using System.Collections;
using System.Collections.Generic;
using System.Linq;

namespace CommonLibrary
{
	public static class CollectionTools
	{
		/// <summary>
		/// Checks whether a collection is the same as another collection
		/// </summary>
		/// <param name="value">The current instance object</param>
		/// <param name="compareList">The collection to compare with</param>
		/// <param name="comparer">The comparer object to use to compare each item in the collection.  If null uses EqualityComparer<TSource>.Default</param>
		/// <returns>True if the two collections contain all the same items in the same order</returns>
		public static bool IsEqualTo<TSource>(this IEnumerable<TSource> value, IEnumerable<TSource> compareList, IEqualityComparer<TSource> comparer)
		{
			if (comparer == null)
			{
				comparer = EqualityComparer<TSource>.Default;
			}

			if (compareList == null || value.Count() != compareList.Count())
			{
				return false;
			}
			else
			{
				IEnumerator<TSource> enumerator1 = value.GetEnumerator();
				IEnumerator<TSource> enumerator2 = compareList.GetEnumerator();

				while (enumerator1.MoveNext() && enumerator2.MoveNext())
				{
					if (!comparer.Equals(enumerator1.Current, enumerator2.Current))
					{
						return false;
					}
				}

				return true;
			}
		}

		/// <summary>
		/// Checks whether a collection is the same as another collection
		/// </summary>
		/// <param name="value">The current instance object</param>
		/// <param name="compareList">The collection to compare with</param>
		/// <returns>True if the two collections contain all the same items in the same order</returns>
		public static bool IsEqualTo<TSource>(this IEnumerable<TSource> value, IEnumerable<TSource> compareList)
		{
			return IsEqualTo(value, compareList, null);
		}

		/// <summary>
		/// Checks whether a collection is the same as another collection
		/// </summary>
		/// <param name="value">The current instance object</param>
		/// <param name="compareList">The collection to compare with</param>
		/// <returns>True if the two collections contain all the same items in the same order</returns>
		public static bool IsEqualTo(this IEnumerable value, IEnumerable compareList)
		{
			return IsEqualTo<object>(value.OfType<object>(), compareList.OfType<object>());
		}
	}
}