import { type ClassValue, clsx } from 'clsx';
import { twMerge } from 'tailwind-merge';

export function cn(...inputs: ClassValue[]) {
	return twMerge(clsx(inputs));
}

export function generateId(): string {
	return Math.random().toString(36).substring(2) + Date.now().toString(36);
}

export function formatTime(time: string): string {
	const [hours, minutes] = time.split(':');
	const hour = parseInt(hours);
	const ampm = hour >= 12 ? 'PM' : 'AM';
	const displayHour = hour % 12 || 12;
	return `${displayHour}:${minutes} ${ampm}`;
}

export function formatDate(date: string): string {
	return new Date(date).toLocaleDateString('en-IE', {
		weekday: 'long',
		year: 'numeric',
		month: 'long',
		day: 'numeric',
	});
}

export function isWithinBookingWindow(date: string): boolean {
	const bookingDate = new Date(date);
	const today = new Date();
	const maxDate = new Date();
	maxDate.setDate(today.getDate() + 6); // 7 days including today

	// Reset time to start of day for comparison
	today.setHours(0, 0, 0, 0);
	maxDate.setHours(23, 59, 59, 999);
	bookingDate.setHours(0, 0, 0, 0);

	return bookingDate >= today && bookingDate <= maxDate;
}

// Ireland localization - Monday as first day of week
export function getWeekDays(): Array<{ value: number; label: string }> {
	return [
		{ value: 1, label: 'Monday' },
		{ value: 2, label: 'Tuesday' },
		{ value: 3, label: 'Wednesday' },
		{ value: 4, label: 'Thursday' },
		{ value: 5, label: 'Friday' },
		{ value: 6, label: 'Saturday' },
		{ value: 0, label: 'Sunday' },
	];
}

// Convert JavaScript's getDay() (0=Sunday) to Irish standard (0=Monday)
export function getIrishDayOfWeek(date: Date): number {
	const jsDay = date.getDay();
	return jsDay === 0 ? 6 : jsDay - 1; // Sunday becomes 6, Monday becomes 0
}

// Convert Irish day index (0=Monday) back to JavaScript's getDay() format
export function getJavaScriptDayOfWeek(irishDay: number): number {
	return irishDay === 6 ? 0 : irishDay + 1; // 6 becomes Sunday (0), others shift up
}

// Get day name using Irish week start (0=Monday)
export function getIrishDayName(irishDayIndex: number): string {
	const days = ['Monday', 'Tuesday', 'Wednesday', 'Thursday', 'Friday', 'Saturday', 'Sunday'];
	return days[irishDayIndex];
}

export function generateTimeSlots(startHour: number, endHour: number): string[] {
	const slots = [];
	for (let hour = startHour; hour < endHour; hour++) {
		const hourStr = hour < 10 ? '0' + hour : hour.toString();
		slots.push(`${hourStr}:00`);
	}
	return slots;
}