import { Integer } from '@epdoc/typeutil';
import { AppTimer } from './apptimer';
import { Style, StyleDef, StyleName, StyleOptions } from './style';
export declare const logLevel: {
    readonly trace: 1;
    readonly debug: 3;
    readonly verbose: 5;
    readonly info: 7;
    readonly warn: 8;
    readonly error: 9;
};
export type LogLevel = keyof typeof logLevel;
export type LogLevelValue = (typeof logLevel)[LogLevel];
/**
 * Checks if the given value is a valid LogLevel.
 * @param {any} val - The value to check.
 * @returns {boolean} True if the value is a valid LogLevel, false otherwise.
 */
export declare function isLogLevelValue(val: any): val is LogLevelValue;
export type TimePrefix = 'local' | 'utc' | 'elapsed' | false;
export declare function isValidTimePrefix(val: any): val is TimePrefix;
/**
 * Configuration options for the Logger.
 * @typedef {Object} LoggerOptions
 * @property {boolean} [enableStyles] - Whether to enable styling of console messages. Defaults to false.
 * @property {Style} [style] - Custom Style instance to use for formatting. Defaults to the default style.
 * @property {LogLevel | LogLevelValue} [level] - The minimum log level to output.
 * @property {Integer} [tab] - The number of spaces to use for indentation. Defaults to 2.
 * @property {boolean} [levelPrefix] - Whether to prefix log messages with their level. Defaults to false.
 * @property {TimePrefix} [timePrefix] - The type of time prefix to use ('local', 'utc', 'elapsed', or false). Defaults to false.
 * @property {AppTimer} [elapsed] - Custom Elapsed instance for tracking time. Defaults to the elapsed time object.
 * @property {boolean} [keepLines] - Whether to keep log lines in memory instead of outputting immediately. Defaults to false.
 */
export type LoggerOptions = StyleOptions & {
    enableStyles?: boolean;
    style?: Style;
    level?: LogLevel | LogLevelValue;
    tab?: Integer;
    levelPrefix?: boolean;
    timePrefix?: TimePrefix;
    appTimer?: AppTimer;
    keepLines?: boolean;
};
/**
 * Logger class
 * @example
 * ```typescript
 * const log:LoggerInstance = new Logger();
 * log.info('Hello, world!');
 * ```
 */
export declare class Logger {
    protected _style: Style;
    protected _level: LogLevelValue;
    protected _tab: Integer;
    protected _levelPrefix: boolean;
    protected _timePrefix: TimePrefix;
    protected _appTimer: AppTimer;
    protected _pre: string[];
    protected _showElapsed: boolean;
    protected _keepLines: boolean;
    protected _lines: any[];
    [key: string]: ((val: any) => this) | any;
    /**
     * Constructor for the Logger class.
     * @param {LoggerOptions} options - The options for the logger.
     */
    constructor(options?: LoggerOptions);
    /**
     * Sets an alternate style for the logger.
     * @param {Style} style - The style to set.
     */
    setStyle(style: Style): this;
    /**
     * Gets the current style.
     * @returns {Style} The current style.
     */
    get style(): Style;
    /**
     * Gets the lines stored in memory. Only applicable if keepLines is true.
     * @returns {string[]} The lines stored in memory.
     */
    get lines(): string[];
    /**
     * Sets the log level.
     * @param {LogLevel | 'trace' | 'debug' | 'verbose' | 'info' | 'error'} level - The log level to set.
     * @returns {this} The Logger instance.
     */
    setLevel(level: LogLevel | LogLevelValue): this;
    /**
     * Gets the current log level.
     * @returns {LogLevel} The current log level.
     */
    get level(): LogLevelValue;
    /**
     * Sets whether to include a prefix with the log level.
     * @param {boolean} val - Whether to include a prefix with the log level.
     * @returns {this} The Logger instance.
     */
    setLevelPrefix(val: boolean): this;
    /**
     * Sets the number of spaces to use for indentation.
     * @param {Integer} val - The number of spaces to use for indentation.
     * @returns {this} The Logger instance.
     */
    setTab(val: Integer): this;
    /**
     * Sets the time prefix.
     * @param {TimePrefix} val - The time prefix to set.
     * @returns {this} The Logger instance.
     */
    setTimePrefix(val: TimePrefix): this;
    /**
     * Sets the elapsed time object.
     * @param {AppTimer} val - The elapsed time object to set.
     * @returns {this} The Logger instance.
     */
    setAppTimer(val: AppTimer): this;
    /**
     * Sets whether to keep lines in memory rather than outputting them immediately to the console.
     * @param {boolean} val - Whether to keep lines in memory.
     * @returns {this} The Logger instance.
     */
    setKeepLines(val: boolean): this;
    /**
     * Checks if the logger is enabled for the given log level. This can eliminate
     * running logging code if the log level is not enabled and the logging would
     * not be output anyway.
     * @param {LogLevel} val - The log level to check.
     * @returns {boolean} True if the logger is enabled for the given level, false
     * otherwise.
     */
    isEnabledFor(val: LogLevel | LogLevelValue): boolean;
    /**
     * Enables elapsed time logging for this line of output, which will result in
     * the elapsed time being output at the end the log line.
     * @returns {this} The Logger instance.
     * @throws {Error} If elapsed time logging is already enabled.
     */
    elapsed(): this;
    clearLines(): this;
    /**
     * Clears the logger's internal state, essentially resetting the output line.
     * @returns {this} The Logger instance.
     */
    clearLine(): this;
    /**
     * Adds stringified data to the log message. This text will be formatted with
     * the default style.
     * @param {any} arg - The data to stringify and add.
     * @returns {this} The Logger instance.
     */
    data(arg: any): this;
    /**
     * Indents the log message by this many characters or the string to indent with.
     * @param {Integer | string} n - The number of spaces to indent or the string to indent with.
     * @returns {this} The Logger instance.
     */
    indent(n?: Integer | string): this;
    /**
     * Adds indented text to the log message.
     * @param {Integer} n - The number of tabs by which to indent.
     * @returns {this} The Logger instance.
     */
    tab(n?: Integer): this;
    /**
     * Adds indented text to the log message. 'res' stands for 'response', and
     * might be used to indent the response to an action.
     * @param {...any[]} args - The text arguments to add.
     * @returns {this} The Logger instance.
     * @deprecated Use indent() instead.
     */
    res(...args: any[]): this;
    /**
     * Adds double-indented text to the log message.
     * @param {...any[]} args - The text arguments to add.
     * @returns {this} The Logger instance.
     * @deprecated Use indent() instead.
     */
    res2(...args: any[]): this;
    /**
     * Adds styled text to the log message.
     * @param {any} val - The value to style.
     * @param {StyleName | StyleDef} style - The style to use.
     * @returns {this} The Logger instance.
     */
    stylize(style: StyleName | StyleDef, ...args: any[]): this;
    /**
     * Adds our dynamic style methods to the logger instance.
     * @returns {void}
     */
    addStyleMethods(): this;
    /**
     * Outputs a trace level log message if the current log level allows it.
     * @param {...any[]} args - The message arguments to log.
     * @returns {this} The Logger instance.
     */
    trace(...args: any[]): this;
    /**
     * Outputs a debug level log message if the current log level allows it.
     * @param {...any[]} args - The message arguments to log.
     * @returns {this} The Logger instance.
     */
    debug(...args: any[]): this;
    /**
     * Outputs a verbose level log message if the current log level allows it.
     * @param {...any[]} args - The message arguments to log.
     * @returns {this} The Logger instance.
     */
    verbose(...args: any[]): this;
    /**
     * Outputs an info level log message if the current log level allows it.
     * @param {...any[]} args - The message arguments to log.
     * @returns {this} The Logger instance.
     */
    info(...args: any[]): this;
    /**
     * Outputs a warn level log message if the current log level allows it.
     * @param {...any[]} args - The message arguments to log.
     * @returns {this} The Logger instance.
     */
    warn(...args: any[]): this;
    /**
     * Outputs an error level log message if the current log level allows it.
     * @param {...any[]} args - The message arguments to log.
     * @returns {this} The Logger instance.
     */
    error(...args: any[]): this;
    protected addPrefix(level: string): this;
    /**
     * Outputs the log message.
     * @param {...any[]} args - The message arguments to log.
     * @returns {this} The Logger instance.
     */
    output(...args: any[]): this;
    /**
     * Placeholder method for skipping log messages.
     * @param {any} val - The value to potentially skip.
     * @returns {boolean} Always returns false in this implementation.
     */
    skip(val: any): boolean;
}
export type LoggerInstance = Logger & Record<StyleName, (...args: any[]) => Logger>;