Add DOW-average fallback for dry/wet forecast when covers data is zero

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/api/public.py

@@ -386,6 +386,24 @@ async def get_revenue_forecast(
         logger.warning(f"Covers forecast failed: {e}")
         covers_by_date = {}
 
+    # DOW averages from recent 8 weeks — fallback when covers gives zero for future dates
+    dow_result = await db.execute(
+        text("""
+            SELECT EXTRACT(ISODOW FROM date)::int AS dow,
+                   AVG(dry)  FILTER (WHERE dry  > 0) AS avg_dry,
+                   AVG(wet)  FILTER (WHERE wet  > 0) AS avg_wet
+            FROM newbook_net_revenue_data
+            WHERE date >= :cutoff AND date < :today
+            GROUP BY dow
+        """),
+        {"cutoff": today - timedelta(days=56), "today": today}
+    )
+    dow_dry = {}
+    dow_wet = {}
+    for row in dow_result.fetchall():
+        dow_dry[int(row.dow)] = float(row.avg_dry) if row.avg_dry else 0
+        dow_wet[int(row.dow)] = float(row.avg_wet) if row.avg_wet else 0
+
     data = []
     current = start
     while current <= end:
@@ -461,7 +479,12 @@ async def get_revenue_forecast(
                     dinner_forecast * get_spend_by_period('dinner', 'wet')
                 )
             else:
-                dry_otb = dry_forecast = wet_otb = wet_forecast = 0
+                # No covers data — fall back to DOW average from recent 8 weeks
+                dow = current.isoweekday()  # 1=Mon … 7=Sun
+                dry_otb = 0
+                dry_forecast = dow_dry.get(dow, 0)
+                wet_otb = 0
+                wet_forecast = dow_wet.get(dow, 0)
 
         day_data = {
             "date": current.isoformat(),