Schedule Olist sync from last completion

backend/index.js

@@ -8,7 +8,7 @@ const start = async () => {
     await markInterruptedOlistRuns();
 
     const app = createApp();
-    if (OLIST_SYNC_ENABLED) scheduleOlistSync();
+    if (OLIST_SYNC_ENABLED) await scheduleOlistSync();
     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`);

backend/services/olistService.js

@@ -20,6 +20,7 @@ let activeSync = null;
 let activeRunId = null;
 let stopRequested = false;
 let scheduledSync = null;
+let nextScheduledSyncAt = null;
 let nextOlistRequestAt = 0;
 
 const normalizeText = (value) => String(value || '').trim();
@@ -110,6 +111,17 @@ const listSyncRuns = async (limit = 5) => {
     return result.rows.map(mapRun);
 };
 
+const getLastCompletedSyncAt = async () => {
+    const result = await pool.query(`
+        SELECT completed_at
+        FROM olist_sync_runs
+        WHERE status = 'completed' AND completed_at IS NOT NULL
+        ORDER BY completed_at DESC
+        LIMIT 1;
+    `);
+    return result.rows[0]?.completed_at || null;
+};
+
 const logRunEvent = async (runId, {
     level = 'info',
     eventType,
@@ -235,6 +247,7 @@ const getOlistStatus = async () => {
         connected: Boolean(connection),
         tokenExpiresAt: connection?.token_expires_at || null,
         syncInProgress: Boolean(activeSync),
+        nextScheduledSyncAt,
         productCache,
         runs
     };
@@ -691,12 +704,38 @@ const requestOlistSyncStop = async () => {
     return { accepted: true, initializing: false };
 };
 
-const scheduleOlistSync = () => {
-    if (scheduledSync) clearInterval(scheduledSync);
-    scheduledSync = setInterval(() => {
-        startOlistSync({ trigger: 'scheduled' }).catch(error => console.error('Scheduled Olist sync skipped:', error.message));
-    }, OLIST_SYNC_INTERVAL_MS);
-    return scheduledSync;
+const scheduleOlistSync = async () => {
+    if (scheduledSync) clearTimeout(scheduledSync);
+
+    let delay = OLIST_SYNC_INTERVAL_MS;
+    try {
+        const lastCompletedAt = await getLastCompletedSyncAt();
+        const lastCompletedMs = lastCompletedAt ? new Date(lastCompletedAt).getTime() : Number.NaN;
+        if (!Number.isNaN(lastCompletedMs)) {
+            delay = Math.max(0, lastCompletedMs + OLIST_SYNC_INTERVAL_MS - Date.now());
+        }
+    } catch (error) {
+        console.error('Could not calculate the next Olist sync:', error.message);
+    }
+
+    nextScheduledSyncAt = new Date(Date.now() + delay).toISOString();
+    scheduledSync = setTimeout(async () => {
+        scheduledSync = null;
+        nextScheduledSyncAt = null;
+        try {
+            assertConfigured();
+            if (!await getConnection()) {
+                console.error('Scheduled Olist sync skipped: no connected Olist account.');
+                return;
+            }
+            await runOlistSync({ trigger: 'scheduled' });
+        } catch (error) {
+            console.error('Scheduled Olist sync failed:', error.message);
+        } finally {
+            await scheduleOlistSync();
+        }
+    }, delay);
+    return nextScheduledSyncAt;
 };
 
 const getOlistFrontendRedirect = (outcome) => `${OLIST_FRONTEND_URL.replace(/\/$/, '')}/#/admin/olist?olist=${outcome}`;