Aislo/B07_DesignDetail/openwebcad/src/helpers/get-draw-guides.ts

import type { Point } from '@flatten-js/core';
import { compact } from 'es-toolkit';
import { SNAP_ANGLE_DISTANCE } from '../App.consts';
import { type SnapPoint, SnapPointType } from '../App.types';
import type { Entity } from '../entities/Entity';
import type { LineEntity } from '../entities/LineEntity';
import { findClosestEntity } from './find-closest-entity';
import { getAngleGuideLines } from './get-angle-guide-lines';
import { getClosestSnapPointWithinRadius } from './get-closest-snap-point';
import { getIntersectionPoints } from './get-intersection-points';

/**
 * Gets the angle guides from the angle point to the mouse if the mouse is close to one of the angle steps and also returns the closest snap point
 * @param entities entities that are drawn on the canvas
 * @param anglePoints the points that should get angle guides
 * @param worldMouseLocation the current mouse location
 * @param angleStep the angle in degrees at which the angle guides should be drawn
 * @param maxSnapDistance The distance that the mouse can snap to a snap point or angle guide
 */
export function getDrawHelpers(
	entities: Entity[],
	anglePoints: Point[],
	worldMouseLocation: Point,
	angleStep: number,
	maxSnapDistance: number
): {
	angleGuides: LineEntity[];
	entitySnapPoint: SnapPoint | null;
	angleSnapPoint: SnapPoint | null;
} {
	let entitySnapPoint: SnapPoint | null = null;
	let angleSnapPoint: SnapPoint | null = null;
	const nearestAngleSnapPoints: SnapPoint[] = [];
	const angleGuides: LineEntity[] = [];

	// draw angle guide — angleStep 0은 직교·극좌표 추적을 모두 끈 상태다
	for (const anglePoint of angleStep > 0 ? anglePoints : []) {
		const angleGuideLines = getAngleGuideLines(anglePoint, angleStep);

		const closestLineInfo = findClosestEntity<LineEntity>(worldMouseLocation, angleGuideLines);

		if (closestLineInfo.distance < SNAP_ANGLE_DISTANCE) {
			angleGuides.push(closestLineInfo.entity);
			nearestAngleSnapPoints.push({
				point: closestLineInfo.segment.start,
				type: SnapPointType.AngleGuide,
			});
		}
	}

	// Calculate snap points
	const entitySnapPoints = [
		...entities.flatMap((entity) => {
			return entity.getSnapPoints();
		}),
		...getIntersectionPoints(compact(entities)).map((point) => ({
			point,
			type: SnapPointType.Intersection,
		})),
	];

	const closestSnapPoint = getClosestSnapPointWithinRadius(
		entitySnapPoints,
		worldMouseLocation,
		maxSnapDistance
	);

	if (closestSnapPoint) {
		entitySnapPoint = closestSnapPoint;
	}

	const angleSnapPoints = [
		...nearestAngleSnapPoints,
		// TODO only search for intersections between angle guides and other angle guides and between angle guides and entities, but not between entities
		...getIntersectionPoints([...compact(entities), ...angleGuides]).map((point) => ({
			point,
			type: SnapPointType.Intersection,
		})),
	];
	const closestAngleSnapPoint = getClosestSnapPointWithinRadius(
		angleSnapPoints,
		worldMouseLocation,
		maxSnapDistance
	);

	if (closestAngleSnapPoint) {
		angleSnapPoint = closestAngleSnapPoint;
	}

	return { angleGuides, entitySnapPoint, angleSnapPoint };
}