import type { Slot, VNode } from 'vue'
import type { EventInterface } from './event.interface'
import { Comment, Text } from 'vue'
import { DATE_TIME_STRING_FULL_DAY_PATTERN, DATE_TIME_STRING_PATTERN } from './constants'
import Time from './time'
import { DAY_MODE } from './typings'

export default class Helpers {
	/**
	 * If navigator.languages is present (correlating to the browser's Accept-Language header), then use it
	 * otherwise just use navigator.language
	 */
	static getBrowserNavigatorLocale(): string {
		if (typeof navigator !== 'object') { return 'en-US' }

		return navigator.languages && navigator.languages.length
			? navigator.languages[0]
			: navigator.language
	}

	/**
	 * Solution from https://github.com/vuejs/core/issues/4733#issuecomment-1024816095
	 */
	static hasSlotContent(slot: Slot | undefined) {
		if (!slot) { return false }

		return slot().some((vnode: VNode) => {
			if (vnode.type === Comment) { return false }

			if (Array.isArray(vnode.children) && !vnode.children.length) { return false }

			return (
				vnode.type !== Text
				|| (typeof vnode.children === 'string' && vnode.children.trim() !== '')
			)
		})
	}

	static getEventType(event: EventInterface, time: Time) {
		const isTimedEvent = DATE_TIME_STRING_PATTERN.test(event.time.start)
			&& DATE_TIME_STRING_PATTERN.test(event.time.end)

		const isFullDayEvent = DATE_TIME_STRING_FULL_DAY_PATTERN.test(event.time.start)
			&& DATE_TIME_STRING_FULL_DAY_PATTERN.test(event.time.end)

		if (isTimedEvent) { return this.getTimedEventType(event, time) }

		if (isFullDayEvent) { return this.getFullDayEventType(event, time) }

		throw new Error('Event has invalid type')
	}

	static getTimedEventType(event: EventInterface, time: Time) {
		if (time.dateStringsHaveEqualDates(event.time.start, event.time.end)) {
			return 'SINGLE_DAY_TIMED'
		}

		if (time.dayMode === DAY_MODE.FLEXIBLE) {
			const endBoundaryForSingleHybridDay = time.setHourInDateTimeString(
				time.addDaysToDateTimeString(
					1,
					time.dateStringFrom(event.time.start)
				),
				Time.getHourFromTimePoints(time.DAY_END),
			)

			if (event.time.end < endBoundaryForSingleHybridDay) {
				return 'SINGLE_HYBRID_DAY_TIMED'
			}
		}

		return 'MULTI_DAY_TIMED'
	}

	static getFullDayEventType(event: EventInterface, time: Time) {
		if (time.dateStringsHaveEqualDates(event.time.start, event.time.end)) {
			return 'SINGLE_DAY_FULL_DAY'
		}

		return 'MULTI_DAY_FULL_DAY'
	}

	static isUIEventTouchEvent(event: UIEvent): boolean {
		return 'touches' in event && typeof event.touches === 'object'
	}
}