/***************************************************************************

Copyright (c) Microsoft Corporation. All rights reserved.
This code is licensed under the Visual Studio SDK license terms.
THIS CODE IS PROVIDED *AS IS* WITHOUT WARRANTY OF
ANY KIND, EITHER EXPRESS OR IMPLIED, INCLUDING ANY
IMPLIED WARRANTIES OF FITNESS FOR A PARTICULAR
PURPOSE, MERCHANTABILITY, OR NON-INFRINGEMENT.

***************************************************************************/

using System;
using System.Collections.Generic;
using Microsoft.VisualStudio;
using Microsoft.VisualStudio.Shell.Interop;

namespace Microsoft.VisualStudio.Project
{
	[CLSCompliant(false)]
	public class EnumDependencies : IVsEnumDependencies
	{
		private List<IVsDependency> dependencyList = new List<IVsDependency>();

		private uint nextIndex;

        public EnumDependencies(IList<IVsDependency> dependencyList)
		{
            if (dependencyList == null)
            {
                throw new ArgumentNullException("dependencyList");
            }

			foreach(IVsDependency dependency in dependencyList)
			{
				this.dependencyList.Add(dependency);
			}
		}

        public EnumDependencies(IList<IVsBuildDependency> dependencyList)
		{
            if (dependencyList == null)
            {
                throw new ArgumentNullException("dependencyList");
            }

			foreach(IVsBuildDependency dependency in dependencyList)
			{
				this.dependencyList.Add(dependency);
			}
		}

        public int Clone(out IVsEnumDependencies enumDependencies)
		{
			enumDependencies = new EnumDependencies(this.dependencyList);
			ErrorHandler.ThrowOnFailure(enumDependencies.Skip(this.nextIndex));
			return VSConstants.S_OK;
		}

        public int Next(uint elements, IVsDependency[] dependencies, out uint elementsFetched)
		{
            elementsFetched = 0;
            if (dependencies == null)
            {
                throw new ArgumentNullException("dependencies");
            }
			
            uint fetched = 0;
			int count = this.dependencyList.Count;

			while(this.nextIndex < count && elements > 0 && fetched < count)
			{
				dependencies[fetched] = this.dependencyList[(int)this.nextIndex];
				this.nextIndex++;
				fetched++;
				elements--;

			}

			elementsFetched = fetched;

			// Did we get 'em all?
			return (elements == 0 ? VSConstants.S_OK : VSConstants.S_FALSE);
		}

		public int Reset()
		{
			this.nextIndex = 0;
			return VSConstants.S_OK;
		}

        public int Skip(uint elements)
		{
			this.nextIndex += elements;
			uint count = (uint)this.dependencyList.Count;

			if(this.nextIndex > count)
			{
				this.nextIndex = count;
				return VSConstants.S_FALSE;
			}

			return VSConstants.S_OK;
		}
	}
}