/**
 * 내부 클립보드 — 잘라내기·복사·붙여넣기(기준점 포함).
 * 시스템 클립보드는 도면 객체를 담을 수 없어 앱 안에서만 오간다.
 */
import { Point } from '@flatten-js/core';
import type { Entity } from '../entities/Entity';
import { getBoundingBoxOfMultipleEntities } from './get-bounding-box-of-multiple-entities';

interface ClipboardContent {
	entities: Entity[];
	/** 붙여넣기 기준점 — 지정하지 않으면 선택 영역의 좌하단 */
	basePoint: Point;
}

let clipboard: ClipboardContent | null = null;

export const hasClipboardContent = (): boolean => !!clipboard?.entities.length;

export function copyToClipboard(entities: Entity[], basePoint?: Point): number {
	if (!entities.length) return 0;
	const box = getBoundingBoxOfMultipleEntities(entities);
	clipboard = {
		entities: entities.map((entity) => {
			const copy = entity.clone();
			copy.lineColor = entity.lineColor;
			copy.lineWidth = entity.lineWidth;
			copy.lineDash = entity.lineDash;
			copy.layerId = entity.layerId;
			return copy;
		}),
		basePoint: basePoint ?? new Point(box.minX, box.minY),
	};
	return clipboard.entities.length;
}

/**
 * 클립보드 내용을 새 객체로 꺼낸다.
 * target을 주면 기준점이 그 위치에 오도록 옮기고, 없으면 원래 좌표 그대로 둔다.
 */
export function pasteFromClipboard(target?: Point): Entity[] {
	if (!clipboard) return [];
	return clipboard.entities.map((entity) => {
		const copy = entity.clone();
		copy.lineColor = entity.lineColor;
		copy.lineWidth = entity.lineWidth;
		copy.lineDash = entity.lineDash;
		copy.layerId = entity.layerId;
		if (target) {
			copy.move(
				target.x - (clipboard as ClipboardContent).basePoint.x,
				target.y - (clipboard as ClipboardContent).basePoint.y
			);
		}
		return copy;
	});
}