// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
 
// Description: InputBindingCollection serves the purpose of Storing/Retrieving InputBindings
//
//              See spec at : http://avalon/coreui/Specs/Commanding(new).mht
 
using System.Collections;
using MS.Internal;
 
namespace System.Windows.Input
{
    /// <summary>
    /// InputBindingCollection - Collection of InputBindings.
    ///     Stores the InputBindings Sequentially in an System.Collections.Generic.List"InputBinding"a.
    ///     Will be changed to generic List implementation once the
    ///     parser supports generic collections.
    /// </summary>
    public sealed class InputBindingCollection : IList
    {
        //------------------------------------------------------
        //
        //  Constructors
        //
        //------------------------------------------------------
        #region Constructors
        /// <summary>
        /// Constructor
        /// </summary>
        public InputBindingCollection()
        {
        }
 
        /// <summary>
        /// InputBindingCollection
        /// </summary>
        /// <param name="inputBindings">InputBinding array</param>
        public InputBindingCollection(IList inputBindings)
        {
            if (inputBindings != null && inputBindings.Count > 0)
            {
                this.AddRange(inputBindings as ICollection);
            }
        }
 
        /// <summary>
        ///     Internal Constructor
        /// </summary>
        internal InputBindingCollection(DependencyObject owner)
        {
            _owner = owner;
        }
 
        #endregion Constructors
 
        //------------------------------------------------------
        //
        //  Public Methods
        //
        //------------------------------------------------------
 
        #region Public Methods
 
#region Implementation of IList
 
#region Implementation of ICollection
        /// <summary>
        /// CopyTo - to copy the entire collection into an array
        /// </summary>
        /// <param name="array">generic object array</param>
        /// <param name="index"></param>
        void ICollection.CopyTo(System.Array array, int index)
        {
            if (_innerBindingList != null)
            {
                ((ICollection)_innerBindingList).CopyTo(array, index);
            }
        }
#endregion Implementation of ICollection
 
        /// <summary>
        /// IList.Contains
        /// </summary>
        /// <param name="key">key</param>
        /// <returns>true - if found, false - otherwise</returns>
        bool IList.Contains(object key)
        {
            return this.Contains(key as InputBinding);
        }
 
        /// <summary>
        /// IndexOf - returns the index of the item in the list
        /// </summary>
        /// <param name="value">item whose index is sought</param>
        /// <returns>index of the item or -1 </returns>
        int IList.IndexOf(object value)
        {
            InputBinding inputBinding = value as InputBinding;
            return ((inputBinding != null) ? this.IndexOf(inputBinding) : -1);
        }
 
        /// <summary>
        ///  Insert
        /// </summary>
        /// <param name="index"></param>
        /// <param name="value"></param>
        void IList.Insert(int index, object value)
        {
            this.Insert(index, value as InputBinding);
        }
 
        /// <summary>
        /// Add - appends the given inputbinding to the current list.
        /// </summary>
        /// <param name="inputBinding">InputBinding object to add</param>
        int IList.Add(object inputBinding)
        {
            this.Add(inputBinding as InputBinding);
            return 0; // ICollection.Add no longer returns the indice
        }
 
        /// <summary>
        /// Remove - removes the given inputbinding from the current list.
        /// </summary>
        /// <param name="inputBinding">InputBinding object to remove</param>
        void IList.Remove(object inputBinding)
        {
            this.Remove(inputBinding as InputBinding);
        }
 
        /// <summary>
        /// Indexing operator
        /// </summary>
        object IList.this[int index]
        {
            get
            {
                return this[index];
            }
            set
            {
                InputBinding inputBinding = value as InputBinding;
                if (inputBinding == null)
                   throw new NotSupportedException(SR.CollectionOnlyAcceptsInputBindings);
 
                this[index] = inputBinding;
            }
        }
 
#endregion Implementation of IList
        /// <summary>
        /// Indexing operator
        /// </summary>
        public InputBinding this[int index]
        {
            get
            {
                if (_innerBindingList != null)
                {
                    return _innerBindingList[index];
                }
                else
                {
                    throw new ArgumentOutOfRangeException(nameof(index));
                }
            }
            set
            {
                if (_innerBindingList != null)
                {
                    InputBinding oldInputBinding = null;
                    if (index >= 0 && index < _innerBindingList.Count)
                    {
                        oldInputBinding = _innerBindingList[index];
                    }
                    _innerBindingList[index] = value;
                    if (oldInputBinding != null)
                    {
                        InheritanceContextHelper.RemoveContextFromObject(_owner, oldInputBinding);
                    }
                    InheritanceContextHelper.ProvideContextForObject(_owner, value);
                }
                else
                {
                    throw new ArgumentOutOfRangeException(nameof(index));
                }
            }
        }
 
        /// <summary>
        /// Add
        /// </summary>
        /// <param name="inputBinding"></param>
        public int Add(InputBinding inputBinding)
        {
            if (inputBinding != null)
            {
                if (_innerBindingList == null)
                    _innerBindingList = new System.Collections.Generic.List<InputBinding>(1);
 
                _innerBindingList.Add(inputBinding);
                InheritanceContextHelper.ProvideContextForObject(_owner, inputBinding);
                return 0; // ICollection.Add no longer returns the indice
            }
            else
            {
                throw new NotSupportedException(SR.CollectionOnlyAcceptsInputBindings);
            }
        }
 
        /// <summary>
        /// ICollection.IsSynchronized
        /// </summary>
        public bool IsSynchronized
        {
            get
            {
                if (_innerBindingList != null)
                    return ((IList)_innerBindingList).IsSynchronized;
 
                return false;
            }
        }
 
        /// <summary>
        /// IndexOf
        /// </summary>
        /// <param name="value"></param>
        /// <returns></returns>
        public int IndexOf(InputBinding value)
        {
            return (_innerBindingList != null) ? _innerBindingList.IndexOf(value) : -1;
        }
 
        /// <summary>
        /// Adds the elements of the given collection to the end of this list. If
        /// required, the capacity of the list is increased to twice the previous
        /// capacity or the new size, whichever is larger.
        /// </summary>
        /// <param name="collection">collection to append</param>
        public void AddRange(ICollection collection)
        {
            ArgumentNullException.ThrowIfNull(collection);
 
            if ( collection.Count > 0)
            {
                if (_innerBindingList == null)
                    _innerBindingList = new System.Collections.Generic.List<InputBinding>(collection.Count);
 
                IEnumerator collectionEnum = collection.GetEnumerator();
                while(collectionEnum.MoveNext())
                {
                    InputBinding inputBinding = collectionEnum.Current as InputBinding;
                    if (inputBinding != null)
                    {
                        _innerBindingList.Add(inputBinding);
                        InheritanceContextHelper.ProvideContextForObject(_owner, inputBinding);
                    }
                    else
                    {
                        throw new NotSupportedException(SR.CollectionOnlyAcceptsInputBindings);
                    }
                }
            }
        }
 
        /// <summary>
        ///  Insert at given index
        /// </summary>
        /// <param name="index">index at which to insert the given item</param>
        /// <param name="inputBinding">inputBinding to insert</param>
        public void Insert(int index, InputBinding inputBinding)
        {
            if (inputBinding == null)
            {
                throw new NotSupportedException(SR.CollectionOnlyAcceptsInputBindings);
            }
 
            if (_innerBindingList != null)
            {
                _innerBindingList.Insert(index, inputBinding);
                InheritanceContextHelper.ProvideContextForObject(_owner, inputBinding);
            }
        }
 
        /// <summary>
        /// Remove
        /// </summary>
        /// <param name="inputBinding"></param>
        public void Remove(InputBinding inputBinding)
        {
            if (_innerBindingList != null && inputBinding != null)
            {
                if (_innerBindingList.Remove(inputBinding as InputBinding))
                {
                    InheritanceContextHelper.RemoveContextFromObject(_owner, inputBinding);
                }
            }
        }
 
        /// <summary>
        /// RemoveAt
        /// </summary>
        /// <param name="index">index at which the item needs to be removed</param>
        public void RemoveAt(int index)
        {
            if (_innerBindingList != null)
            {
                InputBinding oldInputBinding = null;
                if (index >= 0 && index < _innerBindingList.Count)
                {
                    oldInputBinding = _innerBindingList[index];
                }
                _innerBindingList.RemoveAt(index);
                if (oldInputBinding != null)
                {
                    InheritanceContextHelper.RemoveContextFromObject(_owner, oldInputBinding);
                }
            }
        }
 
        /// <summary>
        /// IsFixedSize - if readonly - fixed, else false.
        /// </summary>
        public bool IsFixedSize
        {
            get { return IsReadOnly; }
        }
 
        /// <summary>
        /// Count
        /// </summary>
        public int Count
        {
            get
            {
                return (_innerBindingList != null ? _innerBindingList.Count : 0);
            }
        }
 
        /// <summary>
        /// ICollection.SyncRoot
        /// </summary>
        public object SyncRoot
        {
            get
            {
                return this;
            }
        }
 
        /// <summary>
        /// Clears the Entire InputBindingCollection
        /// </summary>
        public void Clear()
        {
            if (_innerBindingList != null)
            {
                List<InputBinding> oldInputBindings = new List<InputBinding>(_innerBindingList);
                _innerBindingList.Clear();
                _innerBindingList = null;
                foreach (InputBinding inputBinding in oldInputBindings)
                {
                    InheritanceContextHelper.RemoveContextFromObject(_owner, inputBinding);
                }
            }
        }
 
#region Implementation of Enumerable
        /// <summary>
        /// IEnumerable.GetEnumerator - For Enumeration purposes
        /// </summary>
        /// <returns></returns>
        public IEnumerator GetEnumerator()
        {
            if (_innerBindingList != null)
                return _innerBindingList.GetEnumerator();
 
            System.Collections.Generic.List<InputBinding> list = new System.Collections.Generic.List<InputBinding>(0);
            return list.GetEnumerator();
        }
#endregion Implementation of IEnumberable
 
        /// <summary>
        /// IList.IsReadOnly - Tells whether this is readonly Collection.
        /// </summary>
        public bool IsReadOnly
        {
            get { return _isReadOnly; }
        }
 
        /// <summary>
        /// Contains
        /// </summary>
        /// <param name="key">key</param>
        /// <returns>true - if found, false - otherwise</returns>
        public bool Contains(InputBinding key)
        {
            if (_innerBindingList != null && key != null)
            {
                return _innerBindingList.Contains(key);
            }
 
            return false;
        }
 
        /// <summary>
        /// CopyTo - to copy the entire collection into an array
        /// </summary>
        /// <param name="inputBindings">type-safe InputBinding array</param>
        /// <param name="index">start index in the current list to copy</param>
        public void CopyTo(InputBinding[] inputBindings, int index)
        {
            _innerBindingList?.CopyTo(inputBindings, index);
        }
#endregion Public
 
#region internal
 
        internal InputBinding FindMatch(object targetElement, InputEventArgs inputEventArgs)
        {
            for (int i = Count - 1; i >= 0; i--)
            {
                InputBinding inputBinding = this[i];
                if ((inputBinding.Command != null) && (inputBinding.Gesture != null) &&
                    inputBinding.Gesture.Matches(targetElement, inputEventArgs))
                {
                    return inputBinding;
                }
            }
 
            return null;
        }
 
#endregion internal
        //------------------------------------------------------
        //
        //  Protected Methods
        //
        //------------------------------------------------------
        //------------------------------------------------------
        //
        //  Private Methods
        //
        //------------------------------------------------------
        //------------------------------------------------------
        //
        //  Private Fields
        //
        //------------------------------------------------------
#region Private Fields
        private List<InputBinding> _innerBindingList;
        private bool  _isReadOnly = false;
        private DependencyObject _owner = null;
#endregion Private Fields
    }
}