helper.js

//helper functions
const fs = require('fs');
const https = require('https');

/**Returns Canvas access token based on Discord ID: goes through JSON file containing pairs
*@param {string} id - User's Discord ID
*/
function getUserToken(id){
    const data = fs.readFileSync('tokens.json', 'utf8');
    var objs = JSON.parse(data);
    return objs[id];
}

/**Checks if the user has a registered access token. Returns true or false.
*@param {string} id - User's Discord ID
*/
function userRegistered(id){
    const data = fs.readFileSync('tokens.json', 'utf8');
    var objs = JSON.parse(data);
    if (objs[id] == undefined)
        return false;
    return true;
}
/**
 * Gets the HTTPS Response from the page, and returns the parsed JSON.
 * Uses callbacks. Try to use the one with promises
 * @param {string} url 
 * @param {function} callback
 */
function httpsGetJSON (url, callback){
    https.get(url, "JSON", function (response) {

        var data;
        response.on('data', function (chunk) {
            if (!data) {
                data = chunk;
            }
            else {
                data += chunk;
            }
        });
        response.on("end", function () {
            data = JSON.parse(data);
            callback(data);
        });

    }).on('error', (e) => {
        console.error(e);
        });
}

/**
 * Gets the HTTPS Response from the page, and returns a promise of the parsed JSON.
 * Uses promises instead of callbacks
 * @param {string} url 
 */
function httpsGetJSON2(url){
    let dataPromise = new Promise((resolve, reject) => {
        https.get(url, "JSON", function (response) {
            var data;
            response.on('data', function (chunk) {
                if (!data) {
                    data = chunk;
                }
                else {
                    data += chunk;
                }
            });
            response.on("end", function () {
                data = JSON.parse(data);
                resolve(data); //sucess, return the data
            });

        }).on('error', (e) => {
            console.error(e);
            reject(e); //error, reject
            });
    });
    //return the promise of the data
    return dataPromise;
}
/**
 * Store the user's course ID's along with their name per user.
 * This is done to reduce the total number of calls to the API.
 * @param {string} filename - where to store the courses
 * @param {string} id - the user's Discord ID
 * @param {JSON} courses - a JSON object of the user's courseID's and courseNames
 */
function storeUserCourses(id, courses){
    //create file if it does not exist
    if(!fs.existsSync('userCourses.json'))  {
        fs.writeFileSync('userCourses.json', "{}", (err) => {
            if (err) console.log("err");
            console.log('User courses file successfully created')
        })
    }

    //console.log(id);

    const data = fs.readFileSync('userCourses.json');

    let objs = JSON.parse(data);
    //console.log(objs);

    objs[id] = courses;
    //console.log("in: ");
    //console.log(objs);

    fs.writeFileSync('userCourses.json', JSON.stringify(objs));

    //1. Read JSON file into JS object
    //2. Append the courses into the object
    //3. Write back to JSON file
    /*fs.readFileSync('userCourses.json', function(err, data) {
        if (err) throw err;
    
        console.log("yo we good");
        let objs = JSON.parse(data);
        objs[id] = courses;
        console.log("yo we good");
    
        fs.writeFileSync('userCourses.json', JSON.stringify(objs), 'utf-8', function(err) {
            if (err) throw err;
        })
    });*/
    //console.log("done")

}

/**
 * Get the user's stored courses based on their id
 * Returns an object containing a list of courseID's and names.
 * @param {string} id s
 */
function getUserCourses(id){
    
    const data = fs.readFileSync('userCourses.json', 'utf8');
    const userData = JSON.parse(data)[id];
    //console.log("out: ");
    //console.log(userData);
    /*for (key in betterData){
        console.log(key + " == " + betterData[key]);
    }*/
    return userData;
}

///Returns a readable string based on a date.
//example date format: 2020-11-03T05:59:59Z
function parseDate (date){

    //get parts of date and time
    var year = date.substring(0, 4);
    var month = date.substring(5, 7) - 1;
    var day = date.substring(8, 10);

    var time = date.substring(11, 19);
    var hour = time.substring(0, 2);
    var minute = time.substring(3, 5);
    var second = time.substring(6);

    //create date and subtract for correct time zone
    var d = new Date(year, month, day, hour, minute, second);
    d.setHours(d.getHours() - 6);

    //console.log(d.toString());
    //console.log(year + " " + month + " " + day + " " + hour + " " + minute + " " + second + "\n");

    return d.toString();
}

///Returns true if the date input is in the future from now
function dateInFuture (date) {
    var now = new Date();

    //get parts of date and time
    var year = date.substring(0, 4);
    var month = date.substring(5, 7) - 1;
    var day = date.substring(8, 10);

    var time = date.substring(11, 19);
    var hour = time.substring(0, 2);
    var minute = time.substring(3, 5);
    var second = time.substring(6);

    //create date
    var inputDate = new Date(year, month, day, hour, minute, second);

    //compare date
    if (inputDate > now)
        return true;
    return false;
}

/**
 * Returns true if {dueDate} is {days} {hours} and {minutes} away from today's date.
 * @param {*} dueDate - date the assignment is due
 * @param {int} days - is todays days this many days away from the due date?
 * @param {int} hours - hours?
 * @param {int} minutes - minutes?
 * @param {int} interval - how many minutes between each check
 */
function isDue(dueDate, days, hours, minutes, interval){

    var now = new Date();

    var year = dueDate.substring(0, 4);
    var month = dueDate.substring(5, 7) - 1;
    var day = dueDate.substring(8, 10);

    var time = dueDate.substring(11, 19);
    var hour = time.substring(0, 2);
    var minute = time.substring(3, 5);
    var second = time.substring(6);
    
    var future = new Date(year, month, day, hour, minute, second);

    const diffTime = Math.abs(future - now);
    const diffDays = Math.floor(diffTime / (1000 * 60 * 60 * 24)); 
    const diffHours = Math.floor(diffTime / (1000 * 60 * 60)) - (24 * diffDays); 
    const diffMins = Math.floor(diffTime / (1000 * 60)) - (60 * diffHours); 
    /*console.log(diffTime + " milliseconds");
    console.log(diffDays + " days");
    console.log(diffHours + " hours");
    console.log(diffMins + " mins");*/

    /*console.log(diff.getDate());
    console.log(diff.getHours());
    console.log(diff.getMinutes());
    console.log(diff.toString())*/

    if (diffDays == days && diffHours== hours && diffMins >= minutes && diffMins <= minutes + interval)
        return true;
    return false;
    


}

module.exports = { getUserToken, userRegistered, httpsGetJSON, httpsGetJSON2, storeUserCourses, getUserCourses, parseDate, dateInFuture, isDue };