import { Collidable } from './collision';
import { Line, Movement, normal } from './line';

import { vec2 } from 'gl-matrix';

export class Point implements Collidable {
	constructor(public readonly p: vec2) {}

	public collide(out: vec2, move: Movement, r: number): boolean {
		const moveLine = move.toLineSegment();

		if (moveLine.projectPointDistance(this.p) < 0)
			return false;

		const d = moveLine.distancePoint(this.p) / r;
		if (Math.abs(d) >= 1)
			return false;

		const e = Math.sqrt(1 - d * d);

		const t = moveLine.getNormal(vec2.create());
		vec2.scale(t, t, d);
		vec2.scaleAndAdd(t, t, moveLine.v, e);

		const tr = vec2.scale(vec2.create(), t, r);

		const refMove = move.translate(tr);

		if (vec2.sqrDist(this.p, move.src) > r * r && !refMove.passes(this.p))
			return false;

		normal(t, t);

		const tang = new Line(this.p, t);
		tang.projectPoint(out, refMove.dest);
		vec2.sub(out, out, tr);

		return true;
	}
}