// 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.Linq;
using Microsoft.CodeAnalysis.CSharp.Syntax;
using Microsoft.CodeAnalysis.Shared.Extensions;

namespace Microsoft.CodeAnalysis.CSharp.Extensions;

internal static class StatementSyntaxExtensions
{
    public static StatementSyntax WithoutLeadingBlankLinesInTrivia(this StatementSyntax statement)
        => statement.WithLeadingTrivia(statement.GetLeadingTrivia().WithoutLeadingBlankLines());

    public static StatementSyntax? GetPreviousStatement(this StatementSyntax? statement)
    {
        if (statement != null)
        {
            var previousToken = statement.GetFirstToken().GetPreviousToken();
            return previousToken.GetAncestors<StatementSyntax>().FirstOrDefault(s => AreSiblingStatements(s, statement));
        }

        return null;
    }

    public static StatementSyntax? GetNextStatement(this StatementSyntax? statement)
    {
        if (statement != null)
        {
            var nextToken = statement.GetLastToken().GetNextToken();
            return nextToken.GetAncestors<StatementSyntax>().FirstOrDefault(s => AreSiblingStatements(s, statement));
        }

        return null;
    }

    private static bool AreSiblingStatements(StatementSyntax first, StatementSyntax second)
    {
        if (first.Parent.IsKind(SyntaxKind.GlobalStatement))
            return second.Parent.IsKind(SyntaxKind.GlobalStatement);
        else
            return first.Parent == second.Parent;
    }
}