import type { Vec2 } from '../geometry/Vec2';
import { polygonArea } from '../geometry/Polygon';

/** 으깨기 모드의 조정값. 간격은 벨트가 실제 진행한 시간이다. */
export const CRUSH = {
  halfWidth: 0.90, halfDepth: 0.70,
  beltHalfWidth: 40, beltHalfDepth: 1.15, beltY: 0.16,
  hover: 1.45, flat: 0.15, spread: 0.25, edge: 0.07,
} as const;
export interface CrushContact { minX: number; maxX: number; minZ: number; maxZ: number }

/** 볼록 압착판에 대한 클리핑. 원본 폴리곤을 변경하지 않는다. */
export function crushScore(outline: readonly Vec2[], x: number): { score: number; contact: CrushContact } {
  const contact = { minX: -CRUSH.halfWidth-x, maxX: CRUSH.halfWidth-x, minZ: -CRUSH.halfDepth, maxZ: CRUSH.halfDepth };
  let points = [...outline];
  for (const [axis, bound, sign] of [['x',contact.minX,1],['x',contact.maxX,-1],['y',contact.minZ,1],['y',contact.maxZ,-1]] as const) {
    const next: Vec2[]=[];
    for (let i=0;i<points.length;i++) {
      const a=points[i], b=points[(i+1)%points.length];
      const da=(a[axis]-bound)*sign, db=(b[axis]-bound)*sign;
      if (da>=0) next.push(a);
      if ((da>=0)!==(db>=0)) {
        const t=da/(da-db); next.push({x:a.x+(b.x-a.x)*t,y:a.y+(b.y-a.y)*t});
      }
    }
    points=next;
  }
  const area=Math.abs(polygonArea(outline));
  const ratio=area>1e-10 ? Math.abs(polygonArea(points))/area : 0;
  return {score:Math.min(100, Math.max(0,ratio*100)),contact};
}