implement repetitionstring validator

parses repetition string and sends a message on fail to the creator
which contains the offending error code

server/handler/repeatingEvents/helper.ts

@@ -1,8 +1,9 @@
 import { format } from "date-fns"
 import add from "date-fns/add"
 import { DateResolvable, Guild, GuildScheduledEvent, GuildScheduledEventCreateOptions } from "discord.js"
+import { client } from "../../.."
 import { findInScheduleTypes } from "../../helper/typeFind"
-import { Maybe } from "../../interfaces"
+import { CustomError, errorCodes, Maybe } from "../../interfaces"
 import { RepetitonInfo, supportedSchedule } from "../../types/scheduledEventTypes"
 
 export const repetitionMarkerIsFound = (desc: string): boolean => desc.includes('$rep')
@@ -14,7 +15,7 @@ export function getRepetitonInfo(description: string): RepetitonInfo {
 	const lines = description.split(`\n`)
 	const repetitionString = lines.find(x => x.startsWith('$rep:'))
 	if (!repetitionString)
-		throw new Error('Cant find repetition string')
+		throw new CustomError('Cant find repetition string', errorCodes.no_string_present)
 	const schedule: supportedSchedule = determineSchedule(repetitionString)
 	const { totalAmount, alreadyOccured } = determineRepetitionCount(repetitionString)
 	const endDate = determineEndDate(repetitionString)
@@ -33,14 +34,18 @@ export function determineSchedule(repetitionLine: string): supportedSchedule {
 	if (easilyKnownScheduleName)
 		return easilyKnownScheduleName
 	else
-		throw new Error('Inferring schedule names is not yet supported')
+		throw new CustomError('Inferring schedule names is not yet supported', errorCodes.schedule_not_supported)
 }
 
 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) {
@@ -72,7 +77,7 @@ export function getNewScheduledStart(oldguildScheduledEvent: GuildScheduledEvent
 			monthsToAdd = 1
 			break
 		default:
-			throw new Error('No schedule found, cant add days')
+			throw new CustomError('No schedule found, cant add days', errorCodes.no_schedule)
 	}
 	const duration: Duration = {
 		days: daysToAdd,
@@ -102,4 +107,45 @@ function determineEndDate(description: string): Maybe<Date> {
 	}
 	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)
+	}
+}