function show_books(courses_data, user_selected_courses) {
    console.log(courses_data)
    console.log(user_selected_courses)
}
function show_course_details(course_id) {
    window.location.href = '/course/' + course_id
}

function on_click_select_course(event) {
    event.stopPropagation(); // 阻止事件冒泡
    const button = event.currentTarget;
    const courseId = button.getAttribute('data-course-id');
    if (!courseId) { alert('缺少课程ID'); return; }
    if (button.classList.contains("selected-button")) { alert('课程已选择'); return; }
    if (button.disabled) { return; }
    button.disabled = true;
    fetch(`/select_course`, {
        method: 'POST',
        headers: {
            'Content-Type': 'application/json',
        },
        body: JSON.stringify({ course_id: courseId })
    })
        .then(async (response) => {
            let data = null;
            try {
                data = await response.json();
            } catch (_) {
            }
            if (!response.ok) {
                throw new Error(data?.message || `请求失败(${response.status})`);
            }
            return data;
        })
        .then((data) => {
            if (!data?.success) {
                throw new Error(data?.message || '选择课程失败');
            }
            button.classList.remove('select-button');
            button.classList.add('selected-button');
            button.textContent = '已选课';
            alert('选择课程成功');
        })
        .catch(error => {
            console.error('Error:', error);
            alert(error?.message || '选择课程失败');
            button.disabled = false;
        });
}

document.addEventListener('DOMContentLoaded', function () {

});