core/utils/Webhook.ts

import {
	APIEmbed,
	ButtonStyle,
	Colors,
	ComponentType,
	DiscordAPIError,
	parseWebhookURL,
	Snowflake,
	WebhookClient,
} from 'discord.js'

import { get, update } from './Query'
import { DiscordBot, ServerListDiscordBot, webhookClients } from './DiscordBot'
import { DiscordEnpoints } from './Constants'
import fetch, { Response } from 'node-fetch'
import { Bot, Server, Webhook, WebhookStatus, WebhookType } from '@types'
import { makeBotURL, makeDiscordCodeblock, makeServerURL } from './Tools'
import crypto from 'crypto'

type RelayOptions = {
	dest: string
	method: 'GET' | 'POST'
	data?: string
	secret: string
}

const timeouts = new Map<Snowflake, Map<number, NodeJS.Timeout>>()

const clearTimeouts = (id: Snowflake) => {
	if (timeouts.has(id)) {
		timeouts.get(id).forEach(clearTimeout)
		timeouts.delete(id)
		return true
	} else {
		return false
	}
}

async function sendRequest({
	retryCount,
	webhook,
	target,
	payload,
}: {
	retryCount: number
	webhook: Webhook
	target: Bot | Server
	payload: WebhookPayload
}) {
	const id = target.id
	const isBot = payload.type === 'bot'

	timeouts.get(id)?.delete(payload.timestamp)

	const result = await relayedFetch({
		dest: webhook.url,
		method: 'POST',
		data: JSON.stringify(payload),
		secret: webhook.secret,
	})
		.then(async (r) => {
			if (!r.ok) {
				return null
			}
			return r.json()
		})
		.catch(() => null)

	if (result === null) return

	if (result.success) {
		const data = result.data
		if (200 <= result.status && result.status < 300 && data.length === 0) {
			await update.webhook(id, isBot ? 'bots' : 'servers', { failedSince: null })
			return
		} else if ((400 <= result.status && result.status < 500) || data.length !== 0) {
			if (!clearTimeouts(id)) return
			await update.webhook(id, isBot ? 'bots' : 'servers', {
				status: WebhookStatus.Disabled,
				failedSince: null,
				secret: null,
			})
			sendFailedMessage(target)
			return
		}
	}
	if (retryCount === 10) {
		if (!webhook.failedSince) {
			await update.webhook(id, isBot ? 'bots' : 'servers', {
				failedSince: Math.floor(Date.now() / 1000),
			})
		} else if (Date.now() - webhook.failedSince * 1000 > 1000 * 60 * 60 * 24) {
			if (!clearTimeouts(id)) return
			await update.webhook(id, isBot ? 'bots' : 'servers', {
				status: WebhookStatus.Disabled,
				failedSince: null,
				secret: null,
			})
			sendFailedMessage(target)
		}
		return
	}

	if (!timeouts.has(id)) {
		timeouts.set(id, new Map())
	}

	timeouts.get(id).set(
		payload.timestamp,
		setTimeout(
			() => {
				sendRequest({
					retryCount: retryCount + 1,
					webhook,
					target,
					payload,
				})
			},
			Math.pow(2, retryCount + 2) * 1000
		)
	)
}

export function destroyWebhookClient(id: string, type: 'bot' | 'server') {
	const client = webhookClients[type].get(id)
	if (client) {
		client.destroy()
		webhookClients[type].delete(id)
	}
}

function relayedFetch(options: RelayOptions): Promise<Response> {
	return fetch(process.env.WEBHOOK_RELAY_URL, {
		method: 'POST',
		body: JSON.stringify(options),
		headers: {
			'Content-Type': 'application/json',
			Authorization: process.env.WEBHOOK_RELAY_SECRET,
		},
	})
}

const sendFailedMessage = async (target: Bot | Server): Promise<void> => {
	const isBot = 'owners' in target
	const users = isBot ? target.owners : [target.owner]

	for (const user of users) {
		const r = await (isBot ? DiscordBot : ServerListDiscordBot).users
			.send(typeof user === 'string' ? user : user.id, {
				embeds: [
					{
						title: '웹후크 전송 실패',
						description:
							`\`\`${target.name}\`\`에 등록된 웹후크 주소가 올바르지 않거나, 제대로 동작하지 않아 비활성화되었습니다.\n` +
							'설정된 웹후크의 주소가 올바른지 확인해주세요.\n' +
							`[개발자 패널](${process.env.KOREANBOTS_URL}/developers/applications/${
								isBot ? 'bots' : 'servers'
							}/${target.id})에서 설정된 내용을 다시 저장하면 웹후크가 활성화됩니다.\n` +
							(isBot
								? '문제가 지속될 경우 본 DM을 통해 문의해주세요.'
								: '문제가 지속될 경우 한디리 공식 디스코드 서버에서 문의해주세요.'),
						color: Colors.Red,
					},
				],
				components: isBot
					? []
					: [
							{
								type: ComponentType.ActionRow,
								components: [
									{
										type: ComponentType.Button,
										label: '공식 디스코드 서버 참가하기',
										style: ButtonStyle.Link,
										url: 'https://discord.gg/koreanlist',
									},
								],
							},
					  ],
			})
			.catch(() => null)
		if (r) return
	}
}

export const verifyWebhook = async (webhookURL: string): Promise<string | false | null> => {
	if (parseWebhookURL(webhookURL)) return null
	const secret = crypto.randomUUID()
	const url = new URL(webhookURL)
	url.searchParams.set('secret', secret)
	const result = await relayedFetch({
		dest: url.toString(),
		method: 'GET',
		secret,
	})
		.then((r) => r.json())
		.catch(() => null)

	if (result) {
		const data = result.data ? JSON.parse(result.data) : null
		if (data?.secret === secret) return secret
	}

	return false
}

export const sendWebhook = async (target: Bot | Server, payload: WebhookPayload): Promise<void> => {
	const id = target.id
	const isBot = payload.type === 'bot'

	const webhook = await get.webhook(id, isBot ? 'bots' : 'servers')
	if (!webhook) return
	if (webhook.status === 0) return

	if (webhook.status === WebhookStatus.Discord) {
		if (!webhookClients[payload.type].has(id)) {
			webhookClients[payload.type].set(
				id,
				new WebhookClient({
					url: webhook.url,
				})
			)
		}
		const client = webhookClients[payload.type].get(id)

		const url = new URL(webhook.url)
		const result = await client
			.send({
				embeds: [buildEmbed({ payload, target })],
				threadId: url.searchParams.get('thread_id') || undefined,
			})
			.catch((r: DiscordAPIError | unknown) => {
				if (r instanceof DiscordAPIError) {
					if (400 <= r.status && r.status < 500) {
						return false
					}
				}
				return true
			})
		if (!result) {
			await update.webhook(id, isBot ? 'bots' : 'servers', { status: WebhookStatus.Disabled })
			sendFailedMessage(target)
			return
		}
	} else if (webhook.status === WebhookStatus.HTTP) {
		sendRequest({
			retryCount: 0,
			webhook,
			target,
			payload,
		})
		return
	}
}

function compare(before, after) {
	if (before < after) {
		return '🔺'
	} else if (before === after) {
		return '➖'
	} else {
		return '🔻'
	}
}

function buildEmbed({
	payload,
	target,
}: {
	payload: WebhookPayload
	target: Bot | Server
}): APIEmbed {
	const author =
		'avatar' in target
			? {
					name: target.name,
					icon_url: DiscordEnpoints.CDN.user(target.id, target.avatar, { format: 'png' }),
					url: process.env.KOREANBOTS_URL + makeBotURL({ id: target.id, vanity: target.vanity }),
			  }
			: {
					name: target.name,
					icon_url: DiscordEnpoints.CDN.guild(target.id, target.icon, { format: 'png' }),
					url: process.env.KOREANBOTS_URL + makeServerURL({ id: target.id, vanity: target.vanity }),
			  }
	const footer = {
		text: '한국 디스코드 리스트',
		icon_url: DiscordBot.user.avatarURL(),
	}
	switch (payload.data.type) {
		case WebhookType.HeartChange:
			return {
				author,
				title: '❤️  하트 수 변동',
				fields: [
					{
						name: '이전',
						value: makeDiscordCodeblock(payload.data.before.toString()),
						inline: true,
					},
					{
						name: '이후',
						value: makeDiscordCodeblock(payload.data.after.toString()),
						inline: true,
					},
				],
				color: 0xcd3e45,
				footer,
				timestamp: new Date().toISOString(),
			}
		case WebhookType.ServerCountChange:
			return {
				author,
				title: '서버 수 변동',
				description: payload.data.before
					? `${payload.data.before} -> ${payload.data.after} (${compare(
							payload.data.before,
							payload.data.after
					  )})`
					: `+ ${payload.data.after}`,
				color: Colors.Aqua,
				footer,
				timestamp: new Date().toISOString(),
			}
	}
}

type WebhookPayload = (BotWebhookPayload | ServerWebhookPayload) & {
	timestamp: number
}

type ServerWebhookData = HeartChange & {
	guildId: Snowflake
}

type BotWebhookData = (HeartChange | ServerCountChange) & {
	botId: Snowflake
}

type ServerWebhookPayload = {
	type: 'server'
	data: ServerWebhookData
}

type BotWebhookPayload = {
	type: 'bot'
	data: BotWebhookData
}

type HeartChange = {
	type: WebhookType.HeartChange
	before: number
	after: number
	userId: Snowflake
}

type ServerCountChange = {
	type: WebhookType.ServerCountChange
	before: number | number
	after: number
}