/// <reference types="node" />

import SMTPConnection = require('./smtp-connection');

import * as stream from 'stream';

export type LoggerLevel = 'trace' | 'debug' | 'info' | 'warn' | 'error' | 'fatal';

export interface Logger {
  level(level: LoggerLevel): void;
  trace(...params: any[]): void;
  debug(...params: any[]): void;
  info(...params: any[]): void;
  warn(...params: any[]): void;
  error(...params: any[]): void;
  fatal(...params: any[]): void;
}

/** Parses connection url to a structured configuration object */
export function parseConnectionUrl(url: string): SMTPConnection.Options;
/** Returns a bunyan-compatible logger interface. Uses either provided logger or creates a default console logger */
export function getLogger(options?: { [key: string]: any }, defaults?: { [key: string]: any }): Logger;
/** Wrapper for creating a callback than either resolves or rejects a promise based on input */
export function callbackPromise(resolve: (...args: any[]) => void, reject: (err: Error) => void): () => void;
/**
 * Resolves a String or a Buffer value for content value. Useful if the value
 * is a Stream or a file or an URL. If the value is a Stream, overwrites
 * the stream object with the resolved value (you can't stream a value twice).
 *
 * This is useful when you want to create a plugin that needs a content value,
 * for example the `html` or `text` value as a String or a Buffer but not as
 * a file path or an URL.
 */
export function resolveContent(data: object | any[], key: string | number, callback: (err: Error | null, value: Buffer | string) => void): void;
export function resolveContent(data: object | any[], key: string | number): Promise<Buffer | string>;
/** Copies properties from source objects to target objects */
export function assign(target: object, ...sources: object[]): object;
export function encodeXText(str: string): string;