// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.

//
// 
// Description: TextCompositionEventArgs class
//
//

using System;

namespace System.Windows.Input 
{
    /// <summary>
    ///     The TextCompositionEventArgs class contains a text representation of
    ///     input.
    /// </summary>
    public class TextCompositionEventArgs : InputEventArgs
    {
        /// <summary>
        ///     Constructs an instance of the TextInputEventArgs class.
        /// </summary>
        /// <param name="inputDevice">
        ///     The input device to associate with this event.
        /// </param>
        /// <param name="composition">
        ///     The TextComposition object that contains the composition text and the composition state.
        /// </param>
        public TextCompositionEventArgs(InputDevice inputDevice, TextComposition composition) : base(inputDevice, Environment.TickCount)
        {
            ArgumentNullException.ThrowIfNull(composition);

            _composition = composition;
        }

        /// <summary>
        ///     The text composition that was provided.
        /// </summary>
        /// <ExternalAPI Inherit="true"/>
        public TextComposition TextComposition
        {
            get {return _composition;}
        }

        /// <summary>
        ///     The result text that was provided as input.
        /// </summary>
        /// <ExternalAPI Inherit="true"/>
        public string Text
        {
            get {return _composition.Text;}
        }

        /// <summary>
        ///     The result system text that was provided as input.
        /// </summary>
        /// <ExternalAPI Inherit="true"/>
        public string SystemText
        {
            get {return _composition.SystemText;}
        }

        /// <summary>
        ///     The result control text that was provided as input.
        /// </summary>
        /// <ExternalAPI Inherit="true"/>
        public string ControlText
        {
            get {return _composition.ControlText;}
        }

        /// <summary>
        ///     The mechanism used to call the type-specific handler on the
        ///     target.
        /// </summary>
        /// <param name="genericHandler">
        ///     The generic handler to call in a type-specific way.
        /// </param>
        /// <param name="genericTarget">
        ///     The target to call the handler on.
        /// </param>
        /// <ExternalAPI/> 
        protected override void InvokeEventHandler(Delegate genericHandler, object genericTarget)
        {
            TextCompositionEventHandler handler = (TextCompositionEventHandler) genericHandler;
            
            handler(genericTarget, this);
        }

        // The target TextComposition object of this event.
        private TextComposition _composition;
    }
}

