#region License
// Copyright (c) 2007 James Newton-King
//
// Permission is hereby granted, free of charge, to any person
// obtaining a copy of this software and associated documentation
// files (the "Software"), to deal in the Software without
// restriction, including without limitation the rights to use,
// copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the
// Software is furnished to do so, subject to the following
// conditions:
//
// The above copyright notice and this permission notice shall be
// included in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
// OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
// HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
// WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
// OTHER DEALINGS IN THE SOFTWARE.
#endregion

using System.Collections.Generic;
#if NET20
using Newtonsoft.Json.Utilities.LinqBridge;
#else
using System.Linq;
#endif
using Newtonsoft.Json.Utilities;
using System.Collections;

namespace Newtonsoft.Json.Linq
{
  /// <summary>
  /// Represents a collection of <see cref="JToken"/> objects.
  /// </summary>
  /// <typeparam name="T">The type of token</typeparam>
  public struct JEnumerable<T> : IJEnumerable<T> where T : JToken
  {
    /// <summary>
    /// An empty collection of <see cref="JToken"/> objects.
    /// </summary>
    public static readonly JEnumerable<T> Empty = new JEnumerable<T>(Enumerable.Empty<T>());

    private readonly IEnumerable<T> _enumerable;

    /// <summary>
    /// Initializes a new instance of the <see cref="JEnumerable{T}"/> struct.
    /// </summary>
    /// <param name="enumerable">The enumerable.</param>
    public JEnumerable(IEnumerable<T> enumerable)
    {
      ValidationUtils.ArgumentNotNull(enumerable, "enumerable");

      _enumerable = enumerable;
    }

    /// <summary>
    /// Returns an enumerator that iterates through the collection.
    /// </summary>
    /// <returns>
    /// A <see cref="T:System.Collections.Generic.IEnumerator`1"/> that can be used to iterate through the collection.
    /// </returns>
    public IEnumerator<T> GetEnumerator()
    {
      return _enumerable.GetEnumerator();
    }

    /// <summary>
    /// Returns an enumerator that iterates through a collection.
    /// </summary>
    /// <returns>
    /// An <see cref="T:System.Collections.IEnumerator"/> object that can be used to iterate through the collection.
    /// </returns>
    IEnumerator IEnumerable.GetEnumerator()
    {
      return GetEnumerator();
    }

    /// <summary>
    /// Gets the <see cref="IJEnumerable{JToken}"/> with the specified key.
    /// </summary>
    /// <value></value>
    public IJEnumerable<JToken> this[object key]
    {
      get { return new JEnumerable<JToken>(Extensions.Values<T, JToken>(_enumerable, key)); }
    }

    /// <summary>
    /// Determines whether the specified <see cref="System.Object"/> is equal to this instance.
    /// </summary>
    /// <param name="obj">The <see cref="System.Object"/> to compare with this instance.</param>
    /// <returns>
    /// 	<c>true</c> if the specified <see cref="System.Object"/> is equal to this instance; otherwise, <c>false</c>.
    /// </returns>
    public override bool Equals(object obj)
    {
      if (obj is JEnumerable<T>)
        return _enumerable.Equals(((JEnumerable<T>)obj)._enumerable);

      return false;
    }

    /// <summary>
    /// Returns a hash code for this instance.
    /// </summary>
    /// <returns>
    /// A hash code for this instance, suitable for use in hashing algorithms and data structures like a hash table. 
    /// </returns>
    public override int GetHashCode()
    {
      return _enumerable.GetHashCode();
    }
  }
}
