// 
// VariableHidesMemberIssue.cs
// 
// Author:
//      Mansheng Yang <lightyang0@gmail.com>
// 
// Copyright (c) 2012 Mansheng Yang <lightyang0@gmail.com>
// 
// 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.Collections.Generic;
using System.Linq;
using ICSharpCode.NRefactory.Semantics;
using ICSharpCode.NRefactory.TypeSystem;
using System;

namespace ICSharpCode.NRefactory.CSharp.Refactoring
{
	public abstract class VariableHidesMemberIssue : ICodeIssueProvider
	{
		public IEnumerable<CodeIssue> GetIssues(BaseRefactoringContext context)
		{
			return GetGatherVisitor(context).GetIssues();
		}

		protected static bool HidesMember(BaseRefactoringContext ctx, AstNode node, string variableName)
		{
			var typeDecl = node.GetParent<TypeDeclaration>();
			if (typeDecl == null)
				return false;
			var entityDecl = node.GetParent<EntityDeclaration>();
			var memberResolveResult = ctx.Resolve(entityDecl) as MemberResolveResult;
			if (memberResolveResult == null)
				return false;
			var typeResolveResult = ctx.Resolve(typeDecl) as TypeResolveResult;
			if (typeResolveResult == null)
				return false;

			var sourceMember = memberResolveResult.Member;

			return typeResolveResult.Type.GetMembers(m => m.Name == variableName).Any(m2 => IsAccessible(sourceMember, m2));
		}

		static bool IsAccessible(IMember sourceMember, IMember targetMember)
		{
			if (sourceMember.IsStatic != targetMember.IsStatic)
				return false;

			var sourceType = sourceMember.DeclaringType;
			var targetType = targetMember.DeclaringType;
			switch (targetMember.Accessibility) {
				case Accessibility.None:
					return false;
				case Accessibility.Private:
					// check for members of outer classes (private members of outer classes can be accessed)
					var targetTypeDefinition = targetType.GetDefinition();
					for (var t = sourceType.GetDefinition(); t != null; t = t.DeclaringTypeDefinition) {
						if (t.Equals(targetTypeDefinition))
							return true;
					}
					return false;
				case Accessibility.Public:
					return true;
				case Accessibility.Protected:
					return IsProtectedAccessible(sourceType, targetType);
				case Accessibility.Internal:
					return IsInternalAccessible(sourceMember.ParentAssembly, targetMember.ParentAssembly);
				case Accessibility.ProtectedOrInternal:
					return IsInternalAccessible(sourceMember.ParentAssembly, targetMember.ParentAssembly) || IsProtectedAccessible(sourceType, targetType);
				case Accessibility.ProtectedAndInternal:
					return IsInternalAccessible(sourceMember.ParentAssembly, targetMember.ParentAssembly) && IsProtectedAccessible(sourceType, targetType);
				default:
					throw new Exception("Invalid value for Accessibility");
			}
		}

		static bool IsProtectedAccessible(IType sourceType, IType targetType)
		{
			return sourceType.GetAllBaseTypes().Any(type => targetType.Equals(type));
		}

		static bool IsInternalAccessible(IAssembly sourceAssembly, IAssembly targetAssembly)
		{
			return sourceAssembly.InternalsVisibleTo(targetAssembly);
		}

		internal abstract GatherVisitorBase GetGatherVisitor(BaseRefactoringContext context);

	}
}