Image Attachments for Issues & Comments

flowchart TD
    subgraph CLI["CLI / Desktop"]
        A["User attaches image"] --> B["SHA-256 hash bytes"]
        B --> C["Store in .fp/blobs/<hash>"]
        B --> D["Write metadata to Ydoc"]
        D --> E["attachments Y.Map"]
    end

    subgraph SYNC["Sync Layer"]
        E --> F["Yjs sync via WebSocket"]
        F --> G["Metadata arrives on server"]
        C --> H["Blob upload via HTTP PUT"]
        H --> I["R2: project/blobs/<hash>"]
    end

    subgraph REMOTE["Other Clients"]
        G --> J["Yjs sync delivers metadata"]
        J --> K["Client sees attachment ref"]
        K --> L{"Blob in local .fp/blobs?"}
        L -->|No| M["HTTP GET from R2"]
        M --> N["Store in .fp/blobs/<hash>"]
        L -->|Yes| O["Render from local cache"]
        N --> O
    end

    classDef cliNode fill:#1e3a5f22,stroke:#1e3a5f
    classDef syncNode fill:#b8860b22,stroke:#b8860b
    classDef remoteNode fill:#4a7c5922,stroke:#4a7c59
    class A,B,C,D,E cliNode
    class F,G,H,I syncNode
    class J,K,L,M,N,O remoteNode
    

sequenceDiagram
    participant C as Client
    participant WS as Sync DO
WebSocket
    participant API as Console API
HTTP
    participant R2 as R2 Bucket

    Note over C,WS: Phase 1: Yjs Sync (existing protocol)
    C->>WS: HELLO + known issues
    WS-->>C: WELCOME + issue manifest
    C->>WS: SYNC messages per issue
    WS-->>C: SYNC replies with updates
    Note over C: Ydocs now contain attachment metadata

    Note over C,R2: Phase 2: Blob Sync (new HTTP layer)
    C->>C: Scan Ydocs for attachment hashes
    C->>C: Compare with local .fp/blobs/
    C->>API: GET /blobs/manifest
    API-->>C: List of hashes server has

    loop For each missing-locally blob
        C->>API: GET /blobs/sha256-abcdef
        API->>R2: Get object
        R2-->>API: Blob bytes
        API-->>C: Blob bytes
        C->>C: Verify hash, store in .fp/blobs/
    end

    loop For each unsynced-locally blob
        C->>API: PUT /blobs/sha256-abcdef
        API->>R2: Put object
        R2-->>API: OK
        API-->>C: 200 OK
        C->>C: Mark blob as synced in SQLite
    end