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

const ROLE_DEPARTMENT = 'DEPARTMENT';

export async function initDepartmentWorkspace() {
    const role = localStorage.getItem('role');
    const userDepartmentId = localStorage.getItem('departmentId');
    const departmentField = document.getElementById('department-workspace-department-field');
    const departmentSelect = document.getElementById('department-workspace-department');
    const startInput = document.getElementById('department-workspace-start');
    const endInput = document.getElementById('department-workspace-end');
    const refreshButton = document.getElementById('department-workspace-refresh');
    const importForm = document.getElementById('department-subject-import-form');
    const subjectsTbody = document.getElementById('department-subjects-tbody');
    const subjectCount = document.getElementById('department-subject-count');
    const commentsCard = document.getElementById('department-comments-card');
    const commentsTitle = document.getElementById('department-comments-title');
    const commentsList = document.getElementById('department-comment-list');
    const commentsForm = document.getElementById('department-comment-form');
    const commentsSubjectInput = document.getElementById('department-comment-subject-id');
    const commentsTextInput = document.getElementById('department-comment-text');
    const commentsCloseButton = document.getElementById('department-comments-close');

    setDefaultDates(startInput, endInput);
    refreshButton?.addEventListener('click', loadWorkspace);
    departmentSelect?.addEventListener('change', loadWorkspace);
    startInput?.addEventListener('change', loadWorkload);
    endInput?.addEventListener('change', loadWorkload);
    importForm?.addEventListener('submit', importSubjects);
    commentsForm?.addEventListener('submit', saveComment);
    commentsCloseButton?.addEventListener('click', () => {
        commentsCard.hidden = true;
        commentsSubjectInput.value = '';
    });
    subjectsTbody?.addEventListener('click', event => {
        const button = event.target.closest('.department-comments-open');
        if (button) {
            openComments(button.dataset.subjectId, button.dataset.subjectName);
        }
    });

    try {
        await loadDepartments(role, userDepartmentId);
        if (role === ROLE_DEPARTMENT) {
            departmentField.hidden = true;
            departmentSelect.value = userDepartmentId || '';
        }
        await loadWorkspace();
    } catch (error) {
        showAlert('department-workspace-alert', error.message || 'Ошибка загрузки кабинета кафедры', 'error');
    }

    async function loadWorkspace() {
        hideAlert('department-workspace-alert');
        await Promise.all([loadSubjects(), loadTeachers(), loadWorkload()]);
    }

    async function loadSubjects() {
        const departmentId = selectedDepartmentId();
        subjectsTbody.innerHTML = '<tr><td colspan="4" class="loading-row">Загрузка...</td></tr>';
        subjectCount.textContent = 'Загрузка...';
        try {
            const subjects = await api.get(`/api/department/subjects?departmentId=${encodeURIComponent(departmentId || '')}`);
            subjectCount.textContent = subjectCountLabel(subjects.length);
            if (!subjects.length) {
                subjectsTbody.innerHTML = '<tr><td colspan="4" class="loading-row">Дисциплины не найдены</td></tr>';
                return;
            }
            subjectsTbody.innerHTML = subjects.map(subject => `
                <tr>
                    <td>${escapeHtml(subject.code || '-')}</td>
                    <td>${escapeHtml(subject.name || '-')}</td>
                    <td>${escapeHtml(subject.description || '-')}</td>
                    <td>
                        <button type="button" class="btn-edit-classroom department-comments-open"
                                data-subject-id="${escapeHtml(subject.id)}"
                                data-subject-name="${escapeHtml(subject.name || '')}">
                            Открыть
                        </button>
                    </td>
                </tr>
            `).join('');
        } catch (error) {
            subjectsTbody.innerHTML = `<tr><td colspan="4" class="loading-row">${escapeHtml(error.message || 'Ошибка загрузки дисциплин')}</td></tr>`;
            subjectCount.textContent = '0 дисциплин';
        }
    }

    async function importSubjects(event) {
        event.preventDefault();
        const alertId = 'department-subject-import-alert';
        hideAlert(alertId);
        const departmentId = selectedDepartmentId();
        const rows = document.getElementById('department-subject-import-text').value
            .split('\n')
            .map(row => row.trim())
            .filter(Boolean)
            .map(row => {
                const [code, ...nameParts] = row.split(';');
                return {
                    code: (code || '').trim(),
                    name: nameParts.join(';').trim(),
                    departmentId: Number(departmentId)
                };
            })
            .filter(item => item.name);

        if (!departmentId) {
            showAlert(alertId, 'Выберите кафедру', 'error');
            return;
        }
        if (!rows.length) {
            showAlert(alertId, 'Добавьте хотя бы одну строку в формате «код; название»', 'error');
            return;
        }

        try {
            const result = await api.post('/api/department/subjects/import', rows);
            showAlert(alertId, result.message || 'Дисциплины загружены', 'success');
            document.getElementById('department-subject-import-text').value = '';
            await loadSubjects();
        } catch (error) {
            showAlert(alertId, error.message || 'Ошибка загрузки дисциплин', 'error');
        }
    }

    async function openComments(subjectId, subjectName) {
        commentsCard.hidden = false;
        commentsTitle.textContent = `Комментарии: ${subjectName || 'дисциплина'}`;
        commentsSubjectInput.value = subjectId;
        commentsTextInput.value = '';
        hideAlert('department-comment-alert');
        commentsList.textContent = 'Загрузка...';

        try {
            const comments = await api.get(`/api/department/subjects/${subjectId}/comments`);
            commentsList.innerHTML = comments.length
                ? comments.map(comment => `
                    <article class="department-comment-item">
                        <strong>${escapeHtml(comment.authorName || 'Автор не указан')}</strong>
                        <span>${escapeHtml(formatDateTime(comment.createdAt))}</span>
                        <p>${escapeHtml(comment.comment)}</p>
                    </article>
                `).join('')
                : '<div class="loading-row">Комментариев пока нет</div>';
        } catch (error) {
            commentsList.innerHTML = `<div class="loading-row">${escapeHtml(error.message || 'Ошибка загрузки комментариев')}</div>`;
        }
    }

    async function saveComment(event) {
        event.preventDefault();
        const subjectId = commentsSubjectInput.value;
        const comment = commentsTextInput.value.trim();
        if (!subjectId) {
            showAlert('department-comment-alert', 'Выберите дисциплину', 'error');
            return;
        }
        if (!comment) {
            showAlert('department-comment-alert', 'Комментарий не должен быть пустым', 'error');
            return;
        }

        try {
            await api.post(`/api/department/subjects/${subjectId}/comments`, { comment });
            showAlert('department-comment-alert', 'Комментарий сохранён', 'success');
            await openComments(subjectId, commentsTitle.textContent.replace('Комментарии: ', ''));
        } catch (error) {
            showAlert('department-comment-alert', error.message || 'Ошибка сохранения комментария', 'error');
        }
    }

    async function loadTeachers() {
        const container = document.getElementById('department-teachers-list');
        container.textContent = 'Загрузка...';
        try {
            const teachers = await api.get(`/api/department/teachers?departmentId=${encodeURIComponent(selectedDepartmentId() || '')}`);
            container.innerHTML = teachers.length
                ? teachers.map(teacher => `
                    <article class="metric-card">
                        <strong>${escapeHtml(teacher.fullName || teacher.username || '-')}</strong>
                        <span>${escapeHtml(teacher.jobTitle || 'Должность не указана')}</span>
                    </article>
                `).join('')
                : '<div class="loading-row">Преподаватели не найдены</div>';
        } catch (error) {
            container.innerHTML = `<div class="loading-row">${escapeHtml(error.message || 'Ошибка загрузки преподавателей')}</div>`;
        }
    }

    async function loadWorkload() {
        const container = document.getElementById('department-workload-list');
        const params = new URLSearchParams({
            startDate: startInput.value,
            endDate: endInput.value
        });
        if (selectedDepartmentId()) {
            params.set('departmentId', selectedDepartmentId());
        }
        container.textContent = 'Загрузка...';
        try {
            const workload = await api.get(`/api/workload/teachers?${params}`);
            container.innerHTML = workload.length
                ? workload.map(item => `
                    <article class="metric-card">
                        <strong>${escapeHtml(item.name || '-')}</strong>
                        <span>${escapeHtml(String(item.academicHours ?? 0))} ак. ч.</span>
                        <small>${escapeHtml(String(item.lessonCount ?? 0))} занятий</small>
                    </article>
                `).join('')
                : '<div class="loading-row">Нагрузка не найдена</div>';
        } catch (error) {
            container.innerHTML = `<div class="loading-row">${escapeHtml(error.message || 'Ошибка расчёта нагрузки')}</div>`;
        }
    }

    function selectedDepartmentId() {
        return role === ROLE_DEPARTMENT ? userDepartmentId : departmentSelect.value;
    }
}

async function loadDepartments(role, userDepartmentId) {
    const departments = await api.get('/api/departments');
    fillSelect('department-workspace-department', departments, item => item.id, item => item.departmentName, 'Выберите кафедру');
    if (role === ROLE_DEPARTMENT && userDepartmentId) {
        document.getElementById('department-workspace-department').value = userDepartmentId;
    } else if (!document.getElementById('department-workspace-department').value && departments.length) {
        document.getElementById('department-workspace-department').value = departments[0].id;
    }
}

function fillSelect(id, items, valueFn, labelFn, emptyLabel) {
    const select = document.getElementById(id);
    if (!select) return;
    select.innerHTML = `<option value="">${escapeHtml(emptyLabel)}</option>` +
        (items || []).map(item => `<option value="${escapeHtml(valueFn(item))}">${escapeHtml(labelFn(item))}</option>`).join('');
}

function setDefaultDates(startInput, endInput) {
    const today = new Date();
    const nextWeek = new Date();
    nextWeek.setDate(today.getDate() + 7);
    startInput.value = toIsoDate(today);
    endInput.value = toIsoDate(nextWeek);
}

function toIsoDate(date) {
    return date.toISOString().slice(0, 10);
}

function formatDateTime(value) {
    if (!value) return '-';
    return String(value).replace('T', ' ').slice(0, 16);
}

function subjectCountLabel(count) {
    const tail = count % 100;
    if (tail >= 11 && tail <= 14) return `${count} дисциплин`;
    if (count % 10 === 1) return `${count} дисциплина`;
    if ([2, 3, 4].includes(count % 10)) return `${count} дисциплины`;
    return `${count} дисциплин`;
}