refactor backend and persist stock campaign queue

backend/services/stockService.js

@@ -0,0 +1,56 @@
+const { pool } = require('../db');
+const { normalizeStockPayload } = require('../mappers/stockMapper');
+const { enqueueStockCampaignItem } = require('./campaignService');
+
+const CAMPAIGN_DELTA_THRESHOLD = 100;
+
+const listStock = async () => {
+    const result = await pool.query('SELECT * FROM stock');
+    return result.rows;
+};
+
+const upsertStockItems = async (payload) => {
+    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 rawItem of payload) {
+            const item = normalizeStockPayload(rawItem);
+            if (!item.produtoId) continue;
+
+            await client.query(insertQuery, [
+                item.produtoId,
+                item.nome,
+                item.saldo,
+                item.deltaEstoque
+            ]);
+
+            if (item.deltaEstoque >= CAMPAIGN_DELTA_THRESHOLD) {
+                await enqueueStockCampaignItem(client, item);
+            }
+        }
+
+        await client.query('COMMIT');
+    } catch (error) {
+        await client.query('ROLLBACK');
+        throw error;
+    } finally {
+        client.release();
+    }
+};
+
+module.exports = {
+    listStock,
+    upsertStockItems
+};