express_server.js

const express = require("express");
const PORT = 8080;
const bodyParser = require("body-parser");
const cookieSession = require("cookie-session");
const bcrypt = require("bcrypt");
const app = express();

const { generateRandomString, emailTaken, userIdFromEmail, urlsForUser, userLoggedIn } = require("./helper");
const urlDatabase = {};
const users = {};

app.set("view engine", "ejs");

app.use(bodyParser.urlencoded({extended: true}));

app.use(cookieSession({
  name: 'session',
  keys: ['MUAHAHAHA'],
  maxAge: 24 * 60 * 60 * 1000,
}));


// GET request response routes
// if there is an active session redirect to urls, else to login
app.get("/", (req, res) => {
  if (userLoggedIn(req.session.user_id, users)) {
    res.redirect("/urls");
  } else {
    res.redirect("/login");
  }
});
// main page, show the user their urls
app.get("/urls", (req, res) => {
  let templateVars = {
    urls: urlsForUser(req.session.user_id, urlDatabase),
    user: users[req.session.user_id],
  };
  res.render("urls_index", templateVars);
});
// create a new short url
app.get("/urls/new", (req, res) => {
  if (!userLoggedIn(req.session.user_id, users)) {
    res.redirect("/login");
  } else {
    let templateVars = {
      user: users[req.session.user_id],
    };
    res.render("urls_new", templateVars);
  }
});
// register
app.get("/register", (req, res) => {
  if (userLoggedIn(req.session.user_id, users)) {
    res.redirect("/urls");
  } else {
    let templateVars = {
      user: users[req.session.user_id],
    };
    res.render("urls_register", templateVars);
  }
});
// login
app.get("/login", (req, res) => {
  if (userLoggedIn(req.session.user_id, users)) {
    res.redirect("/urls");
  } else {
    let templateVars = {
      user: users[req.session.user_id],
    };
    res.render("urls_login", templateVars);
  }
});

app.get("/urls/:shortURL", (req, res) => {
  if (urlDatabase[req.params.shortURL]) {
    let templateVars = {
      shortURL: req.params.shortURL,
      longURL: urlDatabase[req.params.shortURL].longURL,
      urlUserID: urlDatabase[req.params.shortURL].userID,
      user: users[req.session.user_id],
    };
    res.render("urls_show", templateVars);
  } else {
    res.status(404).send("This short url is not in the database.");
  }
});

app.get("/u/:shortURL", (req, res) => {
  if (urlDatabase[req.params.shortURL]) {
    const longURL = urlDatabase[req.params.shortURL].longURL;
    if (longURL === undefined) {
      res.status(302);
    } else {
      res.redirect(longURL);
    }
  } else {
    res.status(404).send("This short URL does not correspond with a long URL.");
  }
});

// POST request response routes

app.post("/urls", (req, res) => {
  if (req.session.user_id) {
    const shortURL = generateRandomString();
    urlDatabase[shortURL] = {
      longURL: req.body.longURL,
      userID: req.session.user_id,
    };
    res.redirect(`/urls/${shortURL}`);
  } else {
    res.status(401).send("Unauthorized, please login or register to perform action.");
  }
});
// performing necessary checks and registering a new user
app.post("/register", (req, res) => {
  const newUserEmail = req.body.email;
  const newUserPassword = req.body.password;

  if (!newUserEmail || !newUserPassword) {
    res.status(400).send("Invalid credentials, you must enter an email address and a password.");
  } else if (emailTaken(newUserEmail, users)) {
    res.status(400).send("An account already exists for this email address");
  } else {
    const newUserID = generateRandomString();
    users[newUserID] = {
      id: newUserID,
      email: newUserEmail,
      password: bcrypt.hashSync(newUserPassword, 10),
    };
    req.session.user_id = newUserID;
    res.redirect("/urls");
  }
});

app.post("/login", (req, res) => {
  const email = req.body.email;
  const password = req.body.password;

  if (!emailTaken(email, users)) {
    res.status(403).send("There's no account associated with this email address");
  } else {
    const userID = userIdFromEmail(email, users);
    if (!bcrypt.compareSync(password, users[userID].password)) {
      res.status(403).send("Invalid password.");
    } else {
      req.session.user_id = userID;
      res.redirect("/urls");
    }
  }
});

app.post("/logout", (req, res) => {
  req.session = null;
  res.redirect('/urls');
});
// delete short urls
app.post("/urls/:shortURL/delete", (req, res) => {
  const userID = req.session.user_id;
  const userUrls = urlsForUser(userID, urlDatabase);
  if (Object.keys(userUrls).includes(req.params.shortURL)) {
    const shortURL = req.params.shortURL;
    delete urlDatabase[shortURL];
    res.redirect('/urls');
  } else {
    res.status(401).send("Unauthorized.");
  }
});

app.post("/urls/:id", (req, res) => {
  const userID = req.session.user_id;
  const userUrls = urlsForUser(userID, urlDatabase);
  if (Object.keys(userUrls).includes(req.params.id)) {
    const shortURL = req.params.id;
    urlDatabase[shortURL].longURL = req.body.newURL;
    res.redirect('/urls');
  } else {
    res.status(401).send("Unauthorized.");
  }
});

app.listen(PORT, () => {
  console.log(`Example app listening on port ${PORT}!`);
});