package models;

import java.util.ArrayList;
import java.util.List;

public class Course {
    private static int nextId = 1;

    private int id;
    private String name;
    private Teacher teacher;
    private List<Student> students;

    public Course(String name) {
        this.id = nextId++;
        this.name = name;
        this.students = new ArrayList<>();
    }

    public int getId() { return id; }
    public String getName() { return name; }
    public Teacher getTeacher() { return teacher; }

    public void setTeacher(Teacher teacher) {
        this.teacher = teacher;
    }

    public boolean addStudent(Student student) {
        if (students.contains(student)) {
            return false;
        }
        students.add(student);
        return true;
    }

    public List<Student> getStudents() {
        return students;  // ساده، بدون unmodifiable
    }

    public void showStudents() {
        if (students.isEmpty()) {
            System.out.println("  No students enrolled yet.");
        } else {
            System.out.println("  Students in " + name + ":");
            for (Student s : students) {
                System.out.println("    - " + s.getUsername());
            }
        }
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj) return true;
        if (obj == null || getClass() != obj.getClass()) return false;
        Course course = (Course) obj;
        return id == course.id;
    }

    @Override
    public String toString() {
        if (teacher != null) {
            return "[ID:" + id + "] " + name + " (Teacher: " + teacher.getUsername() + ")";
        } else {
            return "[ID:" + id + "] " + name + " (No teacher assigned)";
        }
    }
}