﻿// 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 System.Threading;
using System.Threading.Tasks;
using Microsoft.CodeAnalysis.CSharp.Syntax;
using Microsoft.CodeAnalysis.Host.Mef;
using Microsoft.CodeAnalysis.LanguageService;
using Microsoft.CodeAnalysis.Snippets;
using Microsoft.CodeAnalysis.Snippets.SnippetProviders;
using Microsoft.CodeAnalysis.Text;

namespace Microsoft.CodeAnalysis.CSharp.Snippets
{
    [ExportSnippetProvider(nameof(ISnippetProvider), LanguageNames.CSharp), Shared]
    internal sealed class CSharpWhileLoopSnippetProvider : AbstractWhileLoopSnippetProvider
    {
        [ImportingConstructor]
        [Obsolete(MefConstruction.ImportingConstructorMessage, error: true)]
        public CSharpWhileLoopSnippetProvider()
        {
        }

        protected override int GetTargetCaretPosition(ISyntaxFactsService syntaxFacts, SyntaxNode caretTarget, SourceText sourceText)
        {
            var whileStatement = (WhileStatementSyntax)caretTarget;
            var blockStatement = (BlockSyntax)whileStatement.Statement;

            var triviaSpan = blockStatement.CloseBraceToken.LeadingTrivia.Span;
            var line = sourceText.Lines.GetLineFromPosition(triviaSpan.Start);
            // Getting the location at the end of the line before the newline.
            return line.Span.End;
        }

        protected override SyntaxNode GetCondition(SyntaxNode node)
        {
            var whileStatement = (WhileStatementSyntax)node;
            return whileStatement.Condition;
        }

        protected override Task<Document> AddIndentationToDocumentAsync(Document document, CancellationToken cancellationToken)
        {
            return СSharpSnippetIndentationHelpers.AddBlockIndentationToDocumentAsync<WhileStatementSyntax>(
                document,
                FindSnippetAnnotation,
                static s => (BlockSyntax)s.Statement,
                cancellationToken);
        }
    }
}
