// Copyright (c) 2010-2013 AlphaSierraPapa for the SharpDevelop Team
// 
// 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.

using System;

using ICSharpCode.Decompiler.CSharp.Resolver;
using ICSharpCode.Decompiler.Semantics;
using ICSharpCode.Decompiler.TypeSystem;

namespace ICSharpCode.Decompiler.CSharp.TypeSystem
{
	/// <summary>
	/// Represents a reference which could point to a type or namespace.
	/// </summary>
	[Serializable]
	public abstract class TypeOrNamespaceReference : ITypeReference
	{
		/// <summary>
		/// Resolves the reference and returns the ResolveResult.
		/// </summary>
		public abstract ResolveResult Resolve(CSharpResolver resolver);

		/// <summary>
		/// Returns the type that is referenced; or an <c>UnknownType</c> if the type isn't found.
		/// </summary>
		public abstract IType ResolveType(CSharpResolver resolver);

		/// <summary>
		/// Returns the namespace that is referenced; or null if no such namespace is found.
		/// </summary>
		public INamespace ResolveNamespace(CSharpResolver resolver)
		{
			NamespaceResolveResult nrr = Resolve(resolver) as NamespaceResolveResult;
			return nrr != null ? nrr.Namespace : null;
		}

		IType ITypeReference.Resolve(ITypeResolveContext context)
		{
			// Strictly speaking, we might have to resolve the type in a nested compilation, similar
			// to what we're doing with ConstantExpression.
			// However, in almost all cases this will work correctly - if the resulting type is only available in the
			// nested compilation and not in this, we wouldn't be able to map it anyways.
			var ctx = context as CSharpTypeResolveContext;
			if (ctx == null)
			{
				ctx = new CSharpTypeResolveContext(context.CurrentModule ?? context.Compilation.MainModule, null, context.CurrentTypeDefinition, context.CurrentMember);
			}
			return ResolveType(new CSharpResolver(ctx));

			// A potential issue might be this scenario:

			// Assembly 1:
			//  class A { public class Nested {} }

			// Assembly 2: (references asm 1)
			//  class B : A {}

			// Assembly 3: (references asm 1 and 2)
			//  class C { public B.Nested Field; }

			// Assembly 4: (references asm 1 and 3, but not 2):
			//  uses C.Field;

			// Here we would not be able to resolve 'B.Nested' in the compilation of assembly 4, as type B is missing there.
		}
	}
}
