import {client} from "../index";
import {MessageEmbed} from "discord.js";
import {getPrefix} from "../structures";
import {getMessageByID} from "onion-lasers";

client.on("message", (message) => {
    (async () => {
        // 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;

        const linkMessage = await getMessageByID(channelID, messageID);

        // If it's an invalid link (or the bot doesn't have access to it).
        if (typeof linkMessage === "string") {
            return message.channel.send("I don't have access to that channel!");
        }

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

        if (!linkMessage.cleanContent && embeds.length === 0) {
            return message.channel.send({embeds: [new MessageEmbed().setDescription("🚫 The message is empty.")]});
        }

        const infoEmbed = new MessageEmbed()
            .setAuthor(
                linkMessage.author.username,
                linkMessage.author.displayAvatarURL({format: "png", dynamic: true, size: 4096})
            )
            .setTimestamp(linkMessage.createdTimestamp)
            .setDescription(
                `${linkMessage.cleanContent}\n\nSent in **${linkMessage.guild?.name}** | <#${linkMessage.channel.id}> ([link](https://discord.com/channels/${guildID}/${channelID}/${messageID}))`
            );

        if (linkMessage.attachments.size !== 0) {
            const image = linkMessage.attachments.first();
            infoEmbed.setImage(image!.url);
        }

        return await message.channel.send({embeds: [infoEmbed]});
    })();
});

export function extractFirstMessageLink(message: string): [string, string, string] | null {
    const messageLinkMatch = message.match(
        /([!<])?https?:\/\/(?:ptb\.|canary\.)?discord(?:app)?\.com\/channels\/(\d{17,})\/(\d{17,})\/(\d{17,})(>)?/
    );
    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];
}