/**
 * Wheel over the composer: scroll a multi-line / overflowing draft in-place,
 * or signal that the chat transcript may scroll (short single-line drafts).
 */
export declare function composerDraftOverflows(contentLines: number, visibleRows: number): boolean;
/** Multi-line draft (newlines or soft-wrap) owns the wheel — never the chat. */
export declare function composerOwnsWheel(contentLines: number): boolean;
/** Next viewport Y for an overflowing draft; undefined if nothing to scroll. */
export declare function nextComposerScrollOffset(opts: {
    readonly offsetY: number;
    readonly viewportHeight: number;
    readonly totalLines: number;
    readonly direction: "up" | "down" | string;
    readonly delta?: number | undefined;
    readonly lineStep?: number | undefined;
}): number | undefined;
/** Minimal editor surface used for draft-internal wheel scroll. */
export interface ComposerWheelEditor {
    readonly lineCount?: number;
    readonly virtualLineCount?: number;
    readonly plainText?: string;
    readonly editorView: {
        getViewport(): {
            offsetY: number;
            offsetX: number;
            height: number;
            width: number;
        };
        getTotalVirtualLineCount?: () => number;
        setViewport(x: number, y: number, width: number, height: number, moveCursor?: boolean): void;
    };
    moveCursorUp(): unknown;
    moveCursorDown(): unknown;
}
/** Best-effort visual line count from the live editor (React state can lag). */
export declare function measureComposerLines(editor: ComposerWheelEditor | null | undefined, contentLinesFallback: number): number;
/**
 * Scroll the draft when the composer owns the wheel.
 * Returns true when chat must NOT scroll (multi-line / overflow draft).
 */
export declare function tryScrollComposerDraft(editor: ComposerWheelEditor, opts: {
    readonly contentLines: number;
    readonly visibleRows: number;
    readonly direction: "up" | "down" | string;
    readonly delta?: number | undefined;
}): boolean;
/** Wheel delta → transcript scroll steps (shared by composer + app). */
export declare function wheelChatDelta(direction: "up" | "down" | string, delta?: number): number;
/**
 * Resolve composer wheel: "draft" | "chat" | "none".
 * Unfocused composer never scrolls the draft (avoids dual scroll with chat).
 */
export declare function resolveComposerWheelTarget(opts: {
    readonly composerFocused: boolean;
    readonly editor: ComposerWheelEditor | null | undefined;
    readonly contentLines: number;
    readonly visibleRows: number;
}): "draft" | "chat";