// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.
 
using System;
using System.Composition;
using Microsoft.CodeAnalysis.CSharp.Syntax;
using Microsoft.CodeAnalysis.Host.Mef;
using Microsoft.CodeAnalysis.ReassignedVariable;
using Microsoft.CodeAnalysis.Shared.Extensions;
using Roslyn.Utilities;
 
namespace Microsoft.CodeAnalysis.CSharp.ReassignedVariable;
 
[ExportLanguageService(typeof(IReassignedVariableService), LanguageNames.CSharp), Shared]
internal class CSharpReassignedVariableService : AbstractReassignedVariableService<
    ParameterSyntax,
    VariableDeclaratorSyntax,
    SingleVariableDesignationSyntax,
    IdentifierNameSyntax>
{
    [ImportingConstructor]
    [Obsolete(MefConstruction.ImportingConstructorMessage, error: true)]
    public CSharpReassignedVariableService()
    {
    }
 
    protected override SyntaxToken GetIdentifierOfVariable(VariableDeclaratorSyntax variable)
        => variable.Identifier;
 
    protected override SyntaxToken GetIdentifierOfSingleVariableDesignation(SingleVariableDesignationSyntax variable)
        => variable.Identifier;
 
    protected override bool HasInitializer(SyntaxNode variable)
        => (variable as VariableDeclaratorSyntax)?.Initializer != null;
 
    protected override SyntaxNode GetMemberBlock(SyntaxNode methodOrPropertyDeclaration)
        => methodOrPropertyDeclaration;
 
    protected override SyntaxNode GetParentScope(SyntaxNode localDeclaration)
    {
        var current = localDeclaration;
        while (current != null)
        {
            if (current is BlockSyntax or SwitchSectionSyntax or ArrowExpressionClauseSyntax or AnonymousMethodExpressionSyntax or MemberDeclarationSyntax)
                break;
 
            current = current.Parent;
        }
 
        Contract.ThrowIfNull(current, "Couldn't find a suitable parent of this local declaration");
        return current is GlobalStatementSyntax
            ? current.GetRequiredParent()
            : current;
    }
}