const DECIMAL_PART_COUNT = 2;
const DEFAULT_MINOR_UNITS = 2;

type FormatMoneyOptions = {
	withRoundedCents?: boolean;
	withSign?: boolean;
	withZeroCents?: boolean;
};

const portfolioCategoryPresentation = {
	BOND: { color: "grape.6", label: "portfolio.bonds" },
	CASH: { color: "green.6", label: "portfolio.structure.cash" },
	OTHER: { color: "orange.6", label: "portfolio.structure.other" },
	STOCK: { color: "blue.6", label: "portfolio.stocks" },
} as const;

type Money = { currency: string; value: string };

const dateFormatter = new Intl.DateTimeFormat("ru-RU", {
	day: "2-digit",
	month: "2-digit",
	timeZone: "UTC",
	year: "numeric",
});

// ISO 4217 minor units (JPY 0, KWD 3); unknown codes fall back to 2.
function currencyMinorUnits(currency: string): number {
	try {
		return new Intl.NumberFormat("en", { currency, style: "currency" })
			.resolvedOptions().maximumFractionDigits ?? DEFAULT_MINOR_UNITS;
	}
	catch {
		return DEFAULT_MINOR_UNITS;
	}
}

function formatDate(value: string): string {
	return dateFormatter.format(new Date(value));
}

function formatDecimal(value: string): string {
	const [integer = "", fraction] = value.split(".", DECIMAL_PART_COUNT);
	const sign = integer.startsWith("-") ? "-" : "";
	const digits = sign ? integer.slice(1) : integer;
	const groupSize = 3;
	const groups: string[] = [];

	for (let end = digits.length; end > 0; end -= groupSize) {
		groups.push(digits.slice(Math.max(0, end - groupSize), end));
	}

	const grouped = groups.toReversed().join(" ");
	const suffix = fraction ? `,${fraction}` : "";

	return `${sign}${grouped}${suffix}`;
}

function formatMoney(
	money: Money
		| null
		| undefined,
	{
		withRoundedCents = false,
		withSign = false,
		withZeroCents = false,
	}: FormatMoneyOptions = {},
): string {
	if (!money) return "—";

	const minorUnits = currencyMinorUnits(money.currency);

	const value = withRoundedCents
		? roundDecimal(money.value, minorUnits)
		: money.value;

	const [integerPart = "", fractionPart = ""] = value.split(
		".",
		DECIMAL_PART_COUNT,
	);

	const normalizedFraction = withRoundedCents || withZeroCents
		? fractionPart.padEnd(minorUnits, "0")
		: fractionPart;

	const decimal = normalizedFraction
		? `${integerPart}.${normalizedFraction}`
		: integerPart;

	const currency = money.currency === "RUB" ? "₽" : money.currency;
	const formatted = `${formatDecimal(decimal)} ${currency}`;

	if (!withSign) return formatted;
	if (isZeroDecimal(value))
		return value.startsWith("-") ? formatted.slice(1) : formatted;

	return value.startsWith("-") ? `−${formatted.slice(1)}` : `+${formatted}`;
}

function isZeroDecimal(value: string) {
	const unsigned = value.startsWith("-") ? value.slice(1) : value;

	const [integer = "", fraction = ""] = unsigned.split(
		".",
		DECIMAL_PART_COUNT,
	);

	return integer.replaceAll("0", "") === ""
		&& fraction.replaceAll("0", "") === "";
}

function roundDecimal(value: string, places: number): string {
	const [integer = "", fraction = ""] = value.split(".", DECIMAL_PART_COUNT);
	const digits = integer.startsWith("-") ? integer.slice(1) : integer;
	const paddedFraction = fraction.padEnd(places + 1, "0");
	const units = `${digits}${paddedFraction.slice(0, places)}`;
	const roundingDigit = paddedFraction.at(places) ?? "0";

	const rounded = (roundingDigit >= "5" ? BigInt(units) + 1n : BigInt(units))
		.toString()
		.padStart(places + 1, "0");

	// A value rounded to zero has no sign: "-0.004" → "0.00".
	const sign = integer.startsWith("-") && /[1-9]/.test(rounded) ? "-" : "";
	const roundedInteger = rounded.slice(0, rounded.length - places);
	const roundedFraction = rounded.slice(rounded.length - places);

	return roundedFraction
		? `${sign}${roundedInteger}.${roundedFraction}`
		: `${sign}${roundedInteger}`;
}

// Без timeZone Intl берёт часовой пояс браузера пользователя.
const snapshotFormatter = new Intl.DateTimeFormat("ru-RU", {
	dateStyle: "short",
	timeStyle: "short",
});

function formatSnapshotTime(value: string): string {
	return snapshotFormatter.format(new Date(value));
}

const logoSize = 160;

const chartFormatter = new Intl.NumberFormat("ru-RU", { maximumFractionDigits: 4 });

function formatChartValue(value: number) {
	return chartFormatter.format(value);
}

function instrumentLogoUrl(logoName?: null | string): null | string {
	const stem = logoName?.trim().replace(/\.png$/i, "");

	return stem
		? `https://invest-brands.cdn-tinkoff.ru/${stem}x${logoSize}.png`
		: null;
}

export {
	formatChartValue,
	formatDate,
	formatDecimal,
	formatMoney,
	formatSnapshotTime,
	instrumentLogoUrl,
	portfolioCategoryPresentation,
};