// 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.Collections.Immutable;
using System.Threading;
using System.Threading.Tasks;
using Microsoft.CodeAnalysis.CodeActions;
using Microsoft.CodeAnalysis.CodeFixes;
using Microsoft.CodeAnalysis.Diagnostics;
using Microsoft.CodeAnalysis.Editing;
using Microsoft.CodeAnalysis.LanguageService;
using Microsoft.CodeAnalysis.Shared.Extensions;

namespace Microsoft.CodeAnalysis.RemoveUnnecessaryParentheses
{
    internal abstract class AbstractRemoveUnnecessaryParenthesesCodeFixProvider<TParenthesizedExpressionSyntax>
        : SyntaxEditorBasedCodeFixProvider
        where TParenthesizedExpressionSyntax : SyntaxNode
    {
        public override ImmutableArray<string> FixableDiagnosticIds
           => ImmutableArray.Create(IDEDiagnosticIds.RemoveUnnecessaryParenthesesDiagnosticId);

        protected abstract bool CanRemoveParentheses(
            TParenthesizedExpressionSyntax current, SemanticModel semanticModel, CancellationToken cancellationToken);

        public override Task RegisterCodeFixesAsync(CodeFixContext context)
        {
            RegisterCodeFix(context, AnalyzersResources.Remove_unnecessary_parentheses, nameof(AnalyzersResources.Remove_unnecessary_parentheses));
            return Task.CompletedTask;
        }

        protected override Task FixAllAsync(
            Document document, ImmutableArray<Diagnostic> diagnostics,
            SyntaxEditor editor, CodeActionOptionsProvider fallbackOptions, CancellationToken cancellationToken)
        {
            var syntaxFacts = document.GetRequiredLanguageService<ISyntaxFactsService>();
            var originalNodes = diagnostics.SelectAsArray(
                d => (TParenthesizedExpressionSyntax)d.AdditionalLocations[0].FindNode(
                    findInsideTrivia: true, getInnermostNodeForTie: true, cancellationToken));

            return editor.ApplyExpressionLevelSemanticEditsAsync(
                document, originalNodes,
                (semanticModel, current) => current != null && CanRemoveParentheses(current, semanticModel, cancellationToken),
                (_, currentRoot, current) => currentRoot.ReplaceNode(current, syntaxFacts.Unparenthesize(current)),
                cancellationToken);
        }
    }
}
