/*
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 of merchantability and/or fitness for a particular purpose. This programming example
 assumes that you are familiar with the programming language being demonstrated and
 the tools used to create and debug procedures. i-net software support professionals
 can help explain the functionality of a particular procedure, but they will not modify
 these examples to provide added functionality or construct procedures to meet your
 specific needs.
  
 © i-net software 1998-2013

*/
using ICSharpCode.SharpZipLib.Zip.Compression;
using ICSharpCode.SharpZipLib.Zip.Compression.Streams;
using Inet.Viewer.Resources;

using System;
using System.Drawing;
using System.Drawing.Text;
using System.IO;
using System.Runtime.InteropServices;

namespace Inet.Viewer.Data
{
    /// <summary>
    /// Implementation of the Loader to specifically load the Fonts 
    /// </summary>
    public class FontLoader : Loader
    {
        private FontData result = null;

        /// <summary>
        /// Ovrrides the Load function
        /// </summary>
        /// <param name="token"></param>
        /// <returns></returns>
        protected internal override bool Load(int token)
        {
            switch (token)
            {
                case ViewerTokenConstants.TokenFontId:
                    result.Id = ReadInt();
                    break;
                case ViewerTokenConstants.TokenFontRev:
                    result.Revision = ReadInt();
                    break;
                case ViewerTokenConstants.TokenFontData:

                    bool compressFontData = ReadBoolean();
                    byte[] fontData = ReadByteArray();
                    
                    if (compressFontData)
                    {
                        Inflater inflater = new Inflater();
                        InflaterInputStream input = new InflaterInputStream(new MemoryStream(fontData), inflater);
                        MemoryStream ustream = new MemoryStream();
                        int b;
                        while ((b=input.ReadByte())!=-1)
                        {
                            ustream.WriteByte((byte)b);
                        }
                        fontData = ustream.ToArray();
                    }

                    try
                    {
                        LoadFontFamily(fontData);
                    }
                    catch (IOException e)
                    {
                        throw new ViewerException(strings.ErrorMessage_Font_CouldNotCreate + " " + result.Id, e);
                    }
                    break;
                default:
                    return base.Load(token);
            }
            return true;
        }

        /// <summary>
        /// This method Reads the byte fontData and returns the FontData of this Font
        /// </summary>
        /// <param name="fontData">the font data in form of a byte array</param>
        /// <returns>the parsed FontData instance</returns>
        public virtual FontData ReadFont(byte[] fontData)
        {
            this.result = new FontData();
            this.Data = fontData;
            ReadTokens();

            if (result.Font == null && result.FontFamily == null)
            {
                // set default font
                result.FontFamily = FontFamily.GenericSansSerif;
                result.Font = new Font(FontFamily.GenericSansSerif, 150);
                return result;
            }

            if (result.Font == null)
            {
                try
                {
                    result.Font = new Font(result.FontFamily, 150);
                }
                catch (ArgumentException)
                {
                    // mostelikely the Regular style is not available, so we have to look which style is available
                    FontStyle fStyle = GetAvailableStyle(result.FontFamily);
                    result.Font = new Font(result.FontFamily, 150, fStyle);
                }
            }
            return result;
        }

        /// <summary>
        /// Returns the available Font Style.
        /// Doesn't include strikethrough and underline, as all fonts support that
        /// </summary>        
        public static FontStyle GetAvailableStyle(FontFamily family)
        {
            // To make sure a fontstyle is set that is supported
            FontStyle fStyle = FontStyle.Regular;
            if (family.IsStyleAvailable(FontStyle.Bold))
            {
                fStyle += (int)FontStyle.Bold;
            }
            else if (family.IsStyleAvailable(FontStyle.Italic))
            {
                fStyle += (int)FontStyle.Italic;
            }
            else if (family.IsStyleAvailable(FontStyle.Bold | FontStyle.Italic))
            {
                fStyle = FontStyle.Bold | FontStyle.Italic;
            }
            return fStyle;
        }

        /// <summary>
        /// Helper method to load font family from a byte array   
        /// </summary>
        /// <param name="buffer">the byte array with the font data</param>
        private void LoadFontFamily(byte[] buffer)
        {
            string fileName = result.FileName = Path.GetTempFileName();
            using (FileStream fs = new FileStream(fileName, FileMode.OpenOrCreate, FileAccess.ReadWrite, FileShare.None, 4096, FileOptions.RandomAccess))
            {
                fs.Write(buffer, 0, buffer.Length);
            }
            // Create a temp memory collection 
            PrivateFontCollection fontCollection = result.FontCollection = new PrivateFontCollection();
            // To hold a reference
            fontCollection.AddFontFile(fileName);
            RemoveFontResourceEx(fileName, 16, IntPtr.Zero); // https://stackoverflow.com/questions/26671026/how-to-delete-the-file-of-a-privatefontcollection-addfontfile
            result.FontFamily = fontCollection.Families[0];
         }

        [DllImport("gdi32.dll", CharSet = CharSet.Auto, SetLastError = true)]
        private static extern int RemoveFontResourceEx(string lpszFilename, int fl, IntPtr pdv);
    }
}