// 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.
 
 
using System.Collections.Generic;
using System.Collections.ObjectModel;
 
namespace System.ServiceModel
{
    public sealed class ExtensionCollection<T> : SynchronizedCollection<IExtension<T>>, IExtensionCollection<T>
        where T : IExtensibleObject<T>
    {
        private T _owner;
 
        public ExtensionCollection(T owner)
        {
            if (owner == null)
            {
                throw DiagnosticUtility.ExceptionUtility.ThrowHelperArgumentNull(nameof(owner));
            }
 
            _owner = owner;
        }
 
        public ExtensionCollection(T owner, object syncRoot)
            : base(syncRoot)
        {
            if (owner == null)
            {
                throw DiagnosticUtility.ExceptionUtility.ThrowHelperArgumentNull(nameof(owner));
            }
 
            _owner = owner;
        }
 
        bool ICollection<IExtension<T>>.IsReadOnly
        {
            get { return false; }
        }
 
        protected override void ClearItems()
        {
            IExtension<T>[] array;
 
            lock (SyncRoot)
            {
                array = new IExtension<T>[Count];
                CopyTo(array, 0);
                base.ClearItems();
 
                foreach (IExtension<T> extension in array)
                {
                    extension.Detach(_owner);
                }
            }
        }
 
        public E Find<E>()
        {
            List<IExtension<T>> items = Items;
 
            lock (SyncRoot)
            {
                for (int i = Count - 1; i >= 0; i--)
                {
                    IExtension<T> item = items[i];
                    if (item is E)
                    {
                        return (E)item;
                    }
                }
            }
 
            return default(E);
        }
 
        public Collection<E> FindAll<E>()
        {
            Collection<E> result = new Collection<E>();
            List<IExtension<T>> items = Items;
 
            lock (SyncRoot)
            {
                for (int i = 0; i < items.Count; i++)
                {
                    IExtension<T> item = items[i];
                    if (item is E)
                    {
                        result.Add((E)item);
                    }
                }
            }
 
            return result;
        }
 
        protected override void InsertItem(int index, IExtension<T> item)
        {
            if (item == null)
            {
                throw DiagnosticUtility.ExceptionUtility.ThrowHelperArgumentNull(nameof(item));
            }
 
            lock (SyncRoot)
            {
                item.Attach(_owner);
                base.InsertItem(index, item);
            }
        }
 
        protected override void RemoveItem(int index)
        {
            lock (SyncRoot)
            {
                Items[index].Detach(_owner);
                base.RemoveItem(index);
            }
        }
 
        protected override void SetItem(int index, IExtension<T> item)
        {
            throw DiagnosticUtility.ExceptionUtility.ThrowHelperError(new InvalidOperationException(SRP.SFxCannotSetExtensionsByIndex));
        }
    }
}