import { api } from '../api.js';
import { escapeHtml, showAlert, hideAlert } from '../utils.js';
import { fetchEducationForms } from './edu-forms.js';

export async function initGroups() {
    const groupsTbody = document.getElementById('groups-tbody');
    const createGroupForm = document.getElementById('create-group-form');
    const newGroupEfSelect = document.getElementById('new-group-ef');
    const newGroupDepartmentSelect = document.getElementById('new-group-department');
    const newGroupSpecialitySelect = document.getElementById('new-group-speciality-code');
    const filterEfSelect = document.getElementById('filter-ef');

    let allGroups = [];
    let educationForms = [];
    let departments = [];
    let specialties = [];

    async function loadInitialData() {
        try {
            [educationForms, departments, specialties] = await Promise.all([
                fetchEducationForms(),
                api.get('/api/departments'),
                api.get('/api/specialties')
            ]);
            populateEfSelects(educationForms);
            populateDepartmentSelect(departments);
            populateSpecialitySelect(specialties);
            await loadGroups();
        } catch (e) {
            groupsTbody.innerHTML = '<tr><td colspan="8" class="loading-row">Ошибка загрузки данных</td></tr>';
        }
    }

    async function loadGroups() {
        try {
            allGroups = await api.get('/api/groups');
            applyGroupFilter();
        } catch (e) {
            groupsTbody.innerHTML = '<tr><td colspan="8" class="loading-row">Ошибка загрузки</td></tr>';
        }
    }

    function applyGroupFilter() {
        const filterId = filterEfSelect.value;
        const filtered = filterId
            ? allGroups.filter(g => g.educationFormId == filterId)
            : allGroups;
        renderGroups(filtered);
    }

    filterEfSelect.addEventListener('change', applyGroupFilter);

    function populateEfSelects(forms) {
        // Group creation select
        const currentVal = newGroupEfSelect.value;
        newGroupEfSelect.innerHTML = forms.map(ef =>
            `<option value="${ef.id}">${escapeHtml(ef.name)}</option>`
        ).join('');
        if (currentVal && forms.find(f => f.id == currentVal)) {
            newGroupEfSelect.value = currentVal;
        }
        syncSelects(newGroupEfSelect);

        // Filter select
        const currentFilter = filterEfSelect.value;
        filterEfSelect.innerHTML = '<option value="">Все формы</option>' +
            forms.map(ef =>
                `<option value="${ef.id}">${escapeHtml(ef.name)}</option>`
            ).join('');
        if (currentFilter) filterEfSelect.value = currentFilter;
        syncSelects(filterEfSelect);
    }

    function populateDepartmentSelect(items) {
        const currentVal = newGroupDepartmentSelect.value;
        if (!items || !items.length) {
            newGroupDepartmentSelect.innerHTML = '<option value="">Нет кафедр</option>';
            return;
        }

        newGroupDepartmentSelect.innerHTML = '<option value="">Выберите кафедру</option>' +
            items.map(department => {
                const name = department.departmentName || department.name || 'Без названия';
                const code = department.departmentCode || department.code || department.id;
                return `<option value="${department.id}">${escapeHtml(name)} (${escapeHtml(String(code))})</option>`;
            }).join('');
        if (currentVal && items.find(department => department.id == currentVal)) {
            newGroupDepartmentSelect.value = currentVal;
        }
        syncSelects(newGroupDepartmentSelect);
    }

    function populateSpecialitySelect(items) {
        const currentVal = newGroupSpecialitySelect.value;
        if (!items || !items.length) {
            newGroupSpecialitySelect.innerHTML = '<option value="">Нет специальностей</option>';
            return;
        }

        newGroupSpecialitySelect.innerHTML = '<option value="">Выберите специальность</option>' +
            items.map(speciality => {
                const name = speciality.specialityName || speciality.name || 'Без названия';
                const code = speciality.specialityCode || speciality.specialtyCode || speciality.specialty_code || speciality.id;
                return `<option value="${speciality.id}">${escapeHtml(code)} — ${escapeHtml(name)}</option>`;
            }).join('');
        if (currentVal && items.find(speciality => speciality.id == currentVal)) {
            newGroupSpecialitySelect.value = currentVal;
        }
        syncSelects(newGroupSpecialitySelect);
    }

    function departmentLabel(departmentId) {
        const department = departments.find(item => item.id == departmentId);
        if (!department) return departmentId || '-';
        return department.departmentName || department.name || departmentId;
    }

    function specialityLabel(specialityId) {
        const speciality = specialties.find(item => item.id == specialityId);
        if (!speciality) return specialityId || '-';
        const code = speciality.specialityCode || speciality.specialtyCode || speciality.specialty_code || speciality.id;
        const name = speciality.specialityName || speciality.name || '';
        return name ? `${code} — ${name}` : code;
    }

    function renderGroups(groups) {
        if (!groups || !groups.length) {
            groupsTbody.innerHTML = '<tr><td colspan="8" class="loading-row">Нет групп</td></tr>';
            return;
        }
        groupsTbody.innerHTML = groups.map(g => `
      <tr>
        <td>${g.id}</td>
        <td>${escapeHtml(g.name)}</td>
        <td>${escapeHtml(g.groupSize)}</td>
        <td><span class="badge badge-ef">${escapeHtml(g.educationFormName)}</span></td>
        <td>${escapeHtml(departmentLabel(g.departmentId))}</td>
        <td>${g.course || '-'}</td>
        <td>${escapeHtml(specialityLabel(g.specialityCode))}</td>
        <td><button class="btn-delete" data-id="${g.id}">Удалить</button></td>
      </tr>`).join('');
    }

    createGroupForm.addEventListener('submit', async (e) => {
        e.preventDefault();
        hideAlert('create-group-alert');
        const name = document.getElementById('new-group-name').value.trim();
        const groupSize = document.getElementById('new-group-size').value;
        const educationFormId = newGroupEfSelect.value;
        const departmentId = newGroupDepartmentSelect.value;
        const yearStartStudy = document.getElementById('new-group-yearStartStudy').value;
        const specialityCode = newGroupSpecialitySelect.value;

        if (!name) { showAlert('create-group-alert', 'Введите название группы', 'error'); return; }
        if (!groupSize) { showAlert('create-group-alert', 'Введите размер группы', 'error'); return; }
        if (!educationFormId) { showAlert('create-group-alert', 'Выберите форму обучения', 'error'); return; }
        if (!departmentId) { showAlert('create-group-alert', 'Выберите кафедру', 'error'); return; }
        if (!yearStartStudy) { showAlert('create-group-alert', 'Введите год начала обучения', 'error'); return; }
        if (!specialityCode) { showAlert('create-group-alert', 'Выберите специальность', 'error'); return; }

        try {
            const data = await api.post('/api/groups', { 
                name, 
                groupSize: Number(groupSize), 
                educationFormId: Number(educationFormId),
                departmentId: Number(departmentId),
                yearStartStudy: Number(yearStartStudy),
                specialityCode: Number(specialityCode)
            });
            showAlert('create-group-alert', `Группа "${escapeHtml(data.name || name)}" создана`, 'success');
            createGroupForm.reset();
            syncSelects(newGroupEfSelect, newGroupDepartmentSelect, newGroupSpecialitySelect);
            loadGroups();
        } catch (e) {
            showAlert('create-group-alert', e.message || 'Ошибка создания', 'error');
        }
    });

    groupsTbody.addEventListener('click', async (e) => {
        const btn = e.target.closest('.btn-delete');
        if (!btn) return;
        if (!confirm('Удалить группу?')) return;
        try {
            await api.delete('/api/groups/' + btn.dataset.id);
            loadGroups();
        } catch (e) {
            alert(e.message || 'Ошибка удаления');
        }
    });

    await loadInitialData();

    function syncSelects(...selects) {
        selects.filter(Boolean).forEach(select => {
            select.dispatchEvent(new Event('change', { bubbles: true }));
        });
    }
}