passport.js

var _ = require('lodash'),
    passport = require('passport'),
    LocalStrategy = require('passport-local').Strategy,
    FacebookStrategy = require('passport-facebook').Strategy,
    TwitterStrategy = require('passport-twitter').Strategy,
    GitHubStrategy = require('passport-github').Strategy,
    GoogleStrategy = require('passport-google-oauth').OAuth2Strategy,
    LinkedInStrategy = require('passport-linkedin-oauth2').Strategy,
    // OAuthStrategy = require('passport-oauth').OAuthStrategy,
    // OAuth2Strategy = require('passport-oauth').OAuth2Strategy,
    User = require('../common/models/User'),
    nodemailer = require('nodemailer'),
    secrets = require('./secrets');


passport.serializeUser(function(user, done) {
  done(null, user.id);
});

passport.deserializeUser(function(id, done) {
  User.findById(id, function(err, user) {
    done(err, user);
  });
});

// Sign in using Email and Password.

passport.use(new LocalStrategy({ usernameField: 'email' }, function(email, password, done) {
  User.findOne({ email: email }, function(err, user) {
    if (err) { return done(err); }
    if (!user) return done(null, false, { message: 'Email ' + email + ' not found'});
    user.comparePassword(password, function(err, isMatch) {
      if (isMatch) {
        return done(null, user);
      } else {
        return done(null, false, { message: 'Invalid email or password.' });
      }
    });
  });
}));

/**
 * OAuth Strategy Overview
 *
 * - User is already logged in.
 *   - Check if there is an existing account with a <provider> id.
 *     - If there is, return an error message. (Account merging not supported)
 *     - Else link new OAuth account with currently logged-in user.
 * - User is not logged in.
 *   - Check if it's a returning user.
 *     - If returning user, sign in and we are done.
 *     - Else check if there is an existing account with user's email.
 *       - If there is, return an error message.
 *       - Else create a new account.
 */

// Sign in with Facebook.

passport.use(new FacebookStrategy(secrets.facebook, function(req, accessToken, refreshToken, profile, done) {
  if (req.user) {
    User.findOne({ facebook: profile.id }, function(err, existingUser) {
      if (existingUser) {
        req.flash('errors', { msg: 'There is already a Facebook account that belongs to you. Sign in with that account or delete it, then link it with your current account.' });
        done();
      } else {
        User.findById(req.user.id, function(err, user) {
          if (err) { return done(err); }
          user.facebook = profile.id;
          user.tokens.push({ kind: 'facebook', accessToken: accessToken });
          user.name = user.name || profile.displayName;
          user.gender = user.gender || profile._json.gender;
          user.picture = user.picture || 'https://s3.amazonaws.com/freecodecamp/camper-image-placeholder.png';
          user.save(function(err) {
            if (err) { return done(err); }
            req.flash('info', { msg: 'Facebook account has been linked.' });
            done(null, user);
          });
        });
      }
    });
  } else {
    User.findOne({ facebook: profile.id }, function(err, existingUser) {
      if (existingUser) return done(null, existingUser);
      User.findOne({ email: profile._json.email }, function(err, existingEmailUser) {
        if (err) { return done(err); }
        if (existingEmailUser) {
          req.flash('errors', { msg: 'There is already an account using this email address. Sign in to that account and link it with Facebook manually from Account Settings.' });
          done();
        } else {
          var user = new User();
          user.email = profile._json.email;
          user.facebook = profile.id;
          user.tokens.push({ kind: 'facebook', accessToken: accessToken });
          user.name = profile.displayName;
          user.gender = profile._json.gender;
          user.picture = 'https://graph.facebook.com/' + profile.id + '/picture?type=large';
          user.location = (profile._json.location) ? profile._json.location.name : '';
          user.save(function(err) {
            done(err, user);
            var transporter = nodemailer.createTransport({
              service: 'Mandrill',
              auth: {
                user: secrets.mandrill.user,
                pass: secrets.mandrill.password
              }
            });
            var mailOptions = {
              to: user.email,
              from: 'Team@freecodecamp.com',
              subject: 'Welcome to Free Code Camp!',
              text: [
                'Greetings from San Francisco!\n\n',
                'Thank you for joining our community.\n',
                'Feel free to email us at this address if you have any questions about Free Code Camp.\n',
                "And if you have a moment, check out our blog: blog.freecodecamp.com.\n",
                'Good luck with the challenges!\n\n',
                '- the Free Code Camp Volunteer Team'
              ].join('')
            };
            transporter.sendMail(mailOptions, function(err) {
              if (err) { return err; }
            });
          });
        }
      });
    });
  }
}));

// Sign in with GitHub.

passport.use(new GitHubStrategy(secrets.github, function(req, accessToken, refreshToken, profile, done) {
  if (req.user) {
    User.findOne({ github: profile.id }, function(err, existingUser) {
      if (err) { return done(err); }
      if (existingUser) {
        req.flash('errors', { msg: 'There is already a GitHub account that belongs to you. Sign in with that account or delete it, then link it with your current account.' });
        done();
      } else {
        User.findById(req.user.id, function(err, user) {
          user.github = profile.id;
          user.tokens.push({ kind: 'github', accessToken: accessToken });
          user.name = user.name || profile.displayName;
          user.picture = user.picture || profile._json.avatar_url;
          user.location = user.location || profile._json.location;
          user.website = user.website || profile._json.blog;
          user.save(function(err) {
            if (err) { return done(err); }
            req.flash('info', { msg: 'GitHub account has been linked.' });
            done(null, user);
          });
        });
      }
    });
  } else {
    User.findOne({ github: profile.id }, function(err, existingUser) {
      if (err) { return done(err); }
      if (existingUser) return done(null, existingUser);
      User.findOne({ email: profile._json.email }, function(err, existingEmailUser) {
        if (err) { return done(err); }
        if (existingEmailUser) {
          req.flash('errors', { msg: 'There is already an account using this email address. Sign in to that account and link it with GitHub manually from Account Settings.' });
          done(null);
        } else {
          var user = new User();
          user.email = profile._json.email;
          user.github = profile.id;
          user.tokens.push({ kind: 'github', accessToken: accessToken });
          user.name = profile.displayName;
          user.picture = profile._json.avatar_url;
          user.location = profile._json.location;
          user.website = profile._json.blog;
          user.save(function(err) {
            if (err) { return done(err); }
            var transporter = nodemailer.createTransport({
              service: 'Mandrill',
              auth: {
                user: secrets.mandrill.user,
                pass: secrets.mandrill.password
              }
            });
            var mailOptions = {
              to: user.email,
              from: 'Team@freecodecamp.com',
              subject: 'Welcome to Free Code Camp!',
              text: [
                'Greetings from San Francisco!\n\n',
                'Thank you for joining our community.\n',
                'Feel free to email us at this address if you have any questions about Free Code Camp.\n',
                "And if you have a moment, check out our blog: blog.freecodecamp.com.\n",
                'Good luck with the challenges!\n\n',
                '- the Free Code Camp Volunteer Team'
              ].join('')
            };
            transporter.sendMail(mailOptions, function(err) {
              if (err) { return done(err); }
              done(null, user);
            });
          });
        }
      });
    });
  }
}));

// Sign in with Twitter.

passport.use(new TwitterStrategy(secrets.twitter, function(req, accessToken, tokenSecret, profile, done) {
  if (req.user) {
    User.findOne({ twitter: profile.id }, function(err, existingUser) {
      if (err) { return done(err); }
      if (existingUser) {
        req.flash('errors', { msg: 'There is already a Twitter account that belongs to you. Sign in with that account or delete it, then link it with your current account.' });
        done();
      } else {
        User.findById(req.user.id, function(err, user) {
          user.twitter = profile.id;
          user.tokens.push({ kind: 'twitter', accessToken: accessToken, tokenSecret: tokenSecret });
          user.username = user.username || profile.username.toLowerCase();
          user.name = user.name || profile.displayName;
          user.location = user.location || profile._json.location;
          user.picture = user.picture || profile._json.profile_image_url_https.replace('_normal', '');
          user.twitterHandle = user.twitterHandle || profile.username.toLowerCase();
          user.save(function(err) {
            if (err) { return done(err); }
            req.flash('info', { msg: 'Twitter account has been linked.' });
            done(null, user);
          });
        });
      }
    });

  } else {
    User.findOne({ twitter: profile.id }, function(err, existingUser) {
      if (err) { return done(err); }
      if (existingUser) return done(null, existingUser);
      var user = new User();
      user.username = profile.username.toLowerCase();
      user.twitter = profile.id;
      user.tokens.push({ kind: 'twitter', accessToken: accessToken, tokenSecret: tokenSecret });
      user.name = profile.displayName;
      user.location = profile._json.location;
      user.picture = profile._json.profile_image_url_https.replace('_normal', '');
      user.twitterHandle = user.twitterHandle || profile.username.toLowerCase();
      user.save(function(err) {
        if (err) { return done(err); }
        done(null, user);
      });
    });
  }
}));

// Sign in with Google.

passport.use(new GoogleStrategy(secrets.google, function(req, accessToken, refreshToken, profile, done) {
  if (req.user) {
    User.findOne({ google: profile.id }, function(err, existingUser) {
      if (err) { return done(err); }
      if (existingUser) {
        req.flash('errors', { msg: 'There is already a Google account that belongs to you. Sign in with that account or delete it, then link it with your current account.' });
        done();
      } else {
        User.findById(req.user.id, function(err, user) {
          if (err) { return done(err); }
          user.google = profile.id;
          user.tokens.push({ kind: 'google', accessToken: accessToken });
          user.name = user.name || profile.displayName;
          user.gender = user.gender || profile._json.gender;
          user.picture = user.picture || profile._json.picture;
          user.save(function(err) {
            if (err) { return done(err); }
            req.flash('info', { msg: 'Google account has been linked.' });
            done(null, user);
          });
        });
      }
    });
  } else {
    User.findOne({ google: profile.id }, function(err, existingUser) {
      if (err) { return done(err); }
      if (existingUser) return done(null, existingUser);
      User.findOne({ email: profile._json.email }, function(err, existingEmailUser) {
        if (err) { return done(err); }
        if (existingEmailUser) {
          req.flash('errors', { msg: 'There is already an account using this email address. Sign in to that account and link it with Google manually from Account Settings.' });
          done();
        } else {
          var user = new User();
          user.email = profile._json.email;
          user.google = profile.id;
          user.tokens.push({ kind: 'google', accessToken: accessToken });
          user.name = profile.displayName;
          user.gender = profile._json.gender;
          user.picture = profile._json.picture;
          user.save(function(err) {
            if (err) { return done(err); }
            var transporter = nodemailer.createTransport({
              service: 'Mandrill',
              auth: {
                user: secrets.mandrill.user,
                pass: secrets.mandrill.password
              }
            });
            var mailOptions = {
              to: user.email,
              from: 'Team@freecodecamp.com',
              subject: 'Welcome to Free Code Camp!',
              text: [
                'Greetings from San Francisco!\n\n',
                'Thank you for joining our community.\n',
                'Feel free to email us at this address if you have any questions about Free Code Camp.\n',
                "And if you have a moment, check out our blog: blog.freecodecamp.com.\n",
                'Good luck with the challenges!\n\n',
                '- the Free Code Camp Volunteer Team'
              ].join('')
            };
            transporter.sendMail(mailOptions, function(err) {
              if (err) { return err; }
              done(null, user);
            });
          });
        }
      });
    });
  }
}));

// Sign in with LinkedIn.

passport.use(new LinkedInStrategy(secrets.linkedin, function(req, accessToken, refreshToken, profile, done) {
  if (req.user) {
    User.findOne({ linkedin: profile.id }, function(err, existingUser) {
      if (err) { return done(err); }
      if (existingUser) {
        req.flash('errors', { msg: 'There is already a LinkedIn account that belongs to you. Sign in with that account or delete it, then link it with your current account.' });
        done();
      } else {
        User.findById(req.user.id, function(err, user) {
          if (err) { return done(err); }
          user.linkedin = profile.id;
          user.tokens.push({ kind: 'linkedin', accessToken: accessToken });
          user.name = user.name || profile.displayName;
          user.location = user.location || profile._json.location.name;
          user.picture = user.picture || profile._json.pictureUrl;
          user.website = user.website || profile._json.publicProfileUrl;
          user.save(function(err) {
            if (err) { return done(err); }
            req.flash('info', { msg: 'LinkedIn account has been linked.' });
            done(null, user);
          });
        });
      }
    });
  } else {
    User.findOne({ linkedin: profile.id }, function(err, existingUser) {
      if (existingUser) return done(null, existingUser);
      User.findOne({ email: profile._json.emailAddress }, function(err, existingEmailUser) {
        if (err) { return done(err); }
        if (existingEmailUser) {
          req.flash('errors', { msg: 'There is already an account using this email address. Sign in to that account and link it with LinkedIn manually from Account Settings.' });
          done();
        } else {
          var user = new User();
          user.linkedin = profile.id;
          user.tokens.push({ kind: 'linkedin', accessToken: accessToken });
          user.email = profile._json.emailAddress;
          user.name = profile.displayName;
          user.location = profile._json.location.name;
          user.picture = profile._json.pictureUrl;
          user.website = profile._json.publicProfileUrl;
          user.save(function(err) {
            if (err) { return done(err); }
            var transporter = nodemailer.createTransport({
              service: 'Mandrill',
              auth: {
                user: secrets.mandrill.user,
                pass: secrets.mandrill.password
              }
            });
            var mailOptions = {
              to: user.email,
              from: 'Team@freecodecamp.com',
              subject: 'Welcome to Free Code Camp!',
              text: [
                'Greetings from San Francisco!\n\n',
                'Thank you for joining our community.\n',
                'Feel free to email us at this address if you have any questions about Free Code Camp.\n',
                "And if you have a moment, check out our blog: blog.freecodecamp.com.\n",
                'Good luck with the challenges!\n\n',
                '- the Free Code Camp Volunteer Team'
              ].join('')
            };
            transporter.sendMail(mailOptions, function(err) {
              if (err) { return err; }
              done(null, user);
            });
          });
        }
      });
    });
  }
}));

// Login Required middleware.

exports.isAuthenticated = function(req, res, next) {
  if (req.isAuthenticated()) { return next(); }
  res.redirect('/login');
};

// Authorization Required middleware.

exports.isAuthorized = function(req, res, next) {
  var provider = req.path.split('/').slice(-1)[0];

  if (_.find(req.user.tokens, { kind: provider })) {
    next();
  } else {
    res.redirect('/auth/' + provider);
  }
};