feat(pos/workshop): add 80mm thermal ticket printing for service orders

- Add generate_service_order_ticket() in thermal_printer.py with ESC/POS commands for 58mm and 80mm printers.

- Add POST /pos/api/service-orders/:id/print endpoint returning raw bytes or JSON for browser rendering.

- Extend printer.js with printServiceOrder() using WebUSB/Web Serial.

- Add Imprimir orden button in workshop.js detail modal.

- Update FASES_IMPLEMENTADAS.md.

pos/blueprints/service_order_bp.py

@@ -369,3 +369,61 @@ def delete_catalog_item(item_id):
         return jsonify({'message': 'Catalog item deactivated'})
     finally:
         conn.close()
+
+
+# ─── Thermal printing ─────────────────────────────
+
+
+@service_order_bp.route('/<int:so_id>/print', methods=['POST'])
+@require_auth()
+def print_service_order_ticket(so_id):
+    """Generate a printable ticket for a service order.
+
+    Body (optional): {printer_type: 'escpos_raw' | 'browser', width: 58 | 80}
+      - escpos_raw: returns raw ESC/POS bytes (application/octet-stream)
+      - browser: returns the data dict as JSON for browser-side rendering
+    """
+    from flask import Response
+    from services.thermal_printer import generate_service_order_ticket
+
+    body = request.get_json(silent=True) or {}
+    printer_type = body.get('printer_type', 'escpos_raw')
+    width = int(body.get('width', 80))
+
+    conn = get_tenant_conn(g.tenant_id)
+    cur = conn.cursor()
+
+    order = get_service_order(conn, so_id)
+    if not order:
+        cur.close()
+        conn.close()
+        return jsonify({'error': 'Service order not found'}), 404
+
+    # Fetch business info from config
+    business_info = {'name': 'NEXUS AUTOPARTS', 'rfc': '', 'address': ''}
+    try:
+        cur.execute(
+            "SELECT key, value FROM config WHERE key IN ('business_name','rfc','address')"
+        )
+        for rw in cur.fetchall():
+            if rw[0] == 'business_name':
+                business_info['name'] = rw[1]
+            else:
+                business_info[rw[0]] = rw[1]
+    except Exception:
+        pass
+
+    cur.close()
+    conn.close()
+
+    if printer_type == 'browser':
+        return jsonify(order)
+
+    raw = generate_service_order_ticket(order, business_info, width=width)
+    return Response(
+        raw,
+        mimetype='application/octet-stream',
+        headers={
+            'Content-Disposition': f'attachment; filename=orden_{order.get("order_number", so_id)}.bin'
+        },
+    )

pos/services/thermal_printer.py

@@ -204,3 +204,140 @@ def _total_line(label, amount, width):
     """Format a totals line like 'Subtotal:        $1,234.56'."""
     val = f'${abs(amount):,.2f}' if amount >= 0 else f'-${abs(amount):,.2f}'
     return _format_line(label, val, width) + '\n'
+
+
+def generate_service_order_ticket(so_data, business_info, width=80):
+    """Generate ESC/POS bytes for a workshop service order ticket.
+
+    Args:
+        so_data: dict with service order info:
+            order_number, status, customer_name, vehicle_plate, vehicle_make,
+            vehicle_model, mileage_in, fuel_level, reception_notes,
+            employee_name, created_at, items[{name, part_number, quantity,
+            unit_price}], labor[{description, hours, hourly_rate, total_cost}],
+            estimated_cost, total
+        business_info: dict with name, rfc, address
+        width: 58 or 80 (mm)
+
+    Returns: bytes ready to send to printer
+    """
+    chars = 32 if width == 58 else 48
+    buf = bytearray()
+    buf += INIT
+
+    # Header
+    buf += ALIGN_CENTER
+    buf += LARGE_SIZE
+    buf += (business_info.get("name", "NEXUS POS") + "\n").encode("cp437", errors="replace")
+    buf += NORMAL_SIZE
+    if business_info.get("rfc"):
+        buf += (business_info["rfc"] + "\n").encode("cp437", errors="replace")
+    if business_info.get("address"):
+        buf += (business_info["address"] + "\n").encode("cp437", errors="replace")
+    buf += b"\n"
+
+    # Title
+    buf += BOLD_ON + DOUBLE_HEIGHT
+    buf += "ORDEN DE SERVICIO\n".encode("cp437", errors="replace")
+    buf += NORMAL_SIZE + BOLD_OFF
+    buf += b"\n"
+
+    # Order info
+    buf += ALIGN_LEFT
+    buf += BOLD_ON
+    buf += f"Folio: {so_data.get('order_number', 'N/A')}\n".encode("cp437", errors="replace")
+    buf += BOLD_OFF
+    buf += f"Estado: {so_data.get('status', '')}\n".encode("cp437", errors="replace")
+    buf += f"Fecha: {str(so_data.get('created_at', ''))[:19]}\n".encode("cp437", errors="replace")
+    if so_data.get("employee_name"):
+        buf += f"Mecanico: {so_data['employee_name']}\n".encode("cp437", errors="replace")
+    buf += ("-" * chars + "\n").encode()
+
+    # Customer / vehicle
+    if so_data.get("customer_name"):
+        buf += BOLD_ON
+        buf += f"Cliente: {so_data['customer_name']}\n".encode("cp437", errors="replace")
+        buf += BOLD_OFF
+    vehicle = " ".join(
+        str(v) for v in [
+            so_data.get("vehicle_plate", ""),
+            so_data.get("vehicle_make", ""),
+            so_data.get("vehicle_model", ""),
+        ] if v
+    ).strip()
+    if vehicle:
+        buf += f"Vehiculo: {vehicle}\n".encode("cp437", errors="replace")
+    if so_data.get("mileage_in"):
+        buf += f"Kilometraje: {so_data['mileage_in']}\n".encode("cp437", errors="replace")
+    if so_data.get("fuel_level"):
+        buf += f"Gasolina: {so_data['fuel_level']}\n".encode("cp437", errors="replace")
+    buf += ("-" * chars + "\n").encode()
+
+    # Reception notes
+    if so_data.get("reception_notes"):
+        buf += BOLD_ON
+        buf += "Falla / Observaciones:\n".encode("cp437", errors="replace")
+        buf += BOLD_OFF
+        for line in str(so_data["reception_notes"]).splitlines():
+            buf += (line[:chars] + "\n").encode("cp437", errors="replace")
+        buf += ("-" * chars + "\n").encode()
+
+    # Parts
+    items = so_data.get("items", [])
+    if items:
+        buf += BOLD_ON
+        buf += "REFACCIONES\n".encode("cp437", errors="replace")
+        buf += BOLD_OFF
+        for item in items:
+            name = item.get("name", "")[:chars - 10]
+            part_no = item.get("part_number", "")
+            qty = item.get("quantity", 1)
+            unit_price = item.get("unit_price", 0)
+            line_total = qty * unit_price
+            buf += f"{qty}x {name}\n".encode("cp437", errors="replace")
+            if part_no:
+                buf += f"   #{part_no}\n".encode("cp437", errors="replace")
+            buf += ALIGN_RIGHT
+            buf += f"${line_total:,.2f}\n".encode("cp437", errors="replace")
+            buf += ALIGN_LEFT
+        buf += ("-" * chars + "\n").encode()
+
+    # Labor
+    labor_items = so_data.get("labor", [])
+    if labor_items:
+        buf += BOLD_ON
+        buf += "MANO DE OBRA\n".encode("cp437", errors="replace")
+        buf += BOLD_OFF
+        for labor in labor_items:
+            desc = labor.get("description", "")[:chars - 10]
+            hours = labor.get("hours", 0)
+            rate = labor.get("hourly_rate", 0)
+            total = labor.get("total_cost", hours * rate)
+            buf += f"{desc}\n".encode("cp437", errors="replace")
+            buf += f"   {hours} hrs x ${rate:,.2f}\n".encode("cp437", errors="replace")
+            buf += ALIGN_RIGHT
+            buf += f"${total:,.2f}\n".encode("cp437", errors="replace")
+            buf += ALIGN_LEFT
+        buf += ("-" * chars + "\n").encode()
+
+    # Totals
+    buf += ALIGN_RIGHT
+    if items or labor_items:
+        total = so_data.get("total") or sum(
+            i.get("quantity", 1) * i.get("unit_price", 0) for i in items
+        ) + sum(labor.get("total_cost", 0) for labor in labor_items)
+        buf += BOLD_ON + DOUBLE_HEIGHT
+        buf += _total_line("TOTAL ESTIMADO:", total, chars).encode("cp437", errors="replace")
+        buf += NORMAL_SIZE + BOLD_OFF
+    if so_data.get("estimated_cost"):
+        buf += _total_line("Costo estimado:", so_data["estimated_cost"], chars).encode("cp437", errors="replace")
+
+    # Footer
+    buf += b"\n"
+    buf += ALIGN_CENTER
+    buf += "No es comprobante fiscal\n".encode("cp437", errors="replace")
+    buf += "Nexus Autoparts POS\n".encode("cp437", errors="replace")
+    buf += b"\n\n\n"
+    buf += PARTIAL_CUT
+
+    return bytes(buf)

pos/static/js/printer.js

@@ -134,6 +134,31 @@ window.NexusPrinter = (function () {
         return sendRaw(new Uint8Array(buf));
     }
 
+    /**
+     * Print a workshop service order ticket.
+     * @param {number} soId
+     * @param {number} [width=80] — 58 or 80 mm
+     * @returns {Promise<boolean>}
+     */
+    async function printServiceOrder(soId, width) {
+        width = width || 80;
+        const token = localStorage.getItem('pos_token');
+        const resp = await fetch('/pos/api/service-orders/' + soId + '/print', {
+            method: 'POST',
+            headers: {
+                'Authorization': 'Bearer ' + token,
+                'Content-Type': 'application/json'
+            },
+            body: JSON.stringify({ printer_type: 'escpos_raw', width: width })
+        });
+        if (!resp.ok) {
+            console.error('[NexusPrinter] backend error', resp.status);
+            return false;
+        }
+        const buf = await resp.arrayBuffer();
+        return sendRaw(new Uint8Array(buf));
+    }
+
     // ── Persistence helpers ────────────────────────
 
     function _save() {
@@ -147,6 +172,7 @@ window.NexusPrinter = (function () {
         disconnect: disconnect,
         isConnected: isConnected,
         sendRaw: sendRaw,
-        printSale: printSale
+        printSale: printSale,
+        printServiceOrder: printServiceOrder
     };
 })();

pos/static/js/workshop.js

@@ -250,6 +250,7 @@ var Workshop = (function() {
         var footer = document.getElementById('detailFooter');
         footer.innerHTML =
             '<button class="btn btn--ghost" onclick="Workshop.closeDetailModal()">Cerrar</button>' +
+            '<button class="btn btn--secondary" onclick="Workshop.printOrder()">🖨️ Imprimir orden</button>' +
             (o.status === 'ready' && !o.sale_id ? '<button class="btn btn--primary" onclick="Workshop.convertToSale()">Convertir a venta</button>' : '') +
             (o.sale_id ? '<a class="btn btn--secondary" href="/pos/invoicing?sale_id=' + o.sale_id + '">Ver venta #' + o.sale_id + '</a>' : '');
     }
@@ -328,6 +329,29 @@ var Workshop = (function() {
         }).catch(function(e) { alert('Error: ' + e.message); });
     }
 
+    function printOrder() {
+        if (!currentOrderId) return;
+        if (!window.NexusPrinter || !window.NexusPrinter.isConnected()) {
+            var connect = confirm('No hay impresora conectada. ¿Conectar ahora?');
+            if (connect) {
+                window.NexusPrinter.connect().then(function(r) {
+                    if (r.ok) doPrint();
+                });
+            }
+            return;
+        }
+        doPrint();
+
+        function doPrint() {
+            window.NexusPrinter.printServiceOrder(currentOrderId, 80)
+                .then(function(ok) {
+                    if (ok) alert('Orden enviada a la impresora');
+                    else alert('No se pudo imprimir');
+                })
+                .catch(function(e) { alert('Error: ' + e.message); });
+        }
+    }
+
     // ─── New order ───
 
     function openNewOrderModal() {
@@ -469,6 +493,7 @@ var Workshop = (function() {
         addItemPlaceholder: addItemPlaceholder,
         addLabor: addLabor,
         convertToSale: convertToSale,
+        printOrder: printOrder,
         openNewOrderModal: openNewOrderModal,
         closeNewOrderModal: closeNewOrderModal,
         submitNewOrder: submitNewOrder,