// 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 Microsoft.CodeAnalysis.LanguageService;
using Microsoft.CodeAnalysis.Shared.Extensions;
using Microsoft.CodeAnalysis.Text;
using Microsoft.VisualStudio.Commanding;
using Microsoft.VisualStudio.Text.Editor.Commanding.Commands;

namespace Microsoft.CodeAnalysis.Editor.Implementation.InlineRename;

internal abstract partial class AbstractRenameCommandHandler :
    IChainedCommandHandler<TypeCharCommandArgs>
{
    public CommandState GetCommandState(TypeCharCommandArgs args, Func<CommandState> nextHandler)
        => GetCommandState(nextHandler);

    public void ExecuteCommand(TypeCharCommandArgs args, Action nextHandler, CommandExecutionContext context)
    {
        HandlePossibleTypingCommand(args, nextHandler, context.OperationContext, (activeSession, _, span) =>
        {
            var document = args.SubjectBuffer.CurrentSnapshot.GetOpenDocumentInCurrentContextWithChanges();
            if (document == null)
            {
                nextHandler();
                return;
            }

            var syntaxFactsService = document.GetLanguageService<ISyntaxFactsService>();

            // We are inside the region we can edit, so let's forward only if it's a valid
            // character
            if (syntaxFactsService == null ||
                syntaxFactsService.IsIdentifierStartCharacter(args.TypedChar) ||
                syntaxFactsService.IsIdentifierPartCharacter(args.TypedChar) ||
                syntaxFactsService.IsStartOfUnicodeEscapeSequence(args.TypedChar))
            {
                nextHandler();
            }
        });
    }
}
