import { format } from "date-fns"
import add from "date-fns/add"
import { DateResolvable, Guild, GuildScheduledEvent, GuildScheduledEventCreateOptions } from "discord.js"
import { client } from "../../.."
import { CustomError, errorCodes, Maybe } from "../../interfaces"
import { RepetitonInfo, Schedule, supportedSchedule } from "../../types/scheduledEventTypes"

export const repetitionMarkerIsFound = (desc: string): boolean => desc.includes('$rep')
export function createEventInGuild(guild: Guild, eventInfo: GuildScheduledEventCreateOptions): Promise<any> {
	return guild.scheduledEvents.create(eventInfo)
}
export function getRepetitonInfo(description: string): RepetitonInfo {

	const lines = description.split(`\n`)
	const repetitionString = lines.find(x => x.startsWith('$rep:'))
	if (!repetitionString)
		throw new CustomError('Cant find repetition string', errorCodes.no_string_present)
	const scheduleString = determineScheduleString(repetitionString)
	const schedule: Schedule = new Schedule(scheduleString)
	const { totalAmount, alreadyOccured } = determineRepetitionCount(repetitionString)
	const endDate = determineEndDate(repetitionString)
	return {
		totalAmount,
		alreadyOccured,
		schedule,
		endDate
	}
}

export function determineScheduleString(repetitionLine: string): supportedSchedule {
	const segments = repetitionLine.split(':')
	const scheduleSegment = segments[1]
	if (scheduleSegment)
		return scheduleSegment
	else
		throw new CustomError('No schedule segment found', errorCodes.no_schedule)
}

export function determineRepetitionCount(description: string): { totalAmount: number; alreadyOccured: number } {
	const segments = description.split(':')
	const amountSegment = segments[2]
	if (amountSegment) {
		const amounts = amountSegment.split('/')
		return { totalAmount: Number(amounts[1]) ?? 0, alreadyOccured: Number(amounts[0]) ?? 0 }
	} else {
		throw new CustomError('No amount was defined', errorCodes.no_repetition_amount)
	}
}

export function buildNewRepetitionString(repetitionInfo: RepetitonInfo) {
	if (repetitionInfo.endDate)
		return `$rep:${repetitionInfo.schedule}:${format(repetitionInfo.endDate, 'yyyy-MM-dd')}`
	return `$rep:${repetitionInfo.schedule}:${repetitionInfo.alreadyOccured + 1}/${repetitionInfo.totalAmount}`
}

export function addRepetitonStringToEventDescription(oldguildScheduledEvent: string, newRepetitonString: string): string | undefined {
	const lines = oldguildScheduledEvent.split(`\n`)
	const repLineIndex = lines.findIndex(x => x.startsWith('$rep:'))
	const newLines = lines.filter((_, index) => repLineIndex !== index)
	newLines.push(newRepetitonString)
	return newLines.join('\n')
}

function determineEndDate(description: string): Maybe<Date> {
	const segments = description.split(':')
	if (segments.length === 3) {
		// rep:sched:countOrDate
		const segmentValue = segments[2]
		if (segmentValue.includes('/')) {
			if (segmentValue.match(/\//g) || [].length !== 2) {
				return
			}
		}
		const dateValue = new Date(segmentValue)
		return dateValue
	}
	else if (segments.length === 4) {
		// rep:sched:count:date
		const segmentValue = segments[3]
		const dateValue = new Date(segmentValue)
		return dateValue
	}
	return
}
export function checkIfRepetitionStringIsValid(description: string): string {
	if (!description) return 'not_present'
	if (repetitionMarkerIsFound(description)) {
		let repetitionInfo
		try {
			repetitionInfo = getRepetitonInfo(description)
			if (!repetitionInfo.schedule) return 'no_schedule'
			if (!repetitionInfo.totalAmount && !repetitionInfo.alreadyOccured && !repetitionInfo.endDate) {
				if (!repetitionInfo.totalAmount || !repetitionInfo.alreadyOccured) return 'no_amount'
				if (!repetitionInfo.endDate) return 'no_end'
			}
			return 'valid'
		} catch (error) {
			if (error instanceof CustomError) {
				return error.getCode()
			}
			return 'invalid'
		}
	} return 'not_present'
}

export async function validateRepetitionStringAndSendMessageOnFail(event: GuildScheduledEvent): Promise<void> {

	const validResponses = [
		'valid',
		'not_present'
	]
	const resultstring: string = checkIfRepetitionStringIsValid(event.description ?? "")
	if (validResponses.includes(resultstring)) {
		// do success things?
	} else {
		const creatorMessage = `The repetition string in your event could not be parsed. Reason: ${resultstring}`
		console.log(creatorMessage)
		if (!event.creatorId) throw new CustomError('No creator ID present', errorCodes.no_creator_id)
		const creator = await client.users.fetch(event.creatorId)
		console.log(`Creator ${JSON.stringify(creator)}`)
		if (creator)
			if (!creator.dmChannel)
				await creator.createDM()
		await creator.dmChannel?.send(creatorMessage)
	}
}