/**
 * Shared formatters / icon maps / label resolver for the message layout
 * components. Pure functions only — i18n strings come in via the `roles`
 * argument; the helper has no runtime dependency on the messages context.
 */
import type { PlaygroundMessage, PlaygroundMessageLevel, PlaygroundMessageRole } from '../../types/playground.js';
import type { Messages } from '../../messages/types.js';
export type RoleLabels = Messages['playground']['roles'];
export declare function formatTimestamp(timestamp: string): string;
export declare function formatDuration(ms: number): string;
export declare function getLogLevelIcon(level: PlaygroundMessageLevel | undefined): string;
export declare function getRoleIcon(role: PlaygroundMessageRole): string;
/**
 * Localised author label. Backend-supplied overrides win:
 *   - user → metadata.userName (display name)
 *   - log  → metadata.nodeLabel (human-readable node label)
 * Anything else returns the role's i18n default.
 */
export declare function getRoleLabel(message: Pick<PlaygroundMessage, 'role' | 'metadata'>, roles: RoleLabels): string;