// /home/Autopartes/pos/static/js/pos.js
/**
 * POS Frontend: sale processing, F-key shortcuts, payment modal, ticket printing.
 *
 * Communicates with:
 *   - /pos/api/sales (pos_bp)
 *   - /pos/api/quotations (pos_bp)
 *   - /pos/api/layaways (pos_bp)
 *   - /pos/api/customers (customers_bp)
 *   - /pos/api/register (cashregister_bp)
 *   - /pos/api/inventory/items (inventory_bp) — for item search
 *   - /pos/api/catalog/search (catalog_bp) — for catalog search
 */
const POS = (() => {
    // ─── State ───────────────────────────
    let token = localStorage.getItem('pos_token') || '';
    let cart = [];
    let selectedRow = -1;
    let currentCustomer = null;
    let currentRegister = null;
    let paymentMethod = 'efectivo';
    let canViewCost = false;
    let employeeMaxDiscount = 100;
    let lastSaleId = null;
    let searchTimeout = null;
    let customerSearchTimeout = null;

    const fmt = (n) => '$' + parseFloat(n || 0).toLocaleString('es-MX', { minimumFractionDigits: 2, maximumFractionDigits: 2 });

    function headers() {
        return { 'Content-Type': 'application/json', 'Authorization': 'Bearer ' + token };
    }

    async function api(url, options = {}) {
        options.headers = headers();
        const res = await fetch(url, options);
        const data = await res.json();
        if (!res.ok) throw new Error(data.error || `HTTP ${res.status}`);
        return data;
    }

    // ─── Init ────────────────────────────
    async function init() {
        // Parse JWT to get employee info
        try {
            const payload = JSON.parse(atob(token.split('.')[1]));
            document.getElementById('employeeName').textContent = payload.name || 'Empleado';
            document.getElementById('branchName').textContent = payload.branch_name || '';
            canViewCost = (payload.permissions || []).includes('pos.view_cost');
            employeeMaxDiscount = payload.max_discount_pct || 100;

            // Show cost/margin columns if permission
            if (canViewCost) {
                document.getElementById('thCost').style.display = '';
                document.getElementById('thMargin').style.display = '';
            }
        } catch (e) {
            console.warn('Could not parse token:', e);
        }

        // Load cart from localStorage (from catalog)
        const catalogCart = localStorage.getItem('pos_cart');
        if (catalogCart) {
            try {
                const items = JSON.parse(catalogCart);
                for (const item of items) {
                    addToCart(item);
                }
                localStorage.removeItem('pos_cart');
            } catch (e) { console.warn('Could not load catalog cart:', e); }
        }

        // Load current register
        await loadRegister();

        // Setup event listeners
        setupKeyboard();
        setupSearch();
        setupCustomerSearch();
    }

    // ─── Register ────────────────────────
    async function loadRegister() {
        try {
            const data = await api('/pos/api/register/current');
            if (data.register) {
                currentRegister = data.register;
                document.getElementById('registerInfo').innerHTML =
                    `<span>Caja #${data.register.register_number}</span>`;
                document.getElementById('registerInfo').classList.remove('no-register');
            } else {
                document.getElementById('registerInfo').innerHTML =
                    '<span>Sin caja abierta</span>';
                document.getElementById('registerInfo').classList.add('no-register');
            }
        } catch (e) {
            console.warn('Register check failed:', e);
        }
    }

    // ─── Cart ────────────────────────────
    function addToCart(item) {
        // Check if item already in cart
        const existing = cart.find(c => c.inventory_id === item.inventory_id);
        if (existing) {
            existing.quantity += (item.quantity || 1);
            renderCart();
            return;
        }

        cart.push({
            inventory_id: item.inventory_id || item.id,
            part_number: item.part_number || '',
            name: item.name || '',
            quantity: item.quantity || 1,
            unit_price: parseFloat(item.unit_price || item.price_1 || 0),
            unit_cost: parseFloat(item.cost || 0),
            discount_pct: parseFloat(item.discount_pct || 0),
            tax_rate: parseFloat(item.tax_rate || 0.16),
            stock: item.stock || 0,
        });

        renderCart();
    }

    function removeFromCart(index) {
        cart.splice(index, 1);
        if (selectedRow >= cart.length) selectedRow = cart.length - 1;
        renderCart();
    }

    function renderCart() {
        const tbody = document.getElementById('cartBody');
        const table = document.getElementById('cartTable');
        const empty = document.getElementById('cartEmpty');

        if (cart.length === 0) {
            table.style.display = 'none';
            empty.style.display = 'flex';
            updateTotals();
            return;
        }

        table.style.display = '';
        empty.style.display = 'none';

        let html = '';
        cart.forEach((item, i) => {
            const lineGross = item.unit_price * item.quantity;
            const lineDiscount = lineGross * item.discount_pct / 100;
            const lineSubtotal = lineGross - lineDiscount;

            const costHtml = canViewCost ? `<td class="num">${fmt(item.unit_cost)}</td>` : '';
            let marginHtml = '';
            if (canViewCost) {
                const effectivePrice = item.unit_price * (1 - item.discount_pct / 100);
                const marginPct = effectivePrice > 0
                    ? ((effectivePrice - item.unit_cost) / effectivePrice * 100).toFixed(1)
                    : '0.0';
                const cls = parseFloat(marginPct) < 5 ? 'margin-warning' : 'margin-info';
                marginHtml = `<td class="num"><span class="${cls}">${marginPct}%</span></td>`;
            }

            html += `<tr class="${i === selectedRow ? 'selected' : ''}" onclick="POS.selectRow(${i})">
                <td>${i + 1}</td>
                <td>
                    <div class="part-name">${item.name}</div>
                    <div class="part-number">${item.part_number} | Stock: ${item.stock}</div>
                </td>
                <td><input type="number" class="qty-input" value="${item.quantity}" min="1"
                    onchange="POS.updateQty(${i}, this.value)" onclick="event.stopPropagation()"></td>
                <td class="num">${fmt(item.unit_price)}</td>
                <td><input type="number" class="discount-input" value="${item.discount_pct}" min="0" max="100" step="0.5"
                    onchange="POS.updateDiscount(${i}, this.value)" onclick="event.stopPropagation()">%</td>
                <td class="num">${fmt(lineSubtotal)}</td>
                ${costHtml}
                ${marginHtml}
                <td><button class="btn-remove" onclick="event.stopPropagation(); POS.removeFromCart(${i})">&times;</button></td>
            </tr>`;
        });
        tbody.innerHTML = html;
        updateTotals();
    }

    function updateQty(index, val) {
        const qty = Math.max(1, parseInt(val) || 1);
        cart[index].quantity = qty;
        renderCart();
    }

    function updateDiscount(index, val) {
        let disc = Math.max(0, Math.min(100, parseFloat(val) || 0));
        if (disc > employeeMaxDiscount) {
            alert(`Descuento maximo permitido: ${employeeMaxDiscount}%`);
            disc = employeeMaxDiscount;
        }
        cart[index].discount_pct = disc;
        renderCart();
    }

    function selectRow(index) {
        selectedRow = index;
        renderCart();
    }

    function updateTotals() {
        let subtotal = 0, discountTotal = 0, taxTotal = 0;

        cart.forEach(item => {
            const lineGross = item.unit_price * item.quantity;
            const lineDiscount = lineGross * item.discount_pct / 100;
            const lineAfterDiscount = lineGross - lineDiscount;
            const lineTax = lineAfterDiscount * item.tax_rate;
            subtotal += lineAfterDiscount;
            discountTotal += lineDiscount;
            taxTotal += lineTax;
        });

        const total = subtotal + taxTotal;

        document.getElementById('dispSubtotal').textContent = fmt(subtotal);
        document.getElementById('dispTax').textContent = fmt(taxTotal);
        document.getElementById('dispTotal').textContent = fmt(total);

        if (discountTotal > 0) {
            document.getElementById('discountRow').style.display = '';
            document.getElementById('dispDiscount').textContent = '-' + fmt(discountTotal);
        } else {
            document.getElementById('discountRow').style.display = 'none';
        }
    }

    function getTotal() {
        let subtotal = 0, taxTotal = 0;
        cart.forEach(item => {
            const lineGross = item.unit_price * item.quantity;
            const lineDiscount = lineGross * item.discount_pct / 100;
            const lineAfterDiscount = lineGross - lineDiscount;
            const lineTax = lineAfterDiscount * item.tax_rate;
            subtotal += lineAfterDiscount;
            taxTotal += lineTax;
        });
        return Math.round((subtotal + taxTotal) * 100) / 100;
    }

    // ─── Search ──────────────────────────
    function setupSearch() {
        const input = document.getElementById('itemSearch');
        input.addEventListener('input', () => {
            clearTimeout(searchTimeout);
            searchTimeout = setTimeout(() => searchItems(input.value.trim()), 300);
        });
        input.addEventListener('keydown', (e) => {
            if (e.key === 'Enter') {
                e.preventDefault();
                searchItems(input.value.trim());
            }
            if (e.key === 'Escape') {
                input.value = '';
                hideSearchResults();
            }
        });
    }

    async function searchItems(q) {
        if (!q || q.length < 2) { hideSearchResults(); 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) {
                container.innerHTML = '<div style="padding:20px;text-align:center;color:#999;">Sin resultados</div>';
            } else {
                let html = '';
                data.data.forEach(item => {
                    // Determine price for current customer
                    let price = item.price_1;
                    if (currentCustomer) {
                        const tier = currentCustomer.price_tier || 1;
                        price = tier === 3 ? item.price_3 : tier === 2 ? item.price_2 : item.price_1;
                    }
                    const stockClass = item.stock <= 0 ? 'zero' : '';
                    html += `<div class="search-result-item" onclick='POS.addFromSearch(${JSON.stringify(item).replace(/'/g, "&#39;")}, ${price})'>
                        <div>
                            <div class="sr-name">${item.name}</div>
                            <div class="sr-pn">${item.part_number} | ${item.brand || ''}</div>
                            <div class="sr-stock ${stockClass}">Stock: ${item.stock}</div>
                        </div>
                        <div class="sr-price">${fmt(price)}</div>
                    </div>`;
                });
                container.innerHTML = html;
            }

            container.classList.add('active');
            totals.classList.add('hidden');
        } catch (e) {
            console.error('Search error:', e);
        }
    }

    function addFromSearch(item, price) {
        addToCart({
            inventory_id: item.id,
            part_number: item.part_number,
            name: item.name,
            unit_price: price,
            cost: item.cost,
            tax_rate: item.tax_rate,
            stock: item.stock,
        });
        hideSearchResults();
        document.getElementById('itemSearch').value = '';
        document.getElementById('itemSearch').focus();
    }

    function hideSearchResults() {
        document.getElementById('searchResults').classList.remove('active');
        document.getElementById('totalsPanel').classList.remove('hidden');
    }

    // ─── Customer Search ─────────────────
    function setupCustomerSearch() {
        const input = document.getElementById('customerSearch');
        input.addEventListener('input', () => {
            clearTimeout(customerSearchTimeout);
            customerSearchTimeout = setTimeout(() => searchCustomers(input.value.trim()), 300);
        });
        input.addEventListener('keydown', (e) => {
            if (e.key === 'Escape') {
                input.value = '';
                document.getElementById('customerAutocomplete').style.display = 'none';
            }
        });
    }

    async function searchCustomers(q) {
        if (!q || q.length < 2) {
            document.getElementById('customerAutocomplete').style.display = 'none';
            return;
        }

        try {
            const data = await api(`/pos/api/customers?q=${encodeURIComponent(q)}&per_page=10`);
            const ac = document.getElementById('customerAutocomplete');

            if (data.data.length === 0) {
                ac.innerHTML = '<div class="ac-item" style="color:#999;">Sin resultados</div>';
            } else {
                let html = '';
                data.data.forEach(c => {
                    const tiers = { 1: 'Mostrador', 2: 'Taller', 3: 'Mayoreo' };
                    html += `<div class="ac-item" onclick='POS.selectCustomer(${JSON.stringify(c).replace(/'/g, "&#39;")})'>
                        <div>${c.name}</div>
                        <div class="ac-meta">${c.rfc || ''} | ${c.phone || ''} | ${tiers[c.price_tier] || 'P1'} | Credito: ${fmt(c.credit_balance)}/${fmt(c.credit_limit)}</div>
                    </div>`;
                });
                ac.innerHTML = html;
            }
            ac.style.display = 'block';
        } catch (e) {
            console.error('Customer search error:', e);
        }
    }

    async function selectCustomer(customer) {
        currentCustomer = customer;
        document.getElementById('customerAutocomplete').style.display = 'none';
        document.getElementById('customerSearchWrap').querySelector('input').style.display = 'none';

        const tiers = { 1: 'P1 Mostrador', 2: 'P2 Taller', 3: 'P3 Mayoreo' };
        document.getElementById('customerName').textContent = customer.name;
        document.getElementById('customerTier').textContent = tiers[customer.price_tier] || 'P1';
        document.getElementById('customerCredit').textContent =
            `Credito: ${fmt(customer.credit_balance)} / ${fmt(customer.credit_limit)}`;
        document.getElementById('customerSelected').style.display = '';

        // Show vehicle info
        if (customer.vehicle_info && customer.vehicle_info.length > 0) {
            const v = customer.vehicle_info[0];
            document.getElementById('vehicleInfo').textContent =
                `${v.make || ''} ${v.model || ''} ${v.year || ''} ${v.plates ? '(' + v.plates + ')' : ''}`;
            document.getElementById('vehicleBanner').classList.add('visible');
        }

        // Fetch full customer detail to get recent purchase info
        try {
            const detail = await api(`/pos/api/customers/${customer.id}`);
            if (detail.recent_purchases && detail.recent_purchases.length > 0) {
                const last = detail.recent_purchases[0];
                const daysAgo = Math.floor((Date.now() - new Date(last.created_at).getTime()) / 86400000);
                const daysText = daysAgo === 0 ? 'hoy' : daysAgo === 1 ? 'hace 1 dia' : `hace ${daysAgo} dias`;
                document.getElementById('lastPurchaseInfo').textContent =
                    `Ultima compra: ${fmt(last.total)} ${daysText}`;
                document.getElementById('vehicleBanner').classList.add('visible');
            }
        } catch (e) {
            console.warn('Could not fetch customer detail:', e);
        }

        // Re-apply prices based on customer tier
        cart.forEach(item => {
            // Fetch updated price for this customer tier (would need to re-query)
            // For now, prices stay as-is (they were set at add time)
        });

        renderCart();
    }

    function clearCustomer() {
        currentCustomer = null;
        document.getElementById('customerSelected').style.display = 'none';
        document.getElementById('customerSearchWrap').querySelector('input').style.display = '';
        document.getElementById('customerSearchWrap').querySelector('input').value = '';
        document.getElementById('vehicleBanner').classList.remove('visible');
        renderCart();
    }

    // ─── New Customer Modal ──────────────
    function showNewCustomerModal() {
        document.getElementById('newCustomerModal').classList.add('active');
        document.getElementById('ncName').focus();
    }

    function closeNewCustomerModal() {
        document.getElementById('newCustomerModal').classList.remove('active');
    }

    async function saveNewCustomer() {
        const name = document.getElementById('ncName').value.trim();
        if (!name) { alert('Nombre es requerido'); return; }

        const vehicle_info = [];
        const make = document.getElementById('ncVehMake').value.trim();
        if (make) {
            vehicle_info.push({
                make: make,
                model: document.getElementById('ncVehModel').value.trim(),
                year: document.getElementById('ncVehYear').value.trim(),
                plates: document.getElementById('ncVehPlates').value.trim(),
            });
        }

        const body = {
            name: name,
            rfc: document.getElementById('ncRfc').value.trim() || null,
            razon_social: document.getElementById('ncRazonSocial').value.trim() || null,
            regimen_fiscal: document.getElementById('ncRegimenFiscal').value || null,
            uso_cfdi: document.getElementById('ncUsoCfdi').value || 'G03',
            phone: document.getElementById('ncPhone').value.trim() || null,
            email: document.getElementById('ncEmail').value.trim() || null,
            price_tier: parseInt(document.getElementById('ncPriceTier').value) || 1,
            credit_limit: parseFloat(document.getElementById('ncCreditLimit').value) || 0,
            vehicle_info: vehicle_info.length > 0 ? vehicle_info : null,
        };

        try {
            const result = await api('/pos/api/customers', {
                method: 'POST',
                body: JSON.stringify(body),
            });

            // Select the new customer
            selectCustomer({
                id: result.id,
                name: body.name,
                rfc: body.rfc,
                phone: body.phone,
                price_tier: body.price_tier,
                credit_limit: body.credit_limit,
                credit_balance: 0,
                vehicle_info: body.vehicle_info,
            });

            closeNewCustomerModal();
        } catch (e) {
            alert('Error al crear cliente: ' + e.message);
        }
    }

    // ─── Payment ─────────────────────────
    function checkout() {
        if (cart.length === 0) { alert('Carrito vacio'); return; }
        if (!currentRegister) { alert('No hay caja abierta. Abra una caja primero.'); return; }

        paymentMethod = 'efectivo';
        const total = getTotal();

        document.getElementById('modalTotal').textContent = fmt(total);
        document.getElementById('cashReceived').value = '';
        document.getElementById('changeDisplay').textContent = 'Cambio: $0.00';
        document.getElementById('changeDisplay').className = 'change-display positive';
        document.getElementById('paymentRef').value = '';

        // Reset payment method buttons
        document.querySelectorAll('.pm-btn').forEach(b => b.classList.remove('active'));
        document.querySelector('.pm-btn[data-method="efectivo"]').classList.add('active');
        document.getElementById('cashPayment').style.display = '';
        document.getElementById('refPayment').style.display = 'none';
        document.getElementById('mixedPayment').style.display = 'none';

        document.getElementById('paymentModal').classList.add('active');
        setTimeout(() => document.getElementById('cashReceived').focus(), 100);
    }

    function selectPaymentMethod(method, btn) {
        paymentMethod = method;
        document.querySelectorAll('.pm-btn').forEach(b => b.classList.remove('active'));
        btn.classList.add('active');

        document.getElementById('cashPayment').style.display = method === 'efectivo' ? '' : 'none';
        document.getElementById('refPayment').style.display = (method === 'transferencia' || method === 'tarjeta') ? '' : 'none';
        document.getElementById('mixedPayment').style.display = method === 'mixto' ? '' : 'none';

        if (method === 'efectivo') document.getElementById('cashReceived').focus();
        if (method === 'transferencia' || method === 'tarjeta') document.getElementById('paymentRef').focus();
    }

    function updateChange() {
        const total = getTotal();
        const received = parseFloat(document.getElementById('cashReceived').value) || 0;
        const change = received - total;
        const el = document.getElementById('changeDisplay');
        el.textContent = `Cambio: ${fmt(Math.abs(change))}`;
        el.className = 'change-display ' + (change >= 0 ? 'positive' : 'negative');
    }

    function updateMixedTotal() {
        const total = getTotal();
        let sum = 0;
        document.querySelectorAll('.mixed-amount').forEach(input => {
            sum += parseFloat(input.value) || 0;
        });
        const remaining = total - sum;
        document.getElementById('mixedRemaining').textContent =
            remaining > 0 ? `Faltante: ${fmt(remaining)}` : `Cubierto (${fmt(sum)})`;
        document.getElementById('mixedRemaining').style.color = remaining > 0 ? '#c62828' : '#2e7d32';
    }

    function closePaymentModal() {
        document.getElementById('paymentModal').classList.remove('active');
    }

    async function confirmPayment() {
        const total = getTotal();
        let amountPaid = 0;
        let paymentDetails = [];
        let reference = '';

        if (paymentMethod === 'efectivo') {
            amountPaid = parseFloat(document.getElementById('cashReceived').value) || 0;
            if (amountPaid < total) { alert(`Monto insuficiente. Total: ${fmt(total)}`); return; }
        } else if (paymentMethod === 'transferencia' || paymentMethod === 'tarjeta') {
            amountPaid = total;
            reference = document.getElementById('paymentRef').value.trim();
        } else if (paymentMethod === 'mixto') {
            const rows = document.querySelectorAll('.mixed-row');
            rows.forEach(row => {
                const method = row.querySelector('select').value;
                const amount = parseFloat(row.querySelector('.mixed-amount').value) || 0;
                const ref = row.querySelectorAll('input')[1]?.value || '';
                if (amount > 0) {
                    paymentDetails.push({ method, amount, reference: ref });
                    amountPaid += amount;
                }
            });
            if (amountPaid < total) { alert(`Monto total insuficiente. Falta: ${fmt(total - amountPaid)}`); return; }
        }

        const saleData = {
            items: cart.map(item => ({
                inventory_id: item.inventory_id,
                quantity: item.quantity,
                unit_price: item.unit_price,
                discount_pct: item.discount_pct,
                tax_rate: item.tax_rate,
            })),
            customer_id: currentCustomer ? currentCustomer.id : null,
            payment_method: paymentMethod,
            sale_type: 'cash',
            register_id: currentRegister ? currentRegister.id : null,
            amount_paid: amountPaid,
            payment_details: paymentDetails,
            reference: reference,
        };

        document.getElementById('btnConfirmPayment').disabled = true;
        document.getElementById('btnConfirmPayment').textContent = 'Procesando...';

        try {
            const sale = await api('/pos/api/sales', {
                method: 'POST',
                body: JSON.stringify(saleData),
            });

            lastSaleId = sale.id;
            closePaymentModal();
            showTicket(sale);

            // Clear cart
            cart = [];
            selectedRow = -1;
            clearCustomer();
            renderCart();

        } catch (e) {
            alert('Error al procesar venta: ' + e.message);
        } finally {
            document.getElementById('btnConfirmPayment').disabled = false;
            document.getElementById('btnConfirmPayment').textContent = 'Confirmar Pago';
        }
    }

    // ─── Credit Sale ─────────────────────
    async function creditSale() {
        if (cart.length === 0) { alert('Carrito vacio'); return; }
        if (!currentCustomer) { alert('Seleccione un cliente para venta a credito'); return; }
        if (!currentRegister) { alert('No hay caja abierta.'); return; }

        const total = getTotal();
        const available = (currentCustomer.credit_limit || 0) - (currentCustomer.credit_balance || 0);

        if (currentCustomer.credit_limit > 0 && total > available) {
            if (!confirm(`Credito insuficiente. Disponible: ${fmt(available)}, Total: ${fmt(total)}. Continuar de todas formas?`)) {
                return;
            }
        }

        const saleData = {
            items: cart.map(item => ({
                inventory_id: item.inventory_id,
                quantity: item.quantity,
                unit_price: item.unit_price,
                discount_pct: item.discount_pct,
                tax_rate: item.tax_rate,
            })),
            customer_id: currentCustomer.id,
            payment_method: 'credito',
            sale_type: 'credit',
            register_id: currentRegister ? currentRegister.id : null,
            amount_paid: 0,
        };

        try {
            const sale = await api('/pos/api/sales', {
                method: 'POST',
                body: JSON.stringify(saleData),
            });

            lastSaleId = sale.id;
            showTicket(sale);
            cart = [];
            selectedRow = -1;
            clearCustomer();
            renderCart();
        } catch (e) {
            alert('Error: ' + e.message);
        }
    }

    // ─── Quotation ───────────────────────
    async function saveQuotation() {
        if (cart.length === 0) { alert('Carrito vacio'); return; }

        const body = {
            items: cart.map(item => ({
                inventory_id: item.inventory_id,
                quantity: item.quantity,
                unit_price: item.unit_price,
                discount_pct: item.discount_pct,
                tax_rate: item.tax_rate,
            })),
            customer_id: currentCustomer ? currentCustomer.id : null,
        };

        try {
            const result = await api('/pos/api/quotations', {
                method: 'POST',
                body: JSON.stringify(body),
            });
            alert(`Cotizacion #${result.id} guardada. Total: ${fmt(result.total)}\nValida hasta: ${result.valid_until}`);
        } catch (e) {
            alert('Error: ' + e.message);
        }
    }

    // ─── Layaway ─────────────────────────
    async function createLayaway() {
        if (cart.length === 0) { alert('Carrito vacio'); return; }
        if (!currentCustomer) { alert('Seleccione un cliente para apartado'); return; }

        const total = getTotal();
        const initialPayment = prompt(`Total: ${fmt(total)}\nIngrese monto del anticipo:`);
        if (!initialPayment) return;

        const amount = parseFloat(initialPayment);
        if (isNaN(amount) || amount <= 0) { alert('Monto invalido'); return; }
        if (amount > total) { alert('El anticipo no puede exceder el total'); return; }

        const body = {
            items: cart.map(item => ({
                inventory_id: item.inventory_id,
                quantity: item.quantity,
                unit_price: item.unit_price,
                discount_pct: item.discount_pct,
                tax_rate: item.tax_rate,
            })),
            customer_id: currentCustomer.id,
            initial_payment: amount,
            payment_method: 'efectivo',
            register_id: currentRegister ? currentRegister.id : null,
        };

        try {
            const result = await api('/pos/api/layaways', {
                method: 'POST',
                body: JSON.stringify(body),
            });
            alert(
                `Apartado #${result.id} creado.\n` +
                `Total: ${fmt(result.total)}\n` +
                `Anticipo: ${fmt(result.amount_paid)}\n` +
                `Restante: ${fmt(result.remaining)}\n` +
                `Vence: ${result.expires_at}`
            );
            cart = [];
            selectedRow = -1;
            clearCustomer();
            renderCart();
        } catch (e) {
            alert('Error: ' + e.message);
        }
    }

    // ─── Ticket ──────────────────────────
    function showTicket(sale) {
        const lines = [];
        lines.push('========================================');
        lines.push('              NEXUS POS');
        lines.push('========================================');
        lines.push(`Venta #${sale.id}`);
        lines.push(`Fecha: ${new Date(sale.created_at).toLocaleString('es-MX')}`);
        if (currentCustomer) {
            lines.push(`Cliente: ${currentCustomer.name}`);
            if (currentCustomer.rfc) lines.push(`RFC: ${currentCustomer.rfc}`);
        } else {
            lines.push('Cliente: Publico General');
        }
        lines.push('----------------------------------------');

        (sale.items || []).forEach(item => {
            lines.push(`${item.name}`);
            let line = `  ${item.quantity} x ${fmt(item.unit_price)}`;
            if (item.discount_pct > 0) line += ` (-${item.discount_pct}%)`;
            line += `  ${fmt(item.subtotal)}`;
            lines.push(line);
        });

        lines.push('----------------------------------------');
        lines.push(`Subtotal:      ${fmt(sale.subtotal).padStart(12)}`);
        if (sale.discount_total > 0) {
            lines.push(`Descuento:    -${fmt(sale.discount_total).padStart(12)}`);
        }
        lines.push(`IVA:           ${fmt(sale.tax_total).padStart(12)}`);
        lines.push('========================================');
        lines.push(`TOTAL:         ${fmt(sale.total).padStart(12)}`);
        lines.push('========================================');

        if (sale.payment_method === 'efectivo') {
            lines.push(`Efectivo:      ${fmt(sale.amount_paid).padStart(12)}`);
            lines.push(`Cambio:        ${fmt(sale.change_given).padStart(12)}`);
        } else {
            lines.push(`Pago: ${sale.payment_method}`);
        }

        lines.push('');
        lines.push('       Gracias por su compra!');
        lines.push('');

        document.getElementById('ticketPreview').textContent = lines.join('\n');
        document.getElementById('ticketModal').classList.add('active');
    }

    function closeTicketModal() {
        document.getElementById('ticketModal').classList.remove('active');
    }

    function printTicket() {
        window.print();
    }

    // ─── Last Sale ───────────────────────
    async function showLastSale() {
        if (!lastSaleId) { alert('No hay venta reciente'); return; }
        try {
            const sale = await api(`/pos/api/sales/${lastSaleId}`);
            showTicket(sale);
        } catch (e) {
            alert('Error: ' + e.message);
        }
    }

    // ─── Drawer ──────────────────────────
    function openDrawer() {
        // Cash drawer open command (ESC/POS compatible)
        // In a real implementation, this would send the command to the printer
        alert('Comando enviado al cajon de efectivo.');
    }

    // ─── Keyboard Shortcuts ──────────────
    function setupKeyboard() {
        document.addEventListener('keydown', (e) => {
            // Don't intercept when typing in inputs
            const tag = e.target.tagName;
            const inInput = tag === 'INPUT' || tag === 'TEXTAREA' || tag === 'SELECT';

            switch (e.key) {
                case 'F1':
                    e.preventDefault();
                    document.getElementById('itemSearch').focus();
                    break;
                case 'F2':
                    e.preventDefault();
                    document.getElementById('customerSearch').focus();
                    document.getElementById('customerSearch').style.display = '';
                    document.getElementById('customerSelected').style.display = 'none';
                    break;
                case 'F3':
                    e.preventDefault();
                    checkout();
                    break;
                case 'F4':
                    e.preventDefault();
                    saveQuotation();
                    break;
                case 'F5':
                    e.preventDefault();
                    showLastSale();
                    break;
                case 'F6':
                    e.preventDefault();
                    openDrawer();
                    break;
                case 'Escape':
                    e.preventDefault();
                    if (document.getElementById('paymentModal').classList.contains('active')) {
                        closePaymentModal();
                    } else if (document.getElementById('newCustomerModal').classList.contains('active')) {
                        closeNewCustomerModal();
                    } else if (document.getElementById('ticketModal').classList.contains('active')) {
                        closeTicketModal();
                    } else {
                        hideSearchResults();
                    }
                    break;
                case 'Delete':
                    if (!inInput && selectedRow >= 0 && selectedRow < cart.length) {
                        e.preventDefault();
                        removeFromCart(selectedRow);
                    }
                    break;
                case '+':
                    if (!inInput && selectedRow >= 0 && selectedRow < cart.length) {
                        e.preventDefault();
                        cart[selectedRow].quantity++;
                        renderCart();
                    }
                    break;
                case '-':
                    if (!inInput && selectedRow >= 0 && selectedRow < cart.length) {
                        e.preventDefault();
                        if (cart[selectedRow].quantity > 1) {
                            cart[selectedRow].quantity--;
                            renderCart();
                        }
                    }
                    break;
                case '*':
                    if (!inInput && selectedRow >= 0 && selectedRow < cart.length) {
                        e.preventDefault();
                        const disc = prompt('Descuento %:', cart[selectedRow].discount_pct);
                        if (disc !== null) {
                            updateDiscount(selectedRow, disc);
                        }
                    }
                    break;
                case 'ArrowUp':
                    if (!inInput && cart.length > 0) {
                        e.preventDefault();
                        selectedRow = Math.max(0, selectedRow - 1);
                        renderCart();
                    }
                    break;
                case 'ArrowDown':
                    if (!inInput && cart.length > 0) {
                        e.preventDefault();
                        selectedRow = Math.min(cart.length - 1, selectedRow + 1);
                        renderCart();
                    }
                    break;
                case 'Enter':
                    if (e.target.id === 'cashReceived') {
                        e.preventDefault();
                        confirmPayment();
                    }
                    break;
            }
        });
    }

    // ─── Public API ──────────────────────
    init();

    return {
        addToCart, removeFromCart, selectRow,
        updateQty, updateDiscount,
        addFromSearch, hideSearchResults,
        selectCustomer, clearCustomer,
        showNewCustomerModal, closeNewCustomerModal, saveNewCustomer,
        checkout, confirmPayment, closePaymentModal,
        selectPaymentMethod, updateChange, updateMixedTotal,
        creditSale, saveQuotation, createLayaway,
        showLastSale, openDrawer,
        showTicket, closeTicketModal, printTicket,
    };
})();