/*
 * Author: CHEN Yongyuan (Walter) 1930006025 from OOP(1007)
 * Date: 2022/03/03
 * Description: Student class
 */

public class Student {
    /**
     * Student's ID number
     */
    private int ID;

    /**
     * Student's name
     */
    private String name;

    /**
     * A single character representing the grade of the student
     */
    private char grade;

    /**
     * Constructor A public constructor with one parameter
     * 
     * @param id   the ID of the student, only accept positive integer if the id is
     *             not positive, it will be set to 0
     * 
     * @param name the name of the student.
     */
    public Student(int ID, String name) {
        this(ID, name, 'A');
    }

    /**
     * Constructor A public constructor with three parameters
     * 
     * @param id    the ID of the student, only accept positive integer if the id is
     *              not positive, it will be set to 0
     * 
     * @param name  the name of the student.
     * 
     * @param grade the grade of the student, if the grade is not one of these, it
     *              will be set to 'A'
     */
    public Student(int ID, String name, char grade) {
        // if the id is not positive, set it to 0
        if (ID > 0) {
            this.ID = ID;
        } else {
            this.ID = 0;
        }

        // set the name
        this.name = name;

        // set the grade
        this.grade = grade;
    }

    /**
     * Getter A public getter for the ID.
     * 
     * @return the ID of the student
     */
    public int getID() {
        return ID;
    }

    /**
     * Getter A public getter for the name.
     * 
     * @return the name of the student
     */
    public String getName() {
        return name;
    }

    /**
     * Setter A public setter for the name.
     *
     * @param name the name of the student
     * 
     * @return void
     */
    public void setName(String name) {
        this.name = name;
    }

    /**
     * Getter A public getter for the grade.
     * 
     * @return the grade of the student
     */
    public char getGrade() {
        return grade;
    }

    /**
     * Setter A public setter for the grade.
     *
     * @param grade the grade of the student
     *
     * @return void
     */
    public void setGrade(char grade) {
        this.grade = grade;
    }

    /**
     * Test method A public method to test the class
     *
     * @return void
     */
    public static void testStudent() {
        // create students
        Student s1 = new Student(-1, "Walter");
        Student s2 = new Student(0, "Yongyuan");
        Student s3 = new Student(1, "Chen");

        // print true for id
        System.out.println(s1.getID() == 0);
        System.out.println(s2.getID() == 0);
        System.out.println(s3.getID() == 1);

        // print true for name
        System.out.println(s1.getName().equals("Walter"));
        System.out.println(s2.getName().equals("Yongyuan"));
        System.out.println(s3.getName().equals("Chen"));

        // change the name
        s1.setName("Walter Wang");
        s2.setName("Yongyuan Wang");
        s3.setName("Chen Wang");

        // print true for name
        System.out.println(s1.getName().equals("Walter Wang"));
        System.out.println(s2.getName().equals("Yongyuan Wang"));
        System.out.println(s3.getName().equals("Chen Wang"));

        // check default grade
        System.out.println(s1.getGrade() == 'A');
        System.out.println(s2.getGrade() == 'A');
        System.out.println(s3.getGrade() == 'A');

        // set grade
        s1.setGrade('B');
        s2.setGrade('C');
        s3.setGrade('D');

        // check grade
        System.out.println(s1.getGrade() == 'B');
        System.out.println(s2.getGrade() == 'C');
        System.out.println(s3.getGrade() == 'D');

        // create students with grade different from A
        Student s4 = new Student(2, "Chen", 'B');
        Student s5 = new Student(3, "Yongyuan", 'C');
        Student s6 = new Student(4, "Walter", 'D');

        // print true for grade
        System.out.println(s4.getGrade() == 'B');
        System.out.println(s5.getGrade() == 'C');
        System.out.println(s6.getGrade() == 'D');
    }
}