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

let qualityState = null;

export async function initScheduleQuality() {
    const root = document.querySelector('.quality-lab');
    if (!root) return;
    qualityState = { root, analysis: null, versions: [], visibleProblems: [], selectedProblemId: null, applying: false };
    root.querySelector('#quality-run')?.addEventListener('click', runAnalysis);
    root.querySelector('#quality-semester')?.addEventListener('change', loadVersions);
    root.querySelector('#quality-severity-filter')?.addEventListener('change', renderProblems);
    root.querySelector('#quality-type-filter')?.addEventListener('change', renderProblems);
    root.querySelector('#quality-problems')?.addEventListener('click', handleProblemClick);
    root.querySelector('#quality-recommendations')?.addEventListener('click', handleRulePanelClick);
    await loadSemesters();
}

async function loadSemesters() {
    const select = qualityState?.root.querySelector('#quality-semester');
    if (!select) return;
    try {
        const semesters = await api.get('/api/schedule/semesters');
        select.innerHTML = (semesters || []).map(semester => `
            <option value="${escapeHtml(String(semester.id))}">
                ${escapeHtml(semesterLabel(semester))}
            </option>
        `).join('');
        if (!semesters?.length) {
            select.innerHTML = '<option value="">Семестры не настроены</option>';
            qualityStatus('Сначала создайте учебный год и семестр.', 'warning');
            return;
        }
        const today = localIsoDate(new Date());
        const current = semesters.find(semester =>
            semester.startDate <= today && semester.endDate >= today
        );
        select.value = String(current?.id ?? semesters[0].id);
        const savedSemesterId = localStorage.getItem('magistr.quality.semesterId');
        if (semesters.some(semester => String(semester.id) === savedSemesterId)) {
            select.value = savedSemesterId;
        }
        await loadVersions();
    } catch (error) {
        select.innerHTML = '<option value="">Ошибка загрузки</option>';
        qualityStatus(error.message || 'Не удалось загрузить семестры.', 'error');
    }
}

async function loadVersions() {
    const semesterId = qualityState?.root.querySelector('#quality-semester')?.value;
    const select = qualityState?.root.querySelector('#quality-version');
    if (!select || !semesterId) return;
    select.innerHTML = '<option value="">Загрузка версий…</option>';
    try {
        qualityState.versions = await api.get(
            `/api/edu-office/schedule/versions?semesterId=${encodeURIComponent(semesterId)}`
        );
        select.innerHTML = qualityState.versions.map(version => `
            <option value="${escapeHtml(String(version.id))}">
                v${escapeHtml(String(version.versionNumber))} · ${escapeHtml(version.name)} · ${escapeHtml(versionStatusLabel(version.status))}
            </option>
        `).join('');
        if (!qualityState.versions.length) {
            select.innerHTML = '<option value="">Версии не созданы</option>';
            return;
        }
        const savedVersionId = localStorage.getItem('magistr.quality.versionId');
        const saved = qualityState.versions.find(version => String(version.id) === savedVersionId);
        const published = qualityState.versions.find(version => version.status === 'PUBLISHED');
        select.value = String((saved || published || qualityState.versions[0]).id);
        localStorage.setItem('magistr.quality.semesterId', semesterId);
    } catch (error) {
        select.innerHTML = '<option value="">Ошибка загрузки</option>';
        qualityStatus(error.message || 'Не удалось загрузить версии расписания.', 'error');
    }
}

async function runAnalysis() {
    const semesterId = qualityState?.root.querySelector('#quality-semester')?.value;
    const versionId = qualityState?.root.querySelector('#quality-version')?.value;
    if (!semesterId) {
        qualityStatus('Выберите семестр для анализа.', 'warning');
        return;
    }
    if (!versionId) {
        qualityStatus('Выберите версию расписания для анализа.', 'warning');
        return;
    }
    localStorage.setItem('magistr.quality.semesterId', semesterId);
    localStorage.setItem('magistr.quality.versionId', versionId);
    const button = qualityState.root.querySelector('#quality-run');
    button.disabled = true;
    button.textContent = 'Анализируем…';
    qualityStatus('Строим фактическое расписание и рассчитываем показатели…', 'loading');
    qualityState.root.querySelector('#quality-results').hidden = true;
    try {
        qualityState.analysis = await api.get(
            `/api/edu-office/schedule/quality?semesterId=${encodeURIComponent(semesterId)}&versionId=${encodeURIComponent(versionId)}`
        );
        qualityState.selectedProblemId = null;
        renderAnalysis();
        qualityStatus(
            qualityState.analysis.scheduleVersionStatus === 'DRAFT'
                ? 'Черновик проверен. Проблемные правила можно открыть в конструкторе до публикации.'
                : 'Анализ завершён. Проблемные правила можно открыть в конструкторе расписания.',
            'success'
        );
    } catch (error) {
        qualityStatus(error.message || 'Не удалось выполнить анализ качества.', 'error');
    } finally {
        button.disabled = false;
        button.textContent = 'Выполнить анализ';
    }
}

function renderAnalysis() {
    const analysis = qualityState?.analysis;
    if (!analysis) return;
    qualityState.root.querySelector('#quality-results').hidden = false;
    const band = qualityBand(analysis.score);
    const orbit = qualityState.root.querySelector('#quality-score-orbit');
    orbit.dataset.band = band.code;
    qualityState.root.querySelector('#quality-score-ring-value')
        .setAttribute('stroke-dasharray', `${Math.max(0, Math.min(100, analysis.score))} 100`);
    qualityState.root.querySelector('#quality-score').textContent = String(analysis.score);
    qualityState.root.querySelector('#quality-score-band').textContent = band.label;
    qualityState.root.querySelector('#quality-score-band').dataset.band = band.code;
    qualityState.root.querySelector('#quality-semester-label').textContent = analysis.semesterLabel;
    qualityState.root.querySelector('#quality-score-summary').textContent = band.summary;
    qualityState.root.querySelector('#quality-score-meta').innerHTML = `
        <span>${escapeHtml(versionStatusLabel(analysis.scheduleVersionStatus))} · v${escapeHtml(String(analysis.scheduleVersionNumber || '—'))}</span>
        <span>${escapeHtml(String(analysis.lessonCount))} занятий</span>
        <span>правил с проблемами: ${escapeHtml(String(analysis.totalProblemCount))}</span>
        <span>штраф ${escapeHtml(String(analysis.rawPenalty))}</span>
    `;
    qualityState.root.querySelector('#quality-metrics').innerHTML = (analysis.metrics || [])
        .map((metric, index) => `
            <article class="quality-metric quality-metric-${index + 1}">
                <span class="quality-metric-index">${String(index + 1).padStart(2, '0')}</span>
                <strong>${escapeHtml(formatMetricValue(metric))}</strong>
                <h4>${escapeHtml(metric.label)}</h4>
                <p>${escapeHtml(metric.explanation)}</p>
                <span class="quality-metric-penalty">штраф ${escapeHtml(String(metric.penalty))}</span>
            </article>
        `).join('');
    const totalLabel = analysis.problemsTruncated
        ? `Показаны первые ${analysis.problems.length} из ${analysis.totalProblemCount} правил`
        : `Правил с проблемами: ${analysis.totalProblemCount}`;
    qualityState.root.querySelector('#quality-problem-total').textContent = totalLabel;
    renderProblems();
    renderRulePanelEmpty();
}

function renderProblems() {
    const container = qualityState?.root.querySelector('#quality-problems');
    if (!container || !qualityState.analysis) return;
    const severity = qualityState.root.querySelector('#quality-severity-filter')?.value || '';
    const category = qualityState.root.querySelector('#quality-type-filter')?.value || '';
    qualityState.visibleProblems = filterQualityProblems(
        qualityState.analysis.problems || [], severity, category
    );
    if (!qualityState.visibleProblems.length) {
        container.innerHTML = `
            <div class="quality-empty-state">
                <strong>По выбранному фильтру проблем нет</strong>
                <span>Измените уровень важности или категорию.</span>
            </div>
        `;
        return;
    }
    container.innerHTML = qualityState.visibleProblems.map((problem, index) => {
        const selected = problem.id === qualityState.selectedProblemId;
        const affectedLessonCount = Number(problem.affectedLessonCount || 1);
        const issueLabels = problem.issueLabels?.length ? problem.issueLabels : [problem.title];
        const canEdit = qualityState.analysis.scheduleVersionStatus !== 'ARCHIVED' && problem.scheduleRuleId;
        return `
            <article class="quality-problem ${selected ? 'is-selected' : ''}" data-severity="${escapeHtml(problem.severity)}">
                <button type="button" class="quality-problem-main" data-problem-index="${index}">
                    <span class="quality-severity">${escapeHtml(severityLabel(problem.severity))}</span>
                    <span class="quality-problem-copy">
                        <strong>${escapeHtml(problem.title)}</strong>
                        <span>${escapeHtml(problem.description)}</span>
                        <span class="quality-rule-issues">${issueLabels.map(label => `
                            <span>${escapeHtml(label)}</span>
                        `).join('')}</span>
                        <small>
                            Правило #${escapeHtml(String(problem.scheduleRuleId || '—'))}
                            · затронуто ${escapeHtml(String(affectedLessonCount))} ${escapeHtml(lessonWord(affectedLessonCount))}
                            · суммарный штраф
                        </small>
                    </span>
                    <span class="quality-penalty">−${escapeHtml(String(problem.penalty))}</span>
                </button>
                <div class="quality-problem-action">
                    ${canEdit
                        ? `<button type="button" class="btn btn-sm btn-secondary" data-problem-index="${index}" data-action="edit-rule">
                               Изменить правило
                           </button>`
                        : '<span>Только просмотр</span>'}
                </div>
            </article>
        `;
    }).join('');
}

function handleProblemClick(event) {
    const button = event.target.closest('[data-problem-index]');
    if (!button) return;
    const problem = qualityState?.visibleProblems[Number(button.dataset.problemIndex)];
    if (!problem) return;
    if (button.dataset.action === 'edit-rule') {
        openRuleInConstructor(problem);
        return;
    }
    qualityState.selectedProblemId = problem.id;
    renderProblems();
    renderRuleDetails(problem);
}

function renderRulePanelEmpty() {
    const archived = qualityState?.analysis?.scheduleVersionStatus === 'ARCHIVED';
    renderRulePanelMessage(
        archived ? 'Архивная версия' : 'Работа с правилом',
        archived
            ? 'Правила этой версии доступны только для просмотра. Для правок создайте новый черновик.'
            : 'Выберите правило, чтобы увидеть его суммарное влияние и открыть в конструкторе.'
    );
}

function renderRuleDetails(problem) {
    const panel = qualityState?.root.querySelector('#quality-recommendations');
    if (!panel) return;
    const affectedLessonCount = Number(problem.affectedLessonCount || 1);
    const issueLabels = problem.issueLabels?.length ? problem.issueLabels : [problem.title];
    const canEdit = qualityState.analysis.scheduleVersionStatus !== 'ARCHIVED' && problem.scheduleRuleId;
    panel.innerHTML = `
        <div class="quality-recommendations-head">
            <span class="quality-kicker">Правило #${escapeHtml(String(problem.scheduleRuleId || '—'))}</span>
            <h3>${escapeHtml(problem.subjectName || problem.title)}</h3>
            <p>Затронуто ${escapeHtml(String(affectedLessonCount))} ${escapeHtml(lessonWord(affectedLessonCount))}; суммарный штраф −${escapeHtml(String(problem.penalty))}.</p>
        </div>
        <div class="quality-rule-detail-list">
            ${issueLabels.map(label => `<span>${escapeHtml(label)}</span>`).join('')}
        </div>
        ${canEdit ? `
            <button type="button" class="btn btn-md btn-primary quality-edit-rule" data-edit-rule-id="${escapeHtml(String(problem.scheduleRuleId))}">
                Открыть правило в конструкторе
            </button>
        ` : '<p class="quality-recommendations-note">Архивное расписание нельзя изменить.</p>'}
    `;
}

function handleRulePanelClick(event) {
    const button = event.target.closest('[data-edit-rule-id]');
    if (!button) return;
    const problem = (qualityState?.analysis?.problems || [])
        .find(item => String(item.scheduleRuleId) === button.dataset.editRuleId);
    if (problem) openRuleInConstructor(problem);
}

function openRuleInConstructor(problem) {
    if (!problem?.scheduleRuleId || qualityState?.analysis?.scheduleVersionStatus === 'ARCHIVED') return;
    localStorage.setItem('magistr.schedule.openVersionId', String(qualityState.analysis.scheduleVersionId));
    localStorage.setItem('magistr.schedule.openRuleId', String(problem.scheduleRuleId));
    document.querySelector('.nav-item[data-tab="schedule"]')?.click();
}

function renderRulePanelMessage(title, message) {
    const panel = qualityState?.root.querySelector('#quality-recommendations');
    if (!panel) return;
    panel.innerHTML = `
        <div class="quality-recommendations-empty">
            <span class="quality-recommendations-mark">↗</span>
            <h3>${escapeHtml(title)}</h3>
            <p>${escapeHtml(message)}</p>
        </div>
    `;
}

function qualityStatus(message, tone = '') {
    const status = qualityState?.root.querySelector('#quality-status');
    if (!status) return;
    status.textContent = message;
    status.dataset.tone = tone;
}

export function filterQualityProblems(problems, severity = '', category = '') {
    return (problems || []).filter(problem => {
        const severityMatches = !severity || problem.severity === severity;
        const problemTypes = problem.problemTypes?.length ? problem.problemTypes : [problem.type];
        const categoryMatches = !category || problemTypes.some(type => problemCategory(type) === category);
        return severityMatches && categoryMatches;
    });
}

function problemCategory(type = '') {
    if (type.includes('GAP') || type.includes('COMPACTNESS')) return 'GAPS';
    if (type.includes('LOAD')) return 'LOAD';
    if (type.includes('ROOM')) return 'ROOM';
    return 'PREFERENCE';
}

export function qualityBand(score) {
    if (score >= 90) {
        return { code: 'excellent', label: 'Сильное расписание', summary: 'Найдены только локальные неудобства с небольшим влиянием.' };
    }
    if (score >= 75) {
        return { code: 'stable', label: 'Устойчивое расписание', summary: 'Расписание работоспособно, но несколько перестановок заметно улучшат комфорт.' };
    }
    if (score >= 55) {
        return { code: 'attention', label: 'Нужна доработка', summary: 'Мягкие ограничения и распределение нагрузки требуют внимания учебного отдела.' };
    }
    return { code: 'critical', label: 'Высокая цена неудобств', summary: 'Сначала разберите критические проблемы и перегруженные дни.' };
}

export function formatMetricValue(metric) {
    const value = Number(metric?.value || 0);
    const formatted = Number.isInteger(value)
        ? String(value)
        : value.toLocaleString('ru-RU', { maximumFractionDigits: 1 });
    return `${formatted}${metric?.unit === '%' ? '%' : metric?.unit ? ` ${metric.unit}` : ''}`;
}

function severityLabel(severity) {
    return { CRITICAL: 'Критично', HIGH: 'Высокая', MEDIUM: 'Средняя', LOW: 'Низкая' }[severity] || severity;
}

function semesterLabel(semester) {
    const type = semester.semesterType === 'autumn' ? 'Осенний' : 'Весенний';
    return `${semester.academicYearTitle} · ${type} · ${formatDate(semester.startDate)}—${formatDate(semester.endDate)}`;
}

function formatDate(value) {
    if (!value) return 'дата не указана';
    const [year, month, day] = String(value).split('-');
    return `${day}.${month}.${year}`;
}

function localIsoDate(date) {
    const year = date.getFullYear();
    const month = String(date.getMonth() + 1).padStart(2, '0');
    const day = String(date.getDate()).padStart(2, '0');
    return `${year}-${month}-${day}`;
}

function lessonWord(count) {
    const mod100 = count % 100;
    const mod10 = count % 10;
    if (mod100 >= 11 && mod100 <= 14) return 'занятий';
    if (mod10 === 1) return 'занятие';
    if (mod10 >= 2 && mod10 <= 4) return 'занятия';
    return 'занятий';
}

export function versionStatusLabel(status) {
    return { DRAFT: 'Черновик', PUBLISHED: 'Опубликована', ARCHIVED: 'Архив' }[status] || 'Версия';
}