prep season shift

SCRATCHPAD.md

@@ -77,6 +77,52 @@
 3. Continue replacing oversized legacy test matrices with focused modern integration and unit coverage.
 4. Triage the legacy `Scenario 4` pattern/track failure and decide whether to fix the harness, adapt it to the zero-track guard, or retire that path during the ongoing test-suite migration.
 
+## Shifted Season Status (2026-04-12)
+
+- Current assessment:
+  - The shifted-season subsystem is present end to end and looks feature-complete in shape, but it is not yet hardened.
+  - The storage, TUI CRUD surface, and CLI/TMDB filename application path all exist, so this is no longer a stubbed or half-started area.
+  - The main gap is correctness and direct verification rather than missing surface area.
+
+- Implemented surface confirmed:
+  - Requirements still treat shifted seasons as part of the accepted product surface in [`requirements/project.md`](/home/osgw/.local/src/codex/ffx/requirements/project.md) and [`requirements/architecture.md`](/home/osgw/.local/src/codex/ffx/requirements/architecture.md).
+  - Persistence exists via [`src/ffx/model/shifted_season.py`](/home/osgw/.local/src/codex/ffx/src/ffx/model/shifted_season.py) plus the `Show.shifted_seasons` relationship in [`src/ffx/model/show.py`](/home/osgw/.local/src/codex/ffx/src/ffx/model/show.py).
+  - CRUD logic exists in [`src/ffx/shifted_season_controller.py`](/home/osgw/.local/src/codex/ffx/src/ffx/shifted_season_controller.py).
+  - Textual add/edit/delete flows are wired through [`src/ffx/shifted_season_details_screen.py`](/home/osgw/.local/src/codex/ffx/src/ffx/shifted_season_details_screen.py), [`src/ffx/shifted_season_delete_screen.py`](/home/osgw/.local/src/codex/ffx/src/ffx/shifted_season_delete_screen.py), and the show details table in [`src/ffx/show_details_screen.py`](/home/osgw/.local/src/codex/ffx/src/ffx/show_details_screen.py).
+  - CLI conversion applies season shifts before TMDB lookup and output suffix generation in [`src/ffx/cli.py`](/home/osgw/.local/src/codex/ffx/src/ffx/cli.py).
+
+- Verified current behavior:
+  - `~/.local/share/ffx.venv/bin/python -m unittest discover -s tests/unit -p 'test_*.py'` passed on 2026-04-12: `75` tests in `0.795s`.
+  - That run emitted `ResourceWarning` messages for unclosed SQLite connections, so the suite is green but not perfectly clean.
+  - There is almost no direct shifted-season coverage in the modern tests:
+    - [`tests/unit/test_cli_rename_only.py`](/home/osgw/.local/src/codex/ffx/tests/unit/test_cli_rename_only.py) stubs `ShiftedSeasonController` rather than exercising it.
+    - [`tests/unit/test_screen_support.py`](/home/osgw/.local/src/codex/ffx/tests/unit/test_screen_support.py) only verifies controller bootstrap wiring.
+  - Net effect: the subsystem is integrated, but its core rules are effectively untested by the current modern suite.
+
+- Reproduced correctness gaps:
+  - Overlap validation is broken in [`src/ffx/shifted_season_controller.py:41`](/home/osgw/.local/src/codex/ffx/src/ffx/shifted_season_controller.py:41) because `getOriginalSeason` is compared as a method object instead of being called.
+  - Reproduction on 2026-04-12 with a temp SQLite DB:
+    - Added `S1 E1-E10`.
+    - `checkShiftedSeason(...)` incorrectly returned `True` for overlapping `S1 E5-E15`.
+    - `addShiftedSeason(...)` then stored the overlapping row successfully.
+  - `updateShiftedSeason(...)` in [`src/ffx/shifted_season_controller.py:93`](/home/osgw/.local/src/codex/ffx/src/ffx/shifted_season_controller.py:93) does not enforce episode ordering, so an invalid range like `first_episode=20`, `last_episode=10` was accepted in the same reproduction.
+  - Because [`src/ffx/shifted_season_controller.py:213`](/home/osgw/.local/src/codex/ffx/src/ffx/shifted_season_controller.py:213) returns the first matching sibling and [`src/ffx/shifted_season_controller.py:163`](/home/osgw/.local/src/codex/ffx/src/ffx/shifted_season_controller.py:163) applies no explicit ordering, overlapping rows would also make runtime shifting ambiguous.
+
+- Progress summary:
+  - Good progress:
+    - The subsystem exists across requirements, schema, UI, and conversion flow.
+    - It appears fully integrated into the show-editing workflow rather than parked as dead code.
+  - Incomplete progress:
+    - Validation logic is not trustworthy yet.
+    - Modern tests do not currently protect the subsystem's real behavior.
+    - User-facing error feedback in the shifted-season screens still has placeholder `#TODO: Meldung` branches.
+
+- Recommended next slice:
+  1. Add direct controller tests for overlap rejection, episode-order validation, and `shiftSeason(...)` selection behavior.
+  2. Fix `checkShiftedSeason(...)` and add the same range/order validation to `updateShiftedSeason(...)`.
+  3. Make sibling selection deterministic or enforce non-overlap strongly enough that ordering no longer matters in practice.
+  4. Add at least one focused integration test that proves a stored shifted season changes TMDB lookup and/or generated filename numbering during conversion.
+
 ## Delete When
 
 - Delete this scratchpad once the optimization backlog is either converted into issues/work items or distilled into durable project guidance.