fix(api): accept priceInfoRange-only responses and retry transient empty data

Some markets/accounts (e.g. NL hourly) return an empty
priceInfo(QUARTER_HOURLY).today while priceInfoRange still delivers the full
set of intervals. _check_price_info_empty required today's data and wrongly
classified such complete responses as empty, which blocked setup. It now
treats a response as valid when today OR yesterday data is present, since
priceInfoRange is the authoritative source the interval pool uses.

Additionally, "Empty data received" is now retried a few times with
exponential backoff, smoothing brief Tibber outages that transiently return
empty data within a single update cycle. Long outages are still absorbed by
the IntervalPool cache fallback, so the in-request retry count stays small.

Reported in #141.

Impact: Setup and updates no longer fail with "Empty data received" for NL
hourly accounts (and similar), and short Tibber blips are smoothed over.

custom_components/tibber_prices/api/client.py

@@ -51,6 +51,19 @@ class TibberPricesApiClient:
         self._max_retries = 5
         self._retry_delay = 2  # Base retry delay in seconds
 
+        # Empty-data responses are usually permanent (no data for the requested
+        # range), but during a Tibber outage the API can return empty data
+        # transiently before recovering. Retry a small number of times with backoff
+        # so a brief blip is smoothed out within a single update cycle.
+        #
+        # NOTE: This is NOT the mechanism that bridges multi-hour outages. Long
+        # outages are absorbed by the IntervalPool cache fallback (see
+        # interval_pool/manager.py): as long as cached intervals cover the current
+        # interval, the integration keeps serving cached prices and retries on the
+        # NEXT update cycle. That bridge is unbounded in time, so this in-request
+        # retry count must stay small to avoid blocking the event loop.
+        self._max_empty_data_retries = 2
+
         # Timeout configuration - more granular control
         self._connect_timeout = 10  # Connection timeout in seconds
         self._request_timeout = 25  # Total request timeout in seconds
@@ -834,9 +847,17 @@ class TibberPricesApiClient:
         """Handle retry logic for API-specific errors."""
         error_msg = str(error)
 
-        # Non-retryable: Invalid queries, bad requests, empty data
-        # Empty data means API has no data for the requested range - retrying won't help
-        if "Invalid GraphQL query" in error_msg or "Bad request" in error_msg or "Empty data received" in error_msg:
+        # Non-retryable: Invalid queries and bad requests are permanent client errors.
+        if "Invalid GraphQL query" in error_msg or "Bad request" in error_msg:
+            return False, 0
+
+        # Empty data is usually permanent (API has no data for the requested range),
+        # but can be returned transiently during a Tibber outage. Retry a limited
+        # number of times with exponential backoff before giving up.
+        if "Empty data received" in error_msg:
+            if retry < self._max_empty_data_retries:
+                delay = min(self._retry_delay * (2**retry), 30)
+                return True, delay
             return False, 0
 
         # Rate limits - only retry if server explicitly says so

custom_components/tibber_prices/api/helpers.py

@@ -219,9 +219,13 @@ def _check_price_info_empty(data: dict) -> bool:
         and len(subscription["priceInfo"]["today"]) > 0
     )
 
-    # Only require today's data - yesterday is optional
-    # If subscription exists but no today data, that's a structural problem
-    is_empty = not has_today
+    # Consider the response valid if EITHER today's intervals OR the priceInfoRange
+    # edges are present. Some markets/accounts (e.g. NL hourly accounts) return an
+    # empty priceInfo(QUARTER_HOURLY).today while priceInfoRange still delivers the
+    # full set of intervals. Requiring today's data alone would wrongly classify
+    # such a complete response as "empty" and block setup. priceInfoRange is the
+    # authoritative source the interval pool uses, so its presence means we have data.
+    is_empty = not has_today and not has_yesterday
 
     _LOGGER_DETAILS.debug(
         "Price info check - priceInfoRange: %s, today: %s, is_empty: %s",