# Implementation Plan: QGIS Traffic Signal Overrides

## 1. Contracts and Pure Logic

- [x] Add an auxiliary editable-layer definition without modifying `SCENE_LAYERS` ordering.
- [x] Extend OSM arm parsing with deterministic approach identity inputs.
- [x] Split traffic-signal logic into automatic editable-feature generation, feature validation/normalization, and runtime pose derivation.
- [x] Use stable technical ids for runtime signal ids; keep `display_id` as editable metadata.
- [x] Add pure Node tests for T/cross counts, stable ids, movement/heading reconstruction, disabled features, duplicate ids, and invalid values.

## 2. Intermediates and QGIS

- [x] Write `traffic_signal_assemblies.geojson` after stop-line/intersection outputs are stable.
- [x] Import the auxiliary point layer into the GeoPackage after the nine render layers.
- [x] Extend generated QGIS project code with point/direction styling, labels, and field widgets/constraints.
- [x] Confirm the auxiliary layer is excluded from merged road scene ordering and raster preview behavior.

## 3. Reimport and Stage Ownership

- [x] Extend `reimport-gpkg.js` to discover/export render and auxiliary layers through staging.
- [x] Validate the staged editable layer before replacing any output artifact.
- [x] Rebuild runtime `traffic_signals.json` from editable GeoJSON after `intermediates`, `reimport`, and at Blender entry.
- [x] Remove Blender-entry OSM placement regeneration so QGIS edits remain authoritative.
- [x] Extend stage manifests and diagnostics with auxiliary input/output records and feature counts.

## 4. Cross-Layer Consumers

- [x] Preserve `display_id` and stable runtime ids through Blender and Cesium metadata where useful.
- [x] Verify static signal objects, dynamic lenses, countdown nodes, and vehicle stop behavior all consume the same enabled runtime records.
- [x] Update pipeline specifications to replace the old prohibition with the editable-layer/derived-runtime distinction.

## 5. Validation

- [x] Run Node syntax checks and focused unit tests.
- [x] Run existing preview-assets, preflight, budget, and relevant pipeline tests.
- [x] Run `intermediates` and inspect the GeoPackage/QGIS project feature schema and styling.
- [ ] Make a controlled QGIS edit to one signal (display id, point, heading), run `reimport,blender,cesium,preview`, and verify only the intended assembly changes. (`reimport` and Blender passed; Cesium/preview refresh was not repeated.)
- [x] Confirm an invalid/duplicate edit fails before overwriting valid outputs.
- [ ] Inspect Blender/Cesium structural digests and Safari preview for T and cross junctions. (Blocked this run by Blender 4.5.12 Metal startup SIGSEGV before project Python.)

## Risky Files / Rollback Points

- `scripts/lib/traffic-signals.js`: identity and pose contract; land pure tests before pipeline integration.
- `scripts/build-osm2streets-qgis.js`: GeoPackage recreation and generated QGIS Python; verify auxiliary import independently before styling.
- `scripts/reimport-gpkg.js`: atomic overwrite boundary; preserve staging semantics.
- `scripts/build-area.js`: stage ownership; ensure Blender derives from editable GeoJSON rather than overwriting it.
- `blender/osmassets/traffic_signals.py` and preview runtime should require minimal or no geometry changes; unexpected edits here indicate contract leakage.

## Review Gate Before Start

- [ ] User approves the final planning summary.
- [ ] `prd.md`, `design.md`, and `implement.md` agree on full editable layer ownership and out-of-scope intermediates persistence.
- [ ] No unresolved product decision remains.