import java.sql.*;
import java.util.Scanner;;

public class ClassSelectorApp {

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

    int menuItem = -1;
    while (menuItem != 0) {
      menuItem = menu();
      switch (menuItem) {
        case 1:
          createStudent();
          break;
        case 2:
          signUp();
          break;
        case 3:
          listClasses();
          break;
        case 0:
          break;
        default:
          System.out.println("Invalid Input");
          break;

      }
    }
  }

 static void signUp() {
    System.out.println("nSign Up For a Classn");
    try {
      Scanner input = new Scanner(System.in);
      System.out.println("Enter Student ID: ");
      String user_entered_student_id = input.nextLine();

      Connection con = DriverManager.getConnection("jdbc:mysql://localhost:3306/ClassSelector?autoReconnect=true&useSSL=false", "root", "");
      Statement myStmt = con.createStatement();
      Statement myStmt2 = con.createStatement();
      Statement myStmt3 = con.createStatement();

      ResultSet rs;
      rs = myStmt.executeQuery("SELECT student_name FROM ClassSelector.students WHERE student_id = " + user_entered_student_id);
      while (rs.next()) {
        String userEnterId = rs.getString("student_name");
        System.out.println("Is " + userEnterId + " the correct student? (Y/N)");
        String confirm = input.nextLine();

        if (confirm.equalsIgnoreCase("Y")) {
          ResultSet rs2 = myStmt2.executeQuery("SELECT * FROM ClassSelector.classes");
          while (rs2.next()) {
            String avlClasses = rs2.getString("class_id") + "t" + rs2.getString("classname") + "t" + rs2.getString("description");
            System.out.println(avlClasses);
          }
        } else if (confirm.equalsIgnoreCase("N")) {
          System.out.println("Oops, let start over");
          return;
        }

        System.out.println("Enter Class ID from Classes Listed Above to Join: ");
        String selectedClass = input.nextLine();
        ResultSet rs3 = myStmt3.executeQuery("SELECT * FROM ClassSelector.classes WHERE class_id = " + selectedClass);
        while (rs3.next()) {
          String innerJoin = (userEnterId + " has been added to " + rs3.getString("classname") + " " + rs3.getString("class_id"));
          System.out.println(innerJoin);
          String student_classJoin = "INSERT IGNORE INTO student_x_class" + "(student_id,student_name, class_id, classname)" + "VALUES (?, ?, ?, ?)";
          PreparedStatement pStmt = con.prepareStatement(student_classJoin);
          pStmt.setString(1, user_entered_student_id);
          pStmt.setString(2, userEnterId);
          pStmt.setString(3, rs3.getString("class_id"));
          pStmt.setString(4, rs3.getString("classname"));
          pStmt.executeUpdate();
          System.out.println("Would you like to enroll " + userEnterId + " into another class? (Y/N)");
          String additionalClass = input.nextLine();
          if(additionalClass.equalsIgnoreCase("Y")){
              signUp();
          }
        }
      }
    } catch (java.sql.SQLException SQL) {
      SQL.printStackTrace();
    } catch (Exception EXC) {
      EXC.printStackTrace();
    }

  }

public void signUp(){
    System.out.println("nSign Up For a Classn");
    try{
      Scanner input = new Scanner(System.in);
      System.out.println("Enter Student ID: ");
      String user_entered_student_id = input.nextLine();

      String userEnterId = student_name + (user_entered_student_id);

    System.out.println("Enter Class ID from Classes Listed Above to Join: ");

    String selectedClass = input.nextLine();

    student_x_class(selectedClass);

}
    catch (Exception e) {
        e.printStackTrace();
    }
}


public void student_name(Scanner input,String user_entered_student_id, Statement myStmt, Connection con) {
    try{

    myStmt = con.createStatement();

    String query = ("SELECT student_name FROM ClassSelector.students WHERE student_id = " + user_entered_student_id);

    ResultSet rs;
    rs = myStmt.executeQuery(query);
    while (rs.next()) {
         String userEnterId = rs.getString("student_name");
         System.out.println("Is " + userEnterId + " the correct student? (Y/N)");

         String confirm = input.nextLine();

         if (confirm.equalsIgnoreCase("Y")) {
             getClass();
         }
         else if (confirm.equalsIgnoreCase("N")) {
                System.out.println("Oops, let start over");
         }
         return;
         }
}
    catch (SQLException e) {
        e.printStackTrace();
    }
}

public void getClass(ResultSet rs, Statement myStmt){
        try{
            rs = myStmt.executeQuery("SELECT * FROM ClassSelector.classes");
            while (rs.next()) {
              String avlClasses = rs.getString("class_id") + "t" + rs.getString("classname") + "t" + rs.getString("description");
              System.out.println(avlClasses);
            }

          }
        catch (SQLException e) {
            e.printStackTrace();
        }
}

public void student_x_class(Scanner input,String selectedClass, String userEnterId, String user_entered_student_id, ResultSet rs, Statement myStmt, Connection con){
        try{
         rs = myStmt.executeQuery("SELECT * FROM ClassSelector.classes WHERE class_id = " + selectedClass);

          while (rs.next()) {

          String innerJoin = (userEnterId + " has been added to " + rs.getString("classname") + " " + rs.getString("class_id"));
          System.out.println(innerJoin);

          String student_classJoin = "INSERT IGNORE INTO student_x_class" + "(student_id,student_name, class_id, classname)" + "VALUES (?, ?, ?, ?)";
          PreparedStatement pStmt = con.prepareStatement(student_classJoin);
          pStmt.setString(1, user_entered_student_id);
          pStmt.setString(2, userEnterId);
          pStmt.setString(3, rs.getString("class_id"));
          pStmt.setString(4, rs.getString("classname"));
          pStmt.executeUpdate();
          System.out.println("Would you like to enroll " + userEnterId + " into another class? (Y/N)");
            String additionalClass = input.nextLine();
            if(additionalClass.equalsIgnoreCase("Y")){
                signUp();
            }
        }
    }
        catch (SQLException e) {
            e.printStackTrace();
        }
}