# Streetcast Runtime Parity

## Covered
- Manifest polling: covered by `/player/[screenId]` lightweight runtime refresh loop.
- Sequential creative playback: covered by runtime rotation over active manifest creatives.
- Local media cache: covered by screen-scoped browser cache with cached blob playback preference.
- Background preload: covered by manifest-driven media warming after each runtime refresh.
- Offline continuity: covered by last-good-manifest retention plus cached blob playback fallback.
- Impression retry queue: covered by bounded browser queue flushed on interval and `online` events.
- Browser automation parity: covered by Playwright cached-blob/offline checks on `/player/[screenId]`.

## Intentionally Different
- Ballbox runtime uses Ballbox-owned manifest/impression APIs instead of Streetcast endpoints.
- The production TV runtime path is `/player/[screenId]`.
- Playback source of truth is Ballbox Postgres scheduling, not legacy Streetcast ownership data.

## Still Pending
- Real-device verification is still required before calling Streetcast migration complete.
- The missing proof is hardware/browser behavior for CacheStorage plus object-URL playback outside local desktop automation.
- The runtime now ships an on-screen `Export parity snapshot` action that downloads a JSON snapshot (screen id, manifest/playback/cache/network/reporting state, user agent, capture time) to standardize evidence capture.
- Seeded local evidence now has active TV programming again after the TV seed campaign windows were extended in `prisma/seed-data.ts`, so parity runs can use stock `screen_001` after `pnpm db:seed`.

## Local Validation Update (2026-04-19)
- Machine-local Playwright harness is now installed outside the repo at `/mnt/rpi/repos/browser-harness` and verified separately for Chromium, CacheStorage, and object-URL baseline support.
- Ballbox repo Playwright now uses a production-style built-in `webServer` flow on this Pi (`pnpm build:e2e && pnpm start:e2e` on port `3020`) instead of the unstable `pnpm dev` path.
- Stock seed data now provides active TV programming for `screen_001` after `pnpm db:seed`, so local cached-blob playback, first impression write, queued-impression recovery, and manifest-refresh-failure continuity can be validated without manual TV fixture repair first.

## Manual Real-Device Check
1. Open `/player/screen_001` on the target TV/browser with Ballbox pointed at the real/shared DB.
2. Wait for the runtime diagnostics card to show:
   - `Playback: cached`
   - `Active source: blob`
   - `Cache API: available`
   - `Cached creatives: 1` or higher
   - `Network: online`
3. Confirm the video starts and loops without a visible reload gap while the diagnostics stay on `blob`.
4. Disconnect network on the device or gateway after the blob source is active.
5. Confirm the runtime keeps playing and the diagnostics switch to:
   - `Network: offline`
   - `Playback: cached`
   - `Active source: blob`
6. Keep the device offline past one manifest refresh interval and verify `Manifest refresh: failed` appears without playback stopping.
7. Reconnect network and confirm:
   - `Network: online`
   - queued impressions eventually return to `0`
   - heartbeat timestamp advances again
8. Capture evidence:
    - photo/video of the runtime while online and offline
    - browser version / device model
    - exact screen id used
    - JSON file exported from `Export parity snapshot` in both online and offline moments
    - any deviation from the expected diagnostics

## Exit Criteria
- One real device shows cached blob playback before and during an offline window.
- Runtime keeps playing through at least one failed manifest refresh while offline.
- Heartbeat and impression reporting recover after reconnect.
- This doc should be updated with the device/browser/date/result once the run happens.