import { api } from '../api.js';
import { escapeHtml, showAlert, hideAlert } from '../utils.js';

const ROLE_LABELS = { ADMIN: 'Администратор', TEACHER: 'Преподаватель', STUDENT: 'Студент' };
const ROLE_BADGE = { ADMIN: 'badge-admin', TEACHER: 'badge-teacher', STUDENT: 'badge-student' };

export async function initUsers() {
    const usersTbody = document.getElementById('users-tbody');
    const createForm = document.getElementById('create-form');
    const modalBackdrop = document.getElementById('modal-backdrop');

    // ===== 1-е модальное окно: Добавить занятие =====
    const modalAddLesson = document.getElementById('modal-add-lesson');
    const modalAddLessonClose = document.getElementById('modal-add-lesson-close');
    const addLessonForm = document.getElementById('add-lesson-form');

    const lessonGroupSelect = document.getElementById('lesson-group');
    const lessonDisciplineSelect = document.getElementById('lesson-discipline');
    const lessonClassroomSelect = document.getElementById('lesson-classroom');
    const lessonTypeSelect = document.getElementById('lesson-type');
    const lessonOnlineFormat = document.getElementById('format-online');
    const lessonOfflineFormat = document.getElementById('format-offline');
    const lessonUserId = document.getElementById('lesson-user-id');
    const lessonDaySelect = document.getElementById('lesson-day');
    const weekUpper = document.getElementById('week-upper');
    const weekLower = document.getElementById('week-lower');
    const lessonTimeSelect = document.getElementById('lesson-time');

    // ===== 2-е модальное окно: Просмотр занятий =====
    const modalViewLessons = document.getElementById('modal-view-lessons');
    const modalViewLessonsClose = document.getElementById('modal-view-lessons-close');
    const lessonsContainer = document.getElementById('lessons-container');
    const modalTeacherName = document.getElementById('modal-teacher-name');

    let currentLessonsTeacherId = null;
    let currentLessonsTeacherName = '';
    // ===== Данные =====
    let groups = [];
    let subjects = [];
    let classrooms = [];

    const weekdaysTimes = [
        "8:00-9:30",
        "9:40-11:10",
        "11:40-13:10",
        "13:20-14:50",
        "15:00-16:30",
        "16:50-18:20",
        "18:30-19:00"
    ];

    const saturdayTimes = [
        "8:20-9:50",
        "10:00-11:30",
        "11:40-13:10",
        "13:20-14:50"
    ];

    // =========================================================
    // СИНХРОНИЗАЦИЯ ВЫСОТЫ 1-й МОДАЛКИ -> CSS переменная
    // =========================================================
    const addLessonContent = document.querySelector('#modal-add-lesson .modal-content');

    function setAddLessonHeightVar(px) {
        const h = Math.max(0, Math.ceil(px || 0));
        document.documentElement.style.setProperty('--add-lesson-height', `${h}px`);
    }

    function syncAddLessonHeight() {
        if (!addLessonContent) return;

        if (!modalAddLesson?.classList.contains('open')) {
            // если первая модалка закрыта — "шапки" нет
            setAddLessonHeightVar(0);
            return;
        }

        setAddLessonHeightVar(addLessonContent.getBoundingClientRect().height);
    }

    // Авто-обновление при любом изменении размеров первой модалки
    if (addLessonContent && 'ResizeObserver' in window) {
        const ro = new ResizeObserver(() => syncAddLessonHeight());
        ro.observe(addLessonContent);
    }

    window.addEventListener('resize', () => syncAddLessonHeight());

    // =========================================================
    // Загрузка справочников
    // =========================================================
    async function loadGroups() {
        try {
            groups = await api.get('/api/groups');
            renderGroupOptions();
        } catch (e) {
            console.error('Ошибка загрузки групп:', e);
        }
    }

    async function loadSubjects() {
        try {
            subjects = await api.get('/api/subjects');
            renderSubjectOptions();
        } catch (e) {
            console.error('Ошибка загрузки дисциплин:', e);
        }
    }

    async function loadClassrooms() {
        try {
            classrooms = await api.get('/api/classrooms');
            renderClassroomsOptions();
        } catch (e) {
            console.error('Ошибка загрузки аудиторий:', e);
        }
    }

    function renderGroupOptions() {
        if (!groups || groups.length === 0) {
            lessonGroupSelect.innerHTML = '<option value="">Нет доступных групп</option>';
            return;
        }

        lessonGroupSelect.innerHTML =
            '<option value="">Выберите группу</option>' +
            groups.map(g => {
                let optionText = escapeHtml(g.name);
                if (g.groupSize) optionText += ` (численность: ${g.groupSize} чел.)`;
                return `<option value="${g.id}">${optionText}</option>`;
            }).join('');
    }

    function renderSubjectOptions() {
        lessonDisciplineSelect.innerHTML =
            '<option value="">Выберите дисциплину</option>' +
            subjects.map(s => `<option value="${s.id}">${escapeHtml(s.name)}</option>`).join('');
    }

    function renderClassroomsOptions() {
        if (!classrooms || classrooms.length === 0) {
            lessonClassroomSelect.innerHTML = '<option value="">Нет доступных аудиторий</option>';
            return;
        }

        const selectedGroupId = lessonGroupSelect.value;
        const selectedGroup = groups?.find(g => g.id == selectedGroupId);
        const groupSize = selectedGroup?.groupSize || 0;

        lessonClassroomSelect.innerHTML =
            '<option value="">Выберите аудиторию</option>' +
            classrooms.map(c => {
                let optionText = escapeHtml(c.name);

                if (c.capacity) optionText += ` (вместимость: ${c.capacity} чел.)`;

                if (c.isAvailable === false) {
                    optionText += ` ❌ Занята`;
                } else if (selectedGroupId && groupSize > 0 && c.capacity && groupSize > c.capacity) {
                    optionText += ` ⚠️ Недостаточно места`;
                }

                return `<option value="${c.id}">${optionText}</option>`;
            }).join('');
    }

    lessonGroupSelect.addEventListener('change', function () {
        renderClassroomsOptions();
        requestAnimationFrame(() => syncAddLessonHeight());
    });

    function updateTimeOptions(dayValue) {
        let times = [];
        if (dayValue === "Суббота") {
            times = saturdayTimes;
        } else if (dayValue && dayValue !== '') {
            times = weekdaysTimes;
        } else {
            lessonTimeSelect.innerHTML = '<option value="">Сначала выберите день</option>';
            lessonTimeSelect.disabled = true;
            return;
        }

        lessonTimeSelect.innerHTML =
            '<option value="">Выберите время</option>' +
            times.map(t => `<option value="${t}">${t}</option>`).join('');
        lessonTimeSelect.disabled = false;
    }

    // =========================================================
    // Пользователи
    // =========================================================
    async function loadUsers() {
        try {
            const users = await api.get('/api/users');
            renderUsers(users);
        } catch (e) {
            usersTbody.innerHTML =
                '<tr><td colspan="4" class="loading-row">Ошибка загрузки: ' +
                escapeHtml(e.message) + '</td></tr>';
        }
    }

    function renderUsers(users) {
        if (!users || !users.length) {
            usersTbody.innerHTML = '<tr><td colspan="4" class="loading-row">Нет пользователей</td></tr>';
            return;
        }

        usersTbody.innerHTML = users.map(u => `
            <tr>
                <td>${u.id}</td>
                <td>${escapeHtml(u.username)}</td>
                <td><span class="badge ${ROLE_BADGE[u.role] || ''}">${ROLE_LABELS[u.role] || escapeHtml(u.role)}</span></td>
                <td>
                    <button class="btn-delete" data-id="${u.id}">Удалить</button>
                </td>
                <td>
                    <button class="btn-add-lesson" data-id="${u.id}" data-name="${escapeHtml(u.username)}">Добавить занятие</button>
                </td>
            </tr>
        `).join('');
    }

    function updateBackdrop() {
        if(!modalBackdrop) return;
        const anyOpen =
            modalAddLesson?.classList.contains('open') ||
            modalViewLessons?.classList.contains('open');

        modalBackdrop.classList.toggle('open', anyOpen);
    }
    // Клик мимо модалок закроет их, если не надо, то закомментить этот код
    modalBackdrop?.addEventListener('click', () => {
        if (modalAddLesson?.classList.contains('open')) {
        modalAddLesson.classList.remove('open');
        resetLessonForm();
        syncAddLessonHeight();
        }
        if (modalViewLessons?.classList.contains('open')) {
        closeViewLessonsModal();
        }
    });

    // =========================================================
    // 1-я модалка: добавление занятия
    // =========================================================
    function resetLessonForm() {
        addLessonForm.reset();
        lessonUserId.value = '';

        if (weekUpper) weekUpper.checked = false;
        if (weekLower) weekLower.checked = false;

        if (lessonOfflineFormat) lessonOfflineFormat.checked = true;
        if (lessonOnlineFormat) lessonOnlineFormat.checked = false;

        lessonTimeSelect.innerHTML = '<option value="">Сначала выберите день</option>';
        lessonTimeSelect.disabled = true;

        hideAlert('add-lesson-alert');
    }

    function openAddLessonModal(userId) {
        lessonUserId.value = userId;

        lessonDaySelect.value = '';
        updateTimeOptions('');

        modalAddLesson.classList.add('open');
        updateBackdrop();
        requestAnimationFrame(() => syncAddLessonHeight());
    }

    addLessonForm.addEventListener('submit', async (e) => {
        e.preventDefault();
        hideAlert('add-lesson-alert');

        const userId = lessonUserId.value;
        const groupId = lessonGroupSelect.value;
        const subjectId = lessonDisciplineSelect.value;
        const classroomId = lessonClassroomSelect.value;
        const lessonType = lessonTypeSelect.value;
        const dayOfWeek = lessonDaySelect.value;
        const timeSlot = lessonTimeSelect.value;

        const lessonFormat = document.querySelector('input[name="lessonFormat"]:checked')?.value;

        if (!groupId) { showAlert('add-lesson-alert', 'Выберите группу', 'error'); requestAnimationFrame(() => syncAddLessonHeight()); return; }
        if (!subjectId) { showAlert('add-lesson-alert', 'Выберите дисциплину', 'error'); requestAnimationFrame(() => syncAddLessonHeight()); return; }
        if (!classroomId) { showAlert('add-lesson-alert', 'Выберите аудиторию', 'error'); requestAnimationFrame(() => syncAddLessonHeight()); return; }
        if (!dayOfWeek) { showAlert('add-lesson-alert', 'Выберите день недели', 'error'); requestAnimationFrame(() => syncAddLessonHeight()); return; }
        if (!timeSlot) { showAlert('add-lesson-alert', 'Выберите время', 'error'); requestAnimationFrame(() => syncAddLessonHeight()); return; }

        const weekUpperChecked = weekUpper?.checked || false;
        const weekLowerChecked = weekLower?.checked || false;

        let weekType = null;
        if (weekUpperChecked && weekLowerChecked) weekType = 'Обе';
        else if (weekUpperChecked) weekType = 'Верхняя';
        else if (weekLowerChecked) weekType = 'Нижняя';

        try {
            await api.post('/api/users/lessons/create', {
                teacherId: parseInt(userId),
                groupId: parseInt(groupId),
                subjectId: parseInt(subjectId),
                classroomId: parseInt(classroomId),
                typeLesson: lessonType,
                lessonFormat: lessonFormat,
                day: dayOfWeek,
                week: weekType,
                time: timeSlot
            });

            if (modalViewLessons?.classList.contains('open') && currentLessonsTeacherId == userId) {
                await loadTeacherLessons(currentLessonsTeacherId, currentLessonsTeacherName);
            }

            showAlert('add-lesson-alert', 'Занятие добавлено', 'success');

            lessonGroupSelect.value = '';
            lessonDisciplineSelect.value = '';
            lessonClassroomSelect.value = '';
            lessonTypeSelect.value = '';
            lessonDaySelect.value = '';
            lessonTimeSelect.value = '';
            lessonTimeSelect.disabled = true;

            weekUpper.checked = false;
            weekLower.checked = false;
            document.querySelector('input[name="lessonFormat"][value="Очно"]').checked = true;

            requestAnimationFrame(() => syncAddLessonHeight());

            setTimeout(() => {
                hideAlert('add-lesson-alert');
                syncAddLessonHeight();
            }, 3000);
        } catch (err) {
            showAlert('add-lesson-alert', err.message || 'Ошибка добавления занятия', 'error');
            requestAnimationFrame(() => syncAddLessonHeight());
        }
    });

    lessonDaySelect.addEventListener('change', function () {
        updateTimeOptions(this.value);
        requestAnimationFrame(() => syncAddLessonHeight());
    });

    if (modalAddLessonClose) {
        modalAddLessonClose.addEventListener('click', () => {
            modalAddLesson.classList.remove('open');
            resetLessonForm();
            syncAddLessonHeight();
            updateBackdrop();
        });
    }

    if (modalAddLesson) {
        modalAddLesson.addEventListener('click', (e) => {
            if (e.target === modalAddLesson) {
                modalAddLesson.classList.remove('open');
                resetLessonForm();
                syncAddLessonHeight();
                updateBackdrop();
            }
        });
    }

    // =========================================================
    // Создание пользователя
    // =========================================================
    createForm.addEventListener('submit', async (e) => {
        e.preventDefault();
        hideAlert('create-alert');

        const username = document.getElementById('new-username').value.trim();
        const password = document.getElementById('new-password').value;
        const role = document.getElementById('new-role').value;

        if (!username || !password) {
            showAlert('create-alert', 'Заполните все поля', 'error');
            return;
        }

        try {
            const data = await api.post('/api/users', { username, password, role });
            showAlert('create-alert', `Пользователь "${escapeHtml(data.username)}" создан`, 'success');
            createForm.reset();
            loadUsers();
        } catch (err) {
            showAlert('create-alert', err.message || 'Ошибка соединения', 'error');
        }
    });

    // =========================================================
    // Инициализация
    // =========================================================
    await Promise.all([loadUsers(), loadGroups(), loadSubjects(), loadClassrooms()]);

    // =========================================================
    // 2-я модалка: просмотр занятий
    // =========================================================
    async function loadTeacherLessons(teacherId, teacherName) {
        try {
            lessonsContainer.innerHTML = '<div class="loading-lessons">Загрузка занятий...</div>';

            modalTeacherName.textContent = teacherName
                ? `Занятия преподавателя: ${teacherName}`
                : 'Занятия преподавателя';

            const lessons = await api.get(`/api/users/lessons/${teacherId}`);

            if (!lessons || lessons.length === 0) {
                lessonsContainer.innerHTML = '<div class="no-lessons">У преподавателя пока нет занятий</div>';
                return;
            }

            const daysOrder = ['Понедельник', 'Вторник', 'Среда', 'Четверг', 'Пятница', 'Суббота'];
            const lessonsByDay = {};

            lessons.forEach(lesson => {
                if (!lessonsByDay[lesson.day]) lessonsByDay[lesson.day] = [];
                lessonsByDay[lesson.day].push(lesson);
            });

            Object.keys(lessonsByDay).forEach(day => {
                lessonsByDay[day].sort((a, b) => a.time.localeCompare(b.time));
            });

            let html = '';

            daysOrder.forEach(day => {
                if (!lessonsByDay[day]) return;

                html += `<div class="lesson-day-divider">${day}</div>`;

                lessonsByDay[day].forEach(lesson => {
                    html += `
                        <div class="lesson-card">
                            <div class="lesson-card-header">
                                <span class="lesson-group">${escapeHtml(lesson.groupName)}</span>
                                <span class="lesson-time">${escapeHtml(lesson.time)}</span>
                            </div>
                            <div class="lesson-card-body">
                                <div class="lesson-subject">${escapeHtml(lesson.subjectName)}</div>
                                <div class="lesson-details">
                                    <span class="lesson-detail-item">${escapeHtml(lesson.typeLesson)}</span>
                                    <span class="lesson-detail-item">${escapeHtml(lesson.lessonFormat)}</span>
                                    <span class="lesson-detail-item">${escapeHtml(lesson.week)}</span>
                                    <span class="lesson-detail-item">${escapeHtml(lesson.classroomName)}</span>
                                </div>
                            </div>
                        </div>
                    `;
                });
            });

            lessonsContainer.innerHTML = html;
        } catch (e) {
            lessonsContainer.innerHTML = `<div class="no-lessons">Ошибка загрузки: ${escapeHtml(e.message)}</div>`;
            console.error('Ошибка загрузки занятий:', e);
        }
    }

    function openViewLessonsModal(teacherId, teacherName) {
        currentLessonsTeacherId = teacherId;
        currentLessonsTeacherName = teacherName || '';

        loadTeacherLessons(teacherId, teacherName);

        requestAnimationFrame(() => syncAddLessonHeight());

        modalViewLessons.classList.add('open');
        updateBackdrop();
//        document.body.style.overflow = 'hidden';
    }

    function closeViewLessonsModal() {
        modalViewLessons.classList.remove('open');
        updateBackdrop();
//        document.body.style.overflow = '';

        currentLessonsTeacherId = null;
        currentLessonsTeacherName = '';
    }

    if (modalViewLessonsClose) {
        modalViewLessonsClose.addEventListener('click', closeViewLessonsModal);
    }

    if (modalViewLessons) {
        modalViewLessons.addEventListener('click', (e) => {
            if (e.target === modalViewLessons) closeViewLessonsModal();
        });
    }

    document.addEventListener('keydown', (e) => {
        if (e.key !== 'Escape') return;

        if (modalAddLesson?.classList.contains('open')) {
            modalAddLesson.classList.remove('open');
            resetLessonForm();
            syncAddLessonHeight();
            updateBackdrop();
            return;
        }

        if (modalViewLessons?.classList.contains('open')) {
            closeViewLessonsModal();
            return;
        }
    });

    // =========================================================
    // ЕДИНЫЙ обработчик кликов по таблице (ВАЖНО: без дубля)
    // =========================================================
    usersTbody.addEventListener('click', async (e) => {
        const deleteBtn = e.target.closest('.btn-delete');
        if (deleteBtn) {
            if (!confirm('Удалить пользователя?')) return;
            try {
                await api.delete('/api/users/' + deleteBtn.dataset.id);
                loadUsers();
            } catch (err) {
                alert(err.message || 'Ошибка удаления');
            }
            return;
        }

        const addLessonBtn = e.target.closest('.btn-add-lesson');
        if (addLessonBtn) {
            e.preventDefault();

            const teacherId = addLessonBtn.dataset.id;
            const teacherName = addLessonBtn.dataset.name;

            openAddLessonModal(teacherId);
            openViewLessonsModal(teacherId, teacherName);

            return;
        }

        const viewLessonsBtn = e.target.closest('.btn-view-lessons');
        if (viewLessonsBtn) {
            e.preventDefault();
            const teacherId = viewLessonsBtn.dataset.id;
            const teacherName = viewLessonsBtn.dataset.name;
            openViewLessonsModal(teacherId, teacherName);
            return;
        }
    });
}