## Implementation Complete ### Changes Made 1. **New /api/power/history endpoint** (app/api/power_router.py:104-212) - Implements GET /api/power/history with all required query parameters: - range: 1h|24h|7d|30d (default: 24h) - resolution: 1m|5m|1h (default: 1m for raw data) - outlet_id: Filter by specific outlet (1-24) - device_id: Filter by device (returns all outlets assigned to device) - include_outlets: Include individual outlet readings - Returns time-series data with aggregations (avg, min, max) in statistics 2. **Resolution/Aggregation** (app/api/power_router.py:43-91) - 1m = raw data (no aggregation) - 5m = 5-minute bucket averages - 1h = hourly bucket averages 3. **Data Retention/Cleanup** (app/services/metrics_collector.py:164-199) - Added DATA_RETENTION_DAYS config setting (default: 30 days) - Cleanup runs automatically every ~1 hour - Set to 0 to disable cleanup ### Test Results All 220 tests pass, including 23 new tests for the power history API and 4 new tests for data retention cleanup.