// public/k.js – управление привязкой учителей к корпусам

let currentUser = null;
let teachersList = []; // [{ id, name, subject, campus }]

document.addEventListener('DOMContentLoaded', async () => {
    await checkAuth();
    await loadTeachers();
    setupEventListeners();
});

async function checkAuth() {
    try {
        const res = await fetch('/api/me');
        const data = await res.json();
        if (!data.authenticated || data.user.role !== 'admin') {
            window.location.href = '/login.html';
            return;
        }
        currentUser = data.user;
        document.getElementById('userInfo').innerHTML = `👋 ${currentUser.full_name} (${currentUser.role})`;
    } catch (err) {
        window.location.href = '/login.html';
    }
}

async function loadTeachers() {
    try {
        const res = await fetch('/api/teachers');
        teachersList = await res.json();
        renderTable();
    } catch (err) {
        console.error(err);
        document.getElementById('tableBody').innerHTML = '<tr><td colspan="3">Ошибка загрузки</td></tr>';
    }
}

function renderTable() {
    const tbody = document.getElementById('tableBody');
    if (!teachersList.length) {
        tbody.innerHTML = '<tr><td colspan="3">Нет учителей</td></tr>';
        return;
    }
    tbody.innerHTML = teachersList.map(teacher => `
        <tr data-id="${teacher.id}">
            <td>${escapeHtml(teacher.name)}</td>
            <td>${escapeHtml(teacher.subject || '—')}</td>
            <td>
                <select class="campus-select" data-id="${teacher.id}">
                    <option value="" ${teacher.campus === '' ? 'selected' : ''}>Оба корпуса</option>
                    <option value="Феофанова 10" ${teacher.campus === 'Феофанова 10' ? 'selected' : ''}>Феофанова 10</option>
                    <option value="Цветоносная 2" ${teacher.campus === 'Цветоносная 2' ? 'selected' : ''}>Цветоносная 2</option>
                </select>
            </td>
        </tr>
    `).join('');
}

async function saveAllChanges() {
    const updates = [];
    document.querySelectorAll('.campus-select').forEach(select => {
        const teacherId = parseInt(select.dataset.id);
        const newCampus = select.value;
        updates.push({ id: teacherId, campus: newCampus });
    });
    
    const messageDiv = document.getElementById('message');
    messageDiv.style.display = 'block';
    messageDiv.className = 'message';
    messageDiv.innerHTML = 'Сохранение...';
    
    try {
        const res = await fetch('/api/teachers/campus/batch', {
            method: 'POST',
            headers: { 'Content-Type': 'application/json' },
            body: JSON.stringify({ updates })
        });
        const data = await res.json();
        if (res.ok) {
            messageDiv.className = 'message success';
            messageDiv.innerHTML = '✅ Изменения сохранены';
            setTimeout(() => messageDiv.style.display = 'none', 3000);
            // обновляем локальные данные
            teachersList = teachersList.map(t => {
                const update = updates.find(u => u.id === t.id);
                if (update) t.campus = update.campus;
                return t;
            });
        } else {
            throw new Error(data.error || 'Ошибка сохранения');
        }
    } catch (err) {
        messageDiv.className = 'message error';
        messageDiv.innerHTML = `❌ Ошибка: ${err.message}`;
        setTimeout(() => messageDiv.style.display = 'none', 3000);
    }
}

function setupEventListeners() {
    document.getElementById('saveAllBtn')?.addEventListener('click', saveAllChanges);
    document.getElementById('logoutBtn')?.addEventListener('click', async () => {
        await fetch('/api/logout', { method: 'POST' });
        window.location.href = '/';
    });
}

function escapeHtml(str) {
    if (!str) return '';
    return str.replace(/[&<>]/g, function(m) {
        if (m === '&') return '&amp;';
        if (m === '<') return '&lt;';
        if (m === '>') return '&gt;';
        return m;
    });
}