import java.time.LocalDate;
import java.time.Duration;

/**
 * 培训课程类 - 负责课程信息管理
 * 遵循单一职责原则：只负责课程数据的存储和基本验证
 */
public class TrainingCourse {
    private String courseId;       // 课程ID
    private String courseName;     // 课程名称
    private String description;    // 课程描述
    private int durationHours;     // 课程时长（小时）
    private String trainer;        // 培训师
    private String department;     // 所属部门
    private String category;       // 课程类别
    private int credits;           // 学分
    private boolean active;        // 是否启用
    private LocalDate createdAt;   // 创建时间
    private String requirements;   // 课程要求
    private String objectives;     // 课程目标
    private String materials;      // 课程资料
    
    /**
     * 构造函数 - 创建培训课程
     */
    public TrainingCourse(String courseId, String courseName, String description, 
                         int durationHours, String trainer, String department, 
                         String category, int credits) {
        this.courseId = courseId;
        this.courseName = courseName;
        this.description = description;
        this.durationHours = durationHours;
        this.trainer = trainer;
        this.department = department;
        this.category = category;
        this.credits = credits;
        this.active = true;
        this.createdAt = LocalDate.now();
        this.requirements = "";
        this.objectives = "";
        this.materials = "";
    }
    
    /**
     * 检查课程是否可报名
     * @return true如果课程可报名
     */
    public boolean isEnrollable() {
        return active && durationHours > 0 && credits >= 0;
    }
    
    /**
     * 获取课程时长描述
     * @return 课程时长描述
     */
    public String getDurationDescription() {
        if (durationHours < 1) {
            return "少于1小时";
        } else if (durationHours == 1) {
            return "1小时";
        } else {
            return durationHours + "小时";
        }
    }
    
    /**
     * 获取课程等级（基于学分）
     * @return 课程等级
     */
    public String getLevel() {
        if (credits <= 1) return "初级";
        else if (credits <= 3) return "中级";
        else return "高级";
    }
    
    // Getter和Setter方法
    
    public String getCourseId() { return courseId; }
    
    public String getCourseName() { return courseName; }
    
    public void setCourseName(String courseName) {
        if (courseName == null || courseName.trim().isEmpty()) {
            throw new IllegalArgumentException("课程名称不能为空");
        }
        this.courseName = courseName;
    }
    
    public String getDescription() { return description; }
    
    public void setDescription(String description) { this.description = description; }
    
    public int getDurationHours() { return durationHours; }
    
    public void setDurationHours(int durationHours) {
        if (durationHours < 0) {
            throw new IllegalArgumentException("课程时长不能为负数");
        }
        this.durationHours = durationHours;
    }
    
    public String getTrainer() { return trainer; }
    
    public void setTrainer(String trainer) { this.trainer = trainer; }
    
    public String getDepartment() { return department; }
    
    public void setDepartment(String department) { this.department = department; }
    
    public String getCategory() { return category; }
    
    public void setCategory(String category) { this.category = category; }
    
    public int getCredits() { return credits; }
    
    public void setCredits(int credits) {
        if (credits < 0) {
            throw new IllegalArgumentException("学分不能为负数");
        }
        this.credits = credits;
    }
    
    public boolean isActive() { return active; }
    
    public void setActive(boolean active) { this.active = active; }
    
    public LocalDate getCreatedAt() { return createdAt; }
    
    public String getRequirements() { return requirements; }
    
    public void setRequirements(String requirements) { this.requirements = requirements; }
    
    public String getObjectives() { return objectives; }
    
    public void setObjectives(String objectives) { this.objectives = objectives; }
    
    public String getMaterials() { return materials; }
    
    public void setMaterials(String materials) { this.materials = materials; }
    
    @Override
    public String toString() {
        return "TrainingCourse{" +
               "courseId='" + courseId + "'" +
               ", courseName='" + courseName + "'" +
               ", category='" + category + "'" +
               ", level='" + getLevel() + "'" +
               ", duration=" + getDurationDescription() +
               ", trainer='" + trainer + "'" +
               ", credits=" + credits +
               ", department='" + department + "'" +
               ", active=" + (active ? "启用" : "禁用") +
               "}";
    }
}