unit Myc.Ast.ViewModel;

interface

uses
    System.SysUtils,
    System.Types,
    System.Generics.Collections,
    Myc.Ast.Nodes;

type
    // An enum to identify the specific type of an AST node without relying on RTTI or GUIDs.
    // This allows the renderer to depend only on the ViewModel layer.
    TAstNodeType = (
        antUndefined,
        antConstant,
        antIdentifier,
        antBinaryExpression,
        antUnaryExpression,
        antIfExpression,
        antTernaryExpression,
        antLambdaExpression,
        antFunctionCall,
        antBlockExpression,
        antVariableDeclaration,
        antAssignment,
        antIndexer,
        antMemberAccess,
        antCreateSeries,
        antAddSeriesItem,
        antSeriesLength
    );

    // A unique, stable identifier for a visual node instance.
    TViewModelID = NativeInt;

    // Defines how a view model displays its children.
    TVisualizationMode = (vmSyntactic, vmSemantic);

    // Metadata tied to a logical IAstNode. All visual instances of this node will share this data.
    TLogicalMetadata = record
        // The concrete type of the IAstNode, used for type-safe operations in the renderer.
        NodeType: TAstNodeType;
        Description: String;
    end;

    // Metadata tied to a specific visual instance of a node, identified by its TViewModelID.
    TVisualInstanceMetadata = record
        PositionOverride: TPointF;
        IsCollapsed: Boolean;
        VisualizationMode: TVisualizationMode;
    end;

    // The ViewModel for a node in the visual graph.
    TVisualNodeViewModel = class
    private
        FId: TViewModelID;
        FNode: IAstNode;
        FLogicalMetadata: TLogicalMetadata;
        FParents: TList<TVisualNodeViewModel>;
        FChildren: TList<TVisualNodeViewModel>;
    public
        constructor Create(const ANode: IAstNode; const AId: TViewModelID; const ALogicalMetadata: TLogicalMetadata);
        destructor Destroy; override;

        procedure AddChild(const AChild: TVisualNodeViewModel);

        property Id: TViewModelID read FId;
        property Node: IAstNode read FNode;
        property LogicalMetadata: TLogicalMetadata read FLogicalMetadata;
        property Children: TList<TVisualNodeViewModel> read FChildren;
        property Parents: TList<TVisualNodeViewModel> read FParents;
    end;

implementation

{ TVisualNodeViewModel }

constructor TVisualNodeViewModel.Create(const ANode: IAstNode; const AId: TViewModelID; const ALogicalMetadata: TLogicalMetadata);
begin
    inherited Create;
    FNode := ANode;
    FId := AId;
    FLogicalMetadata := ALogicalMetadata;
    FParents := TList<TVisualNodeViewModel>.Create;
    FChildren := TList<TVisualNodeViewModel>.Create;
end;

destructor TVisualNodeViewModel.Destroy;
begin
    FParents.Free;
    FChildren.Free;
    inherited;
end;

procedure TVisualNodeViewModel.AddChild(const AChild: TVisualNodeViewModel);
begin
    FChildren.Add(AChild);
    AChild.FParents.Add(Self);
end;

end.