// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
 
// Description: The KeyBinding class is used by the developer to create Keyboard Input Bindings 
//
//                  See spec at : http://avalon/coreui/Specs/Commanding(new).mht 
// 
//* KeyBinding class serves the purpose of Input Bindings for Keyboard Device.
using System.ComponentModel;
using System.Windows.Markup;
 
namespace System.Windows.Input
{
    /// <summary>
    /// KeyBinding - Implements InputBinding (generic InputGesture-Command map)
    ///         KeyBinding acts like a map for KeyGesture and Commands. 
    ///         Most of the logic is in InputBinding and KeyGesture, this only 
    ///         facilitates user  to add Key/Modifiers directly without going in
    ///         KeyGesture path. Also it provides the KeyGestureTypeConverter 
    ///         on the Gesture property to have KeyGesture, like Ctrl+X, Alt+V 
    ///         defined in Markup as Gesture="Ctrl+X" working
    /// </summary>
    public class KeyBinding : InputBinding
    {
        //------------------------------------------------------
        //
        //  Constructors
        //
        //------------------------------------------------------
        #region Constructor
        /// <summary>
        /// Constructor 
        /// </summary>
        public KeyBinding() : base()
        {
        }
 
        /// <summary>
        /// Constructor
        /// </summary>
        /// <param name="command">Command associated</param>
        /// <param name="gesture">KeyGesture associated</param>
        public KeyBinding(ICommand command, KeyGesture gesture) : base(command, gesture)
        {
            SynchronizePropertiesFromGesture(gesture);
        }
 
        /// <summary>
        /// Constructor
        /// </summary>
        /// <param name="command"></param>
        /// <param name="modifiers">modifiers</param>
        /// <param name="key">key</param>
        public KeyBinding(ICommand command, Key key, ModifierKeys modifiers) : 
                            this(command, new KeyGesture(key, modifiers))
        {
        }
        #endregion Constructor
 
        //------------------------------------------------------
        //
        //  Public Methods
        //
        //------------------------------------------------------
        #region Public Methods
        /// <summary>
        /// KeyGesture Override, to ensure type-safety and provide a 
        ///  TypeConverter for KeyGesture
        /// </summary>
        [TypeConverter(typeof(KeyGestureConverter))]
        [ValueSerializer(typeof(KeyGestureValueSerializer))]
        public override InputGesture Gesture
        {
            get
            {
                return base.Gesture as KeyGesture;
            }
            set
            {
                KeyGesture keyGesture = value as KeyGesture;
                if (keyGesture != null)
                {
                    base.Gesture = value;
                    SynchronizePropertiesFromGesture(keyGesture);
                }
                else
                {
                    throw new ArgumentException(SR.Format(SR.InputBinding_ExpectedInputGesture, typeof(KeyGesture)));
                }
            }
        }
 
        /// <summary>
        ///     Dependency Property for Modifiers
        /// </summary>
        public static readonly DependencyProperty ModifiersProperty =
            DependencyProperty.Register("Modifiers", typeof(ModifierKeys), typeof(KeyBinding), new UIPropertyMetadata(ModifierKeys.None, new PropertyChangedCallback(OnModifiersPropertyChanged)));
 
        /// <summary>
        ///     Modifiers
        /// </summary>
        public ModifierKeys Modifiers
        {
            get
            {
                return (ModifierKeys)GetValue(ModifiersProperty);
            }
            set
            {
                SetValue(ModifiersProperty, value);
            }
        }
 
        private static void OnModifiersPropertyChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
        {
            KeyBinding keyBinding = (KeyBinding)d;
            keyBinding.SynchronizeGestureFromProperties(keyBinding.Key, (ModifierKeys)(e.NewValue));
        }
 
        /// <summary>
        ///     Dependency Property for Key
        /// </summary>
        public static readonly DependencyProperty KeyProperty =
            DependencyProperty.Register("Key", typeof(Key), typeof(KeyBinding), new UIPropertyMetadata(Key.None, new PropertyChangedCallback(OnKeyPropertyChanged)));
 
        /// <summary>
        ///     Key
        /// </summary>
        public Key Key
        {
            get
            {
                return (Key)GetValue(KeyProperty);
            }
            set
            {
                SetValue(KeyProperty, value);
            }
        }
 
        private static void OnKeyPropertyChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
        {
            KeyBinding keyBinding = (KeyBinding)d;
            keyBinding.SynchronizeGestureFromProperties((Key)(e.NewValue), keyBinding.Modifiers);
        }
 
        #endregion Public Methods
 
        #region Freezable
 
        protected override Freezable CreateInstanceCore()
        {
            return new KeyBinding();
        }
 
        #endregion
 
        #region Private Methods
 
        /// <summary>
        ///     Synchronized Properties from Gesture
        /// </summary>
        private void SynchronizePropertiesFromGesture(KeyGesture keyGesture)
        {
            if (!_settingGesture)
            {
                _settingGesture = true;
                try
                {
                    Key = keyGesture.Key;
                    Modifiers = keyGesture.Modifiers;
                }
                finally
                {
                    _settingGesture = false;
                }
            }
        }
 
        /// <summary>
        ///     Synchronized Gesture from properties
        /// </summary>
        private void SynchronizeGestureFromProperties(Key key, ModifierKeys modifiers)
        {
            if (!_settingGesture)
            {
                _settingGesture = true;
                try
                {
                    Gesture = new KeyGesture(key, modifiers, validateGesture: false);
                }
                finally
                {
                    _settingGesture = false;
                }
            }
        }
 
        #endregion
        //------------------------------------------------------
        //
        //   Private Fields
        //
        //------------------------------------------------------
        #region Data
 
        private bool _settingGesture = false;
 
        #endregion
    }
 }