Add allow_zero_price_sales toggle: config UI, POS enforcement and backend validation

pos/static/js/config.js

@@ -625,6 +625,7 @@ const Config = (() => {
             await saveVehicleCompatSource();
             await saveAllowedBrands();
             await saveModules();
+            await saveSalesSettings();
             await saveReceiptConfig();
             toast('Configuración guardada', 'ok');
         } catch (e) {
@@ -1015,6 +1016,37 @@ const Config = (() => {
         }
     }
 
+    async function loadSalesSettings() {
+        try {
+            var res = await fetch(API + '/sales-settings', { headers: headers() });
+            if (!res.ok) return;
+            var data = await res.json();
+            var cb = document.getElementById('cfg-allow-zero-price');
+            if (cb) cb.checked = data.allow_zero_price_sales !== false;
+        } catch (e) {
+            console.error('Config.loadSalesSettings:', e);
+        }
+    }
+
+    async function saveSalesSettings() {
+        var cb = document.getElementById('cfg-allow-zero-price');
+        if (!cb) return;
+        try {
+            var res = await fetch(API + '/sales-settings', {
+                method: 'PUT',
+                headers: headers(),
+                body: JSON.stringify({ allow_zero_price_sales: cb.checked })
+            });
+            if (!res.ok) {
+                var err = await res.json().catch(function() { return { error: res.statusText }; });
+                throw new Error(err.error || 'Save failed');
+            }
+        } catch (e) {
+            toast(e.message, 'error');
+            throw e;
+        }
+    }
+
     // -------------------------------------------------------------------------
     // Tab navigation
     // -------------------------------------------------------------------------
@@ -1277,6 +1309,7 @@ const Config = (() => {
         loadVehicleCompatSource();
         loadAllowedBrands();
         loadModules();
+        loadSalesSettings();
         loadReceiptConfig();
         if (isAdmin) {
             loadRolePermissions();

pos/static/js/pos.js

@@ -32,6 +32,7 @@ const POS = (() => {
     let canCreateLayaway = false;
     let canCreateRemission = false;
     let counterRemissionEnabled = false;
+    let allowZeroPriceSales = true;
     let currentPerms = [];
     let receiptConfig = {};
     let couriers = [];
@@ -142,6 +143,13 @@ const POS = (() => {
             } catch (e) {
                 counterRemissionEnabled = false;
             }
+            // Sales settings (zero-price sales toggle)
+            try {
+                const ssCfg = await api('/pos/api/config/sales-settings');
+                allowZeroPriceSales = ssCfg.allow_zero_price_sales !== false;
+            } catch (e) {
+                allowZeroPriceSales = true;
+            }
             // Counter remission workflow applies only to the counter role.
             canCreateRemission = counterRemissionEnabled && employeeRole === 'counter' && perms.includes('pos.remission');
 
@@ -442,6 +450,18 @@ const POS = (() => {
         }
     }
 
+    function isZeroPriceItem(item) {
+        const unitPrice = parseFloat(item.unit_price || 0);
+        const qty = parseFloat(item.quantity || 1);
+        const discount = parseFloat(item.discount_pct || 0);
+        return (unitPrice * qty * (1 - discount / 100)) <= 0;
+    }
+
+    function findZeroPriceItem() {
+        if (allowZeroPriceSales) return null;
+        return cart.find(isZeroPriceItem) || null;
+    }
+
     function modifyPrice() {
         if (!canEditPrice) { showToast('No tienes permiso para modificar precios'); return; }
         if (selectedRow < 0 || selectedRow >= cart.length) {
@@ -451,10 +471,13 @@ const POS = (() => {
         const p = prompt('Nuevo precio unitario:', cart[selectedRow].unit_price);
         if (p !== null) {
             const n = parseFloat(p);
-            if (n >= 0) {
-                cart[selectedRow].unit_price = n;
-                renderCart();
+            if (n < 0) { showToast('Precio no válido'); return; }
+            if (!allowZeroPriceSales && n === 0) {
+                showToast('No está permitido dejar el precio en $0');
+                return;
             }
+            cart[selectedRow].unit_price = n;
+            renderCart();
         }
     }
 
@@ -1052,6 +1075,12 @@ const POS = (() => {
             generate_cfdi: document.getElementById('cfdiCheck').checked,
         };
 
+        const zeroItem = findZeroPriceItem();
+        if (zeroItem) {
+            showToast('No está permitido vender artículos en $0: ' + (zeroItem.name || zeroItem.part_number));
+            return;
+        }
+
         const confirmBtn = document.getElementById('btnConfirmPayment');
         confirmBtn.disabled = true;
         confirmBtn.textContent = 'Procesando...';
@@ -1105,6 +1134,11 @@ const POS = (() => {
     async function createRemissionNote() {
         if (cart.length === 0) { showToast('Carrito vacio'); return; }
         if (!canCreateRemission) { showToast('No tienes permiso para generar notas de remision'); return; }
+        const zeroItem = findZeroPriceItem();
+        if (zeroItem) {
+            showToast('No está permitido vender artículos en $0: ' + (zeroItem.name || zeroItem.part_number));
+            return;
+        }
 
         const total = getTotal();
         const noteData = {
@@ -1262,6 +1296,11 @@ const POS = (() => {
     // ─── Quotation ───────────────────────
     async function saveQuotation() {
         if (cart.length === 0) { showToast('Carrito vacio'); return; }
+        const zeroItem = findZeroPriceItem();
+        if (zeroItem) {
+            showToast('No está permitido cotizar artículos en $0: ' + (zeroItem.name || zeroItem.part_number));
+            return;
+        }
 
         const body = {
             items: cart.map(item => ({
@@ -1302,6 +1341,11 @@ const POS = (() => {
     async function createLayaway() {
         if (!canCreateLayaway) { showToast('No tienes permiso para crear apartados'); return; }
         if (cart.length === 0) { alert('Carrito vacio'); return; }
+        const zeroItem = findZeroPriceItem();
+        if (zeroItem) {
+            alert('No está permitido apartar artículos en $0: ' + (zeroItem.name || zeroItem.part_number));
+            return;
+        }
         if (!currentCustomer) { alert('Seleccione un cliente para apartado'); return; }
 
         const total = getTotal();
@@ -1345,6 +1389,11 @@ const POS = (() => {
     function createServiceOrder() {
         if (!canCreateWorkshopOrder) { showToast('No tienes permiso para ordenes de taller'); return; }
         if (cart.length === 0) { showToast('Carrito vacio'); return; }
+        const zeroItem = findZeroPriceItem();
+        if (zeroItem) {
+            showToast('No está permitido generar orden con artículos en $0: ' + (zeroItem.name || zeroItem.part_number));
+            return;
+        }
         const custInput = document.getElementById('soCustomer');
         if (custInput) custInput.value = currentCustomer ? currentCustomer.name : 'Publico General';
         document.getElementById('serviceOrderModal').classList.add('open');

pos/static/pwa/sw.js

@@ -6,7 +6,7 @@
 // The fetch handler normalizes static asset URLs (strips ?v= query strings)
 // so templates can use cache-busting query params freely.
 
-const VERSION = 43;
+const VERSION = 44;
 const CACHE_NAME = 'nexus-pos-v' + VERSION;
 
 const APP_SHELL = [