/// Copyright (c) Microsoft Corporation.  All rights reserved.

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

		public EnumDependencies(IList<IVsBuildDependency> 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)
		{
			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;
		}
	}
}