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

export async function dashboardPage() {
    const app = document.getElementById('app');
    app.innerHTML = `
        <div class="page-header">
            <h1>Questionnaires</h1>
            <div class="actions" id="headerActions"></div>
        </div>
        <div id="qGrid" class="q-grid"><div class="spinner"></div></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');
        renderGrid(data.questionnaires || []);
    } catch (e) {
        showToast(e.message, 'error');
        document.getElementById('qGrid').innerHTML = `<p class="error-text">${e.message}</p>`;
    }
}

function renderGrid(questionnaires) {
    const grid = document.getElementById('qGrid');

    if (!questionnaires.length) {
        grid.innerHTML = `
            <div class="empty-state" style="grid-column:1/-1">
                <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;
    }

    grid.innerHTML = questionnaires.map(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" style="margin-right:6px;cursor:grab;color:var(--text-secondary)">&#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>
        `;
    }).join('');

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

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

    grid.addEventListener('dragover', (e) => {
        e.preventDefault();
        if (!dragItem) return;
        const cards = [...grid.querySelectorAll('.q-card:not([style*="opacity"])')];
        const afterCard = cards.reduce((closest, child) => {
            const box = child.getBoundingClientRect();
            const offset = e.clientY - box.top - box.height / 2;
            if (offset < 0 && offset > closest.offset) return { offset, element: child };
            return closest;
        }, { offset: Number.NEGATIVE_INFINITY }).element;

        if (afterCard) grid.insertBefore(dragItem, afterCard);
        else grid.appendChild(dragItem);
    });

    grid.addEventListener('dragend', async () => {
        if (!dragItem) return;
        dragItem.style.opacity = '';
        const newOrder = [...grid.querySelectorAll('.q-card')].map(el => el.dataset.id);
        dragItem = null;

        for (let i = 0; i < newOrder.length; i++) {
            const id = newOrder[i];
            const q = questionnaires.find(q => q.questionnaireID === id);
            if (q && parseInt(q.orderIndex, 10) !== i) {
                try {
                    await apiPut('questionnaires.php', { questionnaireID: id, orderIndex: i });
                    q.orderIndex = i;
                } catch (e) {
                    showToast(e.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 dashboardPage();
        } 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;
}