import type { SpinnerResult, ProgressResult } from '@clack/prompts';
export type LogFormat = 'default' | 'json';
/**
 * GT_LOG_FORMAT: default | json.
 * - If default, logs will be pretty-printed using @clack/prompts.
 * - If json, logs will be written in JSON format to the console.
 * GT_LOG_FILE: If specified, logs will be written to the file.
 * GT_LOG_LEVEL: The level of logs to write. If not specified, defaults to 'info'.
 * - Valid levels: debug, info, warn, error.
 */
declare class Logger {
    private static instance;
    private pinoLogger;
    private fileLogger;
    private logFormat;
    private constructor();
    static getInstance(): Logger;
    trace(message: string): void;
    debug(message: string): void;
    info(message: string): void;
    warn(message: string): void;
    error(message: string): void;
    fatal(message: string): void;
    silent(message: string): void;
    success(message: string): void;
    step(message: string): void;
    message(message: string, symbol?: string): void;
    createSpinner(indicator?: 'dots' | 'timer'): SpinnerResult;
    createProgressBar(total: number): ProgressResult;
    startCommand(message: string): void;
    endCommand(message: string): void;
    flush(): void;
}
export declare const logger: Logger;
export {};