// Seeded planning requests shared by the frozen-engine check and the engine comparison.
import { frenchPublicHolidaysForYear, isWorkingPlanningDate } from '../declared-non-working-days';
import { OPTIMIZATION_CATALOG } from '../planning-objectives';
import { createOptimizationPresetRules } from '../rule-service';

export function mulberry32(seed: number): () => number {
	let a = seed >>> 0;
	return () => {
		a = (a + 0x6d2b79f5) >>> 0;
		let t = a;
		t = Math.imul(t ^ (t >>> 15), t | 1);
		t ^= t + Math.imul(t ^ (t >>> 7), t | 61);
		return ((t ^ (t >>> 14)) >>> 0) / 4294967296;
	};
}

export const DAY = 86_400_000;
export const weekday = (ms: number) => ![0, 6].includes(new Date(ms).getUTCDay());
export const iso = (ms: number) => new Date(ms).toISOString().slice(0, 10);

export type Req = Record<string, unknown> & { rules: Record<string, unknown>[] };

export function generateRequest(seed: number): Req {
	const rnd = mulberry32(seed);
	const int = (min: number, max: number) => min + Math.floor(rnd() * (max - min + 1));
	const pick = <T>(items: readonly T[]): T => items[int(0, items.length - 1)];
	const chance = (p: number) => rnd() < p;
	const shuffle = <T>(items: T[]): T[] => {
		for (let i = items.length - 1; i > 0; i--) {
			const j = int(0, i);
			[items[i], items[j]] = [items[j], items[i]];
		}
		return items;
	};

	const long = chance(0.1);
	const mode = rnd();
	let startMs = Date.UTC(2025, 0, 1) + int(0, 1094) * DAY;
	if (mode < 0.15) startMs = Date.UTC(pick([2025, 2026]), 11, int(8, 31));
	else if (mode < 0.3) {
		const year = pick([2025, 2026, 2027]);
		const holidays = [...frenchPublicHolidaysForYear(year)].filter((d) =>
			weekday(Date.parse(d)),
		);
		startMs = Date.parse(pick(holidays)) - int(1, 10) * DAY;
	}
	const days = long ? int(29, 70) : int(7, 28);
	const start = iso(startMs);
	const date = (offset: number) => iso(startMs + offset * DAY);
	const types = ['cp', 'rtt', 'other'] as const;

	const balances = Array.from({ length: int(1, 3) }, (_, i) => ({
		id: `b${i}`,
		type: pick(types),
		quantity: int(0, long ? 4 : 3),
		...(chance(0.3) ? { availableFrom: date(int(1, days)) } : {}),
		expiryDate: date(int(-3, days + 40)),
	})).map((b) =>
		b.availableFrom && b.availableFrom > b.expiryDate
			? { ...b, expiryDate: b.availableFrom }
			: b,
	);

	const declaredDays: { date: string; type: string }[] = [];
	for (let n = int(0, 4); n > 0; n--) {
		const ms = startMs + int(0, days) * DAY;
		const d = iso(ms);
		if (isWorkingPlanningDate(d) && !declaredDays.some((x) => x.date === d))
			declaredDays.push({ date: d, type: pick(types) });
	}

	const selectors = ['cp', 'rtt', 'other', 'any'] as const;
	const rules: Record<string, unknown>[] = [];
	for (let n = long ? int(0, 1) : int(0, 2); n > 0; n--) {
		const from = int(0, days - 1);
		rules.push({
			id: `tw${rules.length}`,
			type: chance(0.5) ? 'time_window' : 'TIME_WINDOW',
			force: pick(['obligation', 'preference']),
			startDate: date(from),
			endDate: date(from + int(0, 10)),
			placeDays: int(1, 4),
			placeType: pick(selectors),
		});
	}
	for (let n = long && rules.length ? 0 : long ? int(0, 1) : int(0, 2); n > 0; n--) {
		rules.push({
			id: `it${rules.length}`,
			type: chance(0.5) ? 'if_then' : 'IF_THEN',
			force: pick(['obligation', 'preference']),
			dayOfWeek: int(1, 5),
			placeDays: int(1, 3),
			placeType: pick(selectors),
			placement: pick(['before', 'after', 'around', 'auto']),
			rewardDays: int(0, 2),
			rewardType: pick(types),
		});
	}
	const presets: Record<string, unknown>[] = shuffle(
		createOptimizationPresetRules() as unknown as Record<string, unknown>[],
	).slice(0, long ? int(1, 4) : int(0, 3));
	rules.push(...presets);
	if (!long && chance(0.3)) {
		const row = pick(OPTIMIZATION_CATALOG);
		const conditions = (row.conditions as readonly string[]).filter(() => chance(0.5));
		rules.push({
			id: 'composed',
			type: 'optimization',
			force: 'preference',
			configuration: {
				elements: row.elements,
				conditions,
				measure: row.measure,
				aggregation: pick(row.aggregations),
				direction: pick(['minimize', 'maximize']),
				...(row.measure === 'work-sequence-deficit' ? { thresholdDays: int(1, 8) } : {}),
			},
		});
	}
	for (const rule of shuffle(rules)) if (chance(0.08)) rule['enabled'] = false;

	const request: Req = {
		calculationDate: start,
		horizon: { start, end: date(days) },
		balances,
		declaredDays,
		rules,
	};
	if (chance(0.04)) {
		const breakIt = int(0, 3);
		if (breakIt === 0) balances[0].quantity = -1;
		else if (breakIt === 1) request['horizon'] = { start: date(days), end: start };
		else if (breakIt === 2) rules.push({ id: 'bad', type: 'unknown_type' });
		else declaredDays.push({ date: start, type: 'nope' });
	}
	return request;
}

/**
 * Loaded-year-sized requests: one year, four to eight balances and two to four
 * obligation windows of two or three days. Their obligation search always stops
 * at its solution limit, so the calibration engine previews at most eight solutions.
 */
export function generateLoadedYearRequest(seed: number): Req {
	const rnd = mulberry32(seed);
	const int = (min: number, max: number) => min + Math.floor(rnd() * (max - min + 1));
	const pick = <T>(items: readonly T[]): T => items[int(0, items.length - 1)];
	const year = int(2024, 2026);
	const start = `${year}-01-01`;
	const months = Array.from({ length: 12 }, (_, index) => index + 1);
	for (let i = months.length - 1; i > 0; i--) {
		const j = int(0, i);
		[months[i], months[j]] = [months[j], months[i]];
	}
	const obligations = int(2, 4);
	const windows = months.slice(0, obligations + int(0, 2)).map((month, index) => ({
		id: `window-${index}`,
		type: 'time_window',
		force: index < obligations ? 'obligation' : 'preference',
		startDate: `${year}-${String(month).padStart(2, '0')}-01`,
		endDate: `${year}-${String(month).padStart(2, '0')}-28`,
		placeDays: index < obligations ? int(2, 3) : int(1, 4),
		placeType: pick(['any', 'cp', 'rtt']),
	}));
	const presets = createOptimizationPresetRules() as unknown as Record<string, unknown>[];
	return {
		calculationDate: start,
		horizon: { start, end: `${year + 1}-01-01` },
		balances: Array.from({ length: int(4, 8) }, (_, index) => ({
			id: `b${index}`,
			type: pick(['cp', 'rtt']),
			quantity: int(6, 14),
			availableFrom: start,
			expiryDate: `${year}-12-31`,
		})),
		declaredDays: [],
		rules: [presets[0], ...windows, ...presets.slice(1)],
	};
}