feat: display available stock balance on products page based on n8n inventory updates

backend/index.js

@@ -45,6 +45,16 @@ const initDB = async () => {
         await pool.query(`CREATE UNIQUE INDEX IF NOT EXISTS unique_order_product ON orders (pedido_id, produto_id);`).catch(err => {
             console.error("Notice: Could not create unique index (might already exist or there are duplicates):", err.message);
         });
+
+        await pool.query(`
+            CREATE TABLE IF NOT EXISTS stock (
+                produto_id VARCHAR(100) PRIMARY KEY,
+                nome TEXT,
+                saldo INTEGER DEFAULT 0,
+                delta_estoque INTEGER DEFAULT 0,
+                updated_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
+            );
+        `);
         
         console.log("Database initialized successfully.");
     } catch (err) {
@@ -106,6 +116,17 @@ app.get('/api/data', verifyToken, async (req, res) => {
     }
 });
 
+// GET stock (for the frontend)
+app.get('/api/stock', verifyToken, async (req, res) => {
+    try {
+        const result = await pool.query('SELECT * FROM stock');
+        res.json(result.rows);
+    } catch (error) {
+        console.error("Error fetching stock:", error);
+        res.status(500).json({ error: 'Internal Server Error' });
+    }
+});
+
 // POST data (for n8n) - Protected by API_KEY internally or via middleware if needed
 // Leaving it as it was, checking API_KEY manually? Wait, the previous version didn't actually use 'authenticate' middleware on the POST!
 // Let's add the authenticate middleware to the POST endpoint.
@@ -178,6 +199,51 @@ app.post('/api/data', authenticateAPIKey, async (req, res) => {
     })();
 });
 
+// POST stock (for n8n)
+app.post('/api/stock', authenticateAPIKey, async (req, res) => {
+    res.status(201).json({ message: 'Stock data received, processing in background' });
+
+    const newData = req.body;
+    const payload = Array.isArray(newData) ? newData : [newData];
+
+    (async () => {
+        const client = await pool.connect();
+        try {
+            await client.query('BEGIN');
+            
+            const insertQuery = `
+                INSERT INTO stock (produto_id, nome, saldo, delta_estoque)
+                VALUES ($1, $2, $3, $4)
+                ON CONFLICT (produto_id) DO UPDATE SET
+                    nome = EXCLUDED.nome,
+                    saldo = EXCLUDED.saldo,
+                    delta_estoque = EXCLUDED.delta_estoque,
+                    updated_at = CURRENT_TIMESTAMP
+            `;
+
+            for (const item of payload) {
+                const idProduto = item.idProduto || item.ID_Produto || '';
+                if (!idProduto) continue;
+
+                const values = [
+                    String(idProduto),
+                    item.nome || item.Descricao_Produto || 'Unknown',
+                    parseInt(item.saldo) || 0,
+                    parseInt(item.delta_estoque) || 0
+                ];
+                await client.query(insertQuery, values);
+            }
+            
+            await client.query('COMMIT');
+        } catch (error) {
+            await client.query('ROLLBACK');
+            console.error("Database stock insert error:", error);
+        } finally {
+            client.release();
+        }
+    })();
+});
+
 app.listen(PORT, '0.0.0.0', () => {
     console.log(`Nexstar Backend running at http://localhost:${PORT}`);
     console.log(`Endpoint for n8n: POST http://localhost:${PORT}/api/data`);