package classselector;

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;

      }
    }
  }

  protected static int menu() {
    try {
      int choice;
      Scanner sc = new Scanner(System.in);
      System.out.println("n Class Selection Menu");
      System.out.println("**********************************");
      System.out.println("0: Exit Menu");
      System.out.println("1: Create New Student");
      System.out.println("2: Sign Up For a Class");
      System.out.println("3: List Classes for All Students");
      System.out.println("**********************************");
      System.out.println("Enter a choice: ");
      choice = sc.nextInt();
      return choice;

    } catch (java.util.InputMismatchException e) {
      System.out.println("Invalid choice!");
    } catch (Exception e) {
      System.out.println("Something went wrong...");
    }
    return 0;
  }
  static void createStudent() {
    System.out.println("nCreate Studentn");
    try {
      Scanner input = new Scanner(System.in);
      System.out.println("Enter a Student ID: ");
      String student_id = input.nextLine();
      System.out.println("Enter Student Name: ");
      String student_name = input.nextLine();
      System.out.println("Enter Student Hometown: ");
      String hometown = input.nextLine();
      Connection con = DriverManager.getConnection("jdbc:mysql://localhost:3306/ClassSelector?autoReconnect=true&useSSL=false", "root", "");
      String sql = "INSERT INTO students" + "(student_id, student_name, hometown)" + "VALUES (?, ?, ?)";
      PreparedStatement myStmt = con.prepareStatement(sql);
      myStmt.setString(1, student_id);
      myStmt.setString(2, student_name);
      myStmt.setString(3, hometown);
      myStmt.executeUpdate();
      System.out.println("New Student Added");

    } catch (SQLIntegrityConstraintViolationException ex) {
      System.out.println("This entry has duplicate student ID or Student Name, please try again");
    } catch (SQLException SQL) {
      SQL.printStackTrace();
    } catch (Exception exc) {
      exc.printStackTrace();
    }
  }

  static void signUp() {
    System.out.println("nSign Up For a Classn");
    try {
    Connection con = DriverManager.getConnection("jdbc:mysql://localhost:3306/ClassSelector?autoReconnect=true&useSSL=false", "root", "Volks91!");
    Statement myStmt = con.createStatement();

      Scanner input = new Scanner(System.in);
      System.out.println("Enter Student ID: ");
      String user_entered_student_id = input.nextLine();



      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 = myStmt.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 = myStmt.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();
          }
          else{
              return;
          }
        }
      }
    } catch (java.sql.SQLException SQL) {
      SQL.printStackTrace();
    } catch (Exception EXC) {
      EXC.printStackTrace();
    }
  }

  static void listClasses() {
    System.out.println("nStudent Enrollmentn");
    try {
      Scanner input = new Scanner(System.in);
      System.out.println("Enter Student ID to See What Classes they are enrolled in: ");
      String user_entered_student_id = input.nextLine();

      Connection con = DriverManager.getConnection("jdbc:mysql://localhost:3306/ClassSelector?autoReconnect=true&useSSL=false", "root", "Volks91!");
      Statement myStmt = con.createStatement();

      ResultSet rs;
      boolean found = false;
      rs = myStmt.executeQuery("SELECT student_id, student_name, class_id, classname  FROM ClassSelector.student_x_class WHERE student_id = " + user_entered_student_id);
      while (rs.next()) {
        String studentInClass = (rs.getString("student_id") + "t" + rs.getString("student_name") + "  " + rs.getString("class_id") + " " + rs.getString("classname"));
        if (user_entered_student_id.equals(rs.getString("student_id"))) {
          System.out.println(studentInClass);
          found = true;
        }
      }
      if (!found) {
        System.out.println("This Student does not Exist!");
      }

    } catch (java.sql.SQLException SQL) {
      SQL.printStackTrace();
    } catch (Exception EXC) {
      EXC.printStackTrace();
    }
  }
}