b81108b10b
Task group 1 of planner-route-encoding. Framework-free `route-codec.ts`:
- encodePolyline/decodePolyline — fixed-precision (1e5) delta + zig-zag
varint + base64; lossless to ~1 m, version-tagged ("p1:").
- encodeRuns/decodeRuns — run-length codec for the per-coordinate
road-metadata channels, tagged ("r1:").
- isEncodedPolyline/isEncodedRuns — so the read path (group 3) tells the
new encoding apart from legacy JSON.
Not yet wired into route-data.ts (groups 2–3). Verified: map-core
typecheck + lint clean, 52/52 tests (round-trip within 1 m, empty/single,
RLE collapse, >3x smaller than JSON).
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
23 lines
2.4 KiB
Markdown
23 lines
2.4 KiB
Markdown
## 1. Codec primitives
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- [x] 1.1 Add a framework-free codec in `@trails-cool/map-core` (e.g. `route-codec.ts`): `encodePolyline(coords: [lon,lat][]) -> string` / `decodePolyline(str) -> [lon,lat][]` using fixed-precision (1e5) delta + zig-zag varint + base64, with a version tag
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- [x] 1.2 Add `encodeRuns(values: string[]) -> string` / `decodeRuns(str, length?) -> string[]` run-length codec for the road-metadata channels
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- [x] 1.3 Unit tests: polyline round-trip within ~1 m over random + real fixtures; empty/single-point; RLE round-trip incl. all-same, all-distinct, and a realistic run pattern
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## 2. Write path (new encoding)
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- [ ] 2.1 In `route-data.ts` `writeComputedRoute`: store geometry once as `encodePolyline(coordinates)` (drop the separate `geojson` write); write each `ROAD_METADATA_KEYS` channel via `encodeRuns`; keep `segmentBoundaries` + profile
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- [ ] 2.2 Add a `readGeojson(routeData)` helper that assembles the GeoJSON LineString from decoded coordinates (so callers that needed `geojson` no longer read a stored copy)
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## 3. Read path (dual-format, backward compatible)
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- [ ] 3.1 In `route-data.ts` read helpers (`readComputedRoute`, `readRoadMetadata`, coordinate accessors): detect format per key (encoding version tag/sentinel → new decoder; else `JSON.parse` legacy) and return the same decoded shapes as today
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- [ ] 3.2 Point every reader (SessionView map render, elevation profile, GPX export, save-to-journal, road-type/surface coloring) at the helpers; confirm none reads a raw `routeData.get("geojson"|"coordinates"|<metadata>)` directly
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- [ ] 3.3 Tests: a legacy-format `routeData` decodes correctly through the helpers; a new-format one decodes correctly; both yield identical reader-facing data
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## 4. Verification
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- [ ] 4.1 GPX-export golden test: export the same route via legacy and new encoding → byte-identical output
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- [ ] 4.2 Size assertion on a realistic route fixture (e.g. the ~77 km / multi-waypoint case): new-encoded `Y.encodeStateAsUpdate` size is ≥~4× smaller than legacy and a small fraction of `MAX_DOC_BYTES`
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- [ ] 4.3 Confirm routing-host election / BRouter usage unchanged (no client recompute); `pnpm --filter @trails-cool/planner --filter @trails-cool/map-core typecheck && lint && test`, full `pnpm test`
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- [ ] 4.4 Manual/e2e sanity: open a fresh session, add several waypoints, confirm route renders + colors + exports; reload a session persisted in the legacy format and confirm it still works
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