text: /*
   Licensed to OffGrid Networks (OGN) under one
   or more contributor license agreements.  See the NOTICE file
   distributed with this work for additional information
   regarding copyright ownership.  OGN licenses this file
   to you under the Apache License, Version 2.0 (the
   "License"); you may not use this file except in compliance
   with the License.  You may obtain a copy of the License at
  
   http://apache.org/licenses/LICENSE-2.0
  
   Unless required by applicable law or agreed to in writing,
   software distributed under the License is distributed on an
   "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
   KIND, either express or implied.  See the License for the
   specific language governing permissions and limitations
   under the License.
   */
  
  var ansi = require('ansi');
  var EventEmitter = require('events').EventEmitter;
  var NodeKitError = require('./NodeKitError/NodeKitError');
  var EOL = require('os').EOL;
  
  var INSTANCE;
  
  /**
   * @class NodeKitLogger
   *
   * Implements logging facility that anybody could use. Should not be
   *   instantiated directly, `NodeKitLogger.get()` method should be used instead
   *   to acquire logger instance
   */
  function NodeKitLogger () {
      this.levels = {};
      this.colors = {};
      this.stdout = process.stdout;
      this.stderr = process.stderr;
  
      this.stdoutCursor = ansi(this.stdout);
      this.stderrCursor = ansi(this.stderr);
  
      this.addLevel('verbose', 1000, 'grey');
      this.addLevel('normal' , 2000);
      this.addLevel('warn'   , 2000, 'yellow');
      this.addLevel('info'   , 3000, 'blue');
      this.addLevel('error'  , 5000, 'red');
      this.addLevel('results' , 10000);
  
      this.setLevel('normal');
  }
  
  /**
   * Static method to create new or acquire existing instance.
   *
   * @return  {NodeKitLogger}  Logger instance
   */
  NodeKitLogger.get = function () {
      return INSTANCE || (INSTANCE = new NodeKitLogger());
  };
  
  NodeKitLogger.VERBOSE = 'verbose';
  NodeKitLogger.NORMAL = 'normal';
  NodeKitLogger.WARN = 'warn';
  NodeKitLogger.INFO = 'info';
  NodeKitLogger.ERROR = 'error';
  NodeKitLogger.RESULTS = 'results';
  
  /**
   * Emits log message to process' stdout/stderr depending on message's severity
   *   and current log level. If severity is less than current logger's level,
   *   then the message is ignored.
   *
   * @param   {String}  logLevel  The message's log level. The logger should have
   *   corresponding level added (via logger.addLevel), otherwise
   *   `NodeKitLogger.NORMAL` level will be used.
   * @param   {String}  message   The message, that should be logged to process'
   *   stdio
   *
   * @return  {NodeKitLogger}     Current instance, to allow calls chaining.
   */
  NodeKitLogger.prototype.log = function (logLevel, message) {
      // if there is no such logLevel defined, or provided level has
      // less severity than active level, then just ignore this call and return
      if (!this.levels[logLevel] || this.levels[logLevel] < this.levels[this.logLevel])
          // return instance to allow to chain calls
          return this;
  
      var isVerbose = this.logLevel === 'verbose';
      var cursor = this.stdoutCursor;
  
      if (message instanceof Error || logLevel === NodeKitLogger.ERROR) {
          message = formatError(message, isVerbose);
          cursor = this.stderrCursor;
      }
  
      var color = this.colors[logLevel];
      if (color) {
          cursor.bold().fg[color]();
      }
  
      cursor.write(message).reset().write(EOL);
  
      return this;
  };
  
  /**
   * Adds a new level to logger instance. This method also creates a shortcut
   *   method to log events with the level provided (i.e. after adding new level
   *   'debug', the method `debug(message)`, equal to logger.log('debug', message),
   *   will be added to logger instance)
   *
   * @param  {String}  level     A log level name. The levels with the following
   *   names added by default to every instance: 'verbose', 'normal', 'warn',
   *   'info', 'error', 'results'
   * @param  {Number}  severity  A number that represents level's severity.
   * @param  {String}  color     A valid color name, that will be used to log
   *   messages with this level. Any CSS color code or RGB value is allowed
   *   (according to ansi documentation:
   *   https://github.com/TooTallNate/ansi.js#features)
   *
   * @return  {NodeKitLogger}     Current instance, to allow calls chaining.
   */
  NodeKitLogger.prototype.addLevel = function (level, severity, color) {
  
      this.levels[level] = severity;
  
      if (color) {
          this.colors[level] = color;
      }
  
      // Define own method with corresponding name
      if (!this[level]) {
          this[level] = this.log.bind(this, level);
      }
  
      return this;
  };
  
  /**
   * Sets the current logger level to provided value. If logger doesn't have level
   *   with this name, `NodeKitLogger.NORMAL` will be used.
   *
   * @param  {String}  logLevel  Level name. The level with this name should be
   *   added to logger before.
   *
   * @return  {NodeKitLogger}     Current instance, to allow calls chaining.
   */
  NodeKitLogger.prototype.setLevel = function (logLevel) {
      this.logLevel = this.levels[logLevel] ? logLevel : NodeKitLogger.NORMAL;
  
      return this;
  };
  
  /**
   * Adjusts the current logger level according to the passed options.
   *
   * @param   {Object|Array}  opts  An object or args array with options
   *
   * @return  {NodeKitLogger}     Current instance, to allow calls chaining.
   */
  NodeKitLogger.prototype.adjustLevel = function (opts) {
      if (opts.verbose || (Array.isArray(opts) && opts.indexOf('--verbose') !== -1)) {
          this.setLevel('verbose');
      } else if (opts.silent || (Array.isArray(opts) && opts.indexOf('--silent') !== -1)) {
          this.setLevel('error');
      }
  
      return this;
  };
  
  /**
   * Attaches logger to EventEmitter instance provided.
   *
   * @param   {EventEmitter}  eventEmitter  An EventEmitter instance to attach
   *   logger to.
   *
   * @return  {NodeKitLogger}     Current instance, to allow calls chaining.
   */
  NodeKitLogger.prototype.subscribe = function (eventEmitter) {
  
      if (!(eventEmitter instanceof EventEmitter))
          throw new Error('Subscribe method only accepts an EventEmitter instance as argument');
  
      eventEmitter.on('verbose', this.verbose)
          .on('log', this.normal)
          .on('info', this.info)
          .on('warn', this.warn)
          .on('warning', this.warn)
          // Set up event handlers for logging and results emitted as events.
          .on('results', this.results);
  
      return this;
  };
  
  function formatError(error, isVerbose) {
      var message = '';
  
      if (error instanceof NodeKitError) {
          message = error.toString(isVerbose);
      } else if (error instanceof Error) {
          if (isVerbose) {
              message = error.stack;
          } else {
              message = error.message;
          }
      } else {
          // Plain text error message
          message = error;
      }
  
      if (typeof message === 'string' && message.toUpperCase().indexOf('ERROR:') !== 0) {
          // Needed for backward compatibility with external tools
          message = 'Error: ' + message;
      }
  
      return message;
  }
  
  module.exports = NodeKitLogger;
  