fix: Add throttled logging for sensor errors to prevent log spam (v1.3.16)

Fixed excessive logging when sensors become unavailable, which was causing Home Assistant to log warnings about too frequent logging (200+ messages).

Problem:
- When sensor.potenza_interna_abitazione returns 'unknown', Solar Surplus validation logs full error every minute
- Check runs every 1 minute by default
- Results in 200+ identical error messages
- Home Assistant detects log spam: "Module logging too frequently"

Solution:
- Implemented smart sensor error state tracking (_sensor_error_state dictionary)
- Only log full error details when error FIRST occurs or changes
- Subsequent identical errors: silent (debug level only)
- When sensor recovers: log success message with previous error
- Per-sensor tracking (independent error states)

Behavior:
Before (v1.3.15):
- 12:35:07 - ❌ Sensor validation failed: Home Consumption unknown
- 12:36:07 - ❌ Sensor validation failed: Home Consumption unknown
- 12:37:07 - ❌ Sensor validation failed: Home Consumption unknown
- ... (200+ identical messages)

After (v1.3.16):
- 12:35:07 - ❌ Sensor validation failed: Home Consumption unknown [LOGGED ONCE]
- 12:36:07 - [silent - debug only]
- 12:37:07 - [silent - debug only]
- 12:38:07 - ✅ Home Consumption sensor recovered (was: unknown) [LOGGED]

Technical Changes:
- Added _sensor_error_state dict to SolarSurplusAutomation __init__
- Modified sensor validation loop in _async_periodic_check()
- Track error state per sensor entity_id
- Detect state changes (new error, changed error, recovered)
- Log only on state transitions

Impact:
- Clean logs, no spam warnings
- Easier troubleshooting (see when errors start/stop)
- No performance impact
- Same diagnostic sensor updates

Files Modified:
- solar_surplus.py: Added error tracking, modified validation logic
- const.py: VERSION = 1.3.16
- manifest.json: version = 1.3.16
- CLAUDE.md: v1.3.16 release notes

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Author: Antonio ...

CLAUDE.md

@@ -753,6 +753,25 @@ async def _set_amperage(self, target_amperage: int):
 
 ## Version History
 
+### v1.3.16 (2025-11-05)
+**Throttled Logging for Sensor Errors**
+- **Problem Fixed**: When sensors become unavailable (e.g., `unknown` state), Solar Surplus logged errors every minute, causing log spam (200+ messages)
+- **Solution**: Implemented smart error state tracking that only logs when errors change
+- **New Behavior**:
+  - First error occurrence: Full error logged with details
+  - Subsequent occurrences: Silent (only debug level logging)
+  - Sensor recovery: Success message logged when sensor becomes available again
+- **Example**:
+  ```
+  12:35:07 - ❌ Sensor Home Consumption (sensor.xyz) state is 'unknown'  [LOGGED ONCE]
+  12:36:07 - [silent - error persists]
+  12:37:07 - [silent - error persists]
+  12:38:07 - ✅ Home Consumption sensor recovered (was: state is 'unknown')  [LOGGED]
+  ```
+- **Technical**: Added `_sensor_error_state` dictionary to track per-sensor error states
+- **User Impact**: Cleaner logs, no more Home Assistant warnings about excessive logging
+- **Upgrade priority**: 🟡 RECOMMENDED - Eliminates log spam when sensors temporarily offline
+
 ### v1.3.15 (2025-11-05)
 **Unified 60s Stability Delay for All Surplus Operations**
 - **Change**: Initial charger start (OFF → ON) now uses same 60s delay as amperage increases

custom_components/ev_smart_charger/const.py

@@ -2,7 +2,7 @@
 
 # ========== INTEGRATION METADATA ==========
 DOMAIN = "ev_smart_charger"
-VERSION = "1.3.15"
+VERSION = "1.3.16"
 DEFAULT_NAME = "EV Smart Charger"
 
 # ========== PLATFORMS ==========

custom_components/ev_smart_charger/manifest.json

@@ -1,7 +1,7 @@
 {
   "domain": "ev_smart_charger",
   "name": "EV Smart Charger",
-  "version": "1.3.15",
+  "version": "1.3.16",
   "documentation": "https://github.com/antbald/ha-ev-smart-charger",
   "issue_tracker": "https://github.com/antbald/ha-ev-smart-charger/issues",
   "codeowners": ["@antbald"],

custom_components/ev_smart_charger/solar_surplus.py

@@ -105,6 +105,9 @@ def __init__(
         self._check_count = 0
         self._check_count_reset_time = None
 
+        # Sensor error tracking (prevent log spam)
+        self._sensor_error_state = {}  # {sensor_entity_id: error_message}
+
     def _find_entity_by_suffix(self, suffix: str) -> str | None:
         """Find an entity by its suffix using EntityRegistryService."""
         entity_id = self._registry_service.find_by_suffix_filtered(suffix)
@@ -344,23 +347,41 @@ async def _async_periodic_check(self, now=None) -> None:
 
         self.logger.info(f"Charger status: '{charger_status}' - proceeding")
 
-        # === 7. Validate Sensors ===
+        # === 7. Validate Sensors (with throttled logging to prevent spam) ===
         sensor_errors = []
         sensors_to_validate = [
             (self._fv_production, "Solar Production"),
             (self._home_consumption, "Home Consumption"),
             (self._grid_import, "Grid Import"),
         ]
 
+        # Check each sensor and track error state changes
+        new_errors = False
         for entity_id, sensor_name in sensors_to_validate:
             is_valid, error_msg = validate_sensor(self.hass, entity_id, sensor_name)
+
             if not is_valid:
                 sensor_errors.append(error_msg)
+                # Only log if this is a NEW error or error message changed
+                if entity_id not in self._sensor_error_state or self._sensor_error_state[entity_id] != error_msg:
+                    self._sensor_error_state[entity_id] = error_msg
+                    new_errors = True
+            else:
+                # Sensor is now valid - check if it was previously in error state
+                if entity_id in self._sensor_error_state:
+                    self.logger.info(f"✅ {sensor_name} sensor recovered (was: {self._sensor_error_state[entity_id]})")
+                    del self._sensor_error_state[entity_id]
 
         if sensor_errors:
-            self.logger.error("Sensor validation failed:")
-            for error in sensor_errors:
-                self.logger.error(f"  - {error}")
+            # Only log full error details if there are NEW errors
+            if new_errors:
+                self.logger.error("Sensor validation failed:")
+                for error in sensor_errors:
+                    self.logger.error(f"  - {error}")
+            else:
+                # Existing errors - just update diagnostic sensor quietly
+                self.logger.debug(f"Sensor errors still present ({len(sensor_errors)} sensors unavailable)")
+
             await self._update_diagnostic_sensor(
                 "ERROR: Invalid sensor values",
                 {"errors": sensor_errors, "last_check": datetime.now().isoformat()}