/**
 * 教师端功能管理
 */
class TeacherManager {
    constructor() {
        this.apiBase = '/api/teacher';
        this.init();
    }
    
    init() {
        this.initDashboard();
        this.updateCurrentTime();
        setInterval(() => this.updateCurrentTime(), 1000);
    }
    
    updateCurrentTime() {
        const timeElement = document.getElementById('currentTime');
        if (timeElement) {
            const now = new Date();
            const options = { 
                year: 'numeric', month: 'long', day: 'numeric',
                hour: '2-digit', minute: '2-digit', second: '2-digit'
            };
            timeElement.textContent = now.toLocaleString('zh-CN', options);
        }
    }
    
    async initDashboard() {
        // 检查是否在仪表板页面
        if (!document.getElementById('courseList')) return;
        
        try {
            const response = await fetch(`${this.apiBase}/courses`);
            const result = await response.json();
            
            if (result.success) {
                this.renderDashboard(result.data.courses);
            } else {
                if (window.authManager) {
                    window.authManager.showNotification(result.message || '获取课程失败', 'error');
                }
            }
        } catch (error) {
            console.error('Fetch teacher data failed:', error);
        }
    }
    
    renderDashboard(courses) {
        const courseList = document.getElementById('courseList');
        if (!courseList) return;
        
        if (!courses || courses.length === 0) {
            courseList.innerHTML = '<div class="col-12 text-center py-5 text-muted">暂无负责课程</div>';
            return;
        }
        
        courseList.innerHTML = courses.map(course => `
            <div class="col-md-6 col-xl-4 mb-4">
                <div class="card h-100 border-0 shadow-sm course-card">
                    <div class="card-body">
                        <div class="d-flex justify-content-between align-items-center mb-3">
                            <span class="badge bg-primary bg-opacity-10 text-primary px-3 py-2">
                                <i class="fas fa-book me-1"></i> ${course.course_code || 'CODE'}
                            </span>
                            <span class="text-muted small">${course.credit} 学分</span>
                        </div>
                        <h5 class="card-title fw-bold mb-2">${course.course_name}</h5>
                        <p class="card-text text-secondary small mb-4">
                            <i class="fas fa-users me-1"></i> 学生人数: ${course.student_count || 0}
                        </p>
                        <div class="d-grid gap-2">
                            <a href="/teacher/grade_entry?courseId=${course.id}" class="btn btn-outline-primary btn-sm">
                                <i class="fas fa-edit me-1"></i> 成绩录入
                            </a>
                            <a href="/teacher/grade_management?courseId=${course.id}" class="btn btn-primary btn-sm">
                                <i class="fas fa-tasks me-1"></i> 成绩管理
                            </a>
                        </div>
                    </div>
                </div>
            </div>
        `).join('');
        
        // 更新统计数据
        document.getElementById('courseCount').textContent = courses.length;
        const totalStudents = courses.reduce((sum, c) => sum + (c.student_count || 0), 0);
        document.getElementById('totalStudents').textContent = totalStudents;
    }
}

// 初始化
document.addEventListener('DOMContentLoaded', () => {
    window.teacherManager = new TeacherManager();
    
    // 从 Session 获取用户信息并更新 UI
    fetch('/api/auth/me')
        .then(res => res.json())
        .then(result => {
            if (result.success && result.data.user) {
                const user = result.data.user;
                const nameEl = document.getElementById('userName');
                const teacherNameEl = document.getElementById('teacherName');
                
                if (nameEl) nameEl.textContent = user.name;
                if (teacherNameEl) teacherNameEl.textContent = user.name;
            }
        });
});