const express = require("express");
const app = express();
const methodOverride = require("method-override");
const morgan = require("morgan");
const bodyParser = require("body-parser");
const passport = require("passport");
const findOrCreate = require("mongoose-findorcreate");
const FacebookStrategy = require("passport-facebook").Strategy;
const mongoose = require("mongoose");
const session = require("cookie-session");
const flash = require("connect-flash");
mongoose.Promise = Promise;

app.set("view engine", "pug");
app.use(express.static(__dirname + "/public"));
app.use(morgan("tiny"));
app.use(bodyParser.urlencoded({ extended: true }));
app.use(methodOverride("_method"));

app.use(session({ secret: process.env.SECRET_KEY }));
app.use(passport.initialize());
app.use(passport.session());
app.use(flash());

// Redirect the user to Facebook for authentication.  When complete,
// Facebook will redirect the user back to the application at
//     /auth/facebook/callback
app.get("/auth/facebook", passport.authenticate("facebook"));

// Facebook will redirect the user to this URL after approval.  Finish the
// authentication process by attempting to obtain an access token.  If
// access was granted, the user will be logged in.  Otherwise,
// authentication has failed.
app.get(
  "/auth/facebook/callback",
  passport.authenticate("facebook", {
    successRedirect: "/",
    failureRedirect: "/login"
  })
);

app.get("/", (req, res, next) => {
  // send the authenticated user
  res.send(req.user);
});

app.get("/logout", (req, res, next) => {
  // send the authenticated user
  req.logout();
  res.redirect("/");
});

var userSchema = new mongoose.Schema({
  facebook_id: String
});

userSchema.plugin(findOrCreate); // give us a findOrCreate method!

var User = mongoose.model("User", userSchema);

// instead of a username and password we will be using information that Facebook has given us when we create an application with them
passport.use(
  new FacebookStrategy(
    {
      // these should ALL be values coming from a .env file
      clientID: process.env.FACEBOOK_APP_ID,
      clientSecret: process.env.FACEBOOK_APP_SECRET,
      // when you deploy your application you can add an environment variable for CALLBACK_URL, right now let's stick with localhost:3000/auth/facebook/callback
      callbackURL:
        process.env.CALLBACK_URL ||
        "http://localhost:3000/auth/facebook/callback"
    },
    // in the verify callback we will get an accessToken to make authenticated requests on the users behalf along with a refreshToken which is used in some authentication strategies to refresh an expired accessToken. We also are given an object called "profile" which has data on the authenticated user
    (accessToken, refreshToken, profile, done) => {
      User.findOrCreate({ facebook_id: profile.id }, (err, user) => {
        if (err) done(err);
        done(null, user);
      });
    }
  )
);

// same process as before:
passport.serializeUser((user, done) => {
  done(null, user.id);
});

// same process as before:
passport.deserializeUser((id, done) => {
  User.findById(id, (err, user) => {
    done(err, user);
  });
});

app.listen(3000, () => {
  console.log("Server is listening on port 3000");
});