const fs = require('fs');
const SamlStrategy = require('passport-saml').Strategy;
const dbconn = require('./dbconn');
const methods = require('./methods');
// pwd encryption
const bcrypt = require('bcryptjs');
const saltRounds = 10;
// forgot pwd
const async = require('async');
const crypto = require('crypto');
const nodemailer = require('nodemailer');

module.exports = function (app, config, passport) {

  // =========== PASSPORT =======
  passport.serializeUser(function (user, done) {
    done(null, user);
  });

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

  var samlStrategy = new SamlStrategy({
      // URL that goes from the Identity Provider -> Service Provider
      callbackUrl: config.passport.saml.path,
      // Base address to call logout requests
      logoutUrl: config.passport.saml.logoutUrl,
      
      entryPoint: config.passport.saml.entryPoint,
      issuer: config.passport.saml.issuer,
      identifierFormat: null,
      
      // Service Provider private key
      decryptionPvk: fs.readFileSync(__dirname + '/cert/key.pem', 'utf8'),
      // Service Provider Certificate
      privateCert: fs.readFileSync(__dirname + '/cert/key.pem', 'utf8'),
      // Identity Provider's public key
      cert: fs.readFileSync(__dirname + '/cert/cert_idp.pem', 'utf8'),
      
      validateInResponseTo: false,
      disableRequestedAuthnContext: true
    },
    function (profile, done) {
      return done(null,
        {
          id: profile.nameID,
          idFormat: profile.nameIDFormat,
          email: profile.email,
          firstName: profile.givenName,
          lastName: profile.sn
        });
    });
  
  passport.use(samlStrategy);
  // ============================
/*
  app.all('/', function(req, res){
    req.flash('test', 'it worked');
    res.redirect('/test')
  });
  app.all('/test', function(req, res){
    res.send(JSON.stringify(req.flash('test')));
  });
  */
  app.get('/', function (req, res) {
    res.redirect('/profile')
  });

  app.get('/login',
    passport.authenticate(config.passport.strategy,
      {
        successRedirect: '/',
        failureRedirect: '/login'
      })
  );

  app.post(config.passport.saml.path,
    passport.authenticate(config.passport.strategy,
      {
        failureRedirect: '/',
        failureFlash: true
      }),
    function (req, res) {
      res.redirect('/');
    }
  );

  app.get('/profile', function (req, res) {
    if (req.isAuthenticated()) {   
      res.render('profile', {
        user: req.user // useful for view engine, useless for HTML
      });
    } else {
      res.redirect('/login');
    }
  });

  app.get('/services', function (req, res) {
    if (req.isAuthenticated()) {
      async.waterfall([
        // get userId by email from userdb
        function(done) {
          methods.getUserIdByEmail(req.user.email, function(userId, err) {
            if (!err) {
              done(err, userId)
            }
          })
        },
        // get user-project-role from userdb
        function(userId, done) {
          methods.getUserProjectRole(userId, function(userProjects, err) {
            if (!err) {
              done(err, userProjects)
            }
          })
        },
        // get all projects from projectdb
        function(userProjects, done) {
          methods.getAllProjects(function(projectsOverview, err) {
            if (!err) {
              done(err, userProjects, projectsOverview)
            }
          })
        },
        // create JSON object of projects and user status for front-end
        function(userProjects, projectsOverview, done) {
          var allProjects = []  // JSON object
          
          var userProjectId = []  // array of user's project_id
          for (var i = 0; i < userProjects.length; i++) {
            userProjectId.push(userProjects[i].project_id)
          }

          for (var i = 0; i < projectsOverview.length; i++) {
            // check if projectId is exist in userProjectId[]
            var status = "You cannot access this service"
            if (userProjectId.indexOf(projectsOverview[i].id) > -1) {
              status = "You can access this service"
            }
            // add data to JSON object
            allProjects.push({
              id: projectsOverview[i].id,
              title: projectsOverview[i].title,
              summary: projectsOverview[i].onelinesummary,
              cp: projectsOverview[i].contact_email,
              userStatus: status
            });
          }

          // render the page
          res.render('services', {
            user: req.user,
            project: allProjects
          });
        }
      ])
    } else {
      res.redirect('/login');
    }
  });

  app.get('/security', function (req, res) {
    if (req.isAuthenticated()) {
      res.render('security', {
        user: req.user // useful for view engine, useless for HTML
      });
    } else {
      res.redirect('/login');
    }
  });

  app.post('/updateProfile', function (req, res) {
    var userData = {
      title: req.body.inputTitle,
      firstname: req.body.inputFirstname,
      lastname: req.body.inputLastname,
      email: req.body.inputEmail,
      organisation: req.body.inputOrganisation,
      industry: req.body.inputIndustry,
      speciality: req.body.inputSpeciality,
    }
    
    if (req.isAuthenticated()) {
      if (userData.email) {
        dbconn.query('UPDATE user SET ? WHERE email = "' +userData.email+'"', userData, function (err, rows, fields) {
            //if (err) throw err;
            if (err) {
              req.flash('error', "Failed");
            }
            else {
              req.flash('success', 'Profile updated!');
            }
            res.redirect('/profile');
        })
      }
    } else {
      res.redirect('/login');
    }
  });

  // todo: user registration with captcha
  
  app.post('/changePwd', function (req, res) {
    if (req.isAuthenticated()) {
      var currPwd = req.body.inputCurrPwd
      var newPwd = req.body.inputNewPwd
      var retypePwd = req.body.inputConfirm
      
      // Load hashed passwd from DB.
      dbconn.query('SELECT password FROM user WHERE email="'+req.user.email+'"', function (err, rows, fields) {
        if (err) {
          res.redirect('/500')
          throw err
        }
        var userPwd = rows[0].password

        // check if the password is correct
        bcrypt.compare(currPwd, userPwd, function(err, isMatch) {
          if (err) {
            res.redirect('/500')
            throw err
          }
          else if (!isMatch) {
            req.flash('error', "Sorry, your password was incorrect. Please double-check your password.")
            res.redirect('/security')
          } else {
            if ( newPwd != retypePwd ) {
              req.flash('error', "Passwords do no match. Please make sure you re-type your new password correctly.")
              res.redirect('/security')
            }
            else {
              // update password
              bcrypt.genSalt(saltRounds, function(err, salt) {
                bcrypt.hash(newPwd, salt, function(err, hash) {
                  methods.updatePassword(hash, req.user.email, function(err){
                    if (err) {
                      req.flash('error', "Database error: Password cannot be modified.")
                      throw err
                    }
                    else {
                      req.flash('success', "Pasword updated!")
                      console.log('pasword updated!')
                    }
                    res.redirect('/security')
                  })
                });
              });
            }
          }
        })
      })
    } else {
      res.redirect('/login');
    }
  });

  app.get('/forgotPwd', function (req, res) {
    res.render('forgotPwd', {
      user: req.user
    });
    /*
      if email found: send generated email or instruction to reset password
      if email not found: send notification, example: https://www.troyhunt.com/everything-you-ever-wanted-to-know/
    */
  });

  var smtpTransport = nodemailer.createTransport({
    host: config.mailer.host,
    secureConnection: config.mailer.secureConnection,
    port: config.mailer.port,
    auth: {
      user: config.mailer.authUser,
      pass: config.mailer.authPass
    },
    tls: {
        ciphers: config.mailer.tlsCiphers
    } 
  });
  var mailOptions = {
    to: "",
    from: config.mailer.from,
    subject: "",
    text: ""
  };

  app.post('/forgotPwd', function(req, res, next) {
    //methods.currentDate();
    /* do something: write down reset password procedure in Technical Req. Document
      ref: https://meanstackdeveloper.in/implement-reset-password-functionality-in-node-js-express.html
      https://medium.com/@terrychayes/adding-password-reset-functionality-to-a-react-app-with-a-node-backend-4681480195d4
      http://sahatyalkabov.com/how-to-implement-password-reset-in-nodejs/
    
      if email found: send generated email or instruction to reset password
      if email not found: send notification, example: https://www.troyhunt.com/everything-you-ever-wanted-to-know/
    */
    var emailAddress = req.body.inputEmail;
    var emailContent = "Hi there,\n\n"+
      "we've received a request to reset your password. However, this email address is not on our database of registered users.\n\n"+
      "Thanks,\nM4_LAB Team";
    var emailSubject = "Account Access Attempted";
    
    async.waterfall([
      function(done) {
        crypto.randomBytes(20, function(err, buf) {
          var token = buf.toString('hex');
          done(err, token);
        });
      },
      function(token, done) {
        methods.checkUserEmail(emailAddress, function(err, user){
          if (user) {
            console.log("email: user found");
            emailSubject = "M4_LAB Password Reset";
            emailContent = "Hi User,\n\n"+
              "we've received a request to reset your password. If you didn't make the request, just ignore this email.\n\n"+
              "Otherwise, you can reset your password using this link: http://" + req.headers.host + "/reset/" + token + "\n" +
              "This password reset is only valid for 1 hour.\n\n"+
              "Thanks,\nM4_LAB Team"
            
            user.resetPasswordToken = token;
            user.resetPasswordExpires = Date.now() + 3600000; // 1 hour

            methods.updateUser(user, function(err) {
              done(err, token, user);
            });
          }
          else {
            done(err, null, null);
          }
        });
      },
      function(token, user, done) {
        mailOptions.to = emailAddress;
        mailOptions.subject = emailSubject;
        mailOptions.text = emailContent;
        smtpTransport.sendMail(mailOptions, function(err) {
          done(err, 'done');
        });
      }
    ], function(err) {
      if (err) {
        req.flash('error', 'An error occured. Please try again.');
      }
      else {
        req.flash('success', 'An e-mail has been sent to ' + emailAddress + ' with further instructions.');
      }
      res.redirect('/forgotPwd');
    });
  });

  app.get('/reset/:token', function(req, res) {
    methods.checkUserToken(req.params.token, function(err, user){
      //console.log(user);
      if (!user) {
        req.flash('error', 'Password reset token is invalid or has expired.');
        res.redirect('/forgotPwd');
      }
      else {
        res.render('reset');
      }
    });
  });

  app.post('/reset/:token', function(req, res) {
    methods.checkUserToken(req.params.token, function(err, user){
      if (user) {
        // update password
        bcrypt.genSalt(saltRounds, function(err, salt) {
          bcrypt.hash(req.params.inputNewPwd, salt, function(err, hash) {
            methods.updatePassword(hash, user.email, function(err){
              if (err) {
                req.flash('error', "Database error: Password cannot be modified.")
                throw err
              }
              else {
                req.flash('success', "Your pasword has been updated.")
                console.log('pasword updated!')
                // todo: send confirmation email
              }
            })
          });
        });
      }
      else {
        req.flash('error', "User not found.")
      }
    });
   
    res.redirect('/login')
  });

  app.get('/logout', function (req, res) {
    if (req.user == null) {
      return res.redirect('/');
    }
    
    req.user.nameID = req.user.id;
    req.user.nameIDFormat = req.user.idFormat;
    return samlStrategy.logout(req, function(err, uri) {
      req.logout();
      
      if ( req.session ) {
        req.session.destroy((err) => {
          if(err) {
              return console.log(err);
          }
        });
      }
     
      return res.redirect(uri);
    });

  });

  // to generate Service Provider's XML metadata
  app.get('/saml/metadata', 
    function(req, res) {
      res.type('application/xml');
      var spMetadata = samlStrategy.generateServiceProviderMetadata(fs.readFileSync(__dirname + '/cert/cert.pem', 'utf8'));
      res.status(200).send(spMetadata);
    }
  );

};