import java.util.ArrayList;  //Loads ArrayList java library for use in program

public class Roster
{

    static ArrayList<Student> studentRoster = new ArrayList<>(); //initializes student roster array list

    public static void main(String[] args) //Main program
        {
            Roster.add("1", "John", "Smith", "John1989@gmail.com", 20, 88, 79, 59);
            Roster.add("2", "Suzan", "Erickson", "Erickson_1990@gmailcom", 19, 91, 72, 85);
            Roster.add("3", "Jack", "Napoli", "The_lawyer99yahoo.com", 19, 85, 84, 87);
            Roster.add("4", "Erin", "Black", "Erin.black@comcast.net", 22, 91, 98, 82);
            Roster.add("5", "Ryan", "Lewis", "rlewi57@wgu.edu", 28, 90, 83, 76);

            //prints all students in roster
            print_all();
            //prints any invalid emails along with an error message
            print_invalid_emails();
            //prints out all student's average grade
            print_average_grade();
            //removes student 3 from the roster
            remove("3");
            //removes student 3 from the roster, but returns error message since student 3 no longer exists
            remove("3");

        }

    //Constructor for adding new students to the Student Roster
    public static void add(String studentId, String firstName, String lastName, String emailAddress, int age, int grade1, int grade2, int grade3)
    {
        int[] grades = {grade1, grade2, grade3};
        Student newStudent = new Student(studentId, firstName, lastName, emailAddress, age, grades); //Creates a new student
        studentRoster.add(newStudent); //Adds the new student to the roster array
    }

    //Creates remove method to remove students from the roster. Returns error message if student is not found.
    public static void remove(String studentId)
    {
        for (Student student : studentRoster)
        {
            if (student.getStudentId().equals(studentId))
            {
                   studentRoster.remove(student);
                   System.out.println("Student " + studentId + " has been removed.");
                   return;
            }
        }
        System.out.println("This Student ID cannot be found!");
    }

    //Creates print_all method to print out a list of all students in the roster.  Calls the print() method from the Student class.
    public static void print_all()
    {
        for (int i = 0; i < studentRoster.size(); i++)
        {
            studentRoster.get(i).print();
        }
    }

    //Creates print_average_grade method that calculates the average of each student's three grades
    public static void print_average_grade()
    {
        for (Student student : studentRoster)
        {
            double averageGrade = (student.getGrades()[0] + student.getGrades()[1] + student.getGrades()[2]) / 3.0;
            System.out.println("Student ID:\t" + student.getStudentId() + "\tAverage Grade:\t" + String.format("%.2f",averageGrade));
        } //Added String.format to round the average grades up to 2 decimal points
    }

    //Creates method to print out any emails that do not include either an "@" symbol or a period or contain a space.
    public static void print_invalid_emails()
    {
        for (Student student : studentRoster)
        {     //Added argument to also check the email address for any spaces, and returns them as invalid if it does.
            if (!student.getEmailAddress().contains("@") || !student.getEmailAddress().contains(".") || student.getEmailAddress().contains(" "))
            {
                System.out.println("Student " + student.getStudentId() + "'s email address " + student.getEmailAddress() + " is invalid!");
            }
        }
    }

}