Mejoras de sesion: estabilizacion, IA, Nexus Yonke y marketplace B2B

- F0 blindaje: Redis/Celery, pg_hba sin trust LAN, secretos a env 600, backups, webhook auth, jobs muertos
- F1 caja: bugs POS, reembolsos al corte, apartados, CFDI, topes de descuento en cotizacion/apartado
- F2/F7 IA de catalogo: autocategorizacion, dedup de SKUs con embeddings, OCR de facturas, descripciones, claves SAT, limpieza de fitment
- F3 IA en el flujo: vision Yonke, preguntas MeLi, venta cruzada, anomalias, sinonimos, busqueda semantica (rerank/embeddings)
- F4/F8 escala y cartera: /metrics+Prometheus+Grafana, pool, score de credito, churn, metricas multi-tenant
- Nexus Yonke (M1-M6): modelo de datos 1-de-1, alta por donador, vitrina publica, MeLi usado, consignacion, garantia por dias, reportes, etiquetas
- Marketplace B2B entre yonkes (catalogo + pedidos cross-tenant)
- Seguridad: auth en /api/admin/* (35 endpoints), alertas por tenant
- Migraciones v4.27/v4.28; timers expire-demos y rollup-metrics

pos/static/js/pos.js

@@ -39,6 +39,8 @@ const POS = (() => {
     let receiptConfig = {};
     let couriers = [];
     let selectedCourierId = null;
+    let crossSellTimer = null;
+    let crossSellItems = [];
 
     // Currency-aware formatter: reads pos_currency from localStorage
     const _posCurrency = localStorage.getItem('pos_currency') || 'MXN';
@@ -46,13 +48,29 @@ const POS = (() => {
     const _currLocale = _posCurrency === 'USD' ? 'en-US' : 'es-MX';
     const fmt = (n) => (_currSymbols[_posCurrency] || '$') + parseFloat(n || 0).toLocaleString(_currLocale, { minimumFractionDigits: 2, maximumFractionDigits: 2 });
 
-    // Price based on customer tier: base price (price_1) with tier discount.
-    // Tier 2 = Taller (5% off), Tier 3 = Mayoreo (10% off), Tier 1 = base.
-    function priceForTier(basePrice, tier) {
+    function esc(s) {
+        if (s == null) return '';
+        const d = document.createElement('div');
+        d.textContent = String(s);
+        return d.innerHTML;
+    }
+
+    // Price based on customer tier.
+    // Prefers the tenant's real tier prices (price_2/price_3, materialized
+    // from the tier discounts config) and falls back to the legacy formula.
+    function priceForTier(basePrice, tier, item) {
         const p = parseFloat(basePrice) || 0;
         const t = parseInt(tier, 10) || 1;
-        if (t === 2) return Math.round(p * 0.95 * 100) / 100;
-        if (t === 3) return Math.round(p * 0.90 * 100) / 100;
+        if (t === 2) {
+            const p2 = item ? parseFloat(item.price_2) : 0;
+            if (p2 > 0) return p2;
+            return Math.round(p * 0.95 * 100) / 100;
+        }
+        if (t === 3) {
+            const p3 = item ? parseFloat(item.price_3) : 0;
+            if (p3 > 0) return p3;
+            return Math.round(p * 0.90 * 100) / 100;
+        }
         return p;
     }
 
@@ -209,6 +227,10 @@ const POS = (() => {
         await loadRegister();
         await loadReceiptConfig();
         await loadCouriers();
+        await restoreCartState();
+        replayOfflineSales();
+        scheduleCrossSell();
+        if (navigator.onLine === false && typeof showOfflineBanner === 'function') showOfflineBanner(true);
 
         // Setup event listeners
         setupKeyboard();
@@ -259,6 +281,11 @@ const POS = (() => {
                     selectedCourierId = sel.value ? parseInt(sel.value, 10) : null;
                 });
             }
+            const saleSel = document.getElementById('saleCourier');
+            if (saleSel) {
+                saleSel.innerHTML = '<option value="">— Sin repartidor —</option>' +
+                    couriers.map(c => `<option value="${c.id}">${c.name}</option>`).join('');
+            }
         } catch (e) {
             console.warn('Could not load couriers:', e);
             couriers = [];
@@ -402,18 +429,82 @@ const POS = (() => {
 
         renderCart();
         showToast(`${item.name || 'Articulo'} agregado`);
+        scheduleCrossSell();
     }
 
     function removeFromCart(index) {
         cart.splice(index, 1);
         if (selectedRow >= cart.length) selectedRow = cart.length - 1;
         renderCart();
+        scheduleCrossSell();
     }
 
     function clearCart() {
         cart.length = 0;
         selectedRow = -1;
         renderCart();
+        hideCrossSell();
+    }
+
+    // ─── Cross-sell (A10) ────────────────
+    // Debounced call to /pos/api/recommendations. The panel lives in
+    // pos.html (#crossSellPanel / #crossSellList).
+    function scheduleCrossSell() {
+        if (crossSellTimer) clearTimeout(crossSellTimer);
+        if (!cart.length) { hideCrossSell(); return; }
+        crossSellTimer = setTimeout(refreshCrossSell, 350);
+    }
+
+    async function refreshCrossSell() {
+        const panel = document.getElementById('crossSellPanel');
+        const list = document.getElementById('crossSellList');
+        if (!panel || !list) return;
+        const ids = cart.map(c => c.inventory_id).filter(Boolean);
+        if (!ids.length) { hideCrossSell(); return; }
+        try {
+            const data = await api('/pos/api/recommendations', {
+                method: 'POST',
+                body: JSON.stringify({ inventory_ids: ids, limit: 4 })
+            });
+            crossSellItems = data.recommendations || [];
+        } catch (e) {
+            hideCrossSell();
+            return;
+        }
+        const inCart = new Set(ids);
+        const items = crossSellItems.filter(r => !inCart.has(r.inventory_id));
+        if (!items.length) { hideCrossSell(); return; }
+        list.innerHTML = items.map(r => `
+            <button type="button" onclick="POS.addCrossSellItem(${r.inventory_id})"
+                title="${esc(r.reason || '')}"
+                style="display:flex;justify-content:space-between;align-items:center;gap:8px;text-align:left;width:100%;background:var(--color-bg-surface);border:1px solid var(--color-border);border-radius:var(--radius-sm);padding:5px 8px;cursor:pointer;color:var(--color-text-primary);">
+                <span style="display:flex;flex-direction:column;overflow:hidden;">
+                    <span style="font-size:var(--text-body-sm);white-space:nowrap;overflow:hidden;text-overflow:ellipsis;">${esc(r.name || '')}</span>
+                    <span style="font-size:var(--text-caption);color:var(--color-text-muted);white-space:nowrap;overflow:hidden;text-overflow:ellipsis;">${esc(r.reason || '')}</span>
+                </span>
+                <span style="font-family:var(--font-mono);font-size:var(--text-body-sm);white-space:nowrap;">${fmt(r.price)}</span>
+            </button>`).join('');
+        panel.style.display = '';
+    }
+
+    function hideCrossSell() {
+        if (crossSellTimer) { clearTimeout(crossSellTimer); crossSellTimer = null; }
+        const panel = document.getElementById('crossSellPanel');
+        if (panel) panel.style.display = 'none';
+    }
+
+    function addCrossSellItem(inventoryId) {
+        const rec = crossSellItems.find(r => r.inventory_id === inventoryId);
+        if (!rec) return;
+        addToCart({
+            inventory_id: rec.inventory_id,
+            name: rec.name,
+            part_number: rec.part_number,
+            quantity: 1,
+            unit_price: rec.price || 0,
+            price_1: rec.price || 0,
+            stock: rec.stock || 0,
+        });
     }
 
     function openCancelModal() {
@@ -504,6 +595,32 @@ const POS = (() => {
         }
     });
 
+    function saveCartState() {
+        try {
+            sessionStorage.setItem('pos_cart_state', JSON.stringify({
+                cart, currentCustomerId: currentCustomer ? currentCustomer.id : null,
+            }));
+        } catch (e) { /* storage lleno o bloqueado */ }
+    }
+
+    async function restoreCartState() {
+        try {
+            const raw = sessionStorage.getItem('pos_cart_state');
+            if (!raw) return;
+            const state = JSON.parse(raw);
+            if (!state || !Array.isArray(state.cart) || !state.cart.length) return;
+            cart = state.cart;
+            if (state.currentCustomerId) {
+                try {
+                    const c = await api('/pos/api/customers/' + state.currentCustomerId);
+                    if (c && c.data) currentCustomer = c.data;
+                } catch (e) { /* cliente ya no existe */ }
+            }
+            renderCart();
+            showToast('Carrito restaurado (' + cart.length + ' partidas)', 'ok');
+        } catch (e) { /* ignore */ }
+    }
+
     function renderCart() {
         const tbody = document.getElementById('cartBody');
         const table = document.getElementById('cartTable');
@@ -558,6 +675,7 @@ const POS = (() => {
         tbody.innerHTML = html;
         updateTotals();
         updateAvgMargin();
+    saveCartState();
     }
 
     function updateQty(index, val) {
@@ -646,6 +764,17 @@ const POS = (() => {
     }
 
     // ─── Search ──────────────────────────
+    let lastSearchResults = [];
+    let lastSearchTier = 1;
+    let searchActiveIndex = -1;
+
+    function highlightSearchResult() {
+        const rows = document.querySelectorAll('#searchResults > div[data-search-idx]');
+        rows.forEach((el, i) => {
+            el.style.background = i === searchActiveIndex ? 'var(--color-primary-muted)' : '';
+        });
+    }
+
     function setupSearch() {
         const input = document.getElementById('itemSearch');
         if (!input) return;
@@ -654,9 +783,35 @@ const POS = (() => {
             searchTimeout = setTimeout(() => searchItems(input.value.trim()), 300);
         });
         input.addEventListener('keydown', (e) => {
+            if (e.key === 'ArrowDown' || e.key === 'ArrowUp') {
+                if (!lastSearchResults.length) return;
+                e.preventDefault();
+                searchActiveIndex = e.key === 'ArrowDown'
+                    ? Math.min(searchActiveIndex + 1, lastSearchResults.length - 1)
+                    : Math.max(searchActiveIndex - 1, 0);
+                highlightSearchResult();
+                return;
+            }
             if (e.key === 'Enter') {
                 e.preventDefault();
-                searchItems(input.value.trim());
+                const q = input.value.trim();
+                if (!q) return;
+                const norm = (s) => (s || '').toUpperCase().replace(/[\s\-\._]/g, '');
+                // 0-click scanner: exact barcode/part_number match adds directly
+                const exact = lastSearchResults.find(r =>
+                    norm(r.part_number) === norm(q) || norm(r.barcode || '') === norm(q));
+                if (exact) {
+                    const tier = currentCustomer ? (currentCustomer.price_tier || 1) : lastSearchTier;
+                    addFromSearch(exact, priceForTier(exact.price_1, tier, exact));
+                    return;
+                }
+                if (searchActiveIndex >= 0 && lastSearchResults[searchActiveIndex]) {
+                    const item = lastSearchResults[searchActiveIndex];
+                    const tier = currentCustomer ? (currentCustomer.price_tier || 1) : lastSearchTier;
+                    addFromSearch(item, priceForTier(item.price_1, tier, item));
+                    return;
+                }
+                searchItems(q);
             }
             if (e.key === 'Escape') {
                 input.value = '';
@@ -665,23 +820,74 @@ const POS = (() => {
         });
     }
 
+    function cacheSearch(q, items) {
+        try {
+            const cache = JSON.parse(localStorage.getItem('pos_search_cache') || '{}');
+            cache[q.toLowerCase()] = { items: items.slice(0, 12), ts: Date.now() };
+            const keys = Object.keys(cache);
+            if (keys.length > 40) keys.slice(0, 5).forEach(k => delete cache[k]);
+            localStorage.setItem('pos_search_cache', JSON.stringify(cache));
+        } catch (e) {}
+    }
+
+    function searchOffline(q) {
+        try {
+            const cache = JSON.parse(localStorage.getItem('pos_search_cache') || '{}');
+            const ql = q.toLowerCase();
+            let hits = [];
+            Object.keys(cache).forEach(function (k) {
+                if (ql.indexOf(k) !== -1 || k.indexOf(ql) !== -1) hits = hits.concat(cache[k].items);
+            });
+            const seen = new Set();
+            return hits.filter(function (i) {
+                if (seen.has(i.id)) return false; seen.add(i.id); return true;
+            }).slice(0, 12);
+        } catch (e) { return []; }
+    }
+
     async function searchItems(q) {
         if (!q || q.length < 2) { hideSearchResults(); return; }
 
+        if (navigator.onLine === false) {
+            const cached = searchOffline(q);
+            const container = document.getElementById('searchResults');
+            const totals = document.getElementById('totalsPanel');
+            const tier = currentCustomer ? (currentCustomer.price_tier || 1) : 1;
+            lastSearchResults = cached;
+            lastSearchTier = tier;
+            searchActiveIndex = -1;
+            container.innerHTML = '<div style="padding:8px var(--space-4);background:var(--color-warning-muted,#fef3c7);font-size:var(--text-caption);">Sin conexión — resultados guardados</div>'
+                + (cached.length ? cached.map(function (item, idx) {
+                    const price = priceForTier(item.price_1, tier, item);
+                    return `<div data-search-idx="${idx}" style="padding:var(--space-3) var(--space-4);border-bottom:1px solid var(--color-border);cursor:pointer;display:flex;justify-content:space-between;align-items:center;" onclick='POS.addFromSearch(${JSON.stringify(item).replace(/'/g, "&#39;")}, ${price})'>
+                        <div><div style="font-weight:var(--font-weight-semibold);">${item.name}</div>
+                        <div style="font-family:var(--font-mono);font-size:var(--text-caption);color:var(--color-text-muted);">${item.part_number} | Stock: ${item.stock}</div></div>
+                        <div style="font-family:var(--font-mono);font-weight:var(--font-weight-bold);color:var(--color-primary);">${fmt(price)}</div></div>`;
+                }).join('') : '<div style="padding:16px;text-align:center;color:var(--color-text-muted);">Sin resultados guardados para esta búsqueda</div>');
+            container.style.display = '';
+            totals.style.display = 'none';
+            return;
+        }
+
         try {
             const data = await api(`/pos/api/inventory/items?q=${encodeURIComponent(q)}&per_page=20`);
             const container = document.getElementById('searchResults');
             const totals = document.getElementById('totalsPanel');
 
-            if (data.data.length === 0) {
+            searchActiveIndex = -1;
+            lastSearchResults = data.data || [];
+            lastSearchTier = 1;
+            if (lastSearchResults.length) cacheSearch(q, lastSearchResults);
+
+            if (lastSearchResults.length === 0) {
                 container.innerHTML = '<div style="padding:20px;text-align:center;color:var(--color-text-muted);">Sin resultados</div>';
                 if (window.BarcodeFeedback) BarcodeFeedback.error();
             } else {
                 let html = '';
-                data.data.forEach(item => {
+                lastSearchResults.forEach((item, idx) => {
                     const tier = currentCustomer ? (currentCustomer.price_tier || 1) : 1;
-                    const price = priceForTier(item.price_1, tier);
-                    html += `<div style="padding:var(--space-3) var(--space-4);border-bottom:1px solid var(--color-border);cursor:pointer;display:flex;justify-content:space-between;align-items:center;transition:var(--transition-fast);" onmouseover="this.style.background='var(--color-primary-muted)'" onmouseout="this.style.background=''" onclick='POS.addFromSearch(${JSON.stringify(item).replace(/'/g, "&#39;")}, ${price})'>
+                    const price = priceForTier(item.price_1, tier, item);
+                    html += `<div data-search-idx="${idx}" style="padding:var(--space-3) var(--space-4);border-bottom:1px solid var(--color-border);cursor:pointer;display:flex;justify-content:space-between;align-items:center;transition:var(--transition-fast);" onmouseover="POS_searchHover(${idx})" onmouseout="this.style.background=''" onclick='POS.addFromSearch(${JSON.stringify(item).replace(/'/g, "&#39;")}, ${price})'>
                         <div>
                             <div style="font-weight:var(--font-weight-semibold);">${item.name}</div>
                             <div style="font-family:var(--font-mono);font-size:var(--text-caption);color:var(--color-text-muted);">${item.part_number} | ${item.brand || ''}</div>
@@ -719,6 +925,290 @@ const POS = (() => {
         document.getElementById('itemSearch').focus();
     }
 
+    window.highlightSearchResult = highlightSearchResult;
+    window.POS_searchHover = function (idx) { searchActiveIndex = idx; highlightSearchResult(); };
+
+
+    // ─── Venta offline (cola + replay) ─────────────────────
+    function offlineQueue() {
+        try { return JSON.parse(localStorage.getItem('pos_offline_sales') || '[]'); }
+        catch (e) { return []; }
+    }
+    function offlineSave(queue) {
+        try { localStorage.setItem('pos_offline_sales', JSON.stringify(queue)); } catch (e) {}
+        const el = document.getElementById('offlineQueueBadge');
+        if (el) el.textContent = queue.length;
+    }
+
+    function queueOfflineSale(saleData) {
+        const queue = offlineQueue();
+        saleData.client_uuid = (crypto.randomUUID ? crypto.randomUUID() : 'off-' + Date.now() + '-' + Math.random().toString(36).slice(2));
+        saleData._queued_at = new Date().toISOString();
+        queue.push(saleData);
+        offlineSave(queue);
+        return saleData.client_uuid;
+    }
+
+    async function replayOfflineSales() {
+        const queue = offlineQueue();
+        if (!queue.length) return 0;
+        const remaining = [];
+        let synced = 0;
+        for (const saleData of queue) {
+            try {
+                await api('/pos/api/sales', { method: 'POST', body: JSON.stringify(saleData) });
+                synced++;
+            } catch (e) {
+                remaining.push(saleData); // aún sin conexión: se reintenta luego
+            }
+        }
+        offlineSave(remaining);
+        if (synced) showToast(synced + ' venta(s) offline sincronizada(s)', 'ok');
+        return synced;
+    }
+
+    window.addEventListener('online', function () {
+        if (typeof showOfflineBanner === 'function') showOfflineBanner(false);
+        replayOfflineSales();
+    });
+    window.addEventListener('offline', function () {
+        if (typeof showOfflineBanner === 'function') showOfflineBanner(true);
+    });
+
+    // ─── Devoluciones UI ──────────────────
+    let returnSale = null;
+
+    function openReturnModal() {
+        if (!currentPerms.includes('pos.sell')) { showToast('Sin permiso para devoluciones'); return; }
+        returnSale = null;
+        document.getElementById('returnSaleId').value = '';
+        document.getElementById('returnSaleInfo').style.display = 'none';
+        document.getElementById('returnItemsList').style.display = 'none';
+        document.getElementById('returnItemsList').innerHTML = '';
+        document.getElementById('returnFooter').style.display = 'none';
+        document.getElementById('returnResult').innerHTML = '';
+        document.getElementById('returnModal').classList.add('open');
+        setTimeout(() => document.getElementById('returnSaleId').focus(), 100);
+    }
+    function closeReturnModal() {
+        document.getElementById('returnModal').classList.remove('open');
+    }
+
+    async function searchReturnSale() {
+        const id = parseInt(document.getElementById('returnSaleId').value, 10);
+        if (!id) return;
+        try {
+            const sale = await api('/pos/api/sales/' + id);
+            if (!sale || !sale.items || !sale.items.length) throw new Error('Venta sin partidas');
+            if (sale.status === 'cancelled') throw new Error('La venta está cancelada');
+            returnSale = sale;
+            document.getElementById('returnSaleInfo').style.display = 'block';
+            document.getElementById('returnSaleInfo').innerHTML =
+                `Venta #${sale.id} — ${sale.customer_name || 'Público General'} — Total: ${fmt(sale.total)} — Estado: ${sale.status}`;
+            const list = document.getElementById('returnItemsList');
+            list.style.display = 'block';
+            list.innerHTML = sale.items.map(it => `
+                <div style="display:flex;align-items:center;gap:8px;padding:8px var(--space-3);border-bottom:1px solid var(--color-border);">
+                    <input type="checkbox" id="ret-chk-${it.id}" checked style="width:auto;" />
+                    <span style="flex:1;font-size:var(--text-body-sm);">${it.name || it.part_number} (${it.part_number})</span>
+                    <span style="font-size:var(--text-caption);color:var(--color-text-muted);">cant: ${it.quantity}</span>
+                    <input type="number" id="ret-qty-${it.id}" class="form-input" min="1" max="${it.quantity}" value="${it.quantity}" style="width:70px;" />
+                    <input type="text" id="ret-reason-${it.id}" class="form-input" placeholder="Motivo" style="width:160px;" />
+                </div>`).join('');
+            document.getElementById('returnFooter').style.display = 'flex';
+        } catch (e) {
+            document.getElementById('returnResult').innerHTML = '<span style="color:var(--color-error);">' + esc(e.message) + '</span>';
+        }
+    }
+
+    async function submitReturn() {
+        if (!returnSale) return;
+        const items = [];
+        returnSale.items.forEach(it => {
+            const chk = document.getElementById('ret-chk-' + it.id);
+            if (chk && chk.checked) {
+                const qty = parseInt(document.getElementById('ret-qty-' + it.id).value, 10) || 0;
+                const reason = (document.getElementById('ret-reason-' + it.id).value || '').trim();
+                if (qty > 0) items.push({ sale_item_id: it.id, quantity: qty, reason: reason || 'Devolución' });
+            }
+        });
+        if (!items.length) {
+            document.getElementById('returnResult').innerHTML = '<span style="color:var(--color-error);">Selecciona al menos una partida</span>';
+            return;
+        }
+        try {
+            const res = await api('/pos/api/returns', {
+                method: 'POST',
+                body: JSON.stringify({
+                    sale_id: returnSale.id,
+                    items,
+                    notes: document.getElementById('returnNotes').value,
+                    register_id: currentRegister ? currentRegister.id : null,
+                    refund_method: returnSale.payment_method || 'efectivo',
+                }),
+            });
+            document.getElementById('returnResult').innerHTML =
+                '<span style="color:var(--color-success);">Devolución registrada: reembolso ' + fmt(res.total_refund || 0) + '</span>';
+            renderCart();
+        } catch (e) {
+            document.getElementById('returnResult').innerHTML = '<span style="color:var(--color-error);">' + esc(e.message) + '</span>';
+        }
+    }
+
+    // ─── Apartados UI ─────────────────────
+    let currentLayawayId = null;
+
+    function openLayawaysModal() {
+        document.getElementById('layawaysModal').classList.add('open');
+        document.getElementById('layawayActions').style.display = 'none';
+        loadLayaways();
+    }
+    function closeLayawaysModal() {
+        document.getElementById('layawaysModal').classList.remove('open');
+    }
+
+    async function loadLayaways() {
+        const el = document.getElementById('layawaysList');
+        try {
+            const data = await api('/pos/api/layaways?status=active&per_page=50');
+            const rows = data.data || data.layaways || [];
+            if (!rows.length) {
+                el.innerHTML = '<span style="color:var(--color-text-muted);font-size:var(--text-caption);">No hay apartados activos</span>';
+                return;
+            }
+            el.innerHTML = rows.map(l => {
+                const balance = (l.total || 0) - (l.amount_paid || 0);
+                return `<div style="display:flex;align-items:center;gap:10px;padding:10px var(--space-3);border-bottom:1px solid var(--color-border);cursor:pointer;"
+                        onmouseover="this.style.background='var(--color-primary-muted)'" onmouseout="this.style.background=''"
+                        onclick="POS.selectLayaway(${l.id}, ${l.total}, ${l.amount_paid || 0}, '${(l.customer_name || '').replace(/'/g, "\\'")}')">
+                    <div style="flex:1;">
+                        <div style="font-weight:var(--font-weight-semibold);">Apartado #${l.id} — ${l.customer_name || 'Sin cliente'}</div>
+                        <div style="font-size:var(--text-caption);color:var(--color-text-muted);">Vence: ${l.expires_at || '—'}</div>
+                    </div>
+                    <div style="text-align:right;">
+                        <div style="font-weight:var(--font-weight-bold);">${fmt(balance)}</div>
+                        <div style="font-size:var(--text-caption);color:var(--color-text-muted);">de ${fmt(l.total)}</div>
+                    </div>
+                </div>`;
+            }).join('');
+        } catch (e) {
+            el.innerHTML = '<span style="color:var(--color-error);">Error cargando apartados</span>';
+        }
+    }
+    function selectLayaway(id, total, paid, customerName) {
+        currentLayawayId = id;
+        document.getElementById('layawayActions').style.display = 'block';
+        document.getElementById('layawayDetail').innerHTML =
+            `<strong>Apartado #${id}</strong> — ${customerName} — Saldo: <strong>${fmt(total - paid)}</strong>`;
+        document.getElementById('layawayPayAmount').value = (Math.round((total - paid) * 100) / 100) || '';
+        document.getElementById('layawayResult').innerHTML = '';
+    }
+
+    async function layawayPay() {
+        if (!currentLayawayId) return;
+        const amount = parseFloat(document.getElementById('layawayPayAmount').value) || 0;
+        if (amount <= 0) return;
+        try {
+            await api(`/pos/api/layaways/${currentLayawayId}/payment`, {
+                method: 'POST',
+                body: JSON.stringify({ amount, payment_method: document.getElementById('layawayPayMethod').value }),
+            });
+            document.getElementById('layawayResult').innerHTML = '<span style="color:var(--color-success);">Abono registrado</span>';
+            loadLayaways();
+        } catch (e) {
+            document.getElementById('layawayResult').innerHTML = '<span style="color:var(--color-error);">' + esc(e.message) + '</span>';
+        }
+    }
+
+    async function layawayComplete() {
+        if (!currentLayawayId) return;
+        try {
+            const res = await api(`/pos/api/layaways/${currentLayawayId}/complete`, {
+                method: 'POST',
+                body: JSON.stringify({
+                    payment_method: document.getElementById('layawayPayMethod').value,
+                    register_id: currentRegister ? currentRegister.id : null,
+                }),
+            });
+            document.getElementById('layawayResult').innerHTML = '<span style="color:var(--color-success);">Apartado liquidado' + (res.id ? ' — Venta #' + res.id : '') + '</span>';
+            loadLayaways();
+        } catch (e) {
+            document.getElementById('layawayResult').innerHTML = '<span style="color:var(--color-error);">' + esc(e.message) + '</span>';
+        }
+    }
+
+    async function layawayCancel() {
+        if (!currentLayawayId) return;
+        if (!confirm('¿Cancelar el apartado? El stock regresará a inventario.')) return;
+        try {
+            await api(`/pos/api/layaways/${currentLayawayId}/cancel`, { method: 'PUT', body: '{}' });
+            document.getElementById('layawayResult').innerHTML = '<span style="color:var(--color-success);">Apartado cancelado</span>';
+            loadLayaways();
+        } catch (e) {
+            document.getElementById('layawayResult').innerHTML = '<span style="color:var(--color-error);">' + esc(e.message) + '</span>';
+        }
+    }
+
+
+    // ─── Vehículo: placa/VIN → piezas compatibles ─────────────────
+    async function vehicleLookup() {
+        const input = document.getElementById('vehicleLookup');
+        const raw = (input.value || '').trim();
+        if (!raw) return;
+        const compact = raw.replace(/[^A-Za-z0-9]/g, '').toUpperCase();
+        const container = document.getElementById('searchResults');
+        const totals = document.getElementById('totalsPanel');
+        container.innerHTML = '<div style="padding:14px;text-align:center;color:var(--color-text-muted);">Buscando vehículo...</div>';
+        container.style.display = '';
+        totals.style.display = 'none';
+
+        let myeId = null, label = '';
+        try {
+            if (compact.length === 17) {
+                const d = await api('/pos/api/catalog/vin/' + encodeURIComponent(compact));
+                const m = d.match || d.catalog_match || d;
+                myeId = d.mye_id || m.mye_id || m.id_mye || null;
+                label = [m.make || d.make, m.model || d.model, m.year || d.year].filter(Boolean).join(' ');
+            } else {
+                const d = await api('/pos/api/catalog/plate/' + encodeURIComponent(raw));
+                if (!d.found) throw new Error('Placa no registrada — regístrala en el cliente');
+                const m = d.catalog_match || {};
+                myeId = m.mye_id || m.id_mye || null;
+                label = [d.make, d.model, d.year].filter(Boolean).join(' ');
+                if (d.customer_id) {
+                    try {
+                        const cust = await api('/pos/api/customers/' + d.customer_id);
+                        if (cust && cust.data && !currentCustomer) currentCustomer = cust.data;
+                    } catch (e) { /* opcional */ }
+                }
+            }
+            if (!myeId) {
+                throw new Error('Vehículo encontrado pero sin motor en catálogo; usa el catálogo por modelo/año');
+            }
+            const data = await api('/pos/api/catalog/vehicle-inventory?mye_id=' + myeId);
+            const items = data.data || [];
+            const tier = currentCustomer ? (currentCustomer.price_tier || 1) : 1;
+            let html = '<div style="padding:10px var(--space-4);background:var(--color-primary-muted);font-weight:var(--font-weight-semibold);">🚗 Piezas compatibles: ' + esc(label || 'vehículo') + ' (' + items.length + ')</div>';
+            if (!items.length) {
+                html += '<div style="padding:16px;text-align:center;color:var(--color-text-muted);">Sin piezas compatibles registradas aún</div>';
+            } else {
+                items.forEach(item => {
+                    const price = priceForTier(item.price_1, tier, item);
+                    html += `<div style="padding:var(--space-3) var(--space-4);border-bottom:1px solid var(--color-border);cursor:pointer;display:flex;justify-content:space-between;align-items:center;" onmouseover="this.style.background='var(--color-primary-muted)'" onmouseout="this.style.background=''" onclick='POS.addFromSearch(${JSON.stringify(item).replace(/'/g, "&#39;")}, ${price})'>
+                        <div>
+                            <div style="font-weight:var(--font-weight-semibold);">${item.name}</div>
+                            <div style="font-family:var(--font-mono);font-size:var(--text-caption);color:var(--color-text-muted);">${item.part_number} | ${item.brand || ''}</div>
+                            <div style="font-size:var(--text-caption);color:${item.stock <= 0 ? 'var(--color-error)' : 'var(--color-text-muted)'};">Stock: ${item.stock}</div>
+                        </div>
+                        <div style="font-family:var(--font-mono);font-weight:var(--font-weight-bold);color:var(--color-primary);">${fmt(price)}</div>
+                    </div>`;
+                });
+            }
+            container.innerHTML = html;
+        } catch (e) {
+            container.innerHTML = '<div style="padding:14px;text-align:center;color:var(--color-error);">' + esc(e.message) + '</div>';
+        }
+    }
     function hideSearchResults() {
         const sr = document.getElementById('searchResults');
         const tp = document.getElementById('totalsPanel');
@@ -923,6 +1413,8 @@ const POS = (() => {
         document.getElementById('changeDisplay').className = 'cambio-amount positive';
         const payRef = document.getElementById('paymentRef');
         if (payRef) payRef.value = '';
+        const saleCourierSel = document.getElementById('saleCourier');
+        if (saleCourierSel) saleCourierSel.value = '';
 
         // Populate quick amounts
         const quickContainer = document.getElementById('quickAmounts');
@@ -998,9 +1490,22 @@ const POS = (() => {
         }
     }
 
+    function getPayCurrency() {
+        const sel = document.getElementById('payCurrency');
+        return sel ? sel.value : 'MXN';
+    }
+
+    function getUsdRate() {
+        const r = parseFloat(localStorage.getItem('pos_exchange_rate')) || 17.5;
+        return r > 0 ? r : 17.5;
+    }
+
     function updateChange() {
         const total = getTotal();
-        const received = parseFloat(document.getElementById('cashReceived').value) || 0;
+        let received = parseFloat(document.getElementById('cashReceived').value) || 0;
+        const hint = document.getElementById('usdRateHint');
+        if (hint) hint.textContent = getPayCurrency() === 'USD' ? ('TC: ' + getUsdRate()) : '';
+        if (getPayCurrency() === 'USD') received = received * getUsdRate();
         const change = received - total;
         const el = document.getElementById('changeDisplay');
         if (change >= 0) {
@@ -1035,8 +1540,14 @@ const POS = (() => {
         let reference = '';
         let saleType = 'cash';
 
+        let payCurrencyNote = '';
         if (paymentMethod === 'efectivo') {
             amountPaid = parseFloat(document.getElementById('cashReceived').value) || 0;
+            if (getPayCurrency() === 'USD') {
+                const usd = amountPaid;
+                amountPaid = Math.round(usd * getUsdRate() * 100) / 100;
+                payCurrencyNote = `Pago en USD: $${usd.toFixed(2)} @ TC ${getUsdRate()}`;
+            }
             if (amountPaid < total) { alert(`Monto insuficiente. Total: ${fmt(total)}`); return; }
         } else if (paymentMethod === 'transferencia' || paymentMethod === 'tarjeta') {
             amountPaid = total;
@@ -1083,8 +1594,10 @@ const POS = (() => {
             register_id: currentRegister ? currentRegister.id : null,
             amount_paid: amountPaid,
             payment_details: paymentDetails,
-            reference: reference,
+            reference: [reference, payCurrencyNote].filter(Boolean).join(' | '),
             generate_cfdi: document.getElementById('cfdiCheck').checked,
+            courier_id: (document.getElementById('saleCourier') || {}).value
+                ? parseInt(document.getElementById('saleCourier').value, 10) : null,
         };
 
         const zeroItem = findZeroPriceItem();
@@ -1126,16 +1639,42 @@ const POS = (() => {
             lastSaleId = sale.id;
             lastSaleData = sale;
             try { sessionStorage.setItem('pos_last_sale_id', sale.id); } catch(e) {}
+            if (saleData.courier_id) {
+                const courier = couriers.find(c => c.id === saleData.courier_id);
+                sale.courier_name = courier ? courier.name : '';
+            }
             closePaymentModal();
             showTicket(sale);
+            if (rc('auto_print', '') === true || rc('auto_print', '') === 'true') {
+                try { printTicket(); } catch (e) { /* impresión no bloquea */ }
+            }
 
             // Clear cart
             cart = [];
             selectedRow = -1;
             clearCustomer();
+            const saleCourierSel2 = document.getElementById('saleCourier');
+            if (saleCourierSel2) saleCourierSel2.value = '';
             renderCart();
         } catch (e) {
-            alert('Error al procesar venta: ' + e.message);
+            // Sin conexión: encolar la venta para sincronizar después
+            if (navigator.onLine === false || /network|failed to fetch/i.test(e.message)) {
+                const uuid = queueOfflineSale(saleData);
+                closePaymentModal();
+                showTicket({
+                    id: 'OFF-' + uuid.slice(0, 8),
+                    total: total,
+                    items: saleData.items.map(it => ({ name: it.part_number || it.inventory_id, quantity: it.quantity, unit_price: it.unit_price, subtotal: it.unit_price * it.quantity })),
+                    customer_name: currentCustomer ? currentCustomer.name : 'Público General',
+                    payment_method: paymentMethod,
+                    offline: true,
+                    created_at: new Date().toISOString(),
+                });
+                cart = []; selectedRow = -1; renderCart();
+                showToast('Sin conexión — venta en cola (' + offlineQueue().length + ' pendientes). Se sincronizará automáticamente.', 'ok');
+            } else {
+                alert('Error al procesar venta: ' + e.message);
+            }
         } finally {
             confirmBtn.disabled = false;
             confirmBtn.textContent = 'Confirmar Pago';
@@ -1593,7 +2132,7 @@ const POS = (() => {
                 <span>Cliente: ${customerName}</span>
                 ${customerRfc ? `<span>RFC: ${customerRfc}</span>` : ''}
             </div>
-            ${isRemission && sale.courier_name ? `<div class="ticket-row" style="font-size: 9px; color: #555; margin-bottom: 4px;"><span>Repartidor: ${sale.courier_name}</span></div>` : ''}
+            ${sale.courier_name ? `<div class="ticket-row" style="font-size: 9px; color: #555; margin-bottom: 4px;"><span>Repartidor: ${sale.courier_name}</span></div>` : ''}
             <hr class="divider">
             <div class="item-line-wide" style="font-weight: bold; font-size: 9px; color: #555; text-transform: uppercase;">
                 <span class="qty">Cant</span>
@@ -1792,7 +2331,15 @@ const POS = (() => {
 
     // ─── Drawer ──────────────────────────
     function openDrawer() {
-        showToast('Comando enviado al cajon de efectivo.');
+        // Kick ESC p 0 25 250 via connected thermal printer (USB/Serial)
+        try {
+            if (window.NexusPrinter && typeof window.NexusPrinter.sendRaw === 'function') {
+                window.NexusPrinter.sendRaw(new Uint8Array([27, 112, 48, 25, 250]))
+                    .then(ok => showToast(ok ? 'Cajón abierto.' : 'Sin impresora conectada — no se pudo abrir el cajón.', ok ? 'ok' : 'error'));
+                return;
+            }
+        } catch (e) { /* fallthrough */ }
+        showToast('Conecta una impresora térmica (Config → Impresora) para abrir el cajón.', 'error');
     }
 
     // ─── Keyboard Shortcuts ──────────────
@@ -1924,6 +2471,9 @@ const POS = (() => {
         addToCart, removeFromCart, clearCart, selectRow,
         updateQty, updateDiscount,
         addFromSearch, hideSearchResults,
+        openReturnModal, closeReturnModal, searchReturnSale, submitReturn, vehicleLookup,
+        openLayawaysModal, closeLayawaysModal, loadLayaways, selectLayaway,
+        layawayPay, layawayComplete, layawayCancel,
         selectCustomer, clearCustomer,
         showNewCustomerModal, closeNewCustomerModal, saveNewCustomer,
         checkout, confirmPayment, closePaymentModal,
@@ -1938,6 +2488,7 @@ const POS = (() => {
         showOpenRegisterModal, closeOpenRegisterModal, openRegister,
         showCutZModal, closeCutZModal, loadCutX, confirmCutZ,
         openCancelModal, closeCancelModal, changeQuantity, applyDiscount, modifyPrice,
+        refreshCrossSell, hideCrossSell, addCrossSellItem,
     };
 
 })();