/*
 * (c) Copyright Ascensio System SIA 2010-2015
 *
 * This program is a free software product. You can redistribute it and/or 
 * modify it under the terms of the GNU Affero General Public License (AGPL) 
 * version 3 as published by the Free Software Foundation. In accordance with 
 * Section 7(a) of the GNU AGPL its Section 15 shall be amended to the effect 
 * that Ascensio System SIA expressly excludes the warranty of non-infringement
 * of any third-party rights.
 *
 * This program is distributed WITHOUT ANY WARRANTY; without even the implied 
 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR  PURPOSE. For 
 * details, see the GNU AGPL at: http://www.gnu.org/licenses/agpl-3.0.html
 *
 * You can contact Ascensio System SIA at Lubanas st. 125a-25, Riga, Latvia,
 * EU, LV-1021.
 *
 * The  interactive user interfaces in modified source and object code versions
 * of the Program must display Appropriate Legal Notices, as required under 
 * Section 5 of the GNU AGPL version 3.
 *
 * Pursuant to Section 7(b) of the License you must retain the original Product
 * logo when distributing the program. Pursuant to Section 7(e) we decline to
 * grant you any rights under trademark law for use of our trademarks.
 *
 * All the Product's GUI elements, including illustrations and icon sets, as
 * well as technical writing content are licensed under the terms of the
 * Creative Commons Attribution-ShareAlike 4.0 International. See the License
 * terms at http://creativecommons.org/licenses/by-sa/4.0/legalcode
 *
 */
 using System;
using System.Net;
using System.Configuration;
using System.Web;
using System.Web.Routing;
using System.IO;
using System.Text;
using System.Linq;
using System.Collections.Generic;

using Microsoft.Win32; 

using FileConverterUtils2;

using log4net;

namespace DocService
{
public class FontServiceRoute : IRouteHandler
{
    public IHttpHandler GetHttpHandler(RequestContext requestContext)
    {
        return new FontService(requestContext);
    }
}

public class FontService : IHttpAsyncHandler
{
    private const string gc_sJsExtention = ".js";
    private readonly ILog _log = LogManager.GetLogger(typeof(FontServiceRoute));
    private string m_sFontName = null;
    private readonly static System.Collections.Generic.Dictionary<string, string> m_mapFontNameToFullPath;
    static FontService()
    {
        m_mapFontNameToFullPath = new System.Collections.Generic.Dictionary<string, string>();

        string sConfigFontDir = ConfigurationManager.AppSettings["utils.common.fontdir"];

        if (null != sConfigFontDir && string.Empty != sConfigFontDir)
        {
            string sConfigSearchPattern = ConfigurationSettings.AppSettings["utils.fonts.search_patterns"] ?? "*.ttf;*.ttc;*.otf";
            InitFontMapByFolder(sConfigFontDir, sConfigSearchPattern);
        }
        else
        {
            InitFontMapBySysFont();
        }

    }
    static private void InitFontMapBySysFont()
    {
        
        DirectoryInfo dirWindowsFolder = Directory.GetParent(Environment.GetFolderPath(Environment.SpecialFolder.System));
        string sWinFontDir = Path.Combine(dirWindowsFolder.FullName, "Fonts");
        RegistryKey key = Registry.LocalMachine.OpenSubKey(@"SOFTWARE\Microsoft\Windows NT\CurrentVersion\Fonts");
        if (null == key)
            key = Registry.LocalMachine.OpenSubKey(@"SOFTWARE\Microsoft\Windows\CurrentVersion\Fonts");
        if (null != key)
        {
            string[] aValues = key.GetValueNames();
            for (int i = 0, length = aValues.Length; i < length; i++)
            {
                string sCurPath = key.GetValue(aValues[i]) as string;
                if (null != sCurPath && !string.IsNullOrEmpty(sCurPath))
                {
                    if (Path.IsPathRooted(sCurPath))
                        m_mapFontNameToFullPath[Path.GetFileName(sCurPath).ToUpper()] = sCurPath;
                    else
                        m_mapFontNameToFullPath[sCurPath.ToUpper()] = Path.Combine(sWinFontDir, sCurPath);
                }
            }
        }
    }
    static private void InitFontMapByFolder(string sConfigFontDir, string sConfigSearchPattern)
    {
        string sFontDir = Environment.ExpandEnvironmentVariables(sConfigFontDir);

        char[] aDelemiters = { '|', ',', ';' };
        List<string> aSearchPatterns = (sConfigSearchPattern.Split(
            aDelemiters, StringSplitOptions.RemoveEmptyEntries)).ToList();

        string[] aFontFiles = { };
        foreach (string sSearchPattern in aSearchPatterns)
        {

            aFontFiles = aFontFiles.Concat(Directory.GetFiles(
                sFontDir, sSearchPattern, SearchOption.AllDirectories)).ToArray();
        }

        foreach (string sFontFile in aFontFiles)
        {
            try
            {
                m_mapFontNameToFullPath.Add(
                    Path.GetFileName(sFontFile).ToUpper(), sFontFile);
            }
            catch (ArgumentException)
            { 
            }
        }
    }
    public FontService(RequestContext context)
    {
        m_sFontName = Convert.ToString(context.RouteData.Values["fontname"]);
    }
    
    public IAsyncResult BeginProcessRequest(HttpContext context, AsyncCallback cb, Object extraData)
    {
        bool bStartAsync = false;
        try
        {
            _log.Info("Starting process request...");
            _log.Info("fontname: " + m_sFontName);

            string sNameToDecode;
            if (m_sFontName.Length > gc_sJsExtention.Length && gc_sJsExtention == m_sFontName.Substring(m_sFontName.Length - gc_sJsExtention.Length))
                sNameToDecode = m_sFontName.Substring(0, m_sFontName.Length - gc_sJsExtention.Length);
            else
                sNameToDecode = m_sFontName;
            byte[] data_decode = Odtff_fonts.ZBase32Encoder.Decode(sNameToDecode);
            string sFontNameDecoded = System.Text.Encoding.UTF8.GetString(data_decode);
            _log.Info("fontnameDecoded: " + sFontNameDecoded);

            context.Response.Clear();
            context.Response.Cache.SetExpires(DateTime.Now.AddMinutes(double.Parse(ConfigurationManager.AppSettings["resource.expires"], Constants.mc_oCultureInfo)));
            context.Response.Cache.SetSlidingExpiration(false);
            context.Response.Cache.SetCacheability(HttpCacheability.Public);
            context.Response.ContentType = Utils.GetMimeType(sFontNameDecoded);
            string contentDisposition = Utils.GetContentDisposition(context.Request.UserAgent, context.Request.Browser.Browser, context.Request.Browser.Version, m_sFontName);
            context.Response.AppendHeader("Content-Disposition", contentDisposition);

            string sRealFontName = sFontNameDecoded;
            if (gc_sJsExtention == Path.GetExtension(sRealFontName))
                sRealFontName = sRealFontName.Substring(0, sRealFontName.Length - gc_sJsExtention.Length);

            string strFilepath;
            m_mapFontNameToFullPath.TryGetValue(sRealFontName.ToUpper(), out strFilepath);

            FileInfo oFileInfo = new FileInfo(strFilepath);
            if (oFileInfo.Exists)
            {
                DateTime oLastModified = oFileInfo.LastWriteTimeUtc;
                string sETag = oLastModified.Ticks.ToString("x");

                DateTime oDateTimeUtcNow = DateTime.UtcNow;

                if (oLastModified.CompareTo(oDateTimeUtcNow) > 0)
                {
                    _log.DebugFormat("LastModifiedTimeStamp changed from {0} to {1}", oLastModified, oDateTimeUtcNow);
                    oLastModified = oDateTimeUtcNow;
                }

                string sRequestIfModifiedSince = context.Request.Headers["If-Modified-Since"];
                string sRequestETag = context.Request.Headers["If-None-Match"];
                bool bNoModify = false;
                if (false == string.IsNullOrEmpty(sRequestETag) || false == string.IsNullOrEmpty(sRequestIfModifiedSince))
                {
                    bool bRequestETag = true;
                    if (false == string.IsNullOrEmpty(sRequestETag) && sRequestETag != sETag)
                        bRequestETag = false;
                    bool bRequestIfModifiedSince = true;
                    if (false == string.IsNullOrEmpty(sRequestIfModifiedSince))
                    {
                        try
                        {
                            DateTime oRequestIfModifiedSince = DateTime.ParseExact(sRequestIfModifiedSince, "R", System.Globalization.CultureInfo.InvariantCulture);
                            if ((oRequestIfModifiedSince - oLastModified).TotalSeconds > 1)
                                bRequestIfModifiedSince = false;
                        }
                        catch 
                        {
                            bRequestIfModifiedSince = false;
                        }
                    }
                    if (bRequestETag && bRequestIfModifiedSince)
                    {
                        context.Response.StatusCode = (int)HttpStatusCode.NotModified;
                        bNoModify = true;
                    }
                }
                if (false == bNoModify)
                {
                    context.Response.Cache.SetETag(sETag);

                    context.Response.Cache.SetLastModified(oLastModified.ToLocalTime());
                    
                    FileStream oFileStreamInput = new FileStream(strFilepath, FileMode.Open, FileAccess.Read, FileShare.Read, (int)oFileInfo.Length, true);
                    byte[] aBuffer = new byte[oFileStreamInput.Length];
                    TransportClass oTransportClass = new TransportClass(context, cb, oFileStreamInput, aBuffer, sFontNameDecoded);
                    oFileStreamInput.BeginRead(aBuffer, 0, aBuffer.Length, ReadFileCallback, oTransportClass);
                    bStartAsync = true;
                }
            }
            else
                context.Response.StatusCode = (int)HttpStatusCode.BadRequest;
        }
        catch(Exception e)
        {
            context.Response.StatusCode = (int)HttpStatusCode.BadRequest;
            
            _log.Error(context.Request.QueryString.ToString());
            _log.Error("Exeption catched in BeginProcessRequest:", e);
        }
        TransportClass oTempTransportClass = new TransportClass(context, cb, null, null, null);
        if (false == bStartAsync)
            cb(new AsyncOperationData(oTempTransportClass));
        return new AsyncOperationData(oTempTransportClass);
    }
    public void EndProcessRequest(IAsyncResult result)
    {
    }
    public void ProcessRequest(HttpContext context)
    {
        throw new InvalidOperationException();
    }

    public bool IsReusable
    {
        get
        {
            return false;
        }
    }
    private void ReadFileCallback(IAsyncResult result)
    {
        TransportClass oTransportClass = result.AsyncState as TransportClass;
        HttpContext context = oTransportClass.m_oContext;
        try
        {
            FileStream oFileStreamInput = oTransportClass.m_oFileStreamInput;
            oTransportClass.nReadWriteBytes = oFileStreamInput.EndRead(result);
            oFileStreamInput.Dispose();
            if (oTransportClass.nReadWriteBytes <= 0)
            {
                context.Response.StatusCode = (int)HttpStatusCode.BadRequest;
                oTransportClass.m_oCallback(new AsyncOperationData(oTransportClass));
            }
            else
            {
                byte[] aOutput = null;
                if (gc_sJsExtention == Path.GetExtension(oTransportClass.m_sFontNameDecoded))
                {
                    aOutput = GetJsContent(oTransportClass.m_aBuffer, oTransportClass.m_sFontNameDecoded.Substring(0, oTransportClass.m_sFontNameDecoded.Length - gc_sJsExtention.Length));
                    oTransportClass.nReadWriteBytes = aOutput.Length;
                }
                else
                {
					aOutput = oTransportClass.m_aBuffer;
					byte[] guidOdttf = {0xA0, 0x66, 0xD6, 0x20, 0x14, 0x96, 0x47, 0xfa, 0x95, 0x69, 0xB8, 0x50, 0xB0, 0x41, 0x49, 0x48};

                    int nMaxLen = Math.Min(32, aOutput.Length);
                    for (int i = 0; i < nMaxLen; ++i)
                        aOutput[i] ^= guidOdttf[i % 16];
				}
                context.Response.OutputStream.BeginWrite(aOutput, 0, aOutput.Length, WriteBufferCallback, oTransportClass);
            }
        }
        catch (Exception e)
        {
            context.Response.StatusCode = (int)HttpStatusCode.BadRequest;
            oTransportClass.m_oCallback(new AsyncOperationData(oTransportClass));

            _log.Error("Exception catched in ReadFileCallback:", e);
        }
    }
    private void WriteBufferCallback(IAsyncResult result)
    {
        TransportClass oTransportClass = result.AsyncState as TransportClass;
        HttpContext context = oTransportClass.m_oContext;
        try
        {
            context.Response.OutputStream.EndWrite(result);
            context.Response.AppendHeader("Content-Length", oTransportClass.nReadWriteBytes.ToString());
            context.Response.StatusCode = (int)HttpStatusCode.OK;
        }
        catch (HttpException httpEx)
        {
            _log.Error("HttpException catched in WriteBufferCallback:", httpEx);
        }
        catch (Exception e)
        {
            _log.Error("Exception catched in WriteBufferCallback:", e);

            context.Response.StatusCode = (int)HttpStatusCode.BadRequest;
        }
        try
        {
            if (context.Response.IsClientConnected)
            {
                context.Response.Flush();
            }
        }
        catch (Exception e)
        {
            _log.Error("Exception catched in WriteBufferCallback, while response end:", e);
        }
		finally
		{
			try
			{
				oTransportClass.m_oCallback(new AsyncOperationData(oTransportClass));
			}
			catch(Exception e)
			{
				_log.Error("Exception catched in WriteBufferCallback, while callback:", e);
			}
		}
    }
    private byte[] GetJsContent(byte[] aBuffer, string sFilename)
    {
        string data = Convert.ToBase64String(aBuffer);
        string sRes = string.Format("window[\"{0}\"] = \"{1};{2}\";", sFilename, aBuffer.Length, data);
        return Encoding.UTF8.GetBytes(sRes);
    }
    private class TransportClass
    {
        public HttpContext m_oContext;
        public AsyncCallback m_oCallback;
        public FileStream m_oFileStreamInput;
        public byte[] m_aBuffer;
        public int nReadWriteBytes;
        public string m_sFontNameDecoded;
        public TransportClass(HttpContext oContext, AsyncCallback oCallback, FileStream oFileStreamInput, byte[] aBuffer, string sFontNameDecoded)
        {
            m_oContext = oContext;
            m_oCallback = oCallback;
            m_oFileStreamInput = oFileStreamInput;
            m_aBuffer = aBuffer;
            m_sFontNameDecoded = sFontNameDecoded;
        }
    }
}
}