(function() {
    'use strict';

    let messageID = "000000000000000000";

    let authToken = "";
    const channelID = window.location.href.spliat('/').pop(); //Get our channel ID from the current window's URL
    const frame = document.body.appendChild(document.createElement("iframe")); //Create an iframe to get the IDs we need from localStorage
    const cloneLS = JSON.parse(JSON.stringify(frame.contentWindow.localStorage)); //Make a copy of the iframe's localStorage
    frame.parentNode.removeChild(frame); //Remove the iframe now that we no longer need it
    const userID = cloneLS.user_id_cache.replace(/"/g, ""); //Get our user ID from localStorage

    if (authToken === "YOUR_AUTH_TOKEN") { //Check if the auth token was filled in
        if (!cloneLS.hasOwnProperty('token')) { //Check if our auth token exists in localStorage
            window.alert("Failed to retrieve your auth token from localStorage, try pasting it into this script manually.\nInstructions to find your auth token are provided in this script.");
            return; //We don't have any auth token to use so we end the process.
        }
        authToken = cloneLS.token.replace(/"/g, ""); //Get our auth token from localStorage
    }
	console.log("Your Discord account's auth token is:\n" + authToken);

    let msgCount = 0; //Keeps track of how many messages we find
    const interval = 500; //The amount of time to wait in-between deleting messages (default "safe" value is 500)

    let delay = (duration) => {
        return new Promise((resolve, reject) => {
            setTimeout(() => resolve(), duration);
        });
    }

    let clearMessages = () => {
        const baseURL = "https://discordapp.com/api/channels/" + channelID + "/messages";
        const headers = {
            "Authorization": authToken
        };

        let clock = 0;

        window.fetch(baseURL + "?before=" + messageID, {
                headers,
                method: 'GET'
            }) //Fetch the message data from discord
            .then((resp) => resp.json()) //Make it into a json
            .then((messages) => { //Call that json "messages" and do this function with it as the parameter:
                if (typeof messages === "undefined" || !messages.hasOwnProperty('length')) {
                    window.alert("Failed to retrieve messages! Try refreshing the page, then running the script again.");
                    return true;
                } else if (messages.length === 0) {
                    window.alert("All your messages have been deleted!\nTotal Messages Deleted: " + msgCount);
                    return true;
                }
                return Promise.all(messages.map(
                    (message) => { //Call this function for all messages we have
                        messageID = message.id; //Update our message ID
                        if (message.author.id === userID) { //Checks to see if message is yours
                            msgCount++;
                            const msgNumber = msgCount; //Remember the count for this message for logging purposes
                            console.log("Found message #" + msgNumber);
                            return delay(clock += interval)
                                .then(() => {
                                    console.log("Deleting message " + msgNumber + "/" + msgCount);
                                    fetch(`${baseURL}/${message.id}`, {
                                        headers,
                                        method: 'DELETE'
                                    });
                                });
                        } else { //If the message is not yours, we skip it.
                            console.log("Skipped message from other user.");
                            return;
                            //Chrome's console groups up repeated logs. If this prints out 3 times, it'll say:
                            //"(3) Skipped message from other user". You can add a variable to track how many
                            //messages it skips and log the count, but beware it will spam your console log.
                        }
                    }));
            })
            .then((isFinished) => {
                if (isFinished === true) { //Check to see if we are finished deleting messages.
                    return; //We finished deleting all our messages, so we end the process!
                }
                clearMessages(); //Once we've deleted all the messages we can see, we ask for more!
            });
    }
    clearMessages();
})();