/* eslint-disable func-style */
import PowerduckState from '../../app/powerduck-state';

export const toDisplayString = Symbol('toDisplayString');
function toDisplayStringImpl(
	this: Temporal.PlainDateTime | Temporal.PlainDate,
	options?: {
		showTime?: boolean;
		showSeconds?: boolean;
		monthLong?: boolean;
		dayLong?: boolean;
		hideDay?: boolean;
		hideMonth?: boolean;
		hideYear?: boolean;
		language?: string;
	} | boolean,
	showTime?: boolean,
	showSeconds?: boolean,
	_monthLong?: boolean,
): string {
	let opts: any = {};
	if (typeof options === 'object') {
		opts = options ?? {};
	} else {
		opts = {
			showTime: options as any,
			showSeconds: showTime as any,
			monthLong: showSeconds,
		};
	}

	const fmt: Intl.DateTimeFormatOptions = {
		year: !opts.hideYear ? 'numeric' : undefined,
		month: !opts.hideMonth ? (opts.monthLong ? 'long' : 'numeric') : undefined,
		day: !opts.hideDay && !opts.dayLong ? 'numeric' : undefined,
		weekday: opts.dayLong ? 'long' : undefined,
	};

	if (showTime || opts.showTime) {
		fmt.hour = 'numeric';
		fmt.minute = '2-digit';
	}

	if (showSeconds || opts.showSeconds) {
		fmt.second = '2-digit';
	}

	try {
		const locale = opts.language || PowerduckState.getCurrentLanguage?.() || undefined;
		return this.toLocaleString(locale, fmt);
	} catch {
		return this.toString();
	}
}

export const fromDate = Symbol('fromDate');
// eslint-disable-next-line unused-imports/no-unused-vars -- referenced via `typeof fromDateImpl` in the module-augmentation declaration below
function fromDateImpl(this: typeof Temporal.PlainDateTime, date: Date): Temporal.PlainDateTime {
	return Temporal.PlainDateTime.from({
		year: date.getFullYear(),
		month: date.getMonth() + 1, // JS Date months are 0-based
		day: date.getDate(),
		hour: date.getHours(),
		minute: date.getMinutes(),
		second: date.getSeconds(),
	});
}

export const utcEpochMilliseconds = Symbol('utcEpochMilliseconds');
function utcEpochMillisecondsImpl(this: Temporal.PlainDateTime): number {
	if (this == null) {
		return null;
	}

	let y = this.year;
	let m = this.month;
	if (m <= 2) {
		y -= 1;
		m += 12;
	}

	// Algorithm from Howard Hinnant's civil date conversion
	const era = Math.floor(y / 400);
	const yoe = y - era * 400;
	const doy = Math.floor((153 * (m - 3) + 2) / 5) + this.day - 1;
	const doe = yoe * 365 + Math.floor(yoe / 4) - Math.floor(yoe / 100) + doy;
	const daysSinceEpoch = era * 146097 + doe - 719468;

	const msOfDay
		= this.hour * 3_600_000
			+ this.minute * 60_000
			+ this.second * 1_000
			+ (this.millisecond ?? 0);

	return daysSinceEpoch * 86_400_000 + msOfDay;
}

export const toJsDate = Symbol('toJsDate');
function toJsDateImpl(this: Temporal.PlainDateTime): Date {
	// eslint-disable-next-line no-restricted-syntax
	return new Date(this.toString());
}

export const toWire = Symbol('toWire');
function toWireImp(
	this: Temporal.PlainDateTime,
	includeTime?: boolean,
	includeMs?: boolean,
): string {
	if (includeTime) {
		if (includeMs) {
			return this.toString();
		} else {
			return this.toString().split('.')[0];
		}
	} else {
		return this.toPlainDate().toString();
	}
}

declare global {
	// eslint-disable-next-line ts/no-namespace
	namespace Temporal {
		interface PlainDateConstructor {
			[fromDate]: typeof fromDateImpl;
		}
		interface PlainDate {
			[toDisplayString]: typeof toDisplayStringImpl;
		}
		interface PlainDateTime {
			[toJsDate]: typeof toJsDateImpl;
			[toWire]: typeof toWireImp;
			[toDisplayString]: typeof toDisplayStringImpl;
			[utcEpochMilliseconds]: typeof utcEpochMillisecondsImpl;
		}
	}
}

export const applyTemporalExtensions = (): void => {
	if (typeof Temporal === 'undefined') {
		return;
	}

	(Temporal.PlainDateTime.prototype as any)[toJsDate] = toJsDateImpl;
	(Temporal.PlainDateTime.prototype as any)[toWire] = toWireImp;
	(Temporal.PlainDateTime.prototype as any)[toDisplayString] = toDisplayStringImpl;
	(Temporal.PlainDate.prototype as any)[toDisplayString] = toDisplayStringImpl;
	(Temporal.PlainDateTime.prototype as any)[utcEpochMilliseconds] = utcEpochMillisecondsImpl;
};

applyTemporalExtensions();