import RBush from 'rbush';
import type { BoundingBox, CADElement } from '../types/cad.types';

interface IndexedItem extends BoundingBox {
  element: CADElement;
}

export class SpatialIndex {
  private tree: RBush<IndexedItem>;

  constructor() {
    this.tree = new RBush<IndexedItem>();
  }

  insert(element: CADElement): void {
    const bbox = this.elementBBox(element);
    this.tree.insert({ ...bbox, element });
  }

  bulkInsert(elements: CADElement[]): void {
    const items = elements.map(el => ({ ...this.elementBBox(el), element: el }));
    this.tree.load(items);
  }

  search(viewport: BoundingBox): CADElement[] {
    return this.tree.search(viewport).map(item => item.element);
  }

  remove(element: CADElement): void {
    const bbox = this.elementBBox(element);
    this.tree.remove({ ...bbox, element }, (a, b) => a.element.id === b.element.id);
  }

  clear(): void {
    this.tree.clear();
  }

  private elementBBox(el: CADElement): BoundingBox {
    const halfW = el.width / 2;
    const halfH = el.height / 2;
    return {
      minX: el.x - halfW,
      minY: el.y - halfH,
      maxX: el.x + halfW,
      maxY: el.y + halfH,
    };
  }
}