# Runtime Flow

## Connect Flow

1. User clicks connect.
2. Client validates auth form/session token and sets up local media.
3. Client connects signaling websocket.
4. Server sends `auth_required`.
   - includes `authPolicy` limits for username/password.
5. Client sends `auth_login`, `auth_register`, or `auth_resume`.
6. Server sends `auth_result`.
   - includes role + permissions for authenticated session.
7. Server sends `welcome` with users/items snapshot.
8. Client:
   - applies `welcome.worldConfig.gridSize` for authoritative grid bounds/rendering
   - applies `welcome.worldConfig.movementTickMs` as movement pacing guidance
   - applies `welcome.worldConfig.movementMaxStepsPerTick` for movement-rate parity
  - uses `welcome.player` as authoritative starting position (restored from server-side account state when available)
   - records `welcome.serverInfo` (`instanceId`, `version`) for restart detection
   - if `welcome.serverInfo.version` differs from running client version, auto-reloads the page
   - applies `welcome.uiDefinitions` for item menus/properties/options and admin menu labels/order
   - sends initial `update_position` echo from server-assigned starting tile
   - sends initial `update_nickname`
   - creates peer runtimes for known users
   - syncs item runtimes (`radio`, `emit`)
   - applies audio layer state
   - starts signaling heartbeat monitor
   - starts game loop

## Main Loop

Each frame:

- Handle local movement input.
- Send movement intents; server remains authoritative on accepted movement updates.
- Update spatial voice audio.
- Update spatial radio audio.
- Update spatial item emit audio.
- Draw canvas scene.

## Message Handling

Core incoming message effects:

- `signal`: WebRTC negotiation and ICE exchange.
- `auth_required`: prompt client to authenticate before gameplay messages.
- `auth_result`: auth success/failure with optional session token + account metadata + `authPolicy`.
- `auth_permissions`: live permission refresh (role + permission set) after role/permission admin changes.
- `admin_roles_list`: role metadata + user counts + permission keys for role management UI.
- `admin_users_list`: user metadata list for role/ban admin flows.
- `admin_action_result`: success/error for role/user admin mutations.
- `update_position`: update peer position; may play movement/teleport world sound.
- `teleport_complete`: play peer teleport landing sound at final tile.
- `update_nickname`: update peer display name.
- `chat_message`: append/readable status; optional system sound class.
- `item_upsert`: replace item snapshot and resync item runtimes.
- `item_remove`: remove item and cleanup runtimes.
- `item_action_result`: success/error status for actions.
- `item_use_sound`: play one-shot spatial sample (world layer gated).
- `item_piano_note`: start/stop synthesized piano notes from remote users (item layer gated).
- `item_piano_status`: structured piano mode/record/playback transitions (client runtime state).
- `pong`:
  - positive `clientSentAt`: user ping response (`P` command)
  - negative `clientSentAt`: internal heartbeat response

## Stale Connection Recovery

- If websocket closes unexpectedly, client starts reconnect flow immediately.
- While running, client also sends heartbeat `ping` every 10 seconds (fallback for silent half-open cases).
- If one heartbeat `pong` is missed (10-second interval), client starts reconnect flow.
- Reconnect flow waits 5 seconds and retries up to 3 times.
- If reconnect lands on a different `welcome.serverInfo.instanceId`, client announces server restart.
- Connect/reconnect status message is emitted from `welcome` and includes server version.

## Authorization Runtime

- Server enforces item/chat/nickname/voice/admin permissions for each packet.
- Role and permission changes apply live to connected users without reconnect.
- `voice.send` revocation is pushed immediately via `auth_permissions`; client mutes outbound voice track.

## Disconnect/Cleanup

On disconnect:

- Close signaling.
- Stop heartbeat monitor.
- Stop local media tracks.
- Cleanup peers and all audio runtimes.
- Reset UI/mode state and lists.

## Runtime Components

- `PeerManager`: peer connection lifecycle and remote track attach.
- `RadioStationRuntime`: shared stream sources + per-item output/effects/spatialization.
- `ItemEmitRuntime`: per-item looping emit source + spatialization.
- `AudioEngine`: shared audio context, samples, effects, voice graph.