// 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 Microsoft.CodeAnalysis.Editor.Shared.Extensions;
using Microsoft.VisualStudio.Commanding;
using Microsoft.VisualStudio.Text;
using Microsoft.VisualStudio.Text.Editor;
using Microsoft.VisualStudio.Text.Editor.Commanding.Commands;
 
namespace Microsoft.CodeAnalysis.Editor.Implementation.InlineRename;
 
internal abstract partial class AbstractRenameCommandHandler :
    ICommandHandler<LineStartCommandArgs>, ICommandHandler<LineEndCommandArgs>,
    ICommandHandler<LineStartExtendCommandArgs>, ICommandHandler<LineEndExtendCommandArgs>
{
    public CommandState GetCommandState(LineStartCommandArgs args)
        => GetCommandState();
 
    public CommandState GetCommandState(LineEndCommandArgs args)
        => GetCommandState();
 
    public CommandState GetCommandState(LineStartExtendCommandArgs args)
        => GetCommandState();
 
    public CommandState GetCommandState(LineEndExtendCommandArgs args)
        => GetCommandState();
 
    public bool ExecuteCommand(LineStartCommandArgs args, CommandExecutionContext context)
        => HandleLineStartOrLineEndCommand(args.SubjectBuffer, args.TextView, lineStart: true, extendSelection: false);
 
    public bool ExecuteCommand(LineEndCommandArgs args, CommandExecutionContext context)
        => HandleLineStartOrLineEndCommand(args.SubjectBuffer, args.TextView, lineStart: false, extendSelection: false);
 
    public bool ExecuteCommand(LineStartExtendCommandArgs args, CommandExecutionContext context)
        => HandleLineStartOrLineEndCommand(args.SubjectBuffer, args.TextView, lineStart: true, extendSelection: true);
 
    public bool ExecuteCommand(LineEndExtendCommandArgs args, CommandExecutionContext context)
        => HandleLineStartOrLineEndCommand(args.SubjectBuffer, args.TextView, lineStart: false, extendSelection: true);
 
    private bool HandleLineStartOrLineEndCommand(ITextBuffer subjectBuffer, ITextView view, bool lineStart, bool extendSelection)
    {
        if (_renameService.ActiveSession == null)
        {
            return false;
        }
 
        var caretPoint = view.GetCaretPoint(subjectBuffer);
        if (caretPoint.HasValue)
        {
            if (_renameService.ActiveSession.TryGetContainingEditableSpan(caretPoint.Value, out var span))
            {
                var newPoint = lineStart ? span.Start : span.End;
                if (newPoint == caretPoint.Value && (view.Selection.IsEmpty || extendSelection))
                {
                    // We're already at a boundary, let the editor handle the command
                    return false;
                }
 
                // The PointTrackingMode should not matter because we are not tracking between
                // versions, and the PositionAffinity is set towards the identifier.
                var newPointInView = view.BufferGraph.MapUpToBuffer(
                    newPoint,
                    PointTrackingMode.Negative,
                    lineStart ? PositionAffinity.Successor : PositionAffinity.Predecessor,
                    view.TextBuffer);
 
                if (!newPointInView.HasValue)
                {
                    return false;
                }
 
                if (extendSelection)
                {
                    view.Selection.Select(view.Selection.AnchorPoint, new VirtualSnapshotPoint(newPointInView.Value));
                }
                else
                {
                    view.Selection.Clear();
                }
 
                view.Caret.MoveTo(newPointInView.Value);
                return true;
            }
        }
 
        return false;
    }
}