/**
 * 블록 삽입 도구 — 라이브러리에서 고른 블록을 커서에 달고 다니다 클릭 한 번으로 놓는다.
 * ponytail: 1:1·0도로만 놓는다. 회전·축척은 기존 ROTATE·SCALE 명령으로 한다.
 */
import type { Point } from '@flatten-js/core';
import { toast } from 'react-toastify';
import { Actor, assign, createMachine } from 'xstate';
import { type BlockDefinition, deserializeBlock } from '../blocks/block-library';
import type { Entity } from '../entities/Entity';
import { getPointFromEvent } from '../helpers/get-point-from-event';
import {
	addEntities,
	setActiveToolActor,
	setAngleGuideOriginPoint,
	setGhostHelperEntities,
	setSelectedEntityIds,
	setShouldDrawHelpers,
} from '../state';
import { Tool } from '../tools';
import { selectToolStateMachine } from './select-tool';
import { ActorEvent, type PointInputEvent, type StateEvent, type ToolContext } from './tool.types';

/** 삽입 대기 중인 객체와 그 객체들이 지금 놓여 있는 기준점 */
let pendingEntities: Entity[] = [];
let anchor: { x: number; y: number } = { x: 0, y: 0 };

function movePendingTo(x: number, y: number): void {
	for (const entity of pendingEntities) entity.move(x - anchor.x, y - anchor.y);
	anchor = { x, y };
}

/** 라이브러리 팔레트에서 블록을 고르면 부른다. 객체를 풀어 두고 삽입 도구를 켠다. */
export async function startBlockInsert(block: BlockDefinition): Promise<void> {
	try {
		pendingEntities = await deserializeBlock(block);
	} catch {
		toast.error(`블록 '${block.name}'을 풀지 못했습니다.`);
		return;
	}
	if (!pendingEntities.length) {
		toast.error(`블록 '${block.name}'에 객체가 없습니다.`);
		return;
	}
	anchor = { ...block.basePoint };
	setActiveToolActor(new Actor(insertBlockToolStateMachine));
}

export enum InsertBlockState {
	INIT = 'INIT',
	WAITING_FOR_INSERTION_POINT = 'WAITING_FOR_INSERTION_POINT',
}

export enum InsertBlockAction {
	INIT_INSERT_BLOCK_TOOL = 'INIT_INSERT_BLOCK_TOOL',
	DRAW_TEMP_BLOCK = 'DRAW_TEMP_BLOCK',
	PLACE_BLOCK = 'PLACE_BLOCK',
	SWITCH_TO_SELECT_TOOL = 'SWITCH_TO_SELECT_TOOL',
}

export const insertBlockToolStateMachine = createMachine(
	{
		types: {} as { context: ToolContext; events: StateEvent },
		context: { type: Tool.INSERT_BLOCK },
		initial: InsertBlockState.INIT,
		states: {
			[InsertBlockState.INIT]: {
				always: {
					actions: InsertBlockAction.INIT_INSERT_BLOCK_TOOL,
					target: InsertBlockState.WAITING_FOR_INSERTION_POINT,
				},
			},
			[InsertBlockState.WAITING_FOR_INSERTION_POINT]: {
				description: '블록을 놓을 위치를 지정한다',
				meta: { instructions: '블록을 놓을 위치를 지정하십시오' },
				on: {
					[ActorEvent.DRAW]: { actions: InsertBlockAction.DRAW_TEMP_BLOCK },
					[ActorEvent.MOUSE_CLICK]: {
						actions: [InsertBlockAction.PLACE_BLOCK, InsertBlockAction.SWITCH_TO_SELECT_TOOL],
					},
					[ActorEvent.ABSOLUTE_POINT_INPUT]: {
						actions: [InsertBlockAction.PLACE_BLOCK, InsertBlockAction.SWITCH_TO_SELECT_TOOL],
					},
					[ActorEvent.ESC]: { actions: InsertBlockAction.SWITCH_TO_SELECT_TOOL },
				},
			},
		},
	},
	{
		actions: {
			[InsertBlockAction.INIT_INSERT_BLOCK_TOOL]: assign(() => {
				setShouldDrawHelpers(true);
				setGhostHelperEntities([]);
				setSelectedEntityIds([]);
				setAngleGuideOriginPoint(null);
				return {};
			}),
			[InsertBlockAction.DRAW_TEMP_BLOCK]: ({ event }) => {
				if (!pendingEntities.length) return;
				const point = getPointFromEvent(null, event as PointInputEvent);
				movePendingTo(point.x, point.y);
				setGhostHelperEntities([...pendingEntities]);
			},
			[InsertBlockAction.PLACE_BLOCK]: ({ event }) => {
				if (!pendingEntities.length) return;
				const point: Point = getPointFromEvent(null, event as PointInputEvent);
				movePendingTo(point.x, point.y);
				addEntities(pendingEntities, true);
				pendingEntities = [];
				setGhostHelperEntities([]);
			},
			[InsertBlockAction.SWITCH_TO_SELECT_TOOL]: () => {
				pendingEntities = [];
				setGhostHelperEntities([]);
				setActiveToolActor(new Actor(selectToolStateMachine));
			},
		},
	}
);