WS-04-oop-review/src/main/java/services/SchoolSystem.java

package services;

import models.*;
import java.util.ArrayList;
import java.util.List;

public class SchoolSystem {
    private List<Student> students;
    private List<Teacher> teachers;
    private List<Course> allCourses;

    public SchoolSystem() {
        this.students = new ArrayList<>();
        this.teachers = new ArrayList<>();
        this.allCourses = new ArrayList<>();
    }

    // ========== Student Management ==========
    public boolean registerStudent(String username, String password) {
        if (findStudent(username) != null) {
            return false;
        }
        students.add(new Student(username, password));
        return true;
    }

    public Student loginStudent(String username, String password) {
        Student student = findStudent(username);
        if (student != null && student.checkPassword(password)) {
            return student;
        }
        return null;
    }

    private Student findStudent(String username) {
        for (Student s : students) {
            if (s.getUsername().equals(username)) return s;
        }
        return null;
    }

    // ========== Teacher Management ==========
    public boolean registerTeacher(String username, String password) {
        if (findTeacher(username) != null) {
            return false;
        }
        teachers.add(new Teacher(username, password));
        return true;
    }

    public Teacher loginTeacher(String username, String password) {
        Teacher teacher = findTeacher(username);
        if (teacher != null && teacher.checkPassword(password)) {
            return teacher;
        }
        return null;
    }

    private Teacher findTeacher(String username) {
        for (Teacher t : teachers) {
            if (t.getUsername().equals(username)) return t;
        }
        return null;
    }

    // ========== Course Management ==========
    public boolean addCourseToSystem(String courseName) {
        for (Course c : allCourses) {
            if (c.getName().equals(courseName)) {
                return false;
            }
        }
        allCourses.add(new Course(courseName));
        return true;
    }

    public Course findCourseById(int id) {
        for (Course c : allCourses) {
            if (c.getId() == id) return c;
        }
        return null;
    }

    public Course findCourseByName(String name) {
        for (Course c : allCourses) {
            if (c.getName().equalsIgnoreCase(name)) return c;
        }
        return null;
    }

    public String getAllCoursesDisplay() {
        if (allCourses.isEmpty()) {
            return " No courses available yet.";
        } else {
            StringBuilder sb = new StringBuilder("\n All Available Courses:\n");
            for (int i = 0; i < allCourses.size(); i++) {
                sb.append("  ").append(i+1).append(". ").append(allCourses.get(i)).append("\n");
            }
            return sb.toString();
        }
    }

    public List<Course> getAllCourses() {
        return allCourses;
    }
}