/*
  This program displays the list of classes taken by each student

  Note how the keys are constructed.  The program starts by retrieving
  a list of all student ids.  Then it uses the ids to construct keys
  for the next level of searching.  "student:"+sid+":major" is a key in 
  the form student:5:major, which is used to retrive the major of
  student 5 from the database.
*/
import java.util.*;
import java.io.*;
import redis.clients.jedis.Jedis; 

class DisplayStudents {

    public static void main(String[] args) throws FileNotFoundException {

	//Connecting to Redis server on localhost 
	Jedis jedis = new Jedis("redis.cs.oberlin.edu"); 

	//check whether server is running or not 
	System.out.println("Server is running: "+jedis.ping()); 

	/* get list of all students */
	List<String> allstudents = jedis.lrange("student",0,-1);

	/* for each student, get a list of sections */
	for(String sid : allstudents){

	    /* get student name and major */
	    String sname = jedis.get("student:"+sid+":sname");
	    String major = jedis.get("student:"+sid+":major");
	    System.out.println(sid+"\t"+sname+"\t"+major);

	    /* get a list of all sections the student is enrolled in */
	    Set<String> sections = jedis.smembers("student:"+sid+":sections");
	    if(sections.size()==0){
		System.out.println("\tnot registered for any classes");
	    }
	    else {
		/* for each section, display details */
		for(String sectid : sections){
		    Map<String,String> smap = jedis.hgetAll("section:"+sectid);
		    String prof = smap.get("prof");
		    String title = smap.get("ctitle");
		    String courseid = smap.get("courseid");
		    String dname = jedis.get("course:"+courseid+":dname");
		    System.out.println("\t"+sectid+"\t"+dname+"\t"+title+"\t"+prof);
		}
	    }
	    System.out.println();
	}
    }
}