/** 대칭·정렬·간격띄우기·신축·길이조정 (조사표 2절) */
import { Box, Point, Polygon } from '@flatten-js/core';
import { toast } from 'react-toastify';
import { type AnyActorRef, assign } from 'xstate';
import { OPT } from '../../commands/prompt';
import type { Entity } from '../../entities/Entity';
import { LineEntity } from '../../entities/LineEntity';
import { PolyLineEntity } from '../../entities/PolyLineEntity';
import { RectangleEntity } from '../../entities/RectangleEntity';
import {
	addEntities,
	deleteEntities,
	getActiveLayerId,
	getEntities,
	setEntities,
	setSelectedEntityIds,
} from '../../state';
import { Tool } from '../../tools';
import { createSequenceTool } from '../factories/sequence-tool';
import { createDisplaceTool } from '../move-tool';
import { SelectState } from '../select-tool';
import type { MouseClickEvent, StateEvent } from '../tool.types';
import { SELECT_CHILD } from '../transform.helpers';
import { copyStyle, lengthenLine, offsetEntity } from './modify.helpers';

/** 원본 특성을 유지한 복사본 */
const cloneStyled = (entity: Entity): Entity => copyStyle(entity, entity.clone());

/** 대칭선 — 두 점이 같으면 없음 */
const mirrorAxis = (first: Point, second: Point): LineEntity | null =>
	first.distanceTo(second)[0] < 1e-9 ? null : new LineEntity(getActiveLayerId(), first, second);

const mirrored = (originals: Entity[], axis: LineEntity): Entity[] =>
	originals.map((entity) => {
		const copy = cloneStyled(entity);
		copy.mirror(axis);
		return copy;
	});

/**
 * MIRROR(337 라 · 설계 1-3) — 「객체 선택:」 → 「대칭선의 첫 번째 점 지정:」 → 「대칭선의 두 번째 점 지정:」 →
 * 「원본 객체를 지우시겠습니까? [예(Y)/아니오(N)] <아니오>:」 · Esc = 안 만듦 · 한 번 뒤 끝.
 */
export const mirrorToolStateMachine = createSequenceTool({
	tool: Tool.MIRROR,
	steps: [
		{ kind: 'selection' },
		{ kind: 'point', id: 'first', prompt: { text: '대칭선의 첫 번째 점 지정' } },
		{ kind: 'point', id: 'second', prompt: { text: '대칭선의 두 번째 점 지정' } },
		{
			kind: 'keyword',
			id: 'erase',
			prompt: {
				text: '원본 객체를 지우시겠습니까?',
				options: [OPT.YES, OPT.NO],
				default: { kind: 'option', key: OPT.NO.key },
			},
		},
	],
	preview: (input) => {
		const [first, second] = input.points();
		const axis = first ? mirrorAxis(first, second ?? input.cursor) : null;
		if (!axis) return [];
		return [...(second ? [] : [axis]), ...mirrored(input.entities(0), axis)];
	},
	commit: (input) => {
		const [first, second] = input.points();
		const axis = mirrorAxis(first, second);
		const originals = input.entities(0);
		if (!axis || !originals.length) return;
		const copies = mirrored(originals, axis);
		if (input.get('erase') === OPT.YES.key) {
			const gone = new Set(originals.map((entity) => entity.id));
			setEntities([...getEntities().filter((entity) => !gone.has(entity.id)), ...copies], true);
		} else {
			addEntities(copies, true);
		}
		setSelectedEntityIds([]);
	},
});

export const alignToolStateMachine = createSequenceTool({
	tool: Tool.ALIGN,
	steps: [
		{ kind: 'selection', instructions: '정렬할 객체를 선택한 뒤 ENTER.' },
		{ kind: 'point', instructions: '첫 번째 원본점을 지정하십시오.' },
		{ kind: 'point', instructions: '첫 번째 대상점을 지정하십시오.' },
		{ kind: 'point', instructions: '두 번째 원본점을 지정하십시오.' },
		{ kind: 'point', instructions: '두 번째 대상점을 지정하십시오.' },
	],
	commit: (input) => {
		const [source1, target1, source2, target2] = input.points();
		const sourceAngle = Math.atan2(source2.y - source1.y, source2.x - source1.x);
		const targetAngle = Math.atan2(target2.y - target1.y, target2.x - target1.x);
		const rotation = targetAngle - sourceAngle;

		// 원본을 그대로 두고 사본을 변환해 교체한다 (실행취소가 원본을 되살릴 수 있어야 한다)
		const originals = input.entities(0);
		const aligned = originals.map((entity) => {
			const copy = cloneStyled(entity);
			copy.move(target1.x - source1.x, target1.y - source1.y);
			copy.rotate(target1, rotation);
			return copy;
		});
		if (originals.length) {
			deleteEntities(originals, false);
			addEntities(aligned, true);
		}
		setSelectedEntityIds([]);
	},
});

export const offsetToolStateMachine = createSequenceTool({
	tool: Tool.OFFSET,
	steps: [
		{ kind: 'number', instructions: '간격띄우기 거리를 입력하십시오 <1>.', defaultValue: 1 },
		{ kind: 'entity', instructions: '간격띄우기할 객체를 선택하십시오.' },
		{ kind: 'point', instructions: '간격을 띄울 방향의 점을 지정하십시오.' },
	],
	commit: (input) => {
		const result = offsetEntity(input.entity(1), input.number(0), input.point(2));
		if (!result) {
			toast.warn('이 객체는 지정한 거리로 간격을 띄울 수 없습니다.');
			return;
		}
		addEntities([result], true);
	},
});

/** 바꾼 것을 원본 자리에 — id · 묶음 · 꼴 그대로 */
const inPlaceOf = <T extends Entity>(source: Entity, made: T): T => {
	copyStyle(source, made);
	made.id = source.id;
	made.groupId = source.groupId;
	made.opacity = source.opacity;
	return made;
};

/**
 * 걸침 창 신축 — 창 안 꼭짓점만 (dx, dy) · 창 안에 통째 든 것 · 하나씩 집은 것(창 밖) = 이동 · 그 밖 = 그대로(null).
 * ponytail: 선 · 폴리선(선 토막) · 사각형만 꼭짓점 신축 — 원 · 호 · 글은 걸치면 그대로(오토캐드는 중심 · 끝점 기준).
 */
function stretchEntity(entity: Entity, box: Box | null, dx: number, dy: number): Entity | null {
	const inside = (point: Point) =>
		!!box &&
		point.x >= box.xmin &&
		point.x <= box.xmax &&
		point.y >= box.ymin &&
		point.y <= box.ymax;
	const shift = (point: Point) => (inside(point) ? new Point(point.x + dx, point.y + dy) : point);
	if (!box || entity.isContainedInBox(box) || !entity.intersectsWithBox(box)) {
		const copy = cloneStyled(entity);
		copy.move(dx, dy);
		return inPlaceOf(entity, copy);
	}
	if (entity instanceof LineEntity) {
		const start = entity.getStartPoint();
		const end = entity.getEndPoint();
		if (!inside(start) && !inside(end)) return null;
		return inPlaceOf(entity, new LineEntity(entity.layerId, shift(start), shift(end)));
	}
	if (entity instanceof PolyLineEntity) {
		let changed = false;
		const parts = entity.getEntities().map((part) => {
			if (!(part instanceof LineEntity)) return cloneStyled(part);
			const start = part.getStartPoint();
			const end = part.getEndPoint();
			if (inside(start) || inside(end)) changed = true;
			return copyStyle(part, new LineEntity(part.layerId, shift(start), shift(end)));
		});
		return changed ? inPlaceOf(entity, new PolyLineEntity(entity.layerId, parts)) : null;
	}
	if (entity instanceof RectangleEntity) {
		const corners = (entity.getShape() as Polygon).vertices;
		if (!corners.some(inside)) return null;
		return inPlaceOf(entity, new RectangleEntity(entity.layerId, new Polygon(corners.map(shift))));
	}
	return null;
}

/** 고르기 중 마지막 걸침 창 — 선택 도구가 두 번째 구석을 기다릴 때의 누름 */
const watchWindow = assign(({ event, self }: { event: StateEvent; self: AnyActorRef }) => {
	const snapshot = self.getSnapshot().children[SELECT_CHILD]?.getSnapshot();
	const start = snapshot?.context?.startPoint as Point | null | undefined;
	if (snapshot?.value !== SelectState.WAITING_FOR_SECOND_SELECT_POINT || !start) return {};
	return { window: [start, (event as MouseClickEvent).worldMouseLocation] as [Point, Point] };
});

/**
 * STRETCH(337 라 · 설계 1-3) — 기록 「걸치기 윈도우 또는 걸치기 폴리곤만큼 신축할 객체 선택...」 → 「객체 선택:」 →
 * MOVE 와 같은 기준점 [변위(D)] · 두 번째 점 · 변위 기억(STRETCH.DISP) · 걸침 창 안 꼭짓점만 옮김.
 */
export const stretchToolStateMachine = createDisplaceTool({
	tool: Tool.STRETCH,
	remember: 'STRETCH.DISP',
	intro: '걸치기 윈도우 또는 걸치기 폴리곤만큼 신축할 객체 선택...',
	watch: watchWindow,
	change: (context, dx, dy) => {
		const window = context.window;
		const box = window
			? new Box(
					Math.min(window[0].x, window[1].x),
					Math.min(window[0].y, window[1].y),
					Math.max(window[0].x, window[1].x),
					Math.max(window[0].y, window[1].y)
				)
			: null;
		return context.originals.flatMap((entity) => stretchEntity(entity, box, dx, dy) ?? []);
	},
});

export const lengthenToolStateMachine = createSequenceTool({
	tool: Tool.LENGTHEN,
	steps: [
		{ kind: 'entity', instructions: '길이를 바꿀 선을 늘릴 쪽 끝 근처에서 선택하십시오.' },
		{
			kind: 'number',
			instructions: '증분 길이를 입력하십시오 (음수는 단축) <10>.',
			defaultValue: 10,
		},
	],
	commit: (input) => {
		const entity = input.entity(0);
		const changed = lengthenLine(entity, input.number(1), input.pick(0));
		if (!changed) {
			toast.warn('선만 길이를 조정할 수 있습니다.');
			return;
		}
		deleteEntities([entity], false);
		addEntities([changed], true);
	},
});