refactor backend and persist stock campaign queue

backend/services/campaignService.js

@@ -0,0 +1,158 @@
+const { pool } = require('../db');
+const { N8N_WHATSAPP_TRIGGER_URL } = require('../config');
+
+const TOP_BUYERS_LIMIT = 100;
+const MAX_CAMPAIGN_ATTEMPTS = 3;
+
+const enqueueStockCampaignItem = async (client, item) => {
+    const query = `
+        INSERT INTO stock_campaign_queue (
+            base_product_name, produto_id, nome, saldo, delta_estoque
+        ) VALUES ($1, $2, $3, $4, $5)
+    `;
+
+    await client.query(query, [
+        item.baseProductName,
+        item.produtoId,
+        item.nome,
+        item.saldo,
+        item.deltaEstoque
+    ]);
+};
+
+const getTopBuyersAllTime = async () => {
+    const result = await pool.query(`
+        SELECT
+            MAX(cliente_nome) as nome,
+            cliente_fone as fone,
+            SUM(quantidade * valor_unitario) as total_gasto,
+            SUM(quantidade) as total_comprado
+        FROM orders
+        WHERE cliente_fone IS NOT NULL
+          AND cliente_fone != ''
+        GROUP BY cliente_fone
+        ORDER BY total_gasto DESC
+        LIMIT $1;
+    `, [TOP_BUYERS_LIMIT]);
+
+    return result.rows;
+};
+
+const claimPendingCampaignItems = async () => {
+    const client = await pool.connect();
+
+    try {
+        await client.query('BEGIN');
+
+        const result = await client.query(`
+            UPDATE stock_campaign_queue
+            SET status = 'processing',
+                attempts = attempts + 1,
+                updated_at = CURRENT_TIMESTAMP,
+                last_error = NULL
+            WHERE id IN (
+                SELECT id
+                FROM stock_campaign_queue
+                WHERE status IN ('pending', 'failed')
+                  AND attempts < $1
+                ORDER BY created_at ASC
+                FOR UPDATE SKIP LOCKED
+            )
+            RETURNING *;
+        `, [MAX_CAMPAIGN_ATTEMPTS]);
+
+        await client.query('COMMIT');
+        return result.rows;
+    } catch (error) {
+        await client.query('ROLLBACK');
+        throw error;
+    } finally {
+        client.release();
+    }
+};
+
+const updateCampaignItemsStatus = async (ids, status, errorMessage = null) => {
+    if (!ids.length) return;
+
+    await pool.query(`
+        UPDATE stock_campaign_queue
+        SET status = $1,
+            last_error = $2,
+            updated_at = CURRENT_TIMESTAMP,
+            sent_at = CASE WHEN $1 = 'sent' THEN CURRENT_TIMESTAMP ELSE sent_at END
+        WHERE id = ANY($3::int[]);
+    `, [status, errorMessage, ids]);
+};
+
+const sendWhatsappCampaign = async (baseProductName, items, customers) => {
+    const totalDelta = items.reduce((sum, item) => sum + Number(item.delta_estoque || 0), 0);
+
+    const response = await fetch(N8N_WHATSAPP_TRIGGER_URL, {
+        method: 'POST',
+        headers: { 'Content-Type': 'application/json' },
+        body: JSON.stringify({
+            baseProduct: baseProductName,
+            total_delta: totalDelta,
+            sizes: items.map(item => ({
+                id: item.produto_id,
+                nome: item.nome,
+                delta: item.delta_estoque,
+                saldo: item.saldo
+            })),
+            customers
+        })
+    });
+
+    if (!response.ok) {
+        throw new Error(`WhatsApp webhook returned status ${response.status}`);
+    }
+};
+
+const processPendingStockCampaigns = async () => {
+    const rows = await claimPendingCampaignItems();
+    const summary = {
+        claimed: rows.length,
+        sentGroups: 0,
+        skippedGroups: 0,
+        failedGroups: 0
+    };
+
+    if (!rows.length) {
+        return summary;
+    }
+
+    const customers = await getTopBuyersAllTime();
+    const groups = rows.reduce((acc, row) => {
+        if (!acc[row.base_product_name]) acc[row.base_product_name] = [];
+        acc[row.base_product_name].push(row);
+        return acc;
+    }, {});
+
+    for (const [baseProductName, items] of Object.entries(groups)) {
+        const ids = items.map(item => item.id);
+
+        if (!customers.length) {
+            await updateCampaignItemsStatus(ids, 'skipped', 'No customers with valid phone numbers found.');
+            summary.skippedGroups += 1;
+            continue;
+        }
+
+        try {
+            await sendWhatsappCampaign(baseProductName, items, customers);
+            await updateCampaignItemsStatus(ids, 'sent');
+            summary.sentGroups += 1;
+            console.log(`[Campaign Queue] Sent ${baseProductName} campaign to ${customers.length} all-time top buyers.`);
+        } catch (error) {
+            await updateCampaignItemsStatus(ids, 'failed', error.message);
+            summary.failedGroups += 1;
+            console.error(`[Campaign Queue] Failed to send ${baseProductName} campaign:`, error);
+        }
+    }
+
+    return summary;
+};
+
+module.exports = {
+    enqueueStockCampaignItem,
+    processPendingStockCampaigns
+};