MycLib/ASTPlayground/Myc.Ast.Visualizer.pas

unit Myc.Ast.Visualizer;

interface

uses
    System.SysUtils,
    System.Classes,
    System.UITypes,
    System.Types,
    System.Generics.Collections,
    FMX.Types,
    FMX.Controls,
    FMX.Objects,
    FMX.Graphics,
    Myc.Ast.Nodes;

type
    TPinConnection = record
        OutputPin: TControl;
        InputPin: TControl;
        constructor Create(AOutputPin, AInputPin: TControl);
    end;

    TPinShape = (psCircle, psTriangle);
    TPinAlignment = (paLeft, paRight);

    // New enum to select the visualization style.
    TVisualizationMode = (vmDetailed, vmControlFlow);

    // A movable panel with a custom-painted border and title.
    TAuraNode = class(TStyledControl)
    private
        // Flag to indicate if the control is currently being dragged.
        FIsDragging: Boolean;
        // Stores the mouse coordinates at the beginning of the drag operation.
        FDownPos: TPointF;
        // Properties for the custom-drawn border.
        FBorderColor: TAlphaColor;
        FBorderWidth: Single;
        FBorderRadius: Single;
        // Properties for the title
        FTitle: string;
        FTitleFont: TFont;
        FTitleFontColor: TAlphaColor;
        // If true, the node is drawn without a border and with a transparent background.
        FFrameless: Boolean;

        procedure SetBorderColor(const Value: TAlphaColor);
        procedure SetBorderWidth(const Value: Single);
        procedure SetBorderRadius(const Value: Single);
        procedure SetTitle(const Value: string);
        procedure SetTitleFont(const Value: TFont);
        procedure SetTitleFontColor(const Value: TAlphaColor);
        procedure TitleFontChanged(Sender: TObject);
        procedure SetFrameless(const Value: Boolean);
    protected
        procedure Paint; override;
        procedure MouseDown(Button: TMouseButton; Shift: TShiftState; X, Y: Single); override;
        procedure MouseMove(Shift: TShiftState; X, Y: Single); override;
        procedure MouseUp(Button: TMouseButton; Shift: TShiftState; X, Y: Single); override;
    public
        constructor Create(AOwner: TComponent); override;
        destructor Destroy; override;
    published
        // Custom border properties
        property BorderColor: TAlphaColor read FBorderColor write SetBorderColor;
        property BorderWidth: Single read FBorderWidth write SetBorderWidth;
        property BorderRadius: Single read FBorderRadius write SetBorderRadius;

        // Title properties
        property Title: string read FTitle write SetTitle;
        property TitleFont: TFont read FTitleFont write SetTitleFont;
        property TitleFontColor: TAlphaColor read FTitleFontColor write SetTitleFontColor;

        // Behavior properties
        property Frameless: Boolean read FFrameless write SetFrameless;

        // Standard control properties
        property Align;
        property Anchors;
        property ClipChildren default True;
        property Cursor default crDefault;
        property DragMode default TDragMode.dmManual;
        property Enabled;
        property Height;
        property HelpContext;
        property HelpKeyword;
        property HelpType;
        property Hint;
        property HitTest default True;
        property Locked;
        property Margins;
        property Opacity;
        property Padding;
        property PopupMenu;
        property Position;
        property RotationAngle;
        property RotationCenter;
        property Scale;
        property Size;
        property StyleLookup;
        property Visible;
        property Width;
        property OnClick;
        property OnDblClick;
        property OnMouseDown;
        property OnMouseMove;
        property OnMouseUp;
        property OnMouseWheel;
        property OnMouseEnter;
        property OnMouseLeave;
    end;

    TAuraWorkspace = class(TStyledControl)
    private
        FConnections: TArray<TPinConnection>;
    protected
        procedure Paint; override;
        procedure DoDeleteChildren; override;
    public
        procedure BuildTree(const Root: IAstNode; const Position: TPointF; AMode: TVisualizationMode);

    published
        // Standard control properties
        property Align;
        property Anchors;
        property ClipChildren default True;
        property Cursor default crDefault;
        property DragMode default TDragMode.dmManual;
        property Enabled;
        property Height;
        property HelpContext;
        property HelpKeyword;
        property HelpType;
        property Hint;
        property HitTest default True;
        property Locked;
        property Margins;
        property Opacity;
        property Padding;
        property PopupMenu;
        property Position;
        property RotationAngle;
        property RotationCenter;
        property Scale;
        property Size;
        property StyleLookup;
        property Visible;
        property Width;
        property OnClick;
        property OnDblClick;
        property OnMouseDown;
        property OnMouseMove;
        property OnMouseUp;
        property OnMouseWheel;
        property OnMouseEnter;
        property OnMouseLeave;
    end;

    TAstToAuraNodeVisitor = class(TInterfacedObject, IAstVisitor)
    public
        type
            // Holds the result of a node visitation, separating layout and connection concerns.
            TAuraNodeResult = record
                LayoutNode: TAuraNode;
                OutputPin: TControl;
            end;
            TAuraNodeResultList = TList<TAuraNodeResult>;
            TChildVisitorProc = reference to procedure(const Visitor: IAstVisitor);
            // The lambda now returns the full result, including the output pin reference.
            TCreateParentNodeProc = reference to function(const InputNodes: TAuraNodeResultList): TAuraNodeResult;
            TVerticalAlignment = (vaCenter, vaTop);

    private
        const
            // Pin Visuals
            cPinSize = 10;
            cDataPinColor = TAlphaColors.Dodgerblue;
            cExecPinColor = TAlphaColors.Lightgreen;

            // Node Layout
            cHorizontalPadding = 25; // Padding inside the node title bar
            cPinOffsetY = 18; // Vertical distance between pins
            cVerticalPadding = 10; // General vertical padding inside container nodes

            // Specific Node Heights
            cDefaultNodeHeight = 25; // Default height for simple nodes like BinaryExpr
            cIfNodeHeight = 40; // Taller height for If nodes with more pins

    private
        FWorkspace: TAuraWorkspace;
        FParentControl: TControl;
        FCurrentPos: TPointF;
        FSpacing: TPointF;
        FLastResult: TAuraNodeResult;
        FConnections: TList<TPinConnection>;
        FCurrentExec: TList<TControl>;
        FMode: TVisualizationMode;

        procedure FinalizeNodeLayout(const Node: TAuraNode);

        function VisitContainerNode(
            const Title, Details: string;
            const InPin, OutPin: String;
            IsExec: Boolean;
            HasResult: Boolean;
            const ChildVisitorProc: TChildVisitorProc
        ): TAuraNode;
        function VisitOperatorNode(
            const InputExpressions: TArray<IExpressionNode>;
            const CreateParentProc: TCreateParentNodeProc;
            Alignment: TVerticalAlignment = vaCenter
        ): TAuraNode;

        function BuildNodeControl(const Title, Details: string): TAuraNode;
        function CreateNodeControl(const Title, Details: string): TAuraNode;
        function CreatePin(
            ParentNode: TAuraNode;
            Shape: TPinShape;
            Alignment: TPinAlignment;
            Color: TAlphaColor;
            const Tag: string
        ): TShape;

        function CreateInput(ParentNode: TAuraNode; const Caption: string): TControl;
        function CreateOutput(ParentNode: TAuraNode): TControl;
        function CreateEntry(ParentNode: TAuraNode; connect: Boolean = true): TControl;
        function CreateExit(ParentNode: TAuraNode; const Caption: string): TControl;

        function TryGetDescr(const Node: IAstNode; out Text: String): Boolean;

    public
        constructor Create(
            AWorkspace: TAuraWorkspace;
            AParentControl: TControl;
            const AStartPosition: TPointF;
            AConnections: TList<TPinConnection>;
            const ACurrentExec: TArray<TControl>;
            AMode: TVisualizationMode
        );
        destructor Destroy; override;

        // Public access to the collected connections
        property Connections: TList<TPinConnection> read FConnections;

        { IAstVisitor }
        function VisitConstant(const Node: IConstantNode): TAstValue;
        function VisitIdentifier(const Node: IIdentifierNode): TAstValue;
        function VisitBinaryExpression(const Node: IBinaryExpressionNode): TAstValue;
        function VisitUnaryExpression(const Node: IUnaryExpressionNode): TAstValue;
        function VisitIfExpression(const Node: IIfExpressionNode): TAstValue;
        function VisitTernaryExpression(const Node: ITernaryExpressionNode): TAstValue;
        function VisitLambdaExpression(const Node: ILambdaExpressionNode): TAstValue;
        function VisitFunctionCall(const Node: IFunctionCallNode): TAstValue;
        function VisitBlockExpression(const Node: IBlockExpressionNode): TAstValue;
        function VisitVariableDeclaration(const Node: IVariableDeclarationNode): TAstValue;
        function VisitAssignment(const Node: IAssignmentNode): TAstValue;
        function VisitIndexer(const Node: IIndexerNode): TAstValue;
        function VisitMemberAccess(const Node: IMemberAccessNode): TAstValue;
        function VisitCreateSeries(const Node: ICreateSeriesNode): TAstValue;
        function VisitAddSeriesItem(const Node: IAddSeriesItemNode): TAstValue;
        function VisitSeriesLength(const Node: ISeriesLengthNode): TAstValue;
    end;

implementation

uses
    System.Math,
    System.StrUtils,
    Myc.Data.Scalar;

type
    // This visitor converts an AST expression subtree into a single string.
    TAstToTextVisitor = class(TInterfacedObject, IAstVisitor)
    public
        { IAstVisitor }
        function VisitConstant(const Node: IConstantNode): TAstValue;
        function VisitIdentifier(const Node: IIdentifierNode): TAstValue;
        function VisitBinaryExpression(const Node: IBinaryExpressionNode): TAstValue;
        function VisitUnaryExpression(const Node: IUnaryExpressionNode): TAstValue;
        function VisitIfExpression(const Node: IIfExpressionNode): TAstValue;
        function VisitTernaryExpression(const Node: ITernaryExpressionNode): TAstValue;
        function VisitLambdaExpression(const Node: ILambdaExpressionNode): TAstValue;
        function VisitFunctionCall(const Node: IFunctionCallNode): TAstValue;
        function VisitBlockExpression(const Node: IBlockExpressionNode): TAstValue;
        function VisitVariableDeclaration(const Node: IVariableDeclarationNode): TAstValue;
        function VisitAssignment(const Node: IAssignmentNode): TAstValue;
        function VisitIndexer(const Node: IIndexerNode): TAstValue;
        function VisitMemberAccess(const Node: IMemberAccessNode): TAstValue;
        function VisitCreateSeries(const Node: ICreateSeriesNode): TAstValue;
        function VisitAddSeriesItem(const Node: IAddSeriesItemNode): TAstValue;
        function VisitSeriesLength(const Node: ISeriesLengthNode): TAstValue;
    end;

{ TAstToTextVisitor }

function TAstToTextVisitor.VisitAddSeriesItem(const Node: IAddSeriesItemNode): TAstValue;
var
    seriesStr, valueStr, lookbackStr: string;
begin
    seriesStr := Node.Series.Accept(Self).AsText;
    valueStr := Node.Value.Accept(Self).AsText;
    lookbackStr := '';
    if Assigned(Node.Lookback) then
        lookbackStr := ', ' + Node.Lookback.Accept(Self).AsText;
    Result := TAstValue.FromText(Format('%s.add(%s%s)', [seriesStr, valueStr, lookbackStr]));
end;

function TAstToTextVisitor.VisitAssignment(const Node: IAssignmentNode): TAstValue;
begin
    Result := TAstValue.FromText(Node.Identifier.Name + ' := ' + Node.Value.Accept(Self).AsText);
end;

function TAstToTextVisitor.VisitBinaryExpression(const Node: IBinaryExpressionNode): TAstValue;
begin
    var leftStr := Node.Left.Accept(Self).AsText;
    var rightStr := Node.Right.Accept(Self).AsText;
    Result := TAstValue.FromText('(' + leftStr + ' ' + Node.Operator.ToString + ' ' + rightStr + ')');
end;

function TAstToTextVisitor.VisitBlockExpression(const Node: IBlockExpressionNode): TAstValue;
begin
    Result := TAstValue.FromText('{...}');
end;

function TAstToTextVisitor.VisitConstant(const Node: IConstantNode): TAstValue;
begin
    Result := TAstValue.FromText(Node.Value.ToString);
end;

function TAstToTextVisitor.VisitCreateSeries(const Node: ICreateSeriesNode): TAstValue;
begin
    Result := TAstValue.FromText('new series(' + Node.Definition + ')');
end;

function TAstToTextVisitor.VisitFunctionCall(const Node: IFunctionCallNode): TAstValue;
var
    i: Integer;
    sb: TStringBuilder;
    calleeStr: string;
begin
    calleeStr := Node.Callee.Accept(Self).AsText;

    sb := TStringBuilder.Create;
    try
        sb.Append(calleeStr);
        sb.Append('(');
        for i := 0 to Node.Arguments.Count - 1 do
        begin
            sb.Append(Node.Arguments[i].Accept(Self).AsText);
            if i < Node.Arguments.Count - 1 then
                sb.Append(', ');
        end;
        sb.Append(')');
        Result := TAstValue.FromText(sb.ToString);
    finally
        sb.Free;
    end;
end;

function TAstToTextVisitor.VisitIdentifier(const Node: IIdentifierNode): TAstValue;
begin
    Result := TAstValue.FromText(Node.Name);
end;

function TAstToTextVisitor.VisitIfExpression(const Node: IIfExpressionNode): TAstValue;
begin
    Result := TAstValue.FromText(Node.Condition.Accept(Self).AsText);
end;

function TAstToTextVisitor.VisitIndexer(const Node: IIndexerNode): TAstValue;
var
    baseStr, indexStr: string;
begin
    baseStr := Node.Base.Accept(Self).AsText;
    indexStr := Node.Index.Accept(Self).AsText;
    Result := TAstValue.FromText(Format('%s[%s]', [baseStr, indexStr]));
end;

function TAstToTextVisitor.VisitLambdaExpression(const Node: ILambdaExpressionNode): TAstValue;
var
    i: Integer;
    sb: TStringBuilder;
begin
    sb := TStringBuilder.Create;
    try
        sb.Append(#$03BB + '(');
        if Length(Node.Parameters) > 0 then
        begin
            for i := 0 to High(Node.Parameters) do
            begin
                // Correctly append the parameter name from the node.
                sb.Append(Node.Parameters[i].Name);
                if i < High(Node.Parameters) then
                    sb.Append(', ');
            end;
        end;
        sb.Append(') => {...}');
        Result := TAstValue.FromText(sb.ToString);
    finally
        sb.Free;
    end;
end;

function TAstToTextVisitor.VisitMemberAccess(const Node: IMemberAccessNode): TAstValue;
var
    baseStr: string;
begin
    baseStr := Node.Base.Accept(Self).AsText;
    Result := TAstValue.FromText(Format('%s.%s', [baseStr, Node.Member.Name]));
end;

function TAstToTextVisitor.VisitSeriesLength(const Node: ISeriesLengthNode): TAstValue;
var
    seriesStr: string;
begin
    // Get the string representation of the series identifier by visiting the node.
    seriesStr := Node.Series.Accept(Self).AsText;
    Result := TAstValue.FromText(Format('length(%s)', [seriesStr]));
end;

function TAstToTextVisitor.VisitTernaryExpression(const Node: ITernaryExpressionNode): TAstValue;
begin
    var condStr := Node.Condition.Accept(Self).AsText;
    var thenStr := Node.ThenBranch.Accept(Self).AsText;
    var elseStr := Node.ElseBranch.Accept(Self).AsText;
    Result := TAstValue.FromText(Format('(%s ? %s : %s)', [condStr, thenStr, elseStr]));
end;

function TAstToTextVisitor.VisitUnaryExpression(const Node: IUnaryExpressionNode): TAstValue;
begin
    Result := TAstValue.FromText(Node.Operator.ToString + ' ' + Node.Right.Accept(Self).AsText);
end;

function TAstToTextVisitor.VisitVariableDeclaration(const Node: IVariableDeclarationNode): TAstValue;
var
    initStr: string;
begin
    if Assigned(Node.Initializer) then
        initStr := ' := ' + Node.Initializer.Accept(Self).AsText
    else
        initStr := '';
    Result := TAstValue.FromText('var ' + Node.Identifier.Name + initStr);
end;

{ TPinConnection }

constructor TPinConnection.Create(AOutputPin, AInputPin: TControl);
begin
    OutputPin := AOutputPin;
    InputPin := AInputPin;
end;

{ TAuraNode }

constructor TAuraNode.Create(AOwner: TComponent);
begin
    inherited Create(AOwner);
    FIsDragging := False;

    // Default border settings
    FBorderColor := TAlphaColors.Gray;
    FBorderWidth := 1;
    FBorderRadius := 9; // Sharp corners by default

    // Default title settings
    FTitle := 'Node';
    FTitleFont := TFont.Create;
    FTitleFont.Family := 'Segoe UI';
    FTitleFont.Size := 11;
    FTitleFont.Style := [TFontStyle.fsBold];
    FTitleFont.OnChanged := TitleFontChanged;
    FTitleFontColor := TAlphaColors.Black;

    // Default state for frameless mode
    FFrameless := False;

    Width := 80;
    Height := 45;

    // The panel must be able to receive mouse events.
    HitTest := True;
    // Clip children to the panel's bounds.
    ClipChildren := True;
end;

destructor TAuraNode.Destroy;
begin
    FTitleFont.Free;
    inherited;
end;

procedure TAuraNode.Paint;
var
    rect, titleRect: TRectF;
    effectiveBorderWidth: Single;
begin
    inherited; // Allow styled painting to occur first (if any)

    if FFrameless then
    begin
        Canvas.Fill.Kind := TBrushKind.Solid;
        Canvas.Fill.Color := $20C0C0C0; // Transparent Silver
        Canvas.Stroke.Kind := TBrushKind.None;

        // In frameless mode, draw a transparent background and ignore the border.
        Canvas.FillRect(TRectF.Create(0, 0, Width, Height), 0, 0, [], 1.0);
        effectiveBorderWidth := 0;
    end
    else
    begin
        // Custom painting for the border
        if (FBorderWidth > 0) and (FBorderColor <> TAlphaColors.Null) then
        begin
            rect := TRectF.Create(0, 0, Width, Height);
            // Inflate inwards so the border is fully visible within the control's bounds
            rect.Inflate(-FBorderWidth / 2, -FBorderWidth / 2);

            Canvas.Stroke.Kind := TBrushKind.Solid;
            Canvas.Stroke.Color := FBorderColor;
            Canvas.Stroke.Thickness := FBorderWidth;

            if FFrameless then
            begin
                Canvas.Fill.Kind := TBrushKind.Solid;
                Canvas.Fill.Color := $20C0C0C0; // Transparent Silver
                Canvas.FillRect(rect, FBorderRadius, FBorderRadius, AllCorners, 1.0, TCornerType.Round);
            end
            else
                Canvas.DrawRect(rect, FBorderRadius, FBorderRadius, AllCorners, 1.0, TCornerType.Round);
        end;
        effectiveBorderWidth := FBorderWidth;
    end;

    // Draw the title
    if not FTitle.IsEmpty then
    begin
        // Define the rectangle for the title at the top of the control
        titleRect := TRectF.Create(0, effectiveBorderWidth, Width, effectiveBorderWidth + FTitleFont.Size * 1.8);

        Canvas.Font.Assign(FTitleFont);
        Canvas.Fill.Color := FTitleFontColor;

        // Draw the text centered horizontally and vertically within the title rectangle
        Canvas.FillText(titleRect, FTitle, False, 1.0, [], TTextAlign.Center, TTextAlign.Center);
    end;
end;

procedure TAuraNode.SetBorderColor(const Value: TAlphaColor);
begin
    if FBorderColor <> Value then
    begin
        FBorderColor := Value;
        Repaint;
    end;
end;

procedure TAuraNode.SetBorderRadius(const Value: Single);
begin
    if FBorderRadius <> Value then
    begin
        FBorderRadius := Value;
        Repaint;
    end;
end;

procedure TAuraNode.SetBorderWidth(const Value: Single);
begin
    if FBorderWidth <> Value then
    begin
        FBorderWidth := Value;
        Repaint;
    end;
end;

procedure TAuraNode.SetFrameless(const Value: Boolean);
begin
    if FFrameless <> Value then
    begin
        FFrameless := Value;
        Repaint;
    end;
end;

procedure TAuraNode.SetTitle(const Value: string);
begin
    if FTitle <> Value then
    begin
        FTitle := Value;
        Repaint;
    end;
end;

procedure TAuraNode.SetTitleFont(const Value: TFont);
begin
    FTitleFont.Assign(Value);
end;

procedure TAuraNode.SetTitleFontColor(const Value: TAlphaColor);
begin
    if FTitleFontColor <> Value then
    begin
        FTitleFontColor := Value;
        Repaint;
    end;
end;

procedure TAuraNode.TitleFontChanged(Sender: TObject);
begin
    Repaint;
end;

procedure TAuraNode.MouseDown(Button: TMouseButton; Shift: TShiftState; X, Y: Single);
begin
    inherited;
    if Button = TMouseButton.mbLeft then
    begin
        if ObjectAtPoint(LocalToScreen(TPointF.Create(X, Y))) = Self as IControl then
        begin
            FIsDragging := True;
            FDownPos := TPointF.Create(X, Y);
        end;
    end;
end;

procedure TAuraNode.MouseMove(Shift: TShiftState; X, Y: Single);
begin
    inherited;
    if FIsDragging then
    begin
        var deltaX := X - FDownPos.X;
        var deltaY := Y - FDownPos.Y;

        Position.X := Position.X + deltaX;
        Position.Y := Position.Y + deltaY;

        if ParentControl <> nil then
            ParentControl.Repaint;
    end;
end;

procedure TAuraNode.MouseUp(Button: TMouseButton; Shift: TShiftState; X, Y: Single);
begin
    inherited;
    if (Button = TMouseButton.mbLeft) and (FIsDragging) then
    begin
        FIsDragging := False;
    end;
end;

{ TAuraWorkspace }

procedure TAuraWorkspace.BuildTree(const Root: IAstNode; const Position: TPointF; AMode: TVisualizationMode);
begin
    var connections := TList<TPinConnection>.Create;
    try
        Root.Accept(TAstToAuraNodeVisitor.Create(Self, Self, Position, connections, nil, AMode));
        FConnections := FConnections + connections.ToArray;
    finally
        connections.Free;
    end;
end;

procedure TAuraWorkspace.DoDeleteChildren;
begin
    FConnections := nil;
    inherited;
end;

procedure TAuraWorkspace.Paint;
var
    connection: TPinConnection;
    startPoint, endPoint, pinCenter: TPointF;
    path: TPathData;
    controlPoint1, controlPoint2: TPointF;
    controlOffset: Single;
begin
    inherited;

    Canvas.Stroke.Kind := TBrushKind.Solid;
    Canvas.Stroke.Thickness := 2;

    // Go through all stored connections and draw them
    for connection in FConnections do
    begin
        // Get the absolute coordinates of the pin centers
        pinCenter := TPointF.Create(connection.OutputPin.Width / 2, connection.OutputPin.Height / 2);
        var absoluteStart := connection.OutputPin.LocalToAbsolute(pinCenter);

        pinCenter := TPointF.Create(connection.InputPin.Width / 2, connection.InputPin.Height / 2);
        var absoluteEnd := connection.InputPin.LocalToAbsolute(pinCenter);

        // Convert them to the local coordinates of the workspace
        startPoint := AbsoluteToLocal(absoluteStart);
        endPoint := AbsoluteToLocal(absoluteEnd);

        var str := connection.InputPin.TagString;
        if Pos('data', str) = 0 then
            Canvas.Stroke.Color := TAstToAuraNodeVisitor.cExecPinColor
        else
            Canvas.Stroke.Color := TAstToAuraNodeVisitor.cDataPinColor;

        // Draw a Bezier curve with horizontal tangents at start and end points.
        path := TPathData.Create;
        try
            controlOffset := max(25, 0.5 * endPoint.Distance(startPoint));

            controlPoint1 := TPointF.Create(startPoint.X + controlOffset, startPoint.Y);
            controlPoint2 := TPointF.Create(endPoint.X - controlOffset, endPoint.Y);

            path.MoveTo(startPoint);
            path.CurveTo(controlPoint1, controlPoint2, endPoint);

            Canvas.DrawPath(path, 1.0);
        finally
            path.Free;
        end;
    end;
end;

{ TAstToAuraNodeVisitor }

constructor TAstToAuraNodeVisitor.Create(
    AWorkspace: TAuraWorkspace;
    AParentControl: TControl;
    const AStartPosition: TPointF;
    AConnections: TList<TPinConnection>;
    const ACurrentExec: TArray<TControl>;
    AMode: TVisualizationMode
);
begin
    inherited Create;
    FWorkspace := AWorkspace;
    FParentControl := AParentControl;
    FCurrentPos := AStartPosition;
    FSpacing := TPointF.Create(20, 10); // Horizontal indent, Vertical spacing
    FConnections := AConnections;
    FCurrentExec := TList<TControl>.Create(ACurrentExec);
    FLastResult.LayoutNode := nil;
    FLastResult.OutputPin := nil;
    FMode := AMode;
end;

destructor TAstToAuraNodeVisitor.Destroy;
begin
    FCurrentExec.Free;
    inherited;
end;

procedure TAstToAuraNodeVisitor.FinalizeNodeLayout(const Node: TAuraNode);
var
    control: TControl;
    leftPins, rightPins: TList<TControl>;
    numLeftPins, numRightPins, maxPins: Integer;
    reqHeight: Single;
    i: Integer;
    totalHeight, startY: Single;
begin
    leftPins := TList<TControl>.Create;
    rightPins := TList<TControl>.Create;
    try
        // 1. Collect all pins and sort them by alignment
        for control in Node.Controls do
        begin
            if (Pos('exec.', control.TagString) = 1) or (Pos('data.', control.TagString) = 1) then
            begin
                // Use the pin's X position to determine if it's on the left or right side.
                if control.Position.X < (Node.Width / 2) then
                    leftPins.Add(control)
                else
                    rightPins.Add(control);
            end;
        end;

        numLeftPins := leftPins.Count;
        numRightPins := rightPins.Count;
        maxPins := Max(numLeftPins, numRightPins);

        if maxPins = 0 then
            exit;

        // 2. Calculate and set new node height.
        // It must accommodate the pins plus vertical padding.
        reqHeight := cVerticalPadding + (maxPins - 1) * cPinOffsetY + cVerticalPadding;
        Node.Height := Max(Node.Height, reqHeight);
        Node.Height := Max(cDefaultNodeHeight, Node.Height); // Ensure minimum height

        // 3. Position left pins. They are arranged centered on the node.
        if numLeftPins > 0 then
        begin
            totalHeight := (numLeftPins - 1) * cPinOffsetY;
            startY := (Node.Height / 2) - (totalHeight / 2.0);
            for i := 0 to numLeftPins - 1 do
                leftPins[i].Position.Y := startY + i * cPinOffsetY - (cPinSize / 2);
        end;

        // 4. Position right pins.
        if numRightPins > 0 then
        begin
            totalHeight := (numRightPins - 1) * cPinOffsetY;
            startY := (Node.Height / 2) - (totalHeight / 2.0);
            for i := 0 to numRightPins - 1 do
                rightPins[i].Position.Y := startY + i * cPinOffsetY - (cPinSize / 2);
        end;

    finally
        leftPins.Free;
        rightPins.Free;
    end;
end;

function TAstToAuraNodeVisitor.BuildNodeControl(const Title, Details: string): TAuraNode;
var
    fullTitle: string;
    textWidth: Single;
    newWidth: Single;
    measureCanvas: TCanvas;
begin
    Result := TAuraNode.Create(FParentControl);
    Result.Parent := FParentControl;

    // Build the full title string first
    fullTitle := Title;
    if not Details.IsEmpty then
        fullTitle := fullTitle + ': ' + Details;
    Result.Title := fullTitle;

    // Adjust the width so that the text is completely visible.
    measureCanvas := TCanvasManager.MeasureCanvas;
    if Assigned(measureCanvas) then
    begin
        measureCanvas.Font.Assign(Result.TitleFont);
        textWidth := measureCanvas.TextWidth(Result.Title);
        newWidth := textWidth + (2 * cHorizontalPadding);
        // Ensure the new width is not smaller than the default width of the node.
        Result.Width := Max(Result.Width, newWidth);
    end;
end;

function TAstToAuraNodeVisitor.CreateInput(ParentNode: TAuraNode; const Caption: string): TControl;
begin
    var cap := Caption;
    if cap <> '' then
        cap := '.' + cap;
    Result := CreatePin(ParentNode, psCircle, paLeft, cDataPinColor, 'data.in' + cap);
    Result.Hint := Caption;
    Result.ShowHint := Caption <> '';
end;

function TAstToAuraNodeVisitor.CreateNodeControl(const Title, Details: string): TAuraNode;
begin
    Result := BuildNodeControl(Title, Details);
    Result.Position.Point := FCurrentPos;

    // Advance vertical position for the next node
    FCurrentPos.Y := FCurrentPos.Y + Result.Height + FSpacing.Y;

    FLastResult.LayoutNode := Result;
    FLastResult.OutputPin := nil; // Default: a new node has no specific data output pin
end;

function TAstToAuraNodeVisitor.CreateOutput(ParentNode: TAuraNode): TControl;
begin
    Result := CreatePin(ParentNode, psCircle, paRight, cDataPinColor, 'data.out');
end;

function TAstToAuraNodeVisitor.CreateEntry(ParentNode: TAuraNode; connect: Boolean = true): TControl;
begin
    Result := CreatePin(ParentNode, psTriangle, paLeft, cExecPinColor, 'exec.in');
    if connect then
    begin
        // Connect all open exits to this new entry
        for var curr in FCurrentExec do
            FConnections.Add(TPinConnection.Create(curr, Result));
        FCurrentExec.Clear;
    end;
end;

function TAstToAuraNodeVisitor.CreateExit(ParentNode: TAuraNode; const Caption: string): TControl;
begin
    var cap := Caption;
    if cap <> '' then
        cap := '.' + cap;
    Result := CreatePin(ParentNode, psTriangle, paRight, cExecPinColor, 'exec.out' + cap);

    FCurrentExec.Add(Result);
end;

function TAstToAuraNodeVisitor.CreatePin(
    ParentNode: TAuraNode;
    Shape: TPinShape;
    Alignment: TPinAlignment;
    Color: TAlphaColor;
    const Tag: string
): TShape;
var
    posX, posY: Single;
begin
    // Vertical position is now set later by FinalizeNodeLayout.
    // Set a temporary Y position.
    posY := 0;

    // Calculate horizontal position
    if Alignment = paLeft then
        posX := 0
    else // paRight
        posX := ParentNode.Width - cPinSize;

    // Create the shape
    case Shape of
        psCircle:
        begin
            var circle := TEllipse.Create(ParentNode);
            circle.Fill.Color := Color;
            circle.Stroke.Kind := TBrushKind.None;
            Result := circle;
        end;
        psTriangle:
        begin
            var triangle := TPath.Create(ParentNode);
            triangle.Data.Data := Format('M 0 0 L %d %d L 0 %d Z', [cPinSize, cPinSize div 2, cPinSize]);
            triangle.Fill.Color := Color;
            triangle.Stroke.Kind := TBrushKind.None;
            Result := triangle;
        end;
    else
        Result := nil;
        exit;
    end;

    // Common properties
    Result.Parent := ParentNode;
    Result.SetBounds(posX, posY, cPinSize, cPinSize);
    Result.HitTest := true;

    // Use TagString to identify the control as a pin and describe its function.
    Result.TagString := Tag;
end;

function TAstToAuraNodeVisitor.TryGetDescr(const Node: IAstNode; out Text: String): Boolean;
begin
    if FMode <> vmControlFlow then
        exit(false);

    var textVisitor: IAstVisitor := TAstToTextVisitor.Create;
    Text := Node.Accept(textVisitor).AsText;
    Result := Pos('{', Text) = 0;
end;

function TAstToAuraNodeVisitor.VisitAddSeriesItem(const Node: IAddSeriesItemNode): TAstValue;
var
    details: string;
    inputs: TArray<IExpressionNode>;
begin
    if (FMode = vmControlFlow) and TryGetDescr(Node, details) then
    begin
        var addNode := CreateNodeControl('Add to Series', details);
        CreateEntry(addNode);
        CreateExit(addNode, '');
        FinalizeNodeLayout(addNode);
    end
    else
    begin
        if Assigned(Node.Lookback) then
            inputs := [Node.Series, Node.Value, Node.Lookback]
        else
            inputs := [Node.Series, Node.Value];

        VisitOperatorNode(
            inputs,
            function(const InputResults: TAuraNodeResultList): TAuraNodeResult
            var
                addNode: TAuraNode;
                seriesPin, valuePin, lookbackPin: TControl;
            begin
                addNode := BuildNodeControl('Add to Series', '');
                CreateEntry(addNode);

                seriesPin := CreateInput(addNode, 'Series');
                valuePin := CreateInput(addNode, 'Value');

                if Assigned(InputResults[0].OutputPin) then
                    FConnections.Add(TPinConnection.Create(InputResults[0].OutputPin, seriesPin));
                if Assigned(InputResults[1].OutputPin) then
                    FConnections.Add(TPinConnection.Create(InputResults[1].OutputPin, valuePin));

                if InputResults.Count > 2 then
                begin
                    lookbackPin := CreateInput(addNode, 'Lookback');
                    if Assigned(InputResults[2].OutputPin) then
                        FConnections.Add(TPinConnection.Create(InputResults[2].OutputPin, lookbackPin));
                end;

                CreateExit(addNode, '');

                FinalizeNodeLayout(addNode);
                Result.LayoutNode := addNode;
                Result.OutputPin := nil; // No data output
            end,
            vaTop
        );
    end;
    Result := TAstValue.Void;
end;

function TAstToAuraNodeVisitor.VisitAssignment(const Node: IAssignmentNode): TAstValue;
begin
    var details: String;
    if (FMode = vmControlFlow) and TryGetDescr(Node, details) then
    begin
        var assignmentNode := CreateNodeControl('Assignment', details);
        CreateEntry(assignmentNode);
        CreateExit(assignmentNode, '');
        FinalizeNodeLayout(assignmentNode);
    end
    else
    begin
        VisitOperatorNode(
            [Node.Value],
            function(const InputResults: TAuraNodeResultList): TAuraNodeResult
            var
                assignmentNode: TAuraNode;
                inputPin: TControl;
                valueResult: TAuraNodeResult;
                outPin: TControl; // variable for the output pin
            begin
                valueResult := InputResults[0];
                assignmentNode := BuildNodeControl('Assignment', Node.Identifier.Name);

                CreateEntry(assignmentNode);
                inputPin := CreateInput(assignmentNode, Node.Identifier.Name);
                CreateExit(assignmentNode, '');

                // Create the output pin before finalizing the layout.
                outPin := CreateOutput(assignmentNode);

                if Assigned(valueResult.OutputPin) then
                    FConnections.Add(TPinConnection.Create(valueResult.OutputPin, inputPin));

                // Now finalize, all pins are present.
                FinalizeNodeLayout(assignmentNode);

                Result.LayoutNode := assignmentNode;
                Result.OutputPin := outPin;
            end,
            vaTop
        );
    end;
    Result := TAstValue.Void;
end;

function TAstToAuraNodeVisitor.VisitBinaryExpression(const Node: IBinaryExpressionNode): TAstValue;
begin
    var exprStr: String;
    if (FMode = vmControlFlow) and TryGetDescr(Node, exprStr) then
    begin
        var exprNode := CreateNodeControl('Expression', exprStr);
        FLastResult.OutputPin := CreateOutput(exprNode); // Provide an output for potential connection
        FinalizeNodeLayout(exprNode);
    end
    else
    begin
        VisitOperatorNode(
            [Node.Left, Node.Right],
            function(const InputResults: TAuraNodeResultList): TAuraNodeResult
            var
                binaryExprNode: TAuraNode;
                inputPin1, inputPin2: TControl;
                leftResult, rightResult: TAuraNodeResult;
                outPin: TControl;
            begin
                leftResult := InputResults[0];
                rightResult := InputResults[1];

                binaryExprNode := BuildNodeControl(Node.Operator.ToString, '');
                binaryExprNode.TitleFont.Size := 20;

                inputPin1 := CreateInput(binaryExprNode, ''); // Caption is in Hint
                inputPin2 := CreateInput(binaryExprNode, '');
                outPin := CreateOutput(binaryExprNode);

                if Assigned(leftResult.OutputPin) then
                    FConnections.Add(TPinConnection.Create(leftResult.OutputPin, inputPin1));
                if Assigned(rightResult.OutputPin) then
                    FConnections.Add(TPinConnection.Create(rightResult.OutputPin, inputPin2));

                FinalizeNodeLayout(binaryExprNode);
                Result.LayoutNode := binaryExprNode;
                Result.OutputPin := outPin;
            end
        );
    end;
    Result := TAstValue.Void;
end;

function TAstToAuraNodeVisitor.VisitBlockExpression(const Node: IBlockExpressionNode): TAstValue;
var
    blockNode: TAuraNode;
    childLastResult: TAuraNodeResult;
begin
    childLastResult.LayoutNode := nil;
    childLastResult.OutputPin := nil;

    // Use the helper to create and populate the container node.
    blockNode :=
        VisitContainerNode(
            '', // No title for blocks
            '',
            '',
            '',
            true,
            false,
            procedure(const Visitor: IAstVisitor)
            var
                expression: IExpressionNode;
            begin
                for expression in Node.Expressions do
                    expression.Accept(Visitor);

                // Capture the full result of the last expression inside the block.
                childLastResult := (Visitor as TAstToAuraNodeVisitor).FLastResult;
            end
        );

    // Blocks are drawn without title and border, with a transparent fill.
    blockNode.Frameless := true;

    // Update the state of the main visitor
    FCurrentPos.Y := blockNode.Position.Y + blockNode.Height + FSpacing.Y;
    FLastResult.LayoutNode := blockNode; // The layout node is the container itself.
    FLastResult.OutputPin := childLastResult.OutputPin; // The connection pin is from the internal node.

    Result := TAstValue.Void;
end;

function TAstToAuraNodeVisitor.VisitConstant(const Node: IConstantNode): TAstValue;
var
    constantNode: TAuraNode;
begin
    // In both modes, a constant is a simple node with an output.
    constantNode := CreateNodeControl('Constant', Node.Value.ToString);
    FLastResult.OutputPin := CreateOutput(constantNode);
    FinalizeNodeLayout(constantNode);
    Result := TAstValue.Void;
end;

function TAstToAuraNodeVisitor.VisitContainerNode(
    const Title, Details: string;
    const InPin, OutPin: String;
    IsExec: Boolean;
    HasResult: Boolean;
    const ChildVisitorProc: TChildVisitorProc
): TAuraNode;
var
    containerNode: TAuraNode;
    childVisitor: IAstVisitor;
    childStartPos: TPointF;
    maxRight: Single;
    maxBottom: Single;
    control: TControl;
    childLastResult: TAuraNodeResult;
begin
    const pinNodeHeight = cPinSize + cVerticalPadding;

    // Step 1: Create container node
    containerNode := BuildNodeControl(Title, Details);
    containerNode.Position.Point := FCurrentPos;
    Result := containerNode; // Set result early

    childStartPos :=
        TPointF.Create(FSpacing.X, FSpacing.Y + max(IfThen(InPin <> '', pinNodeHeight, 0), IfThen(Title <> '', cVerticalPadding, 0)));

    var currExec := FCurrentExec.ToArray;
    if InPin <> '' then
    begin
        // Create a small entry node to define the start of the execution flow inside the container.
        var entryNode := BuildNodeControl(InPin, '');
        entryNode.Parent := containerNode;
        entryNode.Position.Point := TPointF.Create(0, 0);
        entryNode.Height := pinNodeHeight;

        if IsExec then
        begin
            var entryPin := CreateEntry(containerNode);
            var entryExitPin := CreateExit(entryNode, '');
            FinalizeNodeLayout(entryNode);
            entryPin.Position.Y := containerNode.AbsoluteToLocal(entryNode.LocalToAbsolute(entryExitPin.Position.Point)).Y;
        end
        else
        begin
            FCurrentExec.Clear;
            CreateExit(entryNode, '');
            FinalizeNodeLayout(entryNode);
        end;
    end;

    // Step 2: Create child visitor and run the closure.
    // The child visitor starts its execution flow from the entry node's exit pin.
    childVisitor := TAstToAuraNodeVisitor.Create(FWorkspace, containerNode, childStartPos, FConnections, FCurrentExec.ToArray, FMode);
    ChildVisitorProc(childVisitor);

    // Capture the result from the child visitor.
    childLastResult := (childVisitor as TAstToAuraNodeVisitor).FLastResult;

    FCurrentExec.Clear;
    FCurrentExec.AddRange((childVisitor as TAstToAuraNodeVisitor).FCurrentExec);

    // Step 3: Adjust the size of the container node to fit children.
    maxRight := 0;
    maxBottom := 0;
    for control in containerNode.Controls do
    begin
        if control is TAuraNode then
        begin
            maxRight := Max(maxRight, control.Position.X + control.Width);
            maxBottom := Max(maxBottom, control.Position.Y + control.Height);
        end;
    end;

    // The width must be at least the title width, and large enough for children.
    containerNode.Width := Max(containerNode.Width, maxRight + FSpacing.X);
    containerNode.Height := Max(containerNode.Height, maxBottom + FSpacing.Y);

    if OutPin <> '' then
    begin
        var exitNode := BuildNodeControl(OutPin, '');
        exitNode.Parent := containerNode;
        exitNode.Height := pinNodeHeight;
        var exitPin := CreateEntry(exitNode);

        // Create and connect a data pin if the container returns a value.
        if HasResult and Assigned(childLastResult.OutputPin) then
        begin
            var dataResultPin := CreateInput(exitNode, 'Result');
            FConnections.Add(TPinConnection.Create(childLastResult.OutputPin, dataResultPin));
        end;

        FinalizeNodeLayout(exitNode);

        // Enlarge for the exit node
        containerNode.Height := Max(containerNode.Height, maxBottom + FSpacing.Y + exitNode.Height);

        exitNode.Position.Point := TPointF.Create(containerNode.Width - exitNode.Width, containerNode.Height - exitNode.Height);

        if not IsExec then
        begin
            FCurrentExec.Clear;
            FCurrentExec.AddRange(currExec);
        end
        else
            CreateExit(containerNode, '').Position.Y := containerNode.AbsoluteToLocal(exitNode.LocalToAbsolute(exitPin.Position.Point)).Y;
    end;

    FinalizeNodeLayout(containerNode);
end;

function TAstToAuraNodeVisitor.VisitCreateSeries(const Node: ICreateSeriesNode): TAstValue;
var
    seriesNode: TAuraNode;
begin
    // This node creates a new series. It has no inputs, only a data output.
    // The definition is a string literal, so it's part of the node's title.
    seriesNode := CreateNodeControl('Create Series', Node.Definition);
    FLastResult.OutputPin := CreateOutput(seriesNode);
    FinalizeNodeLayout(seriesNode);
    Result := TAstValue.Void;
end;

function TAstToAuraNodeVisitor.VisitFunctionCall(const Node: IFunctionCallNode): TAstValue;
var
    inputExpressions: TArray<IExpressionNode>;
begin
    var details: String;
    if (FMode = vmControlFlow) and TryGetDescr(Node, details) then
    begin
        var funcCallNode := CreateNodeControl('FunctionCall', details);
        CreateEntry(funcCallNode);
        FLastResult.OutputPin := CreateOutput(funcCallNode); // Function calls can return values
        CreateExit(funcCallNode, '');
        FinalizeNodeLayout(funcCallNode);
    end
    else
    begin
        SetLength(inputExpressions, 1 + Node.Arguments.Count);
        inputExpressions[0] := Node.Callee;
        for var i := 0 to Node.Arguments.Count - 1 do
            inputExpressions[i + 1] := Node.Arguments[i];

        VisitOperatorNode(
            inputExpressions,
            function(const InputResults: TAuraNodeResultList): TAuraNodeResult
            var
                funcCallNode: TAuraNode;
                calleePin: TControl;
                argPin: array of TControl;
                i: Integer;
                outPin: TControl;
            begin
                funcCallNode := BuildNodeControl('FunctionCall', '');

                CreateEntry(funcCallNode);
                calleePin := CreateInput(funcCallNode, 'Callee');

                SetLength(argPin, Node.Arguments.Count);
                for i := 0 to Node.Arguments.Count - 1 do
                    argPin[i] := CreateInput(funcCallNode, 'Arg' + i.ToString);

                CreateExit(funcCallNode, '');
                outPin := CreateOutput(funcCallNode);

                if Assigned(InputResults[0].OutputPin) then
                    FConnections.Add(TPinConnection.Create(InputResults[0].OutputPin, calleePin));
                for i := 0 to Node.Arguments.Count - 1 do
                    if Assigned(InputResults[i + 1].OutputPin) then
                        FConnections.Add(TPinConnection.Create(InputResults[i + 1].OutputPin, argPin[i]));

                FinalizeNodeLayout(funcCallNode);
                Result.LayoutNode := funcCallNode;
                Result.OutputPin := outPin;
            end
        );
    end;
    Result := TAstValue.Void;
end;

function TAstToAuraNodeVisitor.VisitIdentifier(const Node: IIdentifierNode): TAstValue;
begin
    var identifierNode := CreateNodeControl('Identifier', Node.Name);
    FLastResult.OutputPin := CreateOutput(identifierNode);
    FinalizeNodeLayout(identifierNode);
    Result := TAstValue.Void;
end;

function TAstToAuraNodeVisitor.VisitIfExpression(const Node: IIfExpressionNode): TAstValue;
var
    startPosition: TPointF;
    ifNode: TAuraNode;
    conditionEndY: Single;
    branchStartX: Single;
    execPathes: TList<TControl>;
    thenEndY, elseEndY: Single;
begin
    startPosition := FCurrentPos;

    var condStr: String;
    if (FMode = vmControlFlow) and TryGetDescr(Node, condStr) then
    begin
        ifNode := CreateNodeControl('If', condStr);
        ifNode.Height := cIfNodeHeight;
    end
    else
    begin
        // Use helper for the condition part
        ifNode :=
            VisitOperatorNode(
                [Node.Condition],
                function(const InputResults: TAuraNodeResultList): TAuraNodeResult
                var
                    conditionInputPin: TControl;
                    condResult: TAuraNodeResult;
                    ifNode: TAuraNode;
                begin
                    condResult := InputResults[0];
                    ifNode := BuildNodeControl('If', '');

                    conditionInputPin := CreateInput(ifNode, 'Condition');

                    if Assigned(condResult.OutputPin) then
                        FConnections.Add(TPinConnection.Create(condResult.OutputPin, conditionInputPin));

                    // Do not finalize here, more pins will be added.
                    Result.LayoutNode := ifNode;
                    Result.OutputPin := nil;
                end
            );
    end;
    CreateEntry(ifNode);
    conditionEndY := FCurrentPos.Y;

    // Visit the 'Then' and 'Else' execution branches, placing them to the right of the 'If' node.
    branchStartX := ifNode.Position.X + ifNode.Width + FSpacing.X;
    execPathes := TList<TControl>.Create;
    try
        // Then branch
        FCurrentExec.Clear;
        CreateExit(ifNode, 'Then');
        FCurrentPos.X := branchStartX;
        FCurrentPos.Y := startPosition.Y;
        Node.ThenBranch.Accept(Self);
        thenEndY := FCurrentPos.Y;
        FLastResult.LayoutNode := ifNode;
        execPathes.AddRange(FCurrentExec);

        // Else branch (if it exists)
        elseEndY := thenEndY;
        FCurrentExec.Clear;
        CreateExit(ifNode, 'Else');
        if Assigned(Node.ElseBranch) then
        begin
            FCurrentPos.X := branchStartX;
            FCurrentPos.Y := thenEndY;
            Node.ElseBranch.Accept(Self);
            elseEndY := FCurrentPos.Y;
        end;
        execPathes.AddRange(FCurrentExec);

        // Finalize layout now that all pins are added.
        FinalizeNodeLayout(ifNode);

        // Finalize visitor state.
        FCurrentPos.X := startPosition.X;
        FCurrentPos.Y := Max(conditionEndY, elseEndY);
        FLastResult.LayoutNode := ifNode;
        // This node is for control-flow only and never produces a data output.
        FLastResult.OutputPin := nil;

        // After a branch, the execution flow has diverged.
        FCurrentExec.Clear;
        FCurrentExec.AddRange(execPathes);
    finally
        execPathes.Free;
    end;

    Result := TAstValue.Void;
end;

function TAstToAuraNodeVisitor.VisitIndexer(const Node: IIndexerNode): TAstValue;
var
    details: String;
begin
    if (FMode = vmControlFlow) and TryGetDescr(Node, details) then
    begin
        var indexerNode := CreateNodeControl('Expression', details);
        FLastResult.OutputPin := CreateOutput(indexerNode);
        FinalizeNodeLayout(indexerNode);
    end
    else
    begin
        VisitOperatorNode(
            [Node.Base, Node.Index],
            function(const InputResults: TAuraNodeResultList): TAuraNodeResult
            var
                indexerNode: TAuraNode;
                basePin, indexPin, outPin: TControl;
            begin
                indexerNode := BuildNodeControl('[]', '');
                indexerNode.TitleFont.Size := 20;

                basePin := CreateInput(indexerNode, 'Base');
                indexPin := CreateInput(indexerNode, 'Index');
                outPin := CreateOutput(indexerNode);

                if Assigned(InputResults[0].OutputPin) then
                    FConnections.Add(TPinConnection.Create(InputResults[0].OutputPin, basePin));
                if Assigned(InputResults[1].OutputPin) then
                    FConnections.Add(TPinConnection.Create(InputResults[1].OutputPin, indexPin));

                FinalizeNodeLayout(indexerNode);
                Result.LayoutNode := indexerNode;
                Result.OutputPin := outPin;
            end
        );
    end;
    Result := TAstValue.Void;
end;

function TAstToAuraNodeVisitor.VisitLambdaExpression(const Node: ILambdaExpressionNode): TAstValue;
var
    paramStr: String;
    lambdaNode: TAuraNode;
    i: Integer;
begin
    // Prepare the parameter string for the title
    paramStr := '(';
    if Length(Node.Parameters) > 0 then
    begin
        paramStr := paramStr + Node.Parameters[0].Name;
        for i := 1 to High(Node.Parameters) do
            paramStr := paramStr + ', ' + Node.Parameters[i].Name;
    end;
    paramStr := paramStr + ')';

    // Use the helper to create and populate the container node.
    lambdaNode :=
        VisitContainerNode(
            #$03BB,
            paramStr,
            'call',
            'return',
            false,
            true,
            procedure(const Visitor: IAstVisitor) begin Node.Body.Accept(Visitor); end
        );

    // Update the state of the main visitor
    FCurrentPos.Y := lambdaNode.Position.Y + lambdaNode.Height + FSpacing.Y;

    FLastResult.LayoutNode := lambdaNode;
    FLastResult.OutputPin := CreateOutput(lambdaNode);

    // Re-finalize layout after adding the data output pin.
    FinalizeNodeLayout(lambdaNode);

    Result := TAstValue.Void;
end;

function TAstToAuraNodeVisitor.VisitMemberAccess(const Node: IMemberAccessNode): TAstValue;
var
    details: String;
begin
    // Implements the visualization for member access (e.g., series.field).
    if (FMode = vmControlFlow) and TryGetDescr(Node, details) then
    begin
        var memberNode := CreateNodeControl('Expression', details);
        FLastResult.OutputPin := CreateOutput(memberNode);
        FinalizeNodeLayout(memberNode);
    end
    else
    begin
        VisitOperatorNode(
            [Node.Base],
            function(const InputResults: TAuraNodeResultList): TAuraNodeResult
            var
                memberAccessNode: TAuraNode;
                basePin, outPin: TControl;
            begin
                memberAccessNode := BuildNodeControl('Get ' + Node.Member.Name, '');

                basePin := CreateInput(memberAccessNode, 'Base');
                outPin := CreateOutput(memberAccessNode);

                if Assigned(InputResults[0].OutputPin) then
                    FConnections.Add(TPinConnection.Create(InputResults[0].OutputPin, basePin));

                FinalizeNodeLayout(memberAccessNode);
                Result.LayoutNode := memberAccessNode;
                Result.OutputPin := outPin;
            end
        );
    end;
    Result := TAstValue.Void;
end;

function TAstToAuraNodeVisitor.VisitOperatorNode(
    const InputExpressions: TArray<IExpressionNode>;
    const CreateParentProc: TCreateParentNodeProc;
    Alignment: TVerticalAlignment
): TAuraNode;
var
    inputResults: TAuraNodeResultList;
    inputNode: IExpressionNode;
    startPosition: TPointF;
    endY, maxChildWidth: Single;
    parentNode: TAuraNode;
    createResult: TAuraNodeResult;
begin
    startPosition := FCurrentPos;
    inputResults := TAuraNodeResultList.Create;
    try
        // 1. Visit all input nodes and collect their visual representations.
        for inputNode in InputExpressions do
        begin
            inputNode.Accept(Self);
            inputResults.Add(FLastResult);
        end;
        endY := FCurrentPos.Y;

        // 2. Determine the layout bounds of the input nodes.
        maxChildWidth := 0;
        for var res in inputResults do
            if Assigned(res.LayoutNode) then
                maxChildWidth := Max(maxChildWidth, res.LayoutNode.Position.X + res.LayoutNode.Width);

        // 3. Let the closure create the parent node (which also finalizes its layout).
        createResult := CreateParentProc(inputResults);
        parentNode := createResult.LayoutNode;
        Result := parentNode;

        // 4. Now position the parent node to the right of the inputs.
        var parentY: Single;
        if Alignment = vaCenter then
        begin
            var totalInputHeight := endY - startPosition.Y;
            var nodeCenterY := startPosition.Y + (totalInputHeight / 2);
            parentY := nodeCenterY - (parentNode.Height / 2);
        end
        else // vaTop
        begin
            parentY := startPosition.Y;
        end;
        parentNode.Position.Point := TPointF.Create(maxChildWidth + FSpacing.X, parentY);

        // 5. Finalize visitor state for the next operation.
        FCurrentPos.Y := Max(endY, parentNode.Position.Y + parentNode.Height + FSpacing.Y);
        FLastResult.LayoutNode := parentNode;
        FLastResult.OutputPin := createResult.OutputPin;
    finally
        inputResults.Free;
    end;
end;

function TAstToAuraNodeVisitor.VisitSeriesLength(const Node: ISeriesLengthNode): TAstValue;
begin
    // Use the standard helper for operator-style nodes.
    VisitOperatorNode(
        [Node.Series], // The single input for this operator is the series identifier.
        function(const InputResults: TAuraNodeResultList): TAuraNodeResult
        var
            lengthNode: TAuraNode;
            seriesPin, outPin: TControl;
        begin
            // Create the visual node for the 'length' operation.
            lengthNode := BuildNodeControl('Series Length', '');

            // Create an input pin for the series and an output pin for the result.
            seriesPin := CreateInput(lengthNode, 'Series');
            outPin := CreateOutput(lengthNode);

            // Connect the output of the visited series identifier to our input pin.
            if Assigned(InputResults[0].OutputPin) then
                FConnections.Add(TPinConnection.Create(InputResults[0].OutputPin, seriesPin));

            // Finalize the node's layout to correctly position the pins.
            FinalizeNodeLayout(lengthNode);

            // The result of this visitation is the new node and its output pin.
            Result.LayoutNode := lengthNode;
            Result.OutputPin := outPin;
        end
    );
    Result := TAstValue.Void;
end;

function TAstToAuraNodeVisitor.VisitTernaryExpression(const Node: ITernaryExpressionNode): TAstValue;
begin
    var exprStr: String;
    if (FMode = vmControlFlow) and TryGetDescr(Node, exprStr) then
    begin
        var ternaryNode := CreateNodeControl('Expression', exprStr);
        FLastResult.OutputPin := CreateOutput(ternaryNode);
        FinalizeNodeLayout(ternaryNode);
    end
    else
    begin
        VisitOperatorNode(
            [Node.Condition, Node.ThenBranch, Node.ElseBranch],
            function(const InputResults: TAuraNodeResultList): TAuraNodeResult
            var
                ternaryNode: TAuraNode;
                condPin, thenPin, elsePin, outPin: TControl;
            begin
                ternaryNode := BuildNodeControl('?', '');
                ternaryNode.TitleFont.Size := 20;

                condPin := CreateInput(ternaryNode, 'Condition');
                thenPin := CreateInput(ternaryNode, 'Then');
                elsePin := CreateInput(ternaryNode, 'Else');
                outPin := CreateOutput(ternaryNode);

                if Assigned(InputResults[0].OutputPin) then
                    FConnections.Add(TPinConnection.Create(InputResults[0].OutputPin, condPin));
                if Assigned(InputResults[1].OutputPin) then
                    FConnections.Add(TPinConnection.Create(InputResults[1].OutputPin, thenPin));
                if Assigned(InputResults[2].OutputPin) then
                    FConnections.Add(TPinConnection.Create(InputResults[2].OutputPin, elsePin));

                FinalizeNodeLayout(ternaryNode);
                Result.LayoutNode := ternaryNode;
                Result.OutputPin := outPin;
            end
        );
    end;
    Result := TAstValue.Void;
end;

function TAstToAuraNodeVisitor.VisitUnaryExpression(const Node: IUnaryExpressionNode): TAstValue;
begin
    var exprStr: String;
    if (FMode = vmControlFlow) and TryGetDescr(Node, exprStr) then
    begin
        var exprNode := CreateNodeControl('Expression', exprStr);
        FLastResult.OutputPin := CreateOutput(exprNode);
        FinalizeNodeLayout(exprNode);
    end
    else
    begin
        VisitOperatorNode(
            [Node.Right],
            function(const InputResults: TAuraNodeResultList): TAuraNodeResult
            var
                unaryExprNode: TAuraNode;
                inputPin: TControl;
                rightResult: TAuraNodeResult;
                outPin: TControl;
            begin
                rightResult := InputResults[0];
                unaryExprNode := BuildNodeControl(Node.Operator.ToString, '');
                unaryExprNode.TitleFont.Size := 20;

                inputPin := CreateInput(unaryExprNode, '');
                outPin := CreateOutput(unaryExprNode);

                if Assigned(rightResult.OutputPin) then
                    FConnections.Add(TPinConnection.Create(rightResult.OutputPin, inputPin));

                FinalizeNodeLayout(unaryExprNode);
                Result.LayoutNode := unaryExprNode;
                Result.OutputPin := outPin;
            end
        );
    end;
    Result := TAstValue.Void;
end;

function TAstToAuraNodeVisitor.VisitVariableDeclaration(const Node: IVariableDeclarationNode): TAstValue;
var
    outPin: TControl;
begin
    var details: String;
    if (FMode = vmControlFlow) and TryGetDescr(Node, details) then
    begin
        var varDeclNode := CreateNodeControl('VarDecl', details);
        CreateEntry(varDeclNode);
        CreateExit(varDeclNode, '');
        FinalizeNodeLayout(varDeclNode);
    end
    else
    begin
        if Assigned(Node.Initializer) then
        begin
            VisitOperatorNode(
                [Node.Initializer],
                function(const InputResults: TAuraNodeResultList): TAuraNodeResult
                var
                    varDeclNode: TAuraNode;
                    inputPin: TControl;
                    initializerResult: TAuraNodeResult;
                    outPin: TControl; // variable for the output pin
                begin
                    initializerResult := InputResults[0];
                    varDeclNode := BuildNodeControl('VarDecl', Node.Identifier.Name);

                    CreateEntry(varDeclNode);
                    inputPin := CreateInput(varDeclNode, 'Value');
                    CreateExit(varDeclNode, '');

                    // Create the output pin before finalizing the layout.
                    outPin := CreateOutput(varDeclNode);

                    if Assigned(initializerResult.OutputPin) then
                        FConnections.Add(TPinConnection.Create(initializerResult.OutputPin, inputPin));

                    // Now finalize, all pins are present.
                    FinalizeNodeLayout(varDeclNode);
                    Result.LayoutNode := varDeclNode;
                    Result.OutputPin := outPin;
                end
            );
        end
        else
        begin
            // Case without initializer is a simple sequential node.
            var varDeclNode := CreateNodeControl('VarDecl', Node.Identifier.Name);
            CreateEntry(varDeclNode);
            CreateExit(varDeclNode, '');
            // Create the output pin before finalizing the layout.
            outPin := CreateOutput(varDeclNode);
            FLastResult.OutputPin := outPin;
            // Now finalize, all pins are present.
            FinalizeNodeLayout(varDeclNode);
        end;
    end;

    Result := TAstValue.Void;
end;

end.