//! RESRCH-1 (R-P6) — the AI chat model. A turn is a query + its (possibly
//! streaming) response. Rendering lives in `render.rs`; this holds the data and
//! the small helpers the streaming loop (R-P7) drives.

/// One research exchange shown in the chat pane.
pub(super) struct ChatTurn {
    /// The user's query (or `/command`), shown as a `[query N]`-style header.
    pub prompt: String,
    /// The assistant's response, appended token-by-token while `streaming`.
    pub response: String,
    /// True while tokens are still arriving (R-P7).
    pub streaming: bool,
    /// Per-turn cost in USD (set on stream completion).
    pub cost: f64,
}

impl ChatTurn {
    pub(super) fn new(prompt: String) -> ChatTurn {
        ChatTurn { prompt, response: String::new(), streaming: false, cost: 0.0 }
    }

    /// A turn pre-filled with a final response (no streaming) — used for
    /// command output (`/diff`, `/verify`) and placeholders.
    pub(super) fn with_response(prompt: String, response: String) -> ChatTurn {
        ChatTurn { prompt, response, streaming: false, cost: 0.0 }
    }
}
