// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
 
//
// 
// Description: Manages Text Services Compartment.
//
//
 
using System.Runtime.InteropServices;
using MS.Win32;
 
namespace System.Windows.Input
{
    //------------------------------------------------------
    //
    //  TextServicesCompartment class
    //
    //------------------------------------------------------
 
    internal class TextServicesCompartment
    {
        //------------------------------------------------------
        //
        //  Constructors
        //
        //------------------------------------------------------
 
        internal TextServicesCompartment(Guid guid, UnsafeNativeMethods.ITfCompartmentMgr compartmentmgr)
        {
            _guid = guid;
            _compartmentmgr = compartmentmgr;
            _cookie = UnsafeNativeMethods.TF_INVALID_COOKIE;
        }
 
        //------------------------------------------------------
        //
        //  Public Methods
        //
        //------------------------------------------------------
 
        #region Public Methods
        #endregion Public Methods        
 
        //------------------------------------------------------
        //
        //  Public Operators
        //
        //------------------------------------------------------
 
 
        //------------------------------------------------------
        //
        //  Public Properties
        //
        //------------------------------------------------------
 
 
        //------------------------------------------------------
        //
        //  Public Events
        //
        //------------------------------------------------------
 
  
        //------------------------------------------------------
        //
        //  Protected Methods
        //
        //------------------------------------------------------
 
 
        //------------------------------------------------------
        //
        //  Internal Methods
        //
        //------------------------------------------------------
 
        #region Internal Methods
 
        /// <summary>
        ///     Advise the notify sink of the compartment update.
        /// </summary>
        internal void AdviseNotifySink(UnsafeNativeMethods.ITfCompartmentEventSink sink)
        {
            Debug.Assert(_cookie == UnsafeNativeMethods.TF_INVALID_COOKIE, "cookie is already set.");
 
            UnsafeNativeMethods.ITfCompartment compartment = GetITfCompartment();
            if (compartment == null)
                return;
 
            UnsafeNativeMethods.ITfSource source = compartment as UnsafeNativeMethods.ITfSource;
 
            // workaround because I can't pass a ref to a readonly constant
            Guid guid = UnsafeNativeMethods.IID_ITfCompartmentEventSink;
 
            source.AdviseSink(ref guid, sink, out _cookie);
            Marshal.ReleaseComObject(compartment);
            Marshal.ReleaseComObject(source);
        }
 
        /// <summary>
        ///     Unadvise the notify sink of the compartment update.
        /// </summary>
        internal void UnadviseNotifySink()
        {
            Debug.Assert(_cookie != UnsafeNativeMethods.TF_INVALID_COOKIE, "cookie is not set.");
 
            UnsafeNativeMethods.ITfCompartment compartment = GetITfCompartment();
            if (compartment == null)
                return;
 
            UnsafeNativeMethods.ITfSource source = compartment as UnsafeNativeMethods.ITfSource;
            source.UnadviseSink(_cookie);
            _cookie = UnsafeNativeMethods.TF_INVALID_COOKIE;
 
            Marshal.ReleaseComObject(compartment);
            Marshal.ReleaseComObject(source);
        }
 
        /// <summary>
        ///    Retrieve ITfCompartment
        /// </summary>
        internal UnsafeNativeMethods.ITfCompartment GetITfCompartment()
        {
            UnsafeNativeMethods.ITfCompartment itfcompartment;
            _compartmentmgr.GetCompartment(ref _guid, out itfcompartment);
            return itfcompartment;
        }
 
        #endregion Internal methods
        
        //------------------------------------------------------
        //
        //  Internal Properties
        //
        //------------------------------------------------------
        
        #region Internal Properties
 
        /// <summary>
        ///     Cast the compartment variant to bool.
        /// </summary>
        internal bool BooleanValue
        {
            get
            {
                object obj = Value;
                if (obj == null)
                    return false;
 
                if ((int)obj != 0)
                    return true;
 
                return false;
            }
            set
            {
                Value = value ? 1 : 0;
            }
        }
 
        /// <summary>
        ///     Cast the compartment variant to int.
        /// </summary>
        internal int IntValue
        {
            get
            {
                object obj = Value;
                if (obj == null)
                    return 0;
 
                return (int)obj;
            }
            set
            {
                Value = value;
            }
        }
 
        /// <summary>
        ///     Get the compartment variant.
        /// </summary>
        internal object Value
        {
            get
            {
                UnsafeNativeMethods.ITfCompartment compartment = GetITfCompartment();
 
                if (compartment == null)
                    return null;
 
                object obj;
 
                compartment.GetValue(out obj);
 
                Marshal.ReleaseComObject(compartment);
 
                return obj;
            }
            set
            {
                UnsafeNativeMethods.ITfCompartment compartment = GetITfCompartment();
 
                if (compartment == null)
                    return;
 
                compartment.SetValue(tid: 0, ref value);
                Marshal.ReleaseComObject(compartment);
            }
        }
 
        #endregion Internal Properties
 
        //------------------------------------------------------
        //
        //  Private Methods
        //
        //------------------------------------------------------
        
        //------------------------------------------------------
        //
        //  Private Fields
        //
        //------------------------------------------------------
                
        #region Private Fields
 
        private readonly UnsafeNativeMethods.ITfCompartmentMgr _compartmentmgr;
 
        private Guid _guid;
        private int _cookie;
 
        #endregion Private Fields
    }
}