Periods can now naturally cross midnight boundaries, and new diagnostic
attributes help users understand price classification changes at midnight.
**New Features:**
1. Midnight-Crossing Period Support (relaxation.py):
- group_periods_by_day() assigns periods to ALL spanned days
- Periods crossing midnight appear in both yesterday and today
- Enables period formation across calendar day boundaries
- Ensures min_periods checking works correctly at midnight
2. Extended Price Data Window (relaxation.py):
- Period calculation now uses full 3-day data (yesterday+today+tomorrow)
- Enables natural period formation without artificial midnight cutoff
- Removed date filter that excluded yesterday's prices
3. Day Volatility Diagnostic Attributes (period_statistics.py, core.py):
- day_volatility_%: Daily price spread as percentage (span/avg × 100)
- day_price_min/max/span: Daily price range in minor currency (ct/øre)
- Helps detect when midnight classification changes are economically significant
- Uses period start day's reference prices for consistency
**Documentation:**
4. Design Principles (period-calculation-theory.md):
- Clarified per-day evaluation principle (always was the design)
- Added comprehensive section on midnight boundary handling
- Documented volatility threshold separation (sensor vs period filters)
- Explained market context for midnight price jumps (EPEX SPOT timing)
5. User Guides (period-calculation.md, automation-examples.md):
- Added \"Midnight Price Classification Changes\" troubleshooting section
- Provided automation examples using volatility attributes
- Explained why Best→Peak classification can change at midnight
- Documented level filter volatility threshold behavior
**Architecture:**
- Per-day evaluation: Each interval evaluated against its OWN day's min/max/avg
(not period start day) ensures mathematical correctness across midnight
- Period boundaries: Periods can naturally cross midnight but may split when
consecutive days differ significantly (intentional, mathematically correct)
- Volatility thresholds: Sensor thresholds (user-configurable) remain separate
from period filter thresholds (fixed internal) to prevent unexpected behavior
Impact: Periods crossing midnight are now consistently visible before and
after midnight turnover. Users can understand and handle edge cases where
price classification changes at midnight on low-volatility days.
BREAKING CHANGE: Period overlap resolution now merges adjacent/overlapping periods
instead of marking them as extensions. This simplifies automation logic and provides
clearer period boundaries for users.
Previous Behavior:
- Adjacent periods created by relaxation were marked with is_extension=true
- Multiple short periods instead of one continuous period
- Complex logic needed to determine actual period length in automations
New Behavior:
- Adjacent/overlapping periods are merged into single continuous periods
- Newer period's relaxation attributes override older period's
- Simpler automation: one period = one continuous time window
Changes:
- Period Overlap Resolution (new file: period_overlap.py):
* Added merge_adjacent_periods() to combine periods and preserve attributes
* Rewrote resolve_period_overlaps() with simplified merge logic
* Removed split_period_by_overlaps() (no longer needed)
* Removed is_extension marking logic
* Removed unused parameters: min_period_length, baseline_periods
- Relaxation Strategy (relaxation.py):
* Removed all is_extension filtering from period counting
* Simplified standalone counting to just len(periods)
* Changed from period_merging import to period_overlap import
* Added MAX_FLEX_HARD_LIMIT constant (0.50)
* Improved debug logging for merged periods
- Code Quality:
* Fixed all remaining linter errors (N806, PLR2004, PLR0912)
* Extracted magic values to module-level constants:
- FLEX_SCALING_THRESHOLD = 0.20
- SCALE_FACTOR_WARNING_THRESHOLD = 0.8
- MAX_FLEX_HARD_LIMIT = 0.50
* Added appropriate noqa comments for unavoidable patterns
- Configuration (from previous work in this session):
* Removed CONF_RELAXATION_STEP_BEST, CONF_RELAXATION_STEP_PEAK
* Hard-coded 3% relaxation increment for reliability
* Optimized defaults: RELAXATION_ATTEMPTS 8→11, ENABLE_MIN_PERIODS False→True,
MIN_PERIODS undefined→2
* Removed relaxation_step UI fields from config flow
* Updated all 5 translation files
- Documentation:
* Updated period_handlers/__init__.py: period_merging → period_overlap
* No user-facing docs changes needed (already described continuous periods)
Rationale - Period Merging:
User experience was complicated by fragmented periods:
- Automations had to check multiple adjacent periods
- Binary sensors showed ON/OFF transitions within same cheap time
- No clear way to determine actual continuous period length
With merging:
- One continuous cheap time = one period
- Binary sensor clearly ON during entire period
- Attributes show merge history via merged_from dict
- Relaxation info preserved from newest/highest flex period
Rationale - Hard-Coded Relaxation Increment:
The configurable relaxation_step parameter proved problematic:
- High base flex + high step → rapid explosion (40% base + 10% step → 100% in 6 steps)
- Users don't understand the multiplicative nature
- 3% increment provides optimal balance: 11 attempts to reach 50% hard cap
Impact:
- Existing installations: Periods may appear longer (merged instead of split)
- Automations benefit from simpler logic (no is_extension checks needed)
- Custom relaxation_step values will use new 3% increment
- Users may need to adjust relaxation_attempts if they relied on high step sizes
