//Set up the Discord bot interface
var Discord = require("discord.js");
var bot = new Discord.Client();

//Set up the channel list
var fs = require("fs");
var channels;
try {
    channels = JSON.parse(fs.readFileSync("./channellist.json", "utf8"));
} catch (err) {
    if (err.code == "ENOENT") {
        fs.writeFileSync("channellist.json", JSON.stringify({}));
        channels = {};
    }
}


//Function to get the key(s) relating to a value
function getChannelKey(object, value) {
    let keys = [];
    for (var key in object) {
        if (object[key].id == value) keys.push(key);
    }
    return keys;
}

//Function to safely handle writing to stdout
function safeWrite(sendstring) {
    if (!process.stdout.write(sendstring)) {
        safe = false;
        process.stdout.once('drain', safeWrite(sendstring));
    } else {
        safe = true;
    }
}
var safe = true;

//Set utf8 encoding for both stdin and stdout
process.stdin.setEncoding('utf8');
process.stdout.setDefaultEncoding('utf8');

//Receive input from primary program
process.stdin.on('readable', () => {
    let input = process.stdin.read();

    if (input !== null) {
        //Get the channelname to send the message to
        let separator = input.indexOf("$");
        let channelid = input.substring(0, separator);
        if (channels[channelid]) {
            //Send the message to the proper channel if channelname has been registered to a channel.
            bot.channels.get(channels[channelid].id).sendMessage("[" + channels[channelid].name + "] " + input.substring(separator + 1));
        } else return;
    }
});

//Receive input from Discord
bot.on('message', (message) => {
    //Ignore own messages
    if (message.author == bot.user) return;

    //Set the prefix
    let prefix = "::";

    //If message is setting the channel
    if (message.content.startsWith(prefix)) {
        let command = message.content.substring(2).split(" ");
        if (command[0] == "setchannel") {
            if (command.length < 3) {
                message.channel.sendMessage("The setchannel command requires 2 arguments. ::setchannel channelid channelname");
                return;
            }
            //Get the first argument of the command (::setchannel channelid channelname)
            let channelid = command[1];
            let channelname = command.slice(2).join(" ");
            channels[channelid] = { id: message.channel.id, name: channelname };
            fs.unlinkSync("channellist.json");
            fs.writeFileSync("channellist.json", JSON.stringify(channels));
            message.channel.sendMessage("Messages from server " + channelid + " will now be sent to this channel with the prefix " + channelname + ".\n");
        } else if (command[0] == "unsetchannel") {
            let removelist = getChannelKey(channels, message.channel.id);
            if (removelist.length === 0) {
                message.channel.sendMessage("There were no servers registered to this channel.");
                return;
            }
            for (let i = 0; i < removelist.length; i++) {
                delete channels[removelist[i]];
            }
            fs.unlinkSync("channellist.json");
            fs.writeFileSync("channellist.json", JSON.stringify(channels));
            message.channel.sendMessage("All servers previously registered to this channel will no longer send messages to this channel.\n");
        } else return;
    } else {
        //Get an array of servers that match this channel id. End function if array length is 0 (unreigstered channel)
        let sendto = getChannelKey(channels, message.channel.id);
        var name;
        if (message.member.nickname === null) name = message.author.username;
        else name = message.member.nickname;
        if (sendto.length === 0) return;
        for (let i = 0; i < sendto.length; i++) {
            while (!safe) {
                console.log("DEBUG: Buffer overflowing, waiting until it is safe.");
            }
            let sendstring = sendto[i] + "$[DISCORD] " + name + ": " + message.content + "\n";
            safeWrite(sendstring);
        }
    }
});

bot.on('ready', () => {
    bot.user.setGame("Factorio");
});

//WARNING: THIS TOKEN IS NOT TO BE SHARED TO THE PUBLIC
var token = JSON.parse(fs.readFileSync("./token.json", "utf8"))
bot.login(token);