;
        }

        protected byte[] GetImageByteArray(Image image)
        {
            byte[] returnData;
            using (var memoryStream = new MemoryStream())
            {
                image.Save(memoryStream, ImageFormat.Jpeg);
                returnData = memoryStream.ToArray();
            }
            return returnData;
        }

        public bool IsReusable
        {
            get
            {
                return false;
            }
        }
    }
}