Visualization.hpp

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#pragma once

 
#include "models/TreeBranch.hpp"
#include "models/TreeLeaf.hpp"
#include "utils/Types.hpp"
 
#include <vector>
#include <utility>
#include <string>
 
namespace ppforest2::viz {
  // ===================================================================
  // Node Data Collection
  // ===================================================================

  struct NodeData {
    bool is_leaf;
    int depth;
    types::FeatureVector projector;
    types::Feature cutpoint;
    types::Outcome value;
    std::vector<types::Feature> projected_values;
    std::vector<types::Outcome> groups;
  };

  class NodeDataVisitor : public TreeNode::Visitor {
  public:
    types::FeatureMatrix const& x; 
    types::OutcomeVector const& y; 
    std::vector<int> indices;      
    int depth;                     
    std::vector<NodeData> nodes;   
 
    NodeDataVisitor(types::FeatureMatrix const& x, types::OutcomeVector const& y);
 
    void visit(TreeBranch const& node) override;
    void visit(TreeLeaf const& node) override;
  };
 
  // ===================================================================
  // Decision Boundary and Region Types
  // ===================================================================

  struct HalfSpace {
    types::FeatureVector projector;
    types::Feature cutpoint;
    bool is_lower = false; 
 
    HalfSpace(types::FeatureVector projector, types::Feature cutpoint, bool is_lower)
        : projector(std::move(projector))
        , cutpoint(cutpoint)
        , is_lower(is_lower) {}
  };

  struct BoundarySegment {
    types::Feature x_start, y_start, x_end, y_end;
    int depth;
  };

  struct RegionPolygon {
    std::vector<std::pair<types::Feature, types::Feature>> vertices;
    types::Outcome predicted_group; 
  };
 
  // ===================================================================
  // 2D Projection Helpers
  // ===================================================================

  types::FeatureVector project_2d(types::FeatureVector const& full_proj, int var_i, int var_j);

  types::Feature adjust_cutpoint(
      types::FeatureVector const& full_proj,
      types::Feature thr,
      std::vector<std::pair<int, types::Feature>> const& fixed_vars
  );

  HalfSpace project_halfspace_2d(
      HalfSpace const& hs, int var_i, int var_j, std::vector<std::pair<int, types::Feature>> const& fixed_vars
  );
 
  // ===================================================================
  // Parametric Line Clipping
  // ===================================================================

  bool clip_param_to_range(
      types::Feature origin,
      types::Feature direction,
      types::Feature range_min,
      types::Feature range_max,
      types::Feature& u_min,
      types::Feature& u_max
  );

  bool clip_boundary_2d(
      types::FeatureVector const& a,
      types::Feature cutpoint,
      std::vector<HalfSpace> const& constraints,
      types::Feature x_min,
      types::Feature x_max,
      types::Feature y_min,
      types::Feature y_max,
      BoundarySegment& segment,
      int depth
  );
 
  // ===================================================================
  // Polygon Clipping (Sutherland–Hodgman)
  // ===================================================================

  using Polygon = std::vector<std::pair<types::Feature, types::Feature>>;

  Polygon clip_polygon_halfspace(
      Polygon const& polygon, types::FeatureVector const& normal, types::Feature cutpoint, bool is_lower
  );
 
  // ===================================================================
  // Spatial Visitor (shared base for boundary and region visitors)
  // ===================================================================

  class SpatialVisitor : public TreeNode::Visitor {
  public:
    int var_i, var_j;                                       
    std::vector<std::pair<int, types::Feature>> fixed_vars; 
    types::Feature x_min, x_max, y_min, y_max;              
    int depth;
    std::vector<HalfSpace> constraints; 
 
    SpatialVisitor(
        int var_i,
        int var_j,
        std::vector<std::pair<int, types::Feature>> const& fixed_vars,
        types::Feature x_min,
        types::Feature x_max,
        types::Feature y_min,
        types::Feature y_max
    );

    void visit(TreeBranch const& node) override;

    void visit(TreeLeaf const& node) override;
  };
 
  // ===================================================================
  // Boundary Visitor
  // ===================================================================

  class BoundaryVisitor : public SpatialVisitor {
  public:
    using SpatialVisitor::SpatialVisitor;
    std::vector<BoundarySegment> segments; 
 
    void visit(TreeBranch const& node) override;
  };
 
  // ===================================================================
  // Region Visitor
  // ===================================================================

  class RegionVisitor : public SpatialVisitor {
  public:
    using SpatialVisitor::SpatialVisitor;
    std::vector<RegionPolygon> regions; 
 
 
    void visit(TreeLeaf const& node) override;
  };
 
  // ===================================================================
  // Tree Layout
  // ===================================================================

  struct LayoutParams {
    types::Feature y_spacing = 1.5f; 
    types::Feature node_w    = 0.8f; 
    types::Feature node_h    = 0.7f; 
    types::Feature leaf_w    = 0.5f; 
    types::Feature leaf_h    = 0.3f; 
    types::Feature gap       = 0.2f; 
  };

  struct LayoutNode {
    types::Feature x, y; 
    bool is_leaf;
    int node_idx; 
  };

  struct LayoutEdge {
    types::Feature from_x, from_y, to_x, to_y;
    std::string label; 
  };

  struct TreeLayout {
    std::vector<LayoutNode> nodes;
    std::vector<LayoutEdge> edges;
  };

  TreeLayout compute_tree_layout(TreeNode const& root, LayoutParams const& params = LayoutParams());
}