erDiagram
    profiles {
        string id PK "Primary Key"
        string email "User's email"
        string avatar_url "URL for avatar"
        string full_name "User's full name"
        string created_at
        string updated_at
    }

    user_settings {
        string id PK "Primary Key"
        string user_id FK "Foreign Key to profiles.id"
        string theme
        string language
        string occupation
        Json notification_preferences
        Json traits
        string created_at
        string updated_at
    }

    chats {
        string id PK "Primary Key"
        string user_id FK "Foreign Key to profiles.id"
        string title "Chat title"
        string model "AI model used"
        boolean public "Is the chat public?"
        Json metadata
        string created_at
        string updated_at
    }

    messages {
        string id PK "Primary Key"
        string chat_id FK "Foreign Key to chats.id"
        string role "e.g., 'user', 'assistant'"
        string content "Message content"
        string type "Message type"
        Json metadata
        string created_at
    }

    attachments {
        string id PK "Primary Key"
        string message_id FK "Foreign Key to messages.id"
        string file_name
        number file_size
        string file_type
        string url
        Json metadata
        string created_at
    }

    code_conversions {
        string id PK "Primary Key"
        string message_id FK "Foreign Key to messages.id"
        number code_block_index
        string target_language
        string converted_content
        Json metadata
        string created_at
    }

    chat_index {
        string id PK "Primary Key"
        string chat_id FK "Foreign Key to chats.id"
        string message_id FK "Foreign Key to messages.id"
        string snippet "Indexed text snippet"
        string type "Index entry type"
        number score "Relevance score"
        Json metadata
        string created_at
    }

    %% --- Relationships ---
    profiles ||--|| user_settings : "has one"
    profiles ||--o{ chats : "has many"
    chats ||--o{ messages : "has many"
    chats ||--o{ chat_index : "is indexed in"
    messages ||--o{ attachments : "has many"
    messages ||--o{ code_conversions : "has many"
    messages ||--o{ chat_index : "is indexed in"