/* This is the driving engine of the program. It parses the command-line
 * arguments and calls the appropriate methods in the other classes.
 *
 * You should edit this file in two ways:
 * 1) Insert your database username and password in the proper places.
 * 2) Implement the three functions getInformation, registerStudent
 *    and unregisterStudent.
 */
import java.sql.*; // JDBC stuff.
import java.util.Properties;
import java.util.Scanner;
import java.io.*;  // Reading user input.

public class StudentPortal
{
    /* TODO Here you should put your database name, username and password */
    static final String DATABASE = "jdbc:postgresql://ate.ita.chalmers.se/";
    static final String USERNAME = "";
    static final String PASSWORD = "";

    /* Print command usage.
     * /!\ you don't need to change this function! */
    public static void usage () {
        System.out.println("Usage:");
        System.out.println("    i[nformation]");
        System.out.println("    r[egister] <course>");
        System.out.println("    u[nregister] <course>");
        System.out.println("    q[uit]");
    }

    /* main: parses the input commands.
     * /!\ You don't need to change this function! */
    public static void main(String[] args) throws Exception
    {
        Class.forName("org.postgresql.Driver");
        Properties props = new Properties();
        props.setProperty("user",USERNAME);
        props.setProperty("password",PASSWORD);
        
        // Try with resource (requires Java 7) to close connection automatically
        try (Connection conn = DriverManager.getConnection(DATABASE, props)) { 

            Console console = System.console();
            // In Eclipse. System.console() returns null due to a bug (https://bugs.eclipse.org/bugs/show_bug.cgi?id=122429)
            // In that case, use the following line instead:
            // BufferedReader console = new BufferedReader(new InputStreamReader(System.in));

            String student;
            if(args.length > 0)
                student = args[0]; // This is the identifier for the student.
            else {
                System.out.println("Input student idnr:");
                // student = "1111111111"; // For quick test runs
                student = console.readLine();
            }

            usage();
            System.out.println("Welcome!");
            while(true) {
            System.out.print("? > ");
                String mode = console.readLine();
                String[] cmd = mode.split(" +");
                cmd[0] = cmd[0].toLowerCase();
                if ("information".startsWith(cmd[0]) && cmd.length == 1) {
                    /* Information mode */
                    getInformation(conn, student);
                } else if ("register".startsWith(cmd[0]) && cmd.length == 2) {
                    /* Register student mode */
                    registerStudent(conn, student, cmd[1]);
                } else if ("unregister".startsWith(cmd[0]) && cmd.length == 2) {
                    /* Unregister student mode */
                    unregisterStudent(conn, student, cmd[1]);
                } else if ("quit".startsWith(cmd[0])) {
                    break;
                } else usage();
            }
            System.out.println("Goodbye!");
        } catch (SQLException e) {
            System.err.println(e);
            System.exit(2);
        }
    }

    /* Given a student identification number, ths function should print
     * - the name of the student, the students national identification number
     *   and their issued login name (something similar to a CID)
     * - the programme and branch (if any) that the student is following.
     * - the courses that the student has read, along with the grade.
     * - the courses that the student is registered to. (queue position if the student is waiting for the course)
     * - the number of mandatory courses that the student has yet to read.
     * - whether or not the student fulfills the requirements for graduation
     */
    static void getInformation(Connection conn, String student) throws SQLException
    {
        // TODO: Your implementation here
    }

    /* Register: Given a student id number and a course code, this function
     * should try to register the student for that course.
     */
    static void registerStudent(Connection conn, String student, String course)
    throws SQLException
    {
        // TODO: Your implementation here
    }

    /* Unregister: Given a student id number and a course code, this function
     * should unregister the student from that course.
     */
    static void unregisterStudent(Connection conn, String student, String course)
    throws SQLException
    {
        // TODO: Your implementation here
    }
}