TravBot-v3/src/modules/messageEmbed.ts

import {client} from "../index";
import {TextChannel, APIMessage, MessageEmbed} from "discord.js";
import {getPrefix} from "../structures";
import {DiscordAPIError} from "discord.js";

client.on("message", async (message) => {
    // Only execute if the message is from a user and isn't a command.
    if (message.content.startsWith(getPrefix(message.guild)) || message.author.bot) return;
    const messageLink = extractFirstMessageLink(message.content);
    if (!messageLink) return;
    const [guildID, channelID, messageID] = messageLink;

    try {
        const channel = client.guilds.cache.get(guildID)?.channels.cache.get(channelID) as TextChannel;
        const link_message = await channel.messages.fetch(messageID);

        let rtmsg: string | APIMessage = "";
        if (link_message.cleanContent) {
            rtmsg = new APIMessage(message.channel as TextChannel, {
                content: link_message.cleanContent,
                disableMentions: "all",
                files: link_message.attachments.array()
            });
        }

        const embeds = [...link_message.embeds.filter((v) => v.type == "rich"), ...link_message.attachments.values()];

        /// @ts-ignore
        if (!link_message.cleanContent && embeds.empty) {
            const Embed = new MessageEmbed().setDescription("🚫 The message is empty.");
            return message.channel.send(Embed);
        }

        const infoEmbed = new MessageEmbed()
            .setAuthor(
                link_message.author.username,
                link_message.author.displayAvatarURL({format: "png", dynamic: true, size: 4096})
            )
            .setTimestamp(link_message.createdTimestamp)
            .setDescription(
                `${link_message.cleanContent}\n\nSent in **${link_message.guild?.name}** | <#${link_message.channel.id}> ([link](https://discord.com/channels/${guildID}/${channelID}/${messageID}))`
            );
        if (link_message.attachments.size !== 0) {
            const image = link_message.attachments.first();
            /// @ts-ignore
            infoEmbed.setImage(image.url);
        }

        await message.channel.send(infoEmbed);
    } catch (error) {
        if (error instanceof DiscordAPIError) {
            message.channel.send("I don't have access to this channel, or something else went wrong.");
        }
        return console.error(error);
    }
});

export function extractFirstMessageLink(message: string): [string, string, string] | null {
    const messageLinkMatch = message.match(
        /([!<])?https?:\/\/(?:ptb\.|canary\.)?discord(?:app)?\.com\/channels\/(\d{17,19})\/(\d{17,19})\/(\d{17,19})(>)?/
    );
    if (messageLinkMatch === null) return null;
    const [, leftToken, guildID, channelID, messageID, rightToken] = messageLinkMatch;
    // "!link" and "<link>" will cancel the embed request.
    if (leftToken === "!" || (leftToken === "<" && rightToken === ">")) return null;
    else return [guildID, channelID, messageID];
}