// Copyright © 2008, 2010, Oracle and/or its affiliates. All rights reserved.
//
// MySQL for Visual Studio is licensed under the terms of the GPLv2
// <http://www.gnu.org/licenses/old-licenses/gpl-2.0.html>, like most 
// MySQL Connectors. There are special exceptions to the terms and 
// conditions of the GPLv2 as it is applied to this software, see the 
// FLOSS License Exception
// <http://www.mysql.com/about/legal/licensing/foss-exception.html>.
//
// This program is free software; you can redistribute it and/or modify 
// it under the terms of the GNU General Public License as published 
// by the Free Software Foundation; version 2 of the License.
//
// This program is distributed in the hope that it will be useful, but 
// WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY 
// or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 
// for more details.
//
// You should have received a copy of the GNU General Public License along 
// with this program; if not, write to the Free Software Foundation, Inc., 
// 51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA

using System;
using System.Collections.Generic;
using System.Text;
using Microsoft.VisualStudio.Shell;
using Microsoft.VisualStudio.Shell.Interop;
using Microsoft.VisualStudio;
using System.Runtime.InteropServices;
using Microsoft.VisualStudio.OLE.Interop;
using IOleServiceProvider = Microsoft.VisualStudio.OLE.Interop.IServiceProvider;

namespace MySql.Data.VisualStudio.Editors
{
  internal class ServiceBroker
  {
    private IOleServiceProvider psp;
    private ServiceProvider site;

    public ServiceBroker(ServiceProvider site)
    {
      this.site = site;
      psp = (IOleServiceProvider)site.GetService(typeof(IOleServiceProvider).GUID);
    }

    public ServiceBroker(IOleServiceProvider psp)
    {
      site = null;
      this.psp = psp;
    }

    #region Common Interfaces

    internal ServiceProvider Site { get { return site; } }

    public IOleServiceProvider IOleServiceProvider
    {
      get { return psp; }
    }

    public ILocalRegistry LocalRegistry
    {
      get { return OleService<ILocalRegistry>(typeof(SLocalRegistry)); }
    }

    public IVsRegisterPriorityCommandTarget VsRegisterPriorityCommandTarget
    {
      get { return OleService<IVsRegisterPriorityCommandTarget>(typeof(SVsRegisterPriorityCommandTarget)); }
    }

    public IVsFilterKeys2 VsFilterKeys2
    {
      get { return OleService<IVsFilterKeys2>(typeof(SVsFilterKeys)); }
    }

    #endregion

    /// <summary>
    /// Creates an object
    /// </summary>
    /// <param name="localRegistry">Establishes a locally-registered COM object relative to the local Visual Studio registry hive</param>
    /// <param name="clsid">GUID if object to be created</param>
    /// <param name="iid">GUID assotiated with specified System.Type</param>
    /// <returns>An object</returns>
    public object CreateObject(ILocalRegistry localRegistry, Guid clsid, Guid iid)
    {
      object objectInstance;
      IntPtr unknown = IntPtr.Zero;

      int hr = localRegistry.CreateInstance(clsid, null, ref iid, (uint)CLSCTX.CLSCTX_INPROC_SERVER, out unknown);

      if (hr != VSConstants.S_OK)
      {
        Marshal.ThrowExceptionForHR(hr);
      }

      try
      {
        objectInstance = Marshal.GetObjectForIUnknown(unknown);
      }
      finally
      {
        if (unknown != IntPtr.Zero)
        {
          Marshal.Release(unknown);
        }
      }

      // Try to site object instance
      IObjectWithSite objectWithSite = objectInstance as IObjectWithSite;
      if (objectWithSite != null)
        objectWithSite.SetSite(psp);

      return objectInstance;
    }


    private InterfaceType OleService<InterfaceType>(Type serviceType)
        where InterfaceType : class
    {
      Guid serviceGuid = serviceType.GUID;
      Guid interfaceGuid = typeof(InterfaceType).GUID;
      IntPtr unknown = IntPtr.Zero;
      InterfaceType service = null;
      int hr = psp.QueryService(ref serviceGuid, ref interfaceGuid, out unknown);

      if (hr != VSConstants.S_OK)
        Marshal.ThrowExceptionForHR(hr);

      try
      {
        service = (InterfaceType)Marshal.GetObjectForIUnknown(unknown);
      }
      finally
      {
        if (unknown != IntPtr.Zero)
          Marshal.Release(unknown);
      }
      return service;
    }
  }
}
