import { apiGet, apiPost, apiPut, apiDelete } from '../api.js';
import { canEdit, pageHeaderHTML, showToast, getRole } from '../app.js';
import { navigate } from '../router.js';

export async function questionnairesPage() {
    const app = document.getElementById('app');
    app.innerHTML = `
        ${pageHeaderHTML('Questionnaires', '<span id="headerActions"></span>')}
        <div id="qGrid" class="q-dashboard-root"><div class="spinner"></div></div>
        <div id="categoryKeysPanel"></div>
    `;

    if (canEdit()) {
        document.getElementById('headerActions').innerHTML = `
            <input type="file" id="importBundleFile" accept=".json,application/json" hidden>
            <button type="button" class="btn" id="importBundleBtn">Import questionnaires</button>
            <a href="#/questionnaire/new" class="btn btn-primary">+ New Questionnaire</a>
        `;
        bindImportBundle();
    }

    try {
        const data = await apiGet('questionnaires.php');
        const categoryKeys = data.categoryKeys || [];
        renderGrid(data.questionnaires || [], categoryKeys);
        renderCategoryKeysPanel(categoryKeys);
        bindCategoryLabelEditors();
    } catch (e) {
        showToast(e.message, 'error');
        document.getElementById('qGrid').innerHTML = `<p class="error-text">${e.message}</p>`;
    }
}

function renderCategoryKeysPanel(categoryKeys) {
    const panel = document.getElementById('categoryKeysPanel');
    if (!panel) return;

    if (!canEdit()) {
        panel.innerHTML = '';
        return;
    }

    if (!categoryKeys.length) {
        panel.innerHTML = `
            <div class="card category-keys-card" style="margin-top:16px">
                <h3 style="margin:0 0 8px;font-size:1rem">Category keys</h3>
                <p class="data-toolbar-hint" style="margin:0">
                    Set a category key on a questionnaire (editor → settings) to group it on the app opening screen.
                    German group titles can be edited below once a key is in use.
                </p>
            </div>`;
        return;
    }

    panel.innerHTML = `
        <div class="card category-keys-card" style="margin-top:16px">
            <h3 style="margin:0 0 8px;font-size:1rem">Category keys</h3>
            <p class="data-toolbar-hint" style="margin:0 0 12px">
                German labels for the app opening screen. Other languages: <a href="#/translations">Translations</a>.
                Delete removes the key from questionnaires, all translations, and catalog defaults.
            </p>
            <div class="table-wrapper" style="max-height:none">
                <table class="data-table category-keys-table">
                    <thead>
                        <tr>
                            <th>Category key</th>
                            <th>App string key</th>
                            <th>German label</th>
                            <th>Questionnaires</th>
                            <th></th>
                        </tr>
                    </thead>
                    <tbody>
                        ${categoryKeys.map(row => `
                            <tr class="${row.orphaned ? 'row-orphan-category' : ''}">
                                <td><code>${esc(row.categoryKey)}</code></td>
                                <td><code class="data-toolbar-hint">${esc(row.stringKey)}</code></td>
                                <td class="category-label-cell">
                                    <input type="text" class="category-german-input"
                                        data-category-key="${esc(row.categoryKey)}"
                                        value="${esc(row.germanLabel || '')}"
                                        placeholder="German label"
                                        aria-label="German label for ${esc(row.categoryKey)}">
                                </td>
                                <td>${row.orphaned
                                    ? '<span class="data-toolbar-hint">unused</span>'
                                    : esc(String(row.questionnaireCount))}</td>
                                <td style="text-align:right;white-space:nowrap">
                                    <button type="button" class="btn btn-sm btn-danger delete-cat-key-btn"
                                        data-key="${esc(row.categoryKey)}"
                                        data-count="${row.questionnaireCount}">Delete</button>
                                </td>
                            </tr>
                        `).join('')}
                    </tbody>
                </table>
            </div>
        </div>`;

    panel.querySelectorAll('.delete-cat-key-btn').forEach(btn => {
        btn.addEventListener('click', async (e) => {
            e.stopPropagation();
            const key = btn.dataset.key;
            const count = parseInt(btn.dataset.count || '0', 10);
            let msg = `Delete category key "${key}"?\n\nThis removes all translations and catalog defaults for questionnaire_group_${key}.`;
            if (count > 0) {
                msg += `\n\n${count} questionnaire(s) will have their category key cleared.`;
            }
            if (!confirm(msg)) return;
            btn.disabled = true;
            try {
                const result = await apiPost('questionnaires.php', { action: 'deleteCategoryKey', categoryKey: key });
                const cleared = result.questionnairesCleared ?? count;
                showToast(
                    cleared
                        ? `Deleted "${key}" and cleared ${cleared} questionnaire(s)`
                        : `Deleted "${key}"`,
                    'success'
                );
                await questionnairesPage();
            } catch (err) {
                showToast(err.message, 'error');
                btn.disabled = false;
            }
        });
    });
}

function categoryGermanInputHTML(categoryKey, label) {
    if (!canEdit() || !categoryKey) {
        return esc(label);
    }
    return `<input type="text" class="category-german-input category-title-input"
        data-category-key="${esc(categoryKey)}"
        value="${esc(label)}"
        aria-label="German category title">`;
}

function bindCategoryLabelEditors() {
    if (!canEdit()) return;

    document.querySelectorAll('.category-german-input').forEach(input => {
        input.dataset.lastSaved = input.value.trim();

        input.addEventListener('keydown', (e) => {
            if (e.key === 'Enter') {
                e.preventDefault();
                input.blur();
            }
        });

        input.addEventListener('blur', () => saveCategoryGermanLabel(input));
    });
}

async function saveCategoryGermanLabel(input) {
    const categoryKey = input.dataset.categoryKey?.trim();
    const label = input.value.trim();
    if (!categoryKey) return;

    const prev = input.dataset.lastSaved ?? '';
    if (label === prev) return;

    if (!label) {
        showToast('German label cannot be empty', 'error');
        input.value = prev;
        return;
    }

    input.disabled = true;
    try {
        await apiPost('questionnaires.php', {
            action: 'updateCategoryLabel',
            categoryKey,
            germanLabel: label,
        });
        input.dataset.lastSaved = label;
        syncCategoryGermanInputs(categoryKey, label);
        showToast('Category label saved', 'success');
    } catch (err) {
        showToast(err.message, 'error');
        input.value = prev;
    } finally {
        input.disabled = false;
    }
}

function syncCategoryGermanInputs(categoryKey, label) {
    document.querySelectorAll('.category-german-input').forEach(el => {
        if (el.dataset.categoryKey === categoryKey) {
            el.value = label;
            el.dataset.lastSaved = label;
        }
    });
}

const UNCATEGORIZED = '__uncategorized__';

function groupQuestionnairesByCategory(questionnaires, categoryKeys) {
    const labelByKey = Object.fromEntries(
        (categoryKeys || [])
            .filter(r => !r.orphaned)
            .map(r => [r.categoryKey, r.germanLabel || r.categoryKey])
    );

    const sorted = [...questionnaires].sort((a, b) => (a.orderIndex ?? 0) - (b.orderIndex ?? 0));
    const buckets = new Map();

    for (const q of sorted) {
        const key = (q.categoryKey || '').trim() || UNCATEGORIZED;
        if (!buckets.has(key)) buckets.set(key, []);
        buckets.get(key).push(q);
    }

    const sections = [...buckets.entries()].map(([key, items]) => ({
        categoryKey: key === UNCATEGORIZED ? '' : key,
        title: key === UNCATEGORIZED ? 'Uncategorized' : (labelByKey[key] || key),
        items,
        sortKey: Math.min(...items.map(q => q.orderIndex ?? 0)),
    }));

    sections.sort((a, b) => {
        const aUncat = a.categoryKey === '';
        const bUncat = b.categoryKey === '';
        if (aUncat !== bUncat) {
            return aUncat ? 1 : -1;
        }
        return a.sortKey - b.sortKey;
    });
    return sections;
}

function renderQuestionnaireCard(q) {
    const stateClass = `badge-${(q.state || 'draft').toLowerCase().replace(/\s+/g, '_')}`;
    const showPts = parseInt(q.showPoints || 0, 10);
    return `
        <div class="q-card" data-id="${q.questionnaireID}" draggable="${canEdit()}">
            <div class="q-card-header">
                <div class="q-card-title">
                    ${canEdit() ? '<span class="drag-handle" title="Drag to reorder" aria-label="Drag to reorder">&#x2630;</span>' : ''}
                    ${esc(q.name)}
                </div>
                <span class="badge ${stateClass}">${esc(q.state || 'draft')}</span>
            </div>
            <div class="q-card-meta">
                <span>v${esc(q.version || '—')}</span>
                <span>${q.questionCount || 0} question${q.questionCount == 1 ? '' : 's'}</span>
                <span>#${q.orderIndex ?? '—'}</span>
                ${showPts ? '<span class="badge badge-active" style="font-size:.7rem;padding:1px 6px">pts</span>' : ''}
            </div>
            <div class="q-card-actions">
                <a href="#/questionnaire/${q.questionnaireID}" class="btn btn-sm">Edit</a>
                <a href="#/questionnaire/${q.questionnaireID}/results" class="btn btn-sm">Results</a>
                ${getRole() === 'admin' ? `<button class="btn btn-sm btn-danger delete-q-btn" data-id="${q.questionnaireID}">Delete</button>` : ''}
            </div>
        </div>`;
}

function renderGrid(questionnaires, categoryKeys = []) {
    const grid = document.getElementById('qGrid');

    if (!questionnaires.length) {
        grid.innerHTML = `
            <div class="empty-state">
                <svg width="48" height="48" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="1.5"><path d="M9 12h6m-3-3v6m-7 4h14a2 2 0 002-2V7a2 2 0 00-2-2H5a2 2 0 00-2 2v10a2 2 0 002 2z"/></svg>
                <h3>No questionnaires yet</h3>
                <p>Create your first questionnaire to get started.</p>
            </div>
        `;
        return;
    }

    const sections = groupQuestionnairesByCategory(questionnaires, categoryKeys);

    grid.innerHTML = `
        <div class="q-dashboard-groups">
            ${sections.map(section => `
                <section class="q-category-group" data-category="${esc(section.categoryKey)}">
                    <h2 class="q-category-title">${categoryGermanInputHTML(section.categoryKey, section.title)}</h2>
                    <div class="q-category-grid">
                        ${section.items.map(q => renderQuestionnaireCard(q)).join('')}
                    </div>
                </section>
            `).join('')}
        </div>`;

    grid.querySelectorAll('.q-card').forEach(card => {
        card.addEventListener('click', (e) => {
            if (e.target.closest('.q-card-actions') || e.target.closest('.drag-handle')) return;
            navigate(`#/questionnaire/${card.dataset.id}`);
        });
    });

    grid.querySelectorAll('.delete-q-btn').forEach(btn => {
        btn.addEventListener('click', async (e) => {
            e.stopPropagation();
            if (!confirm('Delete this questionnaire and all its data?')) return;
            try {
                await apiDelete('questionnaires.php', { questionnaireID: btn.dataset.id });
                showToast('Questionnaire deleted', 'success');
                btn.closest('.q-card').remove();
            } catch (err) {
                showToast(err.message, 'error');
            }
        });
    });

    if (canEdit()) initGridDrag(questionnaires);
}

function collectDashboardCardOrder() {
    const ids = [];
    document.querySelectorAll('.q-category-group').forEach(section => {
        section.querySelectorAll('.q-category-grid .q-card').forEach(card => {
            ids.push(card.dataset.id);
        });
    });
    return ids;
}

function initGridDrag(questionnaires) {
    const root = document.getElementById('qGrid');
    if (!root) return;
    let dragItem = null;
    let dragRow = null;

    root.addEventListener('dragstart', (e) => {
        const card = e.target.closest('.q-card');
        if (!card || !e.target.closest('.drag-handle')) { e.preventDefault(); return; }
        dragItem = card;
        dragRow = card.closest('.q-category-grid');
        card.style.opacity = '0.5';
        e.dataTransfer.effectAllowed = 'move';
    });

    root.addEventListener('dragover', (e) => {
        e.preventDefault();
        if (!dragItem || !dragRow) return;

        const row = e.target.closest('.q-category-grid');
        if (!row || row !== dragRow) return;

        const cards = [...row.querySelectorAll('.q-card')].filter(c => c !== dragItem);
        let insertBefore = null;
        for (const child of cards) {
            const box = child.getBoundingClientRect();
            if (e.clientX < box.left + box.width / 2) {
                insertBefore = child;
                break;
            }
        }
        if (insertBefore) row.insertBefore(dragItem, insertBefore);
        else row.appendChild(dragItem);
    });

    root.addEventListener('dragend', async () => {
        if (!dragItem) return;
        dragItem.style.opacity = '';
        const newOrder = collectDashboardCardOrder();
        dragItem = null;
        dragRow = null;

        for (let i = 0; i < newOrder.length; i++) {
            const id = newOrder[i];
            const q = questionnaires.find(x => x.questionnaireID === id);
            if (q && parseInt(q.orderIndex, 10) !== i) {
                try {
                    await apiPut('questionnaires.php', { questionnaireID: id, orderIndex: i });
                    q.orderIndex = i;
                } catch (err) {
                    showToast(err.message, 'error');
                    return;
                }
            }
        }
        showToast('Order saved', 'success');
    });
}

function bindImportBundle() {
    const fileInput = document.getElementById('importBundleFile');
    const btn = document.getElementById('importBundleBtn');
    if (!fileInput || !btn) return;

    btn.addEventListener('click', () => fileInput.click());

    fileInput.addEventListener('change', async () => {
        const file = fileInput.files?.[0];
        fileInput.value = '';
        if (!file) return;

        let bundle;
        try {
            const text = await file.text();
            bundle = JSON.parse(text);
        } catch {
            showToast('Invalid JSON file', 'error');
            return;
        }

        if (!bundle?.questionnaires || !Array.isArray(bundle.questionnaires)) {
            showToast('Not a questionnaire bundle (missing questionnaires array)', 'error');
            return;
        }

        const count = bundle.questionnaires.length;
        if (!confirm(`Import ${count} questionnaire(s) from this file?`)) return;
        const replace = confirm(
            'If a questionnaire ID from the file already exists:\n\n' +
            'OK — replace that questionnaire\n' +
            'Cancel — import as a new copy (new ID)'
        );

        btn.disabled = true;
        const prev = btn.textContent;
        btn.textContent = 'Importing…';
        try {
            const result = await apiPost('questionnaires.php', {
                action: 'importBundle',
                bundle,
                replaceIfExists: replace,
            });
            const n = result.imported ?? count;
            showToast(`Imported ${n} questionnaire(s)`, 'success');
            await questionnairesPage();
        } catch (e) {
            showToast(e.message, 'error');
        } finally {
            btn.disabled = false;
            btn.textContent = prev;
        }
    });
}

function esc(s) {
    const d = document.createElement('div');
    d.textContent = s ?? '';
    return d.innerHTML;
}