dbManager.mongodb.js

const crypto = require('./crypto');
const MongoDB = require('mongodb');
const ObjectId = require('mongodb').ObjectId
const MongoClient = MongoDB.MongoClient;
const url = 'mongodb+srv://kezhao:Zhaoke328@cluster0.2zapp.mongodb.net/myFirstDatabase?retryWrites=true&w=majority';

//mongodb+srv://' + process.env.DB_USER + ':' + process.env.DB_PASS + '@a3.8ty2i.mongodb.net/myFirstDatabase?retryWrites=true&w=majority
const client = new MongoClient(url, { useNewUrlParser: true, useUnifiedTopology: true });

const connectClient = function () {
    return new Promise(resolve => {
        resolve(client.connect())
    })
};

const DB = function () {
    return new Promise(resolve =>
        connectClient().then(client => resolve(client.db('Scheduler')))
    );
};

// DB().then(db => {
//     db.createCollection('content');
//     db.createCollection('users');
// });


const ContentCollection = function () {
    return new Promise(resolve =>
        DB().then(db =>
            resolve(db.collection('content'))));
};

const UsersCollection = function () {
    return new Promise(resolve =>
        DB().then(db =>
            resolve(db.collection('users'))));
};


exports.getAllContent = function () {
    return new Promise(resolve => {
        ContentCollection().then(collection => {
            collection.find().sort({ artist: 1 }).toArray().then(data => resolve(data));
        });
    })
};

exports.getContentForUser = function (user) {
    return new Promise(resolve => {
        ContentCollection().then(collection => {
            collection.find({ username: user.username }).sort({ artist: 1 }).toArray().then(data => resolve(data));
        });
    })
};

exports.getContentById = function (_id) {
    return new Promise(resolve => {
        ContentCollection().then(collection => {
            collection.find({ _id: ObjectId(_id) }).toArray().then(data => resolve(data));
        });
    })
};

exports.getContectByInfo = function (title, artist) {
    return new Promise(resolve => {
        ContentCollection().then(collection => {
            collection.find({title: title, artist: artist}).toArray().then(data => resolve(data))
        });
    })
};

exports.addOrUpdateContent = function (user, title, artist, coverart, comments, id) {
    return new Promise(resolve => {
        if (id === undefined || id === '') {
            console.log("Adding ", title, " by ", artist, " for ", user.username);
            ContentCollection().then(collection => collection.insertOne({
                username: user.username,
                title: title,
                artist: artist,
                coverart: coverart,
                comments: []
            })).then(result => resolve(result));
        } else {
            console.log('Updating content ', id);
            ContentCollection().then(collection => collection.updateOne({ _id: ObjectId(id) }, {
                $set: {
                    title: title,
                    artist: artist,
                    coverart: coverart,
                    comments: comments
                }
            })).then(result => resolve(result));
        }
    })
};

exports.deleteContent = function (user, contentID) {
    return new Promise(resolve =>
        ContentCollection().then(collection => collection.deleteOne({ _id: ObjectId(contentID) })
            .then(result => resolve(result))))
};

exports.checkPass = function (username, password) {
    return new Promise((resolve, reject) => {
        this.getUser(username).then(user => {
            console.log("CHECK PASS: Got user document for " + username + ": " + user);
            if (user !== null && crypto.compareString(user.password, password)) resolve(user);
            else reject();
        }).catch(() => reject());
    });
};

exports.getUser = function (username) {
    return new Promise((resolve, reject) => {
        UsersCollection().then(collection =>
            collection.findOne({ username: username }).then(user => {
                console.log("GET USER: Got user document for " + username + ": " + user);
                resolve(user);
                if (user === null) reject("User not found!");
            }).catch(error => reject(error))
        );
    })
};

exports.CreateUser = function (username, displayName, password) {
    return new Promise((resolve, reject) => {
        UsersCollection().then(collection => {
            collection.findOne({ username: username }).then(data => {
                if (data === null) {
                    console.log("Creating User: ", username, " with password: ", password);
                    let passHash = crypto.encrypt(password);
                    collection.insertOne({
                        username: username,
                        displayName: displayName,
                        password: passHash
                    }).catch(error => reject(error));
                    resolve("Account created successfully.");
                }
                reject("Username is taken.");
            }
            )
        });
    });
};