Fixed multiple calculation issues with negative prices (Norway/Germany
renewable surplus scenarios):
Bug #6: Rating threshold validation with dead code
- Added threshold validation (low >= high) with warning
- Returns NORMAL as fallback for misconfigured thresholds
Bug #7: Min/Max functions returning 0.0 instead of None
- Changed default from 0.0 to None when window is empty
- Prevents misinterpretation (0.0 looks like price with negatives)
Bug #9: Period price diff percentage wrong sign with negative reference
- Use abs(ref_price) in percentage calculation
- Correct percentage direction for negative prices
Bug #10: Trend diff percentage wrong sign with negative current price
- Use abs(current_interval_price) in percentage calculation
- Correct trend direction when prices cross zero
Bug #11: later_half_diff calculation failed for negative prices
- Changed condition from `if current_interval_price > 0` to `!= 0`
- Use abs(current_interval_price) for percentage
Changes:
- utils/price.py: Add threshold validation, use abs() in percentages
- utils/average.py: Return None instead of 0.0 for empty windows
- period_statistics.py: Use abs() for reference prices
- trend.py: Use abs() for current prices, fix zero-check condition
- tests: 95+ new tests covering negative/zero/mixed price scenarios
Impact: All calculations work correctly with negative electricity prices.
Percentages show correct direction regardless of sign.
Introduce TimeService as single source of truth for all datetime operations,
replacing direct dt_util calls throughout the codebase. This establishes
consistent time context across update cycles and enables future time-travel
testing capability.
Core changes:
- NEW: coordinator/time_service.py with timezone-aware datetime API
- Coordinator now creates TimeService per update cycle, passes to calculators
- Timer callbacks (#2, #3) inject TimeService into entity update flow
- All sensor calculators receive TimeService via coordinator reference
- Attribute builders accept time parameter for timestamp calculations
Key patterns replaced:
- dt_util.now() → time.now() (single reference time per cycle)
- dt_util.parse_datetime() + as_local() → time.get_interval_time()
- Manual interval arithmetic → time.get_interval_offset_time()
- Manual day boundaries → time.get_day_boundaries()
- round_to_nearest_quarter_hour() → time.round_to_nearest_quarter()
Import cleanup:
- Removed dt_util imports from ~30 files (calculators, attributes, utils)
- Restricted dt_util to 3 modules: time_service.py (operations), api/client.py
(rate limiting), entity_utils/icons.py (cosmetic updates)
- datetime/timedelta only for TYPE_CHECKING (type hints) or duration arithmetic
Interval resolution abstraction:
- Removed hardcoded MINUTES_PER_INTERVAL constant from 10+ files
- New methods: time.minutes_to_intervals(), time.get_interval_duration()
- Supports future 60-minute resolution (legacy data) via TimeService config
Timezone correctness:
- API timestamps (startsAt) already localized by data transformation
- TimeService operations preserve HA user timezone throughout
- DST transitions handled via get_expected_intervals_for_day() (future use)
Timestamp ordering preserved:
- Attribute builders generate default timestamp (rounded quarter)
- Sensors override when needed (next interval, daily midnight, etc.)
- Platform ensures timestamp stays FIRST in attribute dict
Timer integration:
- Timer #2 (quarter-hour): Creates TimeService, calls _handle_time_sensitive_update(time)
- Timer #3 (30-second): Creates TimeService, calls _handle_minute_update(time)
- Consistent time reference for all entities in same update batch
Time-travel readiness:
- TimeService.with_reference_time() enables time injection (not yet used)
- All calculations use time.now() → easy to simulate past/future states
- Foundation for debugging period calculations with historical data
Impact: Eliminates timestamp drift within update cycles (previously 60+ independent
dt_util.now() calls could differ by milliseconds). Establishes architecture for
time-based testing and debugging features.
