# Implement Missing Roadmap Features (Phase 2)

I will implement the key missing features from **Phase 2** of the roadmap to improve compatibility with the Supabase client SDK.

## 1. Realtime Presence (`realtime` crate)
**Goal**: Enable user state tracking (online/offline, custom status) compatible with `supabase-js`.

- **Dependencies**: Add `dashmap` for thread-safe concurrent state management.
- **State Management**: Update `RealtimeState` to store presence data in memory: `Arc<DashMap<Topic, DashMap<ClientID, PresenceData>>>`.
- **WebSocket Logic**:
    - Handle `presence` events (join, leave, sync).
    - Implement `track` (user joins/updates state) and `untrack` (user leaves).
    - Broadcast `presence_diff` events to all subscribers on a topic when state changes.

## 2. Storage Image Transformations (`storage` crate)
**Goal**: Support on-the-fly image resizing and formatting via query parameters.

- **Dependencies**: Add `image` crate (with `jpeg`, `png`, `webp` support).
- **Handler Update**: Modify `download_object` to parse query parameters:
    - `w` / `width`: Target width.
    - `h` / `height`: Target height.
    - `q` / `quality`: Compression quality.
    - `f` / `format`: Output format (e.g., `webp`, `png`).
- **Processing Logic**:
    - If parameters are present, decode the downloaded image bytes.
    - Apply resizing (using `Lanczos3` filter for quality).
    - Encode to the target format/quality.
    - Return the processed image with correct `Content-Type`.

## Execution Steps
1.  **Update Dependencies**: Add `dashmap` to `realtime/Cargo.toml` and `image` to `storage/Cargo.toml`.
2.  **Refactor Realtime**: Modify `RealtimeState` and `ws.rs` to implement the Presence protocol.
3.  **Refactor Storage**: Modify `handlers.rs` to implement the Image Transformation pipeline.
4.  **Verification**: Verify compilation and basic functionality (via `cargo check` and manual review of the logic).