import { IOutputStreamOptions, OutputStream, TOutputWritable } from '../ui';
/**
 * Module to handle logging outputs
 */
export declare namespace Log {
    enum LOG_LEVEL {
        OFF = 0,
        TRACE = 1,
        DEBUG = 2,
        INFO = 3,
        WARN = 4,
        ERROR = 5,
        FATAL = 6
    }
    type TLoggerStream = TOutputWritable;
    type TLogFn = (...msg: any[]) => any;
    /**
     * Basic interface for any logger implementation
     */
    interface ILogger {
        name?: string;
        trace: TLogFn;
        debug: TLogFn;
        info: TLogFn;
        warn: TLogFn;
        error: TLogFn;
        fatal: TLogFn;
    }
    /**
     * Options for a logger instance
     */
    interface ILoggerOptions extends IOutputStreamOptions {
        name?: string;
        level?: LOG_LEVEL;
        stream?: TLoggerStream;
    }
    /**
     * Standard logger instance for the program and its commands
     * @todo Allow BYO logger
     */
    class Logger extends OutputStream implements ILogger {
        /**
         * Set a default level to be used by all logger instantantiations
         * @param level default level used for Logger instances
         */
        static setDefaultLevel(level: LOG_LEVEL): typeof Logger;
        /**
         * set a default logger instance
         * @param logger the logger implementation to use
         */
        static setDefaultLogger(logger: ILogger): typeof Logger;
        /**
         * Provide a logging interface to use
         * @param logger alternate logger to utilize
         */
        static provide(logger: ILogger): typeof Logger;
        /**
         * Get a singleton, default logger instance.
         * @param options options for the default logger, when not yet instantiated
         */
        static defaultLogger(options?: ILoggerOptions): ILogger;
        private static _default;
        private static _defaultLevel;
        name: string;
        private _level;
        constructor(options?: ILoggerOptions);
        /**
         * log level setter
         * @param level log level to set
         */
        setLevel(level: LOG_LEVEL): Logger;
        /**
         * Trace log
         * @param msg messages to log
         */
        trace(...msg: any[]): Logger;
        /**
         * Debug log
         * @param msg messages to log
         */
        debug(...msg: any[]): Logger;
        /**
         * Info log
         * @param msg messages to log
         */
        info(...msg: string[]): Logger;
        /**
         * Warn log
         * @param msg messages to log
         */
        warn(...msg: (string | Error)[]): Logger;
        /**
         * Error log
         * @param msg messages to log
         */
        error(...msg: (string | Error)[]): Logger;
        /**
         * Fatal log
         * @param msg messages to log
         */
        fatal(msg: Error): Logger;
        /**
         * Write the log messages to the stream
         * @param msgs messages to write
         * @param level log level to write
         */
        private _log;
    }
}