/**
 * ROTATE · SCALE 공용 틀(337 라 · 설계 1-3) — 「객체 선택:」 → 「기준점 지정:」 →
 * 「<값> 지정 또는 [복사(C)/참조(R)] <기본>:」(누름 = 기준점에서 그 점까지 잰 값 · 숫자 = 값 · 빈 Enter = 기억 값) ·
 * C = 사본 켬/끔 · R → 「참조 … <기본>:」(숫자 · 두 점) → 「새 … 지정 또는 [점(P)] <기본>:」(숫자 · 누름 · P 두 점).
 * 한 번 뒤 끝 · Esc = 제자리 끝 · 원본은 확정까지 도면에 그대로.
 */
import type { Point } from '@flatten-js/core';
import { assign, createMachine } from 'xstate';
import { OPT, type OptionSpec, type PromptSpec, remember } from '../commands/prompt';
import type { Entity } from '../entities/Entity';
import { getPointFromEvent } from '../helpers/get-point-from-event';
import { setAngleGuideOriginPoint, setGhostHelperEntities, setShouldDrawHelpers } from '../state';
import type { Tool } from '../tools';
import {
	type DrawEvent,
	END_STATE,
	type NumberInputEvent,
	type PointInputEvent,
	type StateEvent,
	type ToolContext,
} from './tool.types';
import {
	type PickedContext,
	addCopies,
	changedCopies,
	endState,
	guideLine,
	replaceInPlace,
	selectionState,
	showGhosts,
	startState,
} from './transform.helpers';

export enum PivotState {
	INIT = 'INIT',
	WAITING_FOR_SELECTION = 'WAITING_FOR_SELECTION',
	WAITING_FOR_BASE_POINT = 'WAITING_FOR_BASE_POINT',
	WAITING_FOR_VALUE = 'WAITING_FOR_VALUE',
	WAITING_FOR_REFERENCE = 'WAITING_FOR_REFERENCE',
	WAITING_FOR_REFERENCE_SECOND_POINT = 'WAITING_FOR_REFERENCE_SECOND_POINT',
	WAITING_FOR_NEW_VALUE = 'WAITING_FOR_NEW_VALUE',
	WAITING_FOR_NEW_FIRST_POINT = 'WAITING_FOR_NEW_FIRST_POINT',
	WAITING_FOR_NEW_SECOND_POINT = 'WAITING_FOR_NEW_SECOND_POINT',
}

export interface PivotContext extends ToolContext, PickedContext {
	base: Point | null;
	/** 복사(C) — 원본 두고 사본을 바꿈 */
	copy: boolean;
	/** 참조 값(R) */
	reference: number | null;
	/** 참조 · 새 값 두 점의 첫 점 */
	first: Point | null;
}

interface ValuePrompt {
	text: string;
	remember: string;
	initial: number;
}

export interface PivotConfig {
	tool: Tool;
	format: 'ang' | 'len';
	value: ValuePrompt;
	reference: ValuePrompt;
	next: ValuePrompt;
	/** 값 · 참조 · 새 값 숫자 검사 */
	number?: PromptSpec['number'];
	reject?: string;
	/** C 켬 · 끔 알림 */
	copyNotice: [string, string];
	/** 못 쓰는 값 알림 */
	invalidNotice: string;
	/** 두 점으로 잰 값(각 · 거리) */
	measure: (a: Point, b: Point) => number;
	/** 새 값 · 참조 → 값(못 쓰면 null) */
	combine: (next: number, reference: number) => number | null;
	valid: (value: number) => boolean;
	apply: (entity: Entity, base: Point, value: number) => void;
}

const POINTS: OptionSpec = { key: 'POINTS', kw: 'P', en: 'POINTS', label: '점' };

type Ctx = { context: PivotContext; event: StateEvent };

const noticeLater = (text: string) => {
	void import('../inputController/prompt-input').then(({ notice }) => notice(text));
};

export function createPivotTool(config: PivotConfig) {
	const S = PivotState;
	const valuePrompt = (spec: ValuePrompt, options?: OptionSpec[]): PromptSpec => ({
		text: spec.text,
		...(options ? { options } : {}),
		default: {
			kind: 'value',
			remember: spec.remember,
			initial: spec.initial,
			format: config.format,
		},
		...(config.number ? { number: config.number } : {}),
		...(config.reject ? { reject: config.reject } : {}),
	});
	const PROMPT = {
		base: { text: '기준점 지정' },
		value: valuePrompt(config.value, [OPT.COPY, OPT.REFERENCE]),
		reference: valuePrompt(config.reference),
		second: { text: '두 번째 점 지정' },
		next: valuePrompt(config.next, [POINTS]),
		first: { text: '첫 번째 점 지정' },
	} satisfies Record<string, PromptSpec>;

	const pointOf = (from: Point | null, event: StateEvent) =>
		getPointFromEvent(from, event as PointInputEvent);
	const ok = (value: number | null): value is number =>
		value !== null && Number.isFinite(value) && config.valid(value);

	const transform = (context: PivotContext, value: number) => (entity: Entity) =>
		config.apply(entity, context.base as Point, value);
	const commit = (context: PivotContext, value: number) => {
		if (context.copy) addCopies(context.originals, transform(context, value));
		else replaceInPlace(changedCopies(context.originals, transform(context, value)));
		remember(config.value.remember, value);
	};
	const preview = (context: PivotContext, value: number | null, from: Point, cursor: Point) => {
		if (ok(value))
			showGhosts(context.originals, transform(context, value), guideLine(from, cursor));
		else setGhostHelperEntities([guideLine(from, cursor)]);
	};

	/** 값을 셈해 맞으면 확정 · 끝 · 아니면 알림 뒤 그 물음 */
	const settle = (compute: (args: Ctx) => number | null) => [
		{
			guard: (args: Ctx) => ok(compute(args)),
			actions: (args: Ctx) => commit(args.context, compute(args) as number),
			target: END_STATE,
		},
		{ actions: () => noticeLater(config.invalidNotice) },
	];
	const onPoints = (handler: unknown) => ({
		MOUSE_CLICK: handler,
		ABSOLUTE_POINT_INPUT: handler,
		RELATIVE_POINT_INPUT: handler,
		NUMBER_INPUT: handler,
	});
	const numberOr = (args: Ctx, point: (p: Point) => number) =>
		args.event.type === 'NUMBER_INPUT'
			? (args.event as NumberInputEvent).value
			: point(pointOf(args.context.base, args.event));
	const nextValue = (args: Ctx, raw: number) => {
		remember(config.next.remember, raw);
		return config.combine(raw, args.context.reference ?? 0);
	};
	const cursorOf = (event: StateEvent, from: Point) => getPointFromEvent(from, event as DrawEvent);
	const esc = { ESC: { target: END_STATE } };

	// biome-ignore lint/suspicious/noExplicitAny: 공용 상태 조각(여러 도구 공통)을 섞어 만든다
	const states: Record<string, any> = {
		[S.INIT]: startState(S.WAITING_FOR_BASE_POINT),
		[S.WAITING_FOR_SELECTION]: selectionState(S.WAITING_FOR_BASE_POINT),
		[S.WAITING_FOR_BASE_POINT]: {
			meta: { kind: 'point', prompt: PROMPT.base },
			entry: () => setShouldDrawHelpers(true),
			on: {
				MOUSE_CLICK: {
					actions: assign(({ event }: Ctx) => {
						const base = pointOf(null, event);
						setAngleGuideOriginPoint(base);
						return { base };
					}),
					target: S.WAITING_FOR_VALUE,
				},
				ABSOLUTE_POINT_INPUT: {
					actions: assign(({ event }: Ctx) => {
						const base = pointOf(null, event);
						setAngleGuideOriginPoint(base);
						return { base };
					}),
					target: S.WAITING_FOR_VALUE,
				},
				...esc,
			},
		},
		[S.WAITING_FOR_VALUE]: {
			meta: { kind: 'point', prompt: PROMPT.value },
			on: {
				DRAW: {
					actions: ({ context, event }: Ctx) => {
						const base = context.base as Point;
						const cursor = cursorOf(event, base);
						preview(context, config.measure(base, cursor), base, cursor);
					},
				},
				...onPoints(
					settle((args) => numberOr(args, (p) => config.measure(args.context.base as Point, p)))
				),
				'OPTION.COPY': {
					actions: [
						assign(({ context }: Ctx) => ({ copy: !context.copy })),
						({ context }: Ctx) => noticeLater(config.copyNotice[context.copy ? 0 : 1]),
					],
				},
				'OPTION.REFERENCE': { target: S.WAITING_FOR_REFERENCE },
				...esc,
			},
		},
		[S.WAITING_FOR_REFERENCE]: {
			meta: { kind: 'point', prompt: PROMPT.reference },
			entry: () => setGhostHelperEntities([]),
			on: {
				NUMBER_INPUT: {
					actions: assign(({ event }: Ctx) => {
						const reference = (event as NumberInputEvent).value;
						remember(config.reference.remember, reference);
						return { reference };
					}),
					target: S.WAITING_FOR_NEW_VALUE,
				},
				...Object.fromEntries(
					['MOUSE_CLICK', 'ABSOLUTE_POINT_INPUT', 'RELATIVE_POINT_INPUT'].map((type) => [
						type,
						{
							actions: assign(({ context, event }: Ctx) => {
								const first = pointOf(context.base, event);
								setAngleGuideOriginPoint(first);
								return { first };
							}),
							target: S.WAITING_FOR_REFERENCE_SECOND_POINT,
						},
					])
				),
				...esc,
			},
		},
		[S.WAITING_FOR_REFERENCE_SECOND_POINT]: {
			meta: { kind: 'point', prompt: PROMPT.second },
			on: {
				DRAW: {
					actions: ({ context, event }: Ctx) => {
						const first = context.first as Point;
						setGhostHelperEntities([guideLine(first, cursorOf(event, first))]);
					},
				},
				...onPoints({
					actions: assign(({ context, event }: Ctx) => {
						const first = context.first as Point;
						const reference = config.measure(first, pointOf(first, event));
						remember(config.reference.remember, reference);
						setAngleGuideOriginPoint(context.base);
						return { reference, first: null };
					}),
					target: S.WAITING_FOR_NEW_VALUE,
				}),
				...esc,
			},
		},
		[S.WAITING_FOR_NEW_VALUE]: {
			meta: { kind: 'point', prompt: PROMPT.next },
			on: {
				DRAW: {
					actions: ({ context, event }: Ctx) => {
						const base = context.base as Point;
						const cursor = cursorOf(event, base);
						preview(
							context,
							config.combine(config.measure(base, cursor), context.reference ?? 0),
							base,
							cursor
						);
					},
				},
				...onPoints(
					settle((args) =>
						nextValue(
							args,
							numberOr(args, (p) => config.measure(args.context.base as Point, p))
						)
					)
				),
				'OPTION.POINTS': { target: S.WAITING_FOR_NEW_FIRST_POINT },
				...esc,
			},
		},
		[S.WAITING_FOR_NEW_FIRST_POINT]: {
			meta: { kind: 'point', prompt: PROMPT.first },
			entry: () => setGhostHelperEntities([]),
			on: {
				...Object.fromEntries(
					['MOUSE_CLICK', 'ABSOLUTE_POINT_INPUT', 'RELATIVE_POINT_INPUT'].map((type) => [
						type,
						{
							actions: assign(({ context, event }: Ctx) => {
								const first = pointOf(context.base, event);
								setAngleGuideOriginPoint(first);
								return { first };
							}),
							target: S.WAITING_FOR_NEW_SECOND_POINT,
						},
					])
				),
				...esc,
			},
		},
		[S.WAITING_FOR_NEW_SECOND_POINT]: {
			meta: { kind: 'point', prompt: PROMPT.second },
			on: {
				DRAW: {
					actions: ({ context, event }: Ctx) => {
						const first = context.first as Point;
						const cursor = cursorOf(event, first);
						preview(
							context,
							config.combine(config.measure(first, cursor), context.reference ?? 0),
							first,
							cursor
						);
					},
				},
				...onPoints(
					settle((args) => {
						const first = args.context.first as Point;
						return nextValue(args, config.measure(first, pointOf(first, args.event)));
					})
				),
				...esc,
			},
		},
		[END_STATE]: endState,
	};

	return createMachine({
		types: {} as { context: PivotContext; events: StateEvent },
		context: {
			originals: [],
			base: null,
			copy: false,
			reference: null,
			first: null,
			type: config.tool,
		},
		initial: S.INIT,
		states,
	});
}