// public/info.js – страница просмотра записей

let currentUser = null;
let currentRegistrations = [];

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

async function checkAuth() {
    try {
        const res = await fetch('/api/me');
        const data = await res.json();
        if (!data.authenticated || (data.user.role !== 'admin' && data.user.role !== 'user')) {
            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 loadFilterOptions() {
    try {
        const [classes, teachers, subjects] = await Promise.all([
            fetch('/api/filter-options/class-names').then(r => r.json()),
            fetch('/api/filter-options/teachers').then(r => r.json()),
            fetch('/api/filter-options/subjects').then(r => r.json())
        ]);
        populateSelect('filterClass', classes, 'Все классы');
        populateSelect('filterTeacher', teachers, 'Все учителя');
        populateSelect('filterSubject', subjects, 'Все предметы');
    } catch (err) {
        console.error('Ошибка загрузки опций', err);
    }
}

function populateSelect(selectId, options, defaultLabel) {
    const select = document.getElementById(selectId);
    if (!select) return;
    select.innerHTML = `<option value="">${defaultLabel}</option>`;
    options.forEach(opt => {
        const option = document.createElement('option');
        option.value = opt;
        option.textContent = opt;
        select.appendChild(option);
    });
}

async function loadRegistrations() {
    const params = new URLSearchParams({
        parent_name: document.getElementById('filterParentName').value,
        class_name: document.getElementById('filterClass').value,
        subject: document.getElementById('filterSubject').value,
        teacher: document.getElementById('filterTeacher').value
    });
    try {
        const res = await fetch(`/api/info/registrations?${params}`);
        currentRegistrations = await res.json();
        renderTable(currentRegistrations);
        document.getElementById('recordsCount').innerText = `Найдено: ${currentRegistrations.length}`;
    } catch (err) {
        console.error(err);
        document.getElementById('tableBody').innerHTML = '<tr><td colspan="9">Ошибка загрузки</td></tr>';
    }
}

function renderTable(registrations) {
    const tbody = document.getElementById('tableBody');
    if (!registrations.length) {
        tbody.innerHTML = '<tr><td colspan="9">Нет записей</td></tr>';
        return;
    }
    tbody.innerHTML = registrations.map(reg => `
        <tr>
            <td>${escapeHtml(reg.parent_name)}</td>
            <td>${escapeHtml(reg.parent_phone)}</td>
            <td>${escapeHtml(reg.class_name)}</td>
            <td>${escapeHtml(reg.subject)}</td>
            <td>${escapeHtml(reg.teacher)}</td>
            <td>${escapeHtml(reg.topic || '—')}</td>
            <td>${escapeHtml(reg.date)}</td>
            <td>${escapeHtml(reg.time)}</td>
            <td>${new Date(reg.created_at).toLocaleString()}</td>
        </tr>
    `).join('');
}

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;
    });
}

function exportToCSV() {
    if (!currentRegistrations.length) {
        alert('Нет данных для экспорта');
        return;
    }
    // Заголовки
    const headers = ['ФИО родителя', 'Телефон', 'Класс', 'Предмет', 'Учитель', 'Тема урока', 'Дата урока', 'Время', 'Дата регистрации'];
    const rows = currentRegistrations.map(reg => [
        reg.parent_name,
        reg.parent_phone,
        reg.class_name,
        reg.subject,
        reg.teacher,
        reg.topic || '',
        reg.date,
        reg.time,
        new Date(reg.created_at).toLocaleString()
    ]);
    const csvContent = [headers, ...rows]
        .map(row => row.map(cell => `"${String(cell).replace(/"/g, '""')}"`).join(';'))
        .join('\n');
    // Добавляем BOM для корректной поддержки кириллицы в Excel
    const blob = new Blob(['\uFEFF' + csvContent], { type: 'text/csv;charset=utf-8;' });
    const link = document.createElement('a');
    const url = URL.createObjectURL(blob);
    link.href = url;
    link.setAttribute('download', 'zapis_roditelei.csv');
    document.body.appendChild(link);
    link.click();
    document.body.removeChild(link);
    URL.revokeObjectURL(url);
}

function setupEventListeners() {
    document.getElementById('applyFiltersBtn')?.addEventListener('click', () => loadRegistrations());
    document.getElementById('resetFiltersBtn')?.addEventListener('click', () => {
        document.getElementById('filterParentName').value = '';
        document.getElementById('filterClass').value = '';
        document.getElementById('filterSubject').value = '';
        document.getElementById('filterTeacher').value = '';
        loadRegistrations();
    });
    document.getElementById('exportBtn')?.addEventListener('click', exportToCSV);
    document.getElementById('logoutBtn')?.addEventListener('click', async () => {
        await fetch('/api/logout', { method: 'POST' });
        window.location.href = '/';
    });
}