/**
 * bot.ts
 * Scans the chat for reactions and updates the leaderboard database.
 */

import {
    Client,
    Collection,
    Events,
    GatewayIntentBits,
    Interaction,
    MessageReaction,
    PartialMessageReaction,
    Partials, SlashCommandBuilder,
    TextChannel,
    User
} from 'discord.js';
import fs = require('node:fs');
import path = require('node:path');
import fetch from 'node-fetch';
import { JSDOM } from 'jsdom';
import {logError, logInfo, logWarn} from '../logging';
import {
    db,
    openDb,
    reactionEmojis,
    recordReaction,
    sync
} from './util';


interface CommandClient extends Client {
    commands?: Collection<string, { data: SlashCommandBuilder, execute: (interaction: Interaction) => Promise<void> }>
}

const client: CommandClient = new Client({
    intents: [GatewayIntentBits.Guilds, GatewayIntentBits.GuildMessages, GatewayIntentBits.GuildMessageReactions],
    partials: [Partials.Message, Partials.Channel, Partials.Reaction],
});
client.commands = new Collection();

client.once(Events.ClientReady, async () => {
    logInfo('[bot] Ready.');
    for (let i = 0; i < reactionEmojis.length; ++i)
        logInfo(`[bot] config: reaction_${i + 1} = ${reactionEmojis[i]}`);
});


async function onMessageReactionChanged(reaction: MessageReaction | PartialMessageReaction, user: User)
{
    // When a reaction is received, check if the structure is partial
    if (reaction.partial) {
        // If the message this reaction belongs to was removed, the fetching might result in an API error which should be handled
        try {
            await reaction.fetch();
        } catch (error) {
            logError('[bot] Something went wrong when fetching the reaction:', error);
            // Return as `reaction.message.author` may be undefined/null
            return;
        }
    }
    if (reaction.message.partial) {
        // If the message this reaction belongs to was removed, the fetching might result in an API error which should be handled
        try {
            await reaction.message.fetch();
        } catch (error) {
            logError('[bot] Something went wrong when fetching the message:', error);
            // Return as `reaction.message.author` may be undefined/null
            return;
        }
    }

    // Now the message has been cached and is fully available
    logInfo(`[bot] ${reaction.message.author.id}'s message reaction count changed: ${reaction.emoji.name}x${reaction.count}`);
    await recordReaction(<MessageReaction> reaction);
}

async function fetchMotd()
{
    const res = await fetch(process.env.MOTD_HREF);
    const xml = await res.text();
    const parser = new JSDOM(xml);
    const doc = parser.window.document;
    return doc.querySelector(process.env.MOTD_QUERY).textContent;
}

async function scheduleRandomMessage(firstTime = false)
{
    if (!firstTime) {
        const channel = <TextChannel> await client.channels.fetch(process.env.MOTD_CHANNEL);
        if (!channel) {
            logWarn(`[bot] Channel ${process.env.MOTD_CHANNEL} not found, disabling MOTD.`);
            return;
        }
        const randomMessage = await fetchMotd();
        await channel.send(randomMessage);
        logInfo(`[bot] Sent MOTD: ${randomMessage}`);
    }
    // wait between 2-8 hours
    const timeoutMins = Math.random() * 360 + 120;
    const scheduledTime = new Date();
    scheduledTime.setMinutes(scheduledTime.getMinutes() + timeoutMins);
    logInfo(`[bot] Next MOTD: ${scheduledTime.toLocaleTimeString()}`);
    setTimeout(scheduleRandomMessage, timeoutMins * 60 * 1000);
}

client.on(Events.InteractionCreate, async interaction => {
    if (!interaction.isChatInputCommand()) return;
});

client.on(Events.MessageReactionAdd, onMessageReactionChanged);
client.on(Events.MessageReactionRemove, onMessageReactionChanged);
client.on(Events.InteractionCreate, async interaction => {
    if (!interaction.isChatInputCommand()) return;

    const client: CommandClient = interaction.client;
    const command = client.commands.get(interaction.commandName);

    if (!command) {
        logError(`[bot] No command matching ${interaction.commandName} was found.`);
        return;
    }

    try {
        await command.execute(interaction);
    } catch (error) {
        logError(error);
        if (interaction.replied || interaction.deferred) {
            await interaction.followUp({ content: 'There was an error while executing this command!', ephemeral: true });
        } else {
            await interaction.reply({ content: 'There was an error while executing this command!', ephemeral: true });
        }
    }
});

// startup
(async () => {
    logInfo("[db] Opening...");
    await openDb();
    logInfo("[db] Migrating...");
    await db.migrate();
    logInfo("[db] Ready.");

    logInfo("[bot] Loading commands...");
    const foldersPath = path.join(__dirname, 'commands');
    const commandFolders = fs.readdirSync(foldersPath);
    for (const folder of commandFolders) {
        const commandsPath = path.join(foldersPath, folder);
        const commandFiles = fs.readdirSync(commandsPath).filter(file => file.endsWith('.js'));
        for (const file of commandFiles) {
            const filePath = path.join(commandsPath, file);
            const command = require(filePath);
            client.commands.set(command.data.name, command);
        }
    }

    logInfo("[bot] Logging in...");
    await client.login(process.env.TOKEN);
    await sync(client.guilds);
    if (process.env.ENABLE_MOTD) {
        await scheduleRandomMessage(true);
    }
})();