export const parseTemplateDate = (value) => {
	const match = /^(\d+)-(\d{2})-(\d{2})[T ](\d{2}:\d{2}:\d{2}(?:\.\d+)?)( BC)?$/.exec(value || '');
	if (!match) return null;
	return {
		year: String(match[5] ? 1 - Number(match[1]) : Number(match[1])),
		month: match[2],
		day: match[3],
		time: match[4],
	};
};

export const serializeTemplateDate = ({ year, month, day, time }) => {
	const offset = Number(year);
	const dateYear = String(offset <= 0 ? 1 - offset : offset).padStart(4, '0');
	return `${dateYear}-${String(month).padStart(2, '0')}-${String(day).padStart(2, '0')} ${time.length === 5 ? `${time}:00` : time}${offset <= 0 ? ' BC' : ''}`;
};

export const templateDateNumber = (value) => {
	if (!value || !/^-?\d+$/.test(value.year) || !Number.isSafeInteger(Number(value.year))) return Number.NaN;
	const { month, day, time } = value;
	if (!Number.isInteger(Number(month)) || !Number.isInteger(Number(day)) || Number(month) < 1 || Number(month) > 12 || Number(day) < 1)
		return Number.NaN;
	if (!/^\d{2}:\d{2}(?::\d{2}(?:\.\d{1,6})?)?$/.test(time)) return Number.NaN;
	const [hours, minutes, seconds = 0] = time.split(':').map(Number);
	const year = 2000 + Number(value.year);
	const date = new Date(0);
	date.setUTCFullYear(year, Number(month) - 1, Number(day));
	date.setUTCHours(hours, minutes, Math.floor(seconds), 0);
	if (
		date.getUTCFullYear() !== year ||
		date.getUTCMonth() !== Number(month) - 1 ||
		date.getUTCDate() !== Number(day) ||
		hours > 23 ||
		minutes > 59 ||
		seconds >= 60
	)
		return Number.NaN;
	return date.getTime() + (seconds % 1) * 1000;
};

export const formatTemplateDate = (value) => {
	const date = parseTemplateDate(value);
	if (!date) return value || '—';
	const offset = Number(date.year);
	const year = offset === 0 ? 'год бюджета' : `год бюджета ${offset > 0 ? '+' : '−'} ${Math.abs(offset)}`;
	return `${date.day}.${date.month} (${year})`;
};

export const templateKey = (template) =>
	JSON.stringify([template.form_type, template.sheet, template.direction ?? null, template.phase_code]);