const db = require("../models");
const Vehicle = db.vehicle;
const Customer = db.customer;
const CalendarEvent = db.calendar_event;
const moment = require('moment');
const toSiteNumber = (value) => {
	const parsed = Number(value);
	return Number.isInteger(parsed) && parsed > 0 ? parsed : null;
};

const getAllSites = async () => {
	const [customerSites, vehicleSites, eventSites] = await Promise.all([
		Customer.distinct('site'),
		Vehicle.distinct('site'),
		CalendarEvent.distinct('site')
	]);
	const normalizedSites = [...new Set([...customerSites, ...vehicleSites, ...eventSites]
		.map(toSiteNumber)
		.filter(Boolean))];
	return normalizedSites.length > 0 ? normalizedSites : [1];
};

class ReminderService {
	parseDate(dateString) {
		if (!dateString || typeof dateString !== 'string') return null;
		const [month, day, year] = dateString.split('/').map(Number);
		if (!month || !day || !year) return null;
		const parsedDate = new Date(year, month-1,day);
		return Number.isNaN(parsedDate.getTime()) ? null : parsedDate;
	}

	parseMonthDay(dateString) {
		if (!dateString || typeof dateString !== 'string') return { month: -1, day: -1 };
		const [month, day] = dateString.split('/').map(Number);
		return {
			month: Number.isInteger(month) ? month : -1,
			day: Number.isInteger(day) ? day : -1
		};
	}

	async createVehicleRelatedEvents(daysAhead = 30) {
		const today = new Date();
		const futureDate = new Date();
		futureDate.setDate(today.getDate() + daysAhead); // check 30 days ahead

		const sites = await getAllSites();
		for (const site of sites) {
			const vehicles = await Vehicle.find({status: 'active', site});
			const allVehiclesCalendarEvent = await CalendarEvent.find({type: 'reminder', status: 'active', site, target_type: 'vehicle'});
			for (const vehicle of vehicles) {
				const insuranceExpireDate = this.parseDate(vehicle.insurance_expire_on);
				const titleRegistrationDate = this.parseDate(vehicle.title_registration_on);
				if (!insuranceExpireDate || !titleRegistrationDate) continue;
			const titleExpireDate = new Date(titleRegistrationDate);
			titleExpireDate.setFullYear(titleExpireDate.getFullYear() + 1);
			const emissionTestDate = this.parseDate(vehicle.emission_test_on);
			if (!emissionTestDate) continue;
			const emissionTestExpireDate = new Date(emissionTestDate);
			emissionTestExpireDate.setFullYear(titleExpireDate.getFullYear() + 1);
			const newDate = new Date(insuranceExpireDate);
			newDate.setDate(newDate.getDate() - 15);
			const newDate1 = new Date(emissionTestExpireDate);
			newDate1.setDate(newDate.getDate() - 15);
			const newDate2 = new Date(titleExpireDate);
			newDate2.setDate(newDate.getDate() - 15);
			if ( insuranceExpireDate >= today && insuranceExpireDate < futureDate) {
				if (!allVehiclesCalendarEvent.find(item => item.event_reminder_type === 'insurance_expire' && item.target_uuid === vehicle.id)) {
					const calendarEvent = new CalendarEvent({
						title: `Vehicle ${vehicle?.vehicle_number} (${vehicle?.tag})'s Insurance would expire in 15 days`,
						description: `Vehicle ${vehicle?.vehicle_number} (${vehicle?.tag})'s Insurance would expire in 15 day, please check whether it is renewed properly`,
						type: 'reminder',
						start_time: newDate,
						stop_time: new Date(newDate.getTime() + 10*60*1000),
						color: 'brown',
						target_type: 'vehicle',
						target_uuid: vehicle.id,
						target_name: vechile.vehicle_number,
						event_reminder_type: 'insurance_expire',
						status: 'active',
						site,
						edit_date: new Date(),
						create_date: new Date(),
						create_by: 'system',
						edit_by: 'system',
						edit_history: [{employee: 'system', date: new Date()}]
					})
					await calendarEvent.save(calendarEvent);
				}
			}
			if ( emissionTestExpireDate >= today && emissionTestExpireDate < futureDate) {
				if (!allVehiclesCalendarEvent.find(item => item.event_reminder_type === 'emission_test' && item.target_uuid === vehicle.id)) {
					const calendarEvent = new CalendarEvent({
						title: `Vehicle ${vehicle?.vehicle_number} (${vehicle?.tag})'s Emission Test would expire in 15 days`,
						description: `Vehicle ${vehicle?.vehicle_number} (${vehicle?.tag})'s Emission Test would expire in 15 day, please check whether it is renewed properly`,
						type: 'reminder',
						start_time: newDate1,
						stop_time: new Date(newDate1.getTime() + 10*60*1000),
						color: 'brown',
						target_type: 'vehicle',
						target_uuid: vehicle.id,
						target_name: vechile.vehicle_number,
						event_reminder_type: 'emission_test',
						status: 'active',
						site,
						edit_date: new Date(),
						create_date: new Date(),
						create_by: 'system',
						edit_by: 'system',
						edit_history: [{employee: 'system', date: new Date()}]
					})
					await calendarEvent.save(calendarEvent);
				}
			}
			if ( titleExpireDate >= today && titleExpireDate < futureDate) {
				if (!allVehiclesCalendarEvent.find(item => item.event_reminder_type === 'title_expire' && item.target_uuid === vehicle.id)) {
					const calendarEvent = new CalendarEvent({
						title: `Vehicle ${vehicle?.vehicle_number} (${vehicle?.tag})'s Title would expire in 15 days`,
						description: `Vehicle ${vehicle?.vehicle_number} (${vehicle?.tag})'s Title would expire in 15 day, please check whether it is renewed properly`,
						type: 'reminder',
						start_time: newDate2,
						stop_time: new Date(newDate2.getTime() + 10*60*1000),
						color: 'brown',
						target_type: 'vehicle',
						target_uuid: vehicle.id,
						target_name: vechile.vehicle_number,
						event_reminder_type: 'title_expire',
						status: 'active',
						site,
						edit_date: new Date(),
						create_date: new Date(),
						create_by: 'system',
						edit_by: 'system',
						edit_history: [{employee: 'system', date: new Date()}]
					})
					await calendarEvent.save(calendarEvent);
				}
				}
			}
		}
	}

  async createCustomerRelatedEvents(daysAhead = 30) {
		const today = new Date();
		const upcomingDates = [];

		// Calculate dates for the next 'daysAhead' days
		for (let i=0; i<=daysAhead; i++) {
			const targetDate = new Date(today);
			targetDate.setDate(today.getDate() + i);

			upcomingDates.push(targetDate)
		}

		const sites = await getAllSites();
		for (const site of sites) {
			const allCustomers = await Customer.find({ site });
			const allExistingBirthdayReminders = await CalendarEvent.find({ type: 'reminder', status: 'active', rrule: 'FREQ=YEARLY', event_reminder_type: 'birthday', site });
			const allExistingPaymentReminders = await CalendarEvent.find({ type: 'reminder', status: 'active',  event_reminder_type: 'payment', site });

			for (const customer of allCustomers) {
				const { month, day } = this.parseMonthDay(customer?.birth_date);
				const { month: month1, day: day1 } = this.parseMonthDay(customer?.payment_due_date);
			for (const targetDate of upcomingDates) {
				// Birthday reminders are rendered dynamically in Important Dates calendar.
				if (month1 === targetDate.getMonth() + 1 && day1 === targetDate.getDate()) {
					if (!allExistingPaymentReminders.find((reminder) => reminder.target_uuid === customer?.id)) {
						const calendarEvent = new CalendarEvent({
							title: `${customer?.name}'s Payment Due Date`,
							description: `${customer?.name}'s payment would be due on ${customer?.payment_due_date}`,
							type: 'reminder',
							start_time: targetDate,
							stop_time: new Date(targetDate.getTime() + 10*60*1000),
							color: 'red',
							target_type: 'customer',
							target_uuid: customer?.id,
							target_name: customer?.name,
							event_reminder_type: 'payment',
							status: 'active',
							site,
							edit_date: new Date(),
							create_date: new Date(),
							create_by: 'system',
							edit_by: 'system',
							edit_history: [{employee: 'system', date: new Date()}]
						})
						await calendarEvent.save(calendarEvent);
					}
				}
			}
			}
		}
	}
}
module.exports = new ReminderService();