text: var models = require('../models');
  
  exports.log_in_check = function(req,res){
    console.log("inlogin");
    console.log(req.body);
  
    var email = req.body.email;
    email.toLowerCase();
    var filter = /^([a-zA-Z0-9_\.\-])+\@ucsd.edu+$/;
    var password = req.body.password;
    var errorMsgs = ["nopwd","invalidemail","noaccount","wrongpwd"];
    var error = "";
  
    if (!filter.test(email)){
    	    error = errorMsgs[1];
    	    res.send(error);
    }else if (password == ''){
    	    error = errorMsgs[0];
    	    res.send(error);
    }else{
  	models.User
      	.find({"email": email})
      	.sort()
      	.exec(checkUser);
  
      function checkUser(err, users){
      	if(err) console.log(err);
      	console.log("isHERE" + users);
      	if(users[0] == undefined){//not found user
            error = errorMsgs[2];
            res.send(error);
      	}else{
      	  console.log("that="+users[0]);
      	  if(users[0].pwd != password){
              error = errorMsgs[3];
              res.send(error);
      	  }else{
      	  	error = users[0]._id;
      	  	req.session._id = error;
            req.session.preferred = users[0].preferred;
      	  	console.log("id");
      	  	console.log(req.session._id);
      	  	res.send(error);
      	  }
      	}
  	  }
    }	
  }
  
  exports.sign_up_check = function(req,res){
    console.log("insignup");
    console.log(req.body);
  
    var email = req.body.email;
    email.toLowerCase();
    var filter = /^([a-zA-Z0-9_\.\-])+\@ucsd.edu+$/;
    var password1 = req.body.password1;
    var password2 = req.body.password2;
    var errorMsgs = ["nopwd","invalidemail","accountexist","wrongpwd"];
    var error = "";
  
    if (!filter.test(email)){
          error = errorMsgs[1];
          res.send(error);
    }else if (password1 == '' | password2 == ''){
          error = errorMsgs[0];
          res.send(error);
    }else if(password1 != password2){
          error = errorMsgs[3];
          res.send(error);  
    }else{
    models.User
        .find({"email": email})
        .sort()
        .exec(checkUser);
  
      function checkUser(err, users){
        if(err) console.log(err);
  
        if(users[0] == undefined){//not found user
            req.session.email = email;
            req.session.pwd = password1;
            res.send("pass");
        }else{
          error = errorMsgs[2];
          res.send(error);
        }
      } 
    }
  }
  
  exports.logout = function(req, res){
    req.session.email = "";
    req.session.pwd = "";
    req.session.preferred = "";
    req.session._id = "";
    res.send("successfully log out");
  }