public class loginpage{


 public string username{get;set;}
 public string password{get;set;}
 public string errmsg{get;set;}
 public string hometype{get;set;}
 public pagereference logintype{get;set;}
 public loginpage(){

 username = apexpages.currentpage().getparameters().get('username');
 system.debug('USERNAME:'+username);
 logintype=Page.loginpage;
 hometype = '/mainpage';
 }



 public pagereference login(){

     //  pagereference pr=null;
       system.debug('USERNAME:'+username);
       system.debug('PASSWORD:'+password);
       //pagereference pr= new pagereference('/apex/warehousehome');
       string starturl = apexpages.currentpage().getparameters().get('starturl');
       system.debug('START URL:'+starturl);
       if(starturl == null) starturl = (site.getpathprefix() == null? '' :site.getpathprefix())+hometype;

      //starturl= URL.getSalesforceBaseUrl().toExternalForm();
      system.debug('START URL####:'+starturl);

      list<user>user = [select id,name,username,email,isactive from user where username=:username];
      system.debug('USER@@@@@:'+user);
      if(!user.isEmpty() && user[0].isactive){
      //pr=logintype;
      system.debug('USER EXIST:');
       pr =site.login(username,password,starturl);
       //pr.setredirect(true);
      system.debug('@@@@@:'+pr);
      return pr;

  } else
   return null;
}
}

public loginpage(){
   username = apexpages.currentpage().getparameters().get('username');
   password = apexpages.currentpage().getparameters().get('password');
   system.debug('USERNAME:'+username);
   logintype=Page.loginpage;
   hometype = '/mainpage';
 }