%%{init: {'theme': 'neutral'}}%%
sequenceDiagram
    autonumber
    participant Visitor as Visitor
    participant Editor as Editor/Admin
    participant FE as Frontend
    participant BE as Backend API
    participant DB as Postgres

    Note over Visitor,BE: Public create (same-site only)
    FE->>BE: POST /api/v1/shortlinks/public {url, note}
    BE->>BE: RateLimit(30/min) + origin checks
    BE->>DB: Insert ShortLink
    DB-->>BE: id, code
    BE-->>FE: 201 Created {code, short_url}

    rect rgba(220,255,220,0.2)
    Note over Editor,BE: Editor/Admin management
    FE->>BE: POST /api/v1/shortlinks (editor)
    BE->>DB: Insert ShortLink
    BE-->>FE: 201 Created

    FE->>BE: GET /api/v1/shortlinks (editor)
    BE->>DB: List
    BE-->>FE: 200 OK [shortlinks]

    FE->>BE: GET /api/v1/admin/shortlinks/:id/stats (admin)
    BE->>DB: Aggregate LinkClick
    BE-->>FE: 200 OK {stats}
    end

    rect rgba(230,230,255,0.2)
    Note over FE,BE: Public redirect
    FE->>BE: GET /s/:code (root)
    BE->>DB: Lookup ShortLink by code
    BE->>DB: Insert LinkClick
    BE-->>FE: 302 Redirect to target
    end