Update

const express = require("express");
const app = express();
const sqlite = require("sqlite3").verbose();
const db = new sqlite.Database("databases/db");
const port = process.env.PORT || 5000;;
var command;
var activeUser;//Data base of the user
db.serialize(() => {
    //db.run("drop table Users");
    db.run("Create table if not exists Users(user text, email text, password text)");//Later i need to create more attributes
})

//static page

const path = require("path");
app.use(express.static(path.resolve(__dirname,"build")))

app.get("/", (req, res) => {
    res.send(path.resolve(__dirname,"build", "index.html"))
})


app.get("/home", (req, res) => {
    res.send("Home");
})

app.get("/RegisterUser", (req, res) => {
    const { user, email, password } = req.query;
    activeData = user + "Homework";
    db.get("Select user id from Users where user = ?", user, (err, value) => {
        /*console.log("ID: " + value)
        if (value != undefined) {
            console.log("The user already exists: " + value.id);
        } else {
            console.log("The user dont exists: ")
        }*/
        console.log(value);
        res.send({data: value === undefined? undefined: value.id});//value
    });


    command = db.prepare("Insert into Users values(?,?,?)");
    command.run(user, email, password);
    command.finalize();
    createTableUser(user);
})

app.get("/Loggin", (req, res) => {
    const { user, password } = req.query;
    activeUser = user;
    var bool = false;
    db.get("Select user id, password pass from Users where user = ?", user, (err, value) => {
        if(value != undefined)
        {
            //Exists
            if(value.pass === password)
            {
                console.log("The user " + user + " now is logged")
                bool = true;
            }
        }
        res.send({data:bool});

    });
})

app.get("/Users", (req, res) => {
    db.all("Select * from Users", (err, all) => {
        res.send({ data: all })
    })
    db.each("Select * from Users", (err, v) => {
        console.log(v)
    })
})



function createTableUser(user) {
    db.serialize(() => {
        db.run("Create table if not exists "+user+"Homework(id text,subject text,shortDescription text, description text, date text, dificulty int, time int, total int, done int)");
        db.run("Create table if not exists "+user+"HomeworkCompletes(id text,subject text,shortDescription text, description text, date text, dificulty int, time int, total int, done int)");
    })
}

app.get("/homeworks", (req, res) => {
    db.all("select * from "+activeUser+"Homework order by total desc", (err, all) => {
        res.send({ data: all });
    })
})

app.get("/homeworksCompletes", (req, res) => {
    db.all("select * from "+activeUser+"HomeworkCompletes", (err, all) => {
        res.send({ data: all });
    })
})


app.get("/homeworks/deleteTable", (req, res) => {
    db.run("drop table "+activeUser+"Homework");
    db.run("Create table if not exists "+activeUser+"Homework(id text,subject text,shortDescription text, description text, date text, dificulty int, time int, total int, done int)");
    db.run("Create table if not exists "+activeUser+"HomeworkCompletes(id text,subject text,shortDescription text, description text, date text)");
    res.send("Table deleted");
    console.log("Main tables has been deleted");
})

app.get("/homeworks/add", (req, res) => {
    const { id, subject, shortDescription, description, date, dificulty, time, total } = req.query;
    command = db.prepare("Insert into "+activeUser+"Homework values(?,?,?,?,?,?,?,?,?)");
    command.run(id, subject, shortDescription, description, date, dificulty, time, total, 0);
    command.finalize();
    res.send("Homework added");
    console.log("Homework added")
});

app.get("/homeworks/homeworkDone", (req, res) => {
    const { id } = req.query;
    db.run("Update "+activeUser+"Homework set done = 1 where id = '" + id + "'");
    db.run("Insert into "+activeUser+"HomeworkCompletes select * from "+activeUser+"Homework where id = '" + id + "'");
    db.run("Delete from "+activeUser+"Homework where id = '" + id + "'");
    res.send("Homework done added");
    console.log("Homework " + id + " has been done")
})

app.get("/homeworks/deleteHomework", (req, res) => {
    const { homeworkID, complete } = req.query;
    console.log("The id to delete is: " + homeworkID);
    if (complete === "y") {
        //I mean, if I came from the Completes Page
        db.run("delete from "+activeUser+"HomeworkCompletes where id = '" + homeworkID + "'");
    } else {
        db.run("delete from "+activeUser+"Homework where id = '" + homeworkID + "'");
    }
    res.send("Homework deleted");
})



app.listen(port, () => console.log("Listen on port " + port));