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,
    DraggablePanel;

type
    // ... TPinConnection, TPinShape, TPinAlignment, TAuraWorkspace ...
    TPinConnection = record
        OutputPin: TControl;
        InputPin: TControl;
        constructor Create(AOutputPin, AInputPin: TControl);
    end;

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

    TAuraWorkspace = class;

    TAstToAuraNodeVisitor = class(TInterfacedObject, IAstVisitor)
        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 = 20; // General vertical padding inside container nodes

            // Specific Node Heights
            cDefaultNodeHeight = 45; // Default height for simple nodes like BinaryExpr
            cIfNodeHeight = 60; // Taller height for If nodes with more pins
    private
        FWorkspace: TAuraWorkspace;
        FParentControl: TControl;
        FCurrentPos: TPointF;
        FSpacing: TPointF;
        FLastNode: TAuraNode;
        FConnections: TList<TPinConnection>;
        FCurrentExec: TControl;
        function CreateNodeControl(const ATitle, ADetails: string): TAuraNode;
        function CreatePin(
            AParentNode: TAuraNode;
            AShape: TPinShape;
            AAlignment: TPinAlignment;
            AColor: TAlphaColor;
            const ATag: string;
            AOffsetY: Single = 0
        ): TShape;

        function CreateInput(AParentNode: TAuraNode; const ACaption: string; AOffsetY: Single = 0): TControl;
        function CreateOutput(AParentNode: TAuraNode; AOffsetY: Single = 0): TControl;
        function CreateEntry(AParentNode: TAuraNode; AOffsetY: Single = 0): TControl;
        function CreateExit(AParentNode: TAuraNode; const ACaption: string; AOffsetY: Single = 0): TControl;

        function FindPinByTag(AParentNode: TAuraNode; const ATag: string): TControl;
        function ConnectData(InputPin: TControl; OutputNode: TAuraNode): TControl;
    public
        constructor Create(
            AWorkspace: TAuraWorkspace;
            AParentControl: TControl;
            const AStartPosition: TPointF;
            AConnections: TList<TPinConnection>
        );
        // 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 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;
    end;

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

    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;

implementation

uses
    System.Math;

{ TPinConnection }

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

{ TAstToAuraNodeVisitor }

constructor TAstToAuraNodeVisitor.Create(
    AWorkspace: TAuraWorkspace;
    AParentControl: TControl;
    const AStartPosition: TPointF;
    AConnections: TList<TPinConnection>
);
begin
    inherited Create;
    FWorkspace := AWorkspace;
    FParentControl := AParentControl;
    FCurrentPos := AStartPosition;
    FSpacing := TPointF.Create(20, 10); // Horizontal indent, Vertical spacing
    FConnections := AConnections;
end;

function TAstToAuraNodeVisitor.ConnectData(InputPin: TControl; OutputNode: TAuraNode): TControl;
begin
    Result := FindPinByTag(OutputNode, 'data.out');
    if Assigned(Result) then
        FConnections.Add(TPinConnection.Create(Result, InputPin));
end;

function TAstToAuraNodeVisitor.CreateInput(AParentNode: TAuraNode; const ACaption: string; AOffsetY: Single = 0): TControl;
begin
    var cap := ACaption;
    if cap <> '' then
        cap := '.' + cap;
    Result := CreatePin(AParentNode, psCircle, paLeft, cDataPinColor, 'data.in' + cap, AOffsetY);
    Result.Hint := ACaption;
    Result.ShowHint := ACaption <> '';
end;

function TAstToAuraNodeVisitor.CreateOutput(AParentNode: TAuraNode; AOffsetY: Single = 0): TControl;
begin
    Result := CreatePin(AParentNode, psCircle, paRight, cDataPinColor, 'data.out', AOffsetY);
end;

function TAstToAuraNodeVisitor.CreateEntry(AParentNode: TAuraNode; AOffsetY: Single = 0): TControl;
begin
    Result := CreatePin(AParentNode, psTriangle, paLeft, cExecPinColor, 'exec.in', AOffsetY);
    if FCurrentExec <> nil then
        FConnections.Add(TPinConnection.Create(FCurrentExec, Result));
end;

function TAstToAuraNodeVisitor.CreateExit(AParentNode: TAuraNode; const ACaption: string; AOffsetY: Single = 0): TControl;
begin
    var cap := ACaption;
    if cap <> '' then
        cap := '.' + cap;
    Result := CreatePin(AParentNode, psTriangle, paRight, cExecPinColor, 'exec.out' + cap, AOffsetY);

    FCurrentExec := Result;
end;

function TAstToAuraNodeVisitor.CreateNodeControl(const ATitle, ADetails: string): TAuraNode;
var
    LFullTitle: string;
    LTextWidth: Single;
    LNewWidth: Single;
    LMeasureCanvas: TCanvas;
begin
    Result := TAuraNode.Create(FParentControl);
    Result.Parent := FParentControl;

    // Build the full title string first
    LFullTitle := ATitle;
    if not ADetails.IsEmpty then
        LFullTitle := LFullTitle + ': ' + ADetails;
    Result.Title := LFullTitle;

    Result.Position.Point := FCurrentPos;

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

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

    FLastNode := Result;
end;

function TAstToAuraNodeVisitor.CreatePin(
    AParentNode: TAuraNode;
    AShape: TPinShape;
    AAlignment: TPinAlignment;
    AColor: TAlphaColor;
    const ATag: string;
    AOffsetY: Single = 0
): TShape;
var
    LPosX, LPosY: Single;
begin
    // Calculate vertical position (centered + offset)
    LPosY := (AParentNode.Height / 2) - (cPinSize / 2) + AOffsetY;

    // Calculate horizontal position
    if (AAlignment = paLeft) then
        LPosX := 0
    else // paRight
        LPosX := AParentNode.Width - cPinSize;

    // Create the shape
    case AShape of
        psCircle:
        begin
            var LCircle := TEllipse.Create(AParentNode);
            LCircle.Fill.Color := AColor;
            LCircle.Stroke.Kind := TBrushKind.None;
            Result := LCircle;
        end;
        psTriangle:
        begin
            var LTriangle := TPath.Create(AParentNode);
            LTriangle.Data.Data := Format('M 0 0 L %d %d L 0 %d Z', [cPinSize, cPinSize div 2, cPinSize]);
            LTriangle.Fill.Color := AColor;
            LTriangle.Stroke.Kind := TBrushKind.None;
            Result := LTriangle;
        end;
    else
        Result := nil;
        Exit;
    end;

    // Common properties
    Result.Parent := AParentNode;
    Result.SetBounds(LPosX, LPosY, cPinSize, cPinSize);
    Result.HitTest := true;

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

function TAstToAuraNodeVisitor.FindPinByTag(AParentNode: TAuraNode; const ATag: string): TControl;
var
    LControl: TControl;
begin
    Result := nil;
    if not Assigned(AParentNode) then
        Exit;

    for LControl in AParentNode.Controls do
    begin
        if (LControl.TagString = ATag) then
        begin
            Result := LControl;
            Exit;
        end;
    end;
end;

function TAstToAuraNodeVisitor.VisitAssignment(const Node: IAssignmentNode): TAstValue;
var
    LAssignmentNode, LValueNode: TAuraNode;
    LInputPin: TControl;
    LStartPosition: TPointF;
begin
    LStartPosition := FCurrentPos;

    // Visit the value expression first
    Node.Value.Accept(Self);
    LValueNode := FLastNode;

    // Reposition for the assignment node
    FCurrentPos.X := LValueNode.Position.X + LValueNode.Width + FSpacing.X;
    FCurrentPos.Y := LValueNode.Position.Y;

    // Create the assignment node and its pins
    LAssignmentNode := CreateNodeControl('Assignment', Node.Identifier.Name);
    CreateEntry(LAssignmentNode, 0);
    CreateExit(LAssignmentNode, '', 0);
    LInputPin := CreateInput(LAssignmentNode, Node.Identifier.Name, 0);

    // Connect the value to the assignment
    ConnectData(LInputPin, LValueNode);

    // Finalize visitor state
    FCurrentPos.X := LStartPosition.X;
    FCurrentPos.Y := Max(LValueNode.Position.Y + LValueNode.Height, LAssignmentNode.Position.Y + LAssignmentNode.Height) + FSpacing.Y;
    FLastNode := LAssignmentNode;

    Result := TAstValue.Void;
end;

function TAstToAuraNodeVisitor.VisitBinaryExpression(const Node: IBinaryExpressionNode): TAstValue;
var
    LBinaryExprNode, LLeftNode, LRightNode: TAuraNode;
    LInputPin1, LInputPin2: TControl;
    LStartPosition: TPointF;
    LRightEndY, LMaxChildWidth: Single;
begin
    LStartPosition := FCurrentPos;

    // First, visit the child nodes to create their visual representation
    // Left branch
    Node.Left.Accept(Self);
    LLeftNode := FLastNode;

    // Right branch starts below the left branch
    Node.Right.Accept(Self);
    LRightNode := FLastNode;
    LRightEndY := FCurrentPos.Y;

    // Now, create the node for the binary operation itself
    LMaxChildWidth := Max(LLeftNode.Position.X + LLeftNode.Width, LRightNode.Position.X + LRightNode.Width);
    FCurrentPos.X := LMaxChildWidth + FSpacing.X;

    // Vertically center the binary expression node between its children
    var LTotalChildHeight := LRightEndY - LStartPosition.Y;
    var LNodeCenterY := LStartPosition.Y + (LTotalChildHeight / 2);
    FCurrentPos.Y := LNodeCenterY - (cDefaultNodeHeight / 2);

    LBinaryExprNode := CreateNodeControl(Node.Operator.ToString, '');
    LBinaryExprNode.TitleFont.Size := 20;

    // Create pins for the binary expression node
    LInputPin1 := CreateInput(LBinaryExprNode, LLeftNode.Name, -8);
    LInputPin2 := CreateInput(LBinaryExprNode, LRightNode.Name, 8);
    CreateOutput(LBinaryExprNode, 0);

    // Connect the output of the left child to the first input of the binary node
    ConnectData(LInputPin1, LLeftNode);

    // Connect the output of the right child to the second input of the binary node
    ConnectData(LInputPin2, LRightNode);

    // Finalize visitor state for the next node at this level
    FCurrentPos.X := LStartPosition.X;
    FCurrentPos.Y := Max(LRightEndY, LBinaryExprNode.Position.Y + LBinaryExprNode.Height + FSpacing.Y);
    FLastNode := LBinaryExprNode;

    Result := TAstValue.Void;
end;

function TAstToAuraNodeVisitor.VisitBlockExpression(const Node: IBlockExpressionNode): TAstValue;
var
    Expression: IExpressionNode;
    LBlockNode: TAuraNode;
    LChildVisitor: IAstVisitor;
    LChildStartPos: TPointF;
    LMaxRight: Single;
    LMaxBottom: Single;
    LControl: TControl;
begin
    // A block node visually encloses all its child nodes.
    // Create the container node for the block. Its size will be adjusted later.
    LBlockNode := TAuraNode.Create(FParentControl);
    LBlockNode.Parent := FParentControl;
    LBlockNode.Title := 'Block';
    LBlockNode.Position.Point := FCurrentPos;

    // Create a new visitor for the child nodes. The children will be parented
    // to LBlockNode and positioned relative to it, starting below the title.
    LChildStartPos := TPointF.Create(FSpacing.X, FSpacing.Y + LBlockNode.TitleFont.Size * 1.8);
    LChildVisitor := TAstToAuraNodeVisitor.Create(FWorkspace, LBlockNode, LChildStartPos, FConnections);

    // Visit all expressions within the block using the new visitor.
    for Expression in Node.Expressions do
    begin
        Expression.Accept(LChildVisitor);
    end;

    // Adjust the size of the block node to encompass all its children.
    LMaxRight := 0;
    LMaxBottom := 0;
    for LControl in LBlockNode.Controls do
    begin
        if (LControl is TAuraNode) then
        begin
            LMaxRight := Max(LMaxRight, LControl.Position.X + LControl.Width);
            LMaxBottom := Max(LMaxBottom, LControl.Position.Y + LControl.Height);
        end;
    end;

    // Set the final size with some internal padding.
    LBlockNode.Width := Max(LBlockNode.Width, LMaxRight + FSpacing.X);
    LBlockNode.Height := Max(LBlockNode.Height, LMaxBottom + FSpacing.Y);

    // Update the current Y position of the main visitor to be below the now correctly sized block node.
    FCurrentPos.Y := LBlockNode.Position.Y + LBlockNode.Height + FSpacing.Y;
    FLastNode := LBlockNode;

    Result := TAstValue.Void;
end;

function TAstToAuraNodeVisitor.VisitConstant(const Node: IConstantNode): TAstValue;
var
    LConstantNode: TAuraNode;
begin
    // A constant has a data output pin.
    // Data outputs are round and on the right side of the box.
    LConstantNode := CreateNodeControl('Constant', Node.Value.ToString);
    CreateOutput(LConstantNode, 0);
    Result := TAstValue.Void;
end;

function TAstToAuraNodeVisitor.VisitFunctionCall(const Node: IFunctionCallNode): TAstValue;
var
    LFuncCallNode: TAuraNode;
    LInputResultNodes: TList<TAuraNode>;
    LInputNode: IExpressionNode;
    LStartPosition: TPointF;
    LEndY, LMaxChildWidth: Single;
    i: Integer;
    LCalleePin: TControl;
    LArgPin: array of TControl;
    LCurrentInputOffsetY, LCurrentOutputOffsetY: Single;
begin
    LStartPosition := FCurrentPos;
    LInputResultNodes := TList<TAuraNode>.Create;
    try
        // 1. Visit all input nodes first (Callee + Arguments) and collect their visual representations.
        Node.Callee.Accept(Self);
        LInputResultNodes.Add(FLastNode);

        for LInputNode in Node.Arguments do
        begin
            LInputNode.Accept(Self);
            LInputResultNodes.Add(FLastNode);
        end;
        LEndY := FCurrentPos.Y;

        // 2. Determine the layout bounds of the input nodes.
        LMaxChildWidth := 0;
        for var LNode in LInputResultNodes do
            LMaxChildWidth := Max(LMaxChildWidth, LNode.Position.X + LNode.Width);

        // 3. Position and create the 'FunctionCall' node to the right of the inputs.
        FCurrentPos.X := LMaxChildWidth + FSpacing.X;

        // Calculate dynamic height based on the number of pins
        var LNumInputPins := 2 + Node.Arguments.Count;
        var LNumOutputPins := 2;
        var LMaxPins := Max(LNumInputPins, LNumOutputPins);
        var LNodeHeight := cVerticalPadding + (LMaxPins - 1) * cPinOffsetY;

        var LTotalInputHeight := LEndY - LStartPosition.Y;
        var LNodeCenterY := LStartPosition.Y + (LTotalInputHeight / 2);
        FCurrentPos.Y := LNodeCenterY - (LNodeHeight / 2);

        LFuncCallNode := CreateNodeControl('FunctionCall', '');
        LFuncCallNode.Height := LNodeHeight;

        // 4. Create all necessary pins on the 'FunctionCall' node with proper spacing.
        // Left side (Inputs)
        LCurrentInputOffsetY := -(LNumInputPins - 1) / 2.0 * cPinOffsetY;
        CreateEntry(LFuncCallNode, LCurrentInputOffsetY);
        LCurrentInputOffsetY := LCurrentInputOffsetY + cPinOffsetY;
        LCalleePin := CreateInput(LFuncCallNode, LInputResultNodes[0].Name, LCurrentInputOffsetY);
        LCurrentInputOffsetY := LCurrentInputOffsetY + cPinOffsetY;
        SetLength(LArgPin, Node.Arguments.Count);
        for i := 0 to Node.Arguments.Count - 1 do
        begin
            LArgPin[i] := CreateInput(LFuncCallNode, LInputResultNodes[i + 1].Name + i.ToString, LCurrentInputOffsetY);
            LCurrentInputOffsetY := LCurrentInputOffsetY + cPinOffsetY;
        end;

        // Right side (Outputs)
        LCurrentOutputOffsetY := -(LNumOutputPins - 1) / 2.0 * cPinOffsetY;
        CreateExit(LFuncCallNode, '', LCurrentOutputOffsetY);
        LCurrentOutputOffsetY := LCurrentOutputOffsetY + cPinOffsetY;
        CreateOutput(LFuncCallNode, LCurrentOutputOffsetY);

        // 5. Connect the inputs.
        ConnectData(LCalleePin, LInputResultNodes[0]);
        for i := 0 to Node.Arguments.Count - 1 do
            ConnectData(LArgPin[i], LInputResultNodes[i + 1]);

    finally
        LInputResultNodes.Free;
    end;

    // 6. Finalize visitor state.
    FCurrentPos.X := LStartPosition.X;
    FCurrentPos.Y := Max(LEndY, LFuncCallNode.Position.Y + LFuncCallNode.Height + FSpacing.Y);
    FLastNode := LFuncCallNode;

    Result := TAstValue.Void;
end;

function TAstToAuraNodeVisitor.VisitIdentifier(const Node: IIdentifierNode): TAstValue;
begin
    CreateNodeControl('Identifier', Node.Name);
    // Add a data output pin on the right side.
    CreateOutput(FLastNode, 0);
    Result := TAstValue.Void;
end;

function TAstToAuraNodeVisitor.VisitIfExpression(const Node: IIfExpressionNode): TAstValue;
var
    LIfNode, LConditionNode, LThenNode, LElseNode: TAuraNode;
    LConditionInputPin, LThenOutputPin, LElseOutputPin: TControl;
    LStartPosition: TPointF;
    LConditionEndY, LThenEndY, LElseEndY, LMaxChildWidth: Single;
begin
    LStartPosition := FCurrentPos;

    // Place the input node for the condition to the left of the 'If' node.
    Node.Condition.Accept(Self);
    LConditionNode := FLastNode;
    LConditionEndY := FCurrentPos.Y;

    // Position and create the 'If' node to the right of the condition's subtree.
    LMaxChildWidth := LConditionNode.Position.X + LConditionNode.Width;
    FCurrentPos.X := LMaxChildWidth + FSpacing.X;
    FCurrentPos.Y := LStartPosition.Y + (LConditionNode.Position.Y + LConditionNode.Height / 2) - LStartPosition.Y - (cIfNodeHeight / 2);

    LIfNode := CreateNodeControl('If', '');
    LIfNode.Height := cIfNodeHeight;
    CreateEntry(LIfNode, -12);
    LConditionInputPin := CreateInput(LIfNode, 'Condition', 12);
    LThenOutputPin := CreateExit(LIfNode, 'Then', -12);
    if Assigned(Node.ElseBranch) then
        LElseOutputPin := CreateExit(LIfNode, 'Else', 12)
    else
        LElseOutputPin := nil;

    // Connect the condition's output to the 'If' node's data input.
    ConnectData(LConditionInputPin, LConditionNode);

    // Visit the 'Then' and 'Else' execution branches, placing them to the right of the 'If' node.
    var LBranchStartX := LIfNode.Position.X + LIfNode.Width + FSpacing.X;

    // Then branch
    FCurrentPos.X := LBranchStartX;
    FCurrentPos.Y := LStartPosition.Y;
    Node.ThenBranch.Accept(Self);
    LThenNode := FLastNode;
    LThenEndY := FCurrentPos.Y;
    //    ConnectData(FindPinByTag(LThenNode, 'Pin.Exec.In'), LIfNode, 'Pin.Exec.Out.Then');

    // Else branch (if it exists)
    LElseEndY := LThenEndY;
    if Assigned(Node.ElseBranch) then
    begin
        FCurrentPos.X := LBranchStartX;
        FCurrentPos.Y := LThenEndY;
        Node.ElseBranch.Accept(Self);
        LElseNode := FLastNode;
        LElseEndY := FCurrentPos.Y;
        //        ConnectData(FindPinByTag(LElseNode, 'Pin.Exec.In'), LIfNode, 'Pin.Exec.Out.Else');
    end;

    // Finalize visitor state.
    FCurrentPos.X := LStartPosition.X;
    FCurrentPos.Y := Max(LConditionEndY, LElseEndY);
    FLastNode := LIfNode;

    Result := TAstValue.Void;
end;

function TAstToAuraNodeVisitor.VisitLambdaExpression(const Node: ILambdaExpressionNode): TAstValue;
var
    ParamStr: String;
    LLambdaNode: TAuraNode;
    LChildVisitor: IAstVisitor;
    LChildStartPos: TPointF;
    LMaxRight, LMaxBottom: Single;
    LControl: TControl;
    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 + ')';

    // Create the container node for the lambda. Its size will be adjusted later.
    LLambdaNode := CreateNodeControl('Lambda', ParamStr);

    // Create a new visitor for the child nodes (the lambda body).
    // The children will be parented to LLambdaNode and positioned relative to it.
    LChildStartPos := TPointF.Create(FSpacing.X, FSpacing.Y + LLambdaNode.TitleFont.Size * 1.8);
    LChildVisitor := TAstToAuraNodeVisitor.Create(FWorkspace, LLambdaNode, LChildStartPos, FConnections);

    // Visit the body expression using the new visitor.
    Node.Body.Accept(LChildVisitor);

    // Adjust the size of the lambda node to encompass its body.
    LMaxRight := 0;
    LMaxBottom := 0;
    for LControl in LLambdaNode.Controls do
    begin
        if (LControl is TAuraNode) then
        begin
            LMaxRight := Max(LMaxRight, LControl.Position.X + LControl.Width);
            LMaxBottom := Max(LMaxBottom, LControl.Position.Y + LControl.Height);
        end;
    end;

    // Set the final size with some internal padding.
    LLambdaNode.Width := Max(LLambdaNode.Width, LMaxRight + FSpacing.X);
    LLambdaNode.Height := Max(LLambdaNode.Height, LMaxBottom + FSpacing.Y);

    // Add a data output pin for the resulting closure.
    CreateOutput(LLambdaNode, 0);

    // Update the current Y position of the main visitor to be below the now correctly sized lambda node.
    FCurrentPos.Y := LLambdaNode.Position.Y + LLambdaNode.Height + FSpacing.Y;

    Result := TAstValue.Void;
end;

function TAstToAuraNodeVisitor.VisitUnaryExpression(const Node: IUnaryExpressionNode): TAstValue;
begin
    CreateNodeControl('UnaryExpr', Node.Operator.ToString);
    FCurrentPos.X := FCurrentPos.X + FSpacing.X;
    try
        Node.Right.Accept(Self);
    finally
        FCurrentPos.X := FCurrentPos.X - FSpacing.X;
    end;
    Result := TAstValue.Void;
end;

function TAstToAuraNodeVisitor.VisitVariableDeclaration(const Node: IVariableDeclarationNode): TAstValue;
var
    LVarDeclNode, LInitializerNode: TAuraNode;
    LStartPosition: TPointF;
    LInitializerEndY, LVarDeclNodeEndY: Single;
    LInputPin: TControl;
begin
    LStartPosition := FCurrentPos;
    LInitializerEndY := LStartPosition.Y;
    LInitializerNode := nil;

    if Assigned(Node.Initializer) then
    begin
        Node.Initializer.Accept(Self);

        LInitializerNode := FLastNode;
        LInitializerEndY := FCurrentPos.Y;

        // Position the VarDecl node dynamically to the right of the initializer's visual tree.
        FCurrentPos.X := LInitializerNode.Position.X + LInitializerNode.Width + FSpacing.X;
        FCurrentPos.Y := LStartPosition.Y;
    end;

    LVarDeclNode := CreateNodeControl('VarDecl', Node.Identifier.Name);
    LVarDeclNodeEndY := FCurrentPos.Y;

    CreateEntry(LVarDeclNode, -8);
    CreateExit(LVarDeclNode, '', -8);

    if Assigned(Node.Initializer) then
    begin
        LInputPin := CreateInput(LVarDeclNode, LInitializerNode.Name, 8);
        ConnectData(LInputPin, LInitializerNode);

        // Vertically center the VarDecl node relative to the initializer's visual tree.
        var LInitializerHeight := LInitializerEndY - LStartPosition.Y;
        LVarDeclNode.Position.Y := LStartPosition.Y + (LInitializerHeight / 2) - (LVarDeclNode.Height / 2);
        LVarDeclNodeEndY := LVarDeclNode.Position.Y + LVarDeclNode.Height + FSpacing.Y;

        FCurrentPos.Y := Max(LInitializerEndY, LVarDeclNodeEndY);
        FCurrentPos.X := LStartPosition.X;
    end;
    FLastNode := LVarDeclNode;

    Result := TAstValue.Void;
end;

{ TAuraWorkspace }

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

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

procedure TAuraWorkspace.Paint;
var
    LConnection: TPinConnection;
    LStartPoint, LEndPoint, LPinCenter: TPointF;
    LPath: TPathData;
    LControlPoint1, LControlPoint2: TPointF;
    LDeltaX, LControlOffset: Single;
begin
    inherited;

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

    // Gehe durch alle gespeicherten Verbindungen und zeichne sie
    for LConnection in FConnections do
    begin
        // Hole die absoluten Koordinaten der Pin-Mittelpunkte
        LPinCenter := TPointF.Create(LConnection.OutputPin.Width / 2, LConnection.OutputPin.Height / 2);
        var LAbsoluteStart := LConnection.OutputPin.LocalToAbsolute(LPinCenter);

        LPinCenter := TPointF.Create(LConnection.InputPin.Width / 2, LConnection.InputPin.Height / 2);
        var LAbsoluteEnd := LConnection.InputPin.LocalToAbsolute(LPinCenter);

        // Rechne sie in die lokalen Koordinaten der PaintBox um
        LStartPoint := AbsoluteToLocal(LAbsoluteStart);
        LEndPoint := AbsoluteToLocal(LAbsoluteEnd);

        var str := LConnection.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.
        LPath := TPathData.Create;
        try
            LDeltaX := LEndPoint.X - LStartPoint.X;
            LControlOffset := Abs(LDeltaX) / 2;

            LControlPoint1 := TPointF.Create(LStartPoint.X + LControlOffset, LStartPoint.Y);
            LControlPoint2 := TPointF.Create(LEndPoint.X - LControlOffset, LEndPoint.Y);

            LPath.MoveTo(LStartPoint);
            LPath.CurveTo(LControlPoint1, LControlPoint2, LEndPoint);

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

end.