index.js

const Discord = require("discord.js");
const cron = require("cron");
const client = new Discord.Client();

//.json with token for discord bot
const {
    token,
} = require("./token.json");

client.commands = new Discord.Collection();


client.on("ready", () => {
    console.log("Ready!");
    client.user.setActivity("Type "+prefix+"help to get bot functions");
});

class setAnnounces {
    constructor() {
        this.classList = [];
    }
    newCron(timeInfo,identify,passRepeat) {
        let a = new cron.CronJob(timeInfo,() => testTime(identify,passRepeat));
        this.classList.push(a);
        //return a;
    }
    get returnAll() {
        return this.classList;
    }
    /*get announceNum() {
        return this.classList.length;
    }*/
}

function testTime(passIndentify, passRepeatType) {
    let index = announceList.indexOf(passIndentify);
    let messageOut = contentList[index];
    try {
        announceChannel.send(messageOut);
    } catch {
        message.channel.send(messageOut);
    }
    if(passRepeatType == "once") {
        delAnnounce(index);
    }
}

function delAnnounce(passIndex) {
    allAnnounces.classList[passIndex].stop();
    allAnnounces.classList[passIndex].stop();
    announceList.splice(passIndex);
    contentList.splice(passIndex);
    timeList.splice(passIndex);
}

function setAnnounce(passCommand) {
    let setName = passCommand[1];
    let repeatType = passCommand[2];
    let dayOfWeek = "*";
    if (!(passCommand[2] == "once" || passCommand[2] == "daily")) {
        dayOfWeek = passCommand[2];
    }
    let confirmMessage = "Announcement '"+setName+"' set at " + passCommand[3] + ":" + passCommand[4] + ":" + passCommand[5];
    let TzShift = parseInt(passCommand[3]);
    if (TzShift+userTz < 0) {
        TzShift += userTz+24;
    } else if (TzShift+userTz > 23) {
        TzShift += userTz-24;
    } else {
        TzShift += userTz;
    }
    let passTime = passCommand[5] + " " + passCommand[4] + " " + TzShift + " * * " + dayOfWeek;
    allAnnounces.newCron(passTime,setName,repeatType);
    timeList.push([passCommand[2],passCommand[5],passCommand[4],passCommand[3]]);
    for(let i = 0; i < 6; ++i) {
        passCommand.shift();
    }
    let stringCommand = passCommand.join();
    contentList.push(stringCommand);
    announceList.push(setName);
    allAnnounces.returnAll[announceList.length-1].start();
    return confirmMessage;
}

let allAnnounces = new setAnnounces();
var announceChannel;
var prefix = "?";
var userTz;
const announceList = [];
const contentList = [];
const timeList = [];

client.on("message", message => {

    //Message to console
    console.log(message.content);

    //If the message doesn't start with prefix it exits
    if (!message.content.startsWith(prefix) || message.author.bot) {
        return;
    }

    const args = message.content.slice(prefix.length).trim().split(" ");
    const command = args.map(x => x.toLowerCase());

    //commands

    //ANNOUNCE
    testAnnounce: if (command[0] == "ann") {
        let errMessage = "";
        let announceName = command[1];
        const commander = command.map(x => x);
        if (announceChannel == undefined) {
            errMessage += "You must specify an announcement channel\n";
        }
        if (announceList.includes(announceName)) {
            errMessage += "Announcement name is already taken\n";
        }
        if (command[6] == undefined) {
            errMessage += "An announcement must have content\n";
        }
        if (errMessage != "") {
            message.channel.send("SendErr: "+errMessage);
        } else {
            try {
                message.channel.send(setAnnounce(commander));
            } catch {
                message.channel.send("Something went wrong, this might be because you formatted the 'ann' command incorrectly\nSee "+prefix+"help ann <repeat_type> for correct formatting");
            }
        }
    }

    //Sets announcement channel
	else if (command[0] == "set") {
        announceChannel = client.channels.cache.get(message.channel.id);
        announceChannel.send("Announcements Channel set!");
	}

    //Sends UTC date
    else if (command[0] == "date") {
        message.channel.send(Date());
    }

    //Change prefix
    else if (command[0] == "prefix") {
        prefix = command[1];
        client.user.setActivity("Type "+prefix+"help to get bot functions");
        message.channel.send("Predix has been changed to '"+prefix+"'");
    }

    //Lists set announcements
    else if (command[0] == "list") {
        if(announceList.length == 0) {
            message.channel.send("There are no set announcements!");
            break testAnnounce;
        }
        let listString = "";
        for(let i = 0; i < announceList.length; ++i) {
            x = announceList[i];
            listString += x + " ";
        }
        
        message.channel.send(listString.trim() + "\nNote: To view the content and times of announcements, you need to use "+prefix+"view <announcement_name>");
    }

    //Shows set time and content of an announcement
    else if (command[0] == "view") {
        if(!announceList.includes(command[1])) {
            message.channel.send("There is no announcement with that name");
        } else {
            let index = announceList.indexOf(command[1]);
            message.channel.send("Type: " + timeList[index][0] + "\nTime: " + timeList[index][3] + ":" + timeList[index][2] + ":" + timeList[index][1] + "\nContent: " + contentList[index]);
        }
    }

    //Deletes an announcement
    else if (command[0] == "del") {
        if(!announceList.includes(command[1])) {
            message.channel.send("There is no announcement with that name");
        } else {
            delAnnounce(announceList.indexOf(command[1]));
            message.channel.send("Announcement '"+command[1]+"' has been deleted");
        }
    }

    //Sets timezone (number of hours ahead or behind of UTC)
    else if (command[0] == "tz") {
        if (parseInt(command[1]) > 12 || parseInt(command[1]) < -12) {
            message.channel.send("Time shift cannot be greater than 12 or less than -12");
        } else {
            userTz = parseInt(command[1]);
            message.channel.send("Timezone set to "+userTz+" ahead of UTC");
        }
    }

    //About
    else if (command[0] == "about") {
        message.channel.send({
            embed: {
                "title": "About",
                "description": '**Based off a hackathon project\n\nProfile image by [mohamed Hassan](https://pixabay.com/users/mohamed_hassan-5229782/?utm_source=link-attribution&amp;utm_medium=referral&amp;utm_campaign=image&amp;utm_content=2382008) from [Pixabay](https://pixabay.com/?utm_source=link-attribution&amp;utm_medium=referral&amp;utm_campaign=image&amp;utm_content=2382008)**',
                "color": "#8AE7E7",
            }
        });
    }

    //Help
    else if (command[0] == "help") {
        if (command[1] == undefined) {
            message.channel.send({
                embed: {
                    "title": "List of Bot Commands",
                    "description": '**Utility:\nset, ann (once, daily, weekly), date\n\nMisc:\nabout**\n\n' + prefix + '**help <command_name>" to get specific details.**',
                    "color": "#8AE7E7",
                }
            })
        } else if (command[1] == "set") {
            message.channel.send("Sets the announcements channel");
        } else if (command[1] == "date") {
            message.channel.send("Sends the current UTC date and time (or time relative to the bot if self-hosted)");
        } else if (command[1] == "ann") {
            if (command[2] == "once") {
                message.channel.send("Sets an announcement that only runs once to the announcements channel at a certain time\n"+prefix+"ann <announcement_name> once <hour(24)> <minute> <second> <multi-word_message>\ne.g. "+prefix+"ann firstAnnouncement once 18 22 00 hello everyone\nThis will print an announcement that says 'hello everyone' at the next 18:22:00");
            } else if (command[2] == "daily") {
                message.channel.send("Sets a daily announcement to the announcements channel at a certain time\n"+prefix+"ann <announcement_name> once <hour(24)> <minute> <second> <multi-word_message>\ne.g. "+prefix+"ann firstAnnouncement once 18 22 00 hello everyone\nThis will print an announcement that says 'hello everyone' every day at 18:22:00");
            } else if (command[2] == "weekly") {
                message.channel.send("Sets a weekly announcement to the announcements channel at the set time\n"+prefix+"ann <announcement_name> <daynumber (Monday 1, Tuesday 2, ... Sunday 7)> <hour(24)> <minute> <second> <multi-word_message>\ne.g. "+prefix+"announce firstAnnouncement 6 18 22 00 hello everyone\nThis will print an announcement that says 'hello everyone' every Saturday set at 18:22:00");
            //} else if (command[2] == "specific_once") {
                //message.channel.send("Sets an announcement that only runs once at a certain day and time of a year, either once of ");
            } else {
                message.channel.send("Specify repeat type, once, daily, weekly? e.g. "+prefix+"help ann <repeat_type>");
            }
        } else if (command[1] == "prefix") {
            message.channel.send("Changes prefix\n"+prefix+"prefix <new_prefix>\ne.g. "+prefix+"prefix !");
        } else if (command[1] == "list") {
            message.channel.send("Lists all names of set announcements");
        } else if (command[1] == "view") {
            message.channel.send("Shows the repeat type, set time, and content of a specific announcement\n"+prefix+"view <announcement_name>\ne.g."+prefix+"view firstAnnouncement\n This will print the repeat type, set time, and content, respectively");
        } else if (command[1] == "del") {
            message.channel.send("Deletes a specified announcement\n"+prefix+"del <announcement_name>\ne.g."+prefix+"del firstAnnouncement\n This will delete 'firstAnnouncement' and print a confirmation message");
        } else if (command[1] == "tz") {
            message.channel.send("Sets announcements a certain number of hours ahead or behind UTC\n"+prefix+"tz <time_shift(+/- in hours)>\ne.g."+prefix+"tz -1\n This will make all announcements be set at 1 hour before UTC. Note: Previously set announcements will not be affected");
        } else if (command[1] == "about") {
            message.channel.send("Shows extra information about the bot");
        } else {
            message.channel.send("There is no info on that command, it probably doesn't exist");
        }
    }
});

//Using token from .json
client.login(token);