package basic;

/**
 * 课程类，与学科建立多对一关系
 */
public class Course {
    private int id;
    private String name;
    private int credit;
    
    // 所属学科（多对一关系）
    private Subject subject;
    
    // 先修课程（一门课程可能有多门先修课程）
    private java.util.List<Course> prerequisiteCourses;
    
    public Course(int id, String name, int credit) {
        this.id = id;
        this.name = name;
        this.credit = credit;
        this.prerequisiteCourses = new java.util.ArrayList<>();
    }
    
    // 添加先修课程
    public void addPrerequisiteCourse(Course course) {
        if (course != null) {
            prerequisiteCourses.add(course);
        }
    }
    
    // 移除先修课程
    public void removePrerequisiteCourse(Course course) {
        if (course != null) {
            prerequisiteCourses.remove(course);
        }
    }
    
    // 设置学科
    public void setSubject(Subject subject) {
        this.subject = subject;
    }
    
    // Getters and Setters
    public int getId() {
        return id;
    }
    
    public void setId(int id) {
        this.id = id;
    }
    
    public String getName() {
        return name;
    }
    
    public void setName(String name) {
        this.name = name;
    }
    
    public int getCredit() {
        return credit;
    }
    
    public void setCredit(int credit) {
        this.credit = credit;
    }
    
    public Subject getSubject() {
        return subject;
    }
    
    public java.util.List<Course> getPrerequisiteCourses() {
        return prerequisiteCourses;
    }
    
    public void setPrerequisiteCourses(java.util.List<Course> prerequisiteCourses) {
        this.prerequisiteCourses = prerequisiteCourses;
    }
    
    @Override
    public String toString() {
        return "Course{" +
                "id=" + id +
                ", name='" + name + '\'' +
                ", credit=" + credit +
                ", subject=" + (subject != null ? subject.getName() : "null") +
                ", prerequisites.size()=" + prerequisiteCourses.size() +
                '}';
    }
}