text: /*
   * logger.js: Core logger object used by winston.
   *
   * (C) 2010 Charlie Robbins
   * MIT LICENCE
   *
   */
   
  var events = require('events'),
      util = require('util'),
      async = require('async'),
      config = require('./config'),
      common = require('./common'),
      exception = require('./exception');
  
  //
  // Time constants
  //
  var ticksPerMillisecond = 10000;
  
  //
  // ### function Logger (options)
  // #### @options {Object} Options for this instance.
  // Constructor function for the Logger object responsible
  // for persisting log messages and metadata to one or more transports.
  //
  var Logger = exports.Logger = function (options) {
    events.EventEmitter.call(this);
    options = options || {};
    
    var self = this,
        handleExceptions = false;
    
    //
    // Set Levels and default logging level
    //
    this.padLevels = options.padLevels || false;
    this.setLevels(options.levels);
    if (options.colors) {
      config.addColors(options.colors);
    }
    
    //
    // Hoist other options onto this instance.
    //
    this.level       = options.level || 'info';
    this.emitErrs    = options.emitErrs || false;
    this.stripColors = options.stripColors || false;
    this.exitOnError = typeof options.exitOnError !== 'undefined' 
      ? options.exitOnError 
      : true;
    
    //
    // Setup other intelligent default settings.
    //
    this.transports        = {};
    this.rewriters         = [];
    this.exceptionHandlers = {};
    this.profilers         = {};
    this._names            = [];
    this._hnames           = [];
  
    if (options.transports) {
      options.transports.forEach(function (transport) {
        self.add(transport, null, true);
        
        if (transport.handleExceptions) {
          handleExceptions = true;
        }
      });
    }
    
    if (options.rewriters) {
      options.rewriters.forEach(function(rewriter) {
        self.addRewriter(rewriter);
      });
    }
    
    if (options.exceptionHandlers) {
      handleExceptions = true;
      options.exceptionHandlers.forEach(function (handler) {
        self._hnames.push(handler.name);
        self.exceptionHandlers[handler.name] = handler;
      });
    }
    
    if (options.handleExceptions || handleExceptions) {
      this.handleExceptions();
    }
  };
  
  //
  // Inherit from `events.EventEmitter`.
  //
  util.inherits(Logger, events.EventEmitter);
  
  //
  // ### function extend (target)
  // #### @target {Object} Target to extend.
  // Extends the target object with a 'log' method
  // along with a method for each level in this instance.
  //
  Logger.prototype.extend = function (target) {
    var self = this;
    ['log', 'profile', 'startTimer'].concat(Object.keys(this.levels)).forEach(function (method) {
      target[method] = function () {
        return self[method].apply(self, arguments);
      };
    });
    
    return this;
  };
  
  //
  // ### function log (level, msg, [meta], callback)
  // #### @level {string} Level at which to log the message.
  // #### @msg {string} Message to log
  // #### @meta {Object} **Optional** Additional metadata to attach
  // #### @callback {function} Continuation to respond to when complete.
  // Core logging method exposed to Winston. Metadata is optional.
  //
  Logger.prototype.log = function (level, msg) {
    var self = this, 
        callback,
        meta;
    
    if (arguments.length === 3) {
      if (typeof arguments[2] === 'function') {
        meta = {};
        callback = arguments[2];
      }
      else if (typeof arguments[2] === 'object') {
        meta = arguments[2];
      }
    }
    else if (arguments.length === 4) {
      meta = arguments[2];
      callback = arguments[3];
    }
  
    // If we should pad for levels, do so
    if (this.padLevels) {
      msg = new Array(this.levelLength - level.length).join(' ') + msg;
    }
  
    function onError (err) {
      if (callback) {
        callback(err);
      }
      else if (self.emitErrs) {
        self.emit('error', err);
      };
    }
    
    if (this.transports.length === 0) {
      return onError(new Error('Cannot log with no transports.'));
    }
    else if (typeof self.levels[level] === 'undefined') {
      return onError(new Error('Unknown log level: ' + level));
    }
    
    this.rewriters.forEach(function(rewriter) {
      meta = rewriter(level, msg, meta);
    });
    
    //
    // For consideration of terminal 'color" programs like colors.js,
    // which can add ANSI escape color codes to strings, we destyle the 
    // ANSI color escape codes when `this.stripColors` is set.
    //
    // see: http://en.wikipedia.org/wiki/ANSI_escape_code
    //
    if (this.stripColors) {
      var code = /\u001b\[\d+m/g;
      msg = ('' + msg).replace(code, '');
    }
    
    for (var i = 0, l = this._names.length; i < l; i++) {
      var transport = this.transports[this._names[i]];
      if ((transport.level && self.levels[transport.level] <= self.levels[level])
        || (!transport.level && self.levels[self.level] <= self.levels[level])) {
        transport.log(level, msg, meta, function (err) {
          self.emit('logging', transport, level, msg, meta);
        });
      }
    }
    
    //
    // Immediately respond to the callback
    //
    if (callback) {
      callback(null, level, msg, meta);    
    }
    
    return this;
  };
  
  //
  // ### function close ()
  // Cleans up resources (streams, event listeners) for all
  // transports associated with this instance (if necessary).
  //
  Logger.prototype.close = function () {
    var self = this;
    
    this._names.forEach(function (name) {
      var transport = self.transports[name];
      if (transport && transport.close) {
        transport.close();
      }
    });
  };
  
  //
  // ### function handleExceptions () 
  // Handles `uncaughtException` events for the current process
  //
  Logger.prototype.handleExceptions = function () {
    var args = Array.prototype.slice.call(arguments),
        handlers = [],
        self = this;
        
    args.forEach(function (a) {
      if (Array.isArray(a)) {
        handlers = handlers.concat(a);
      }
      else {
        handlers.push(a);
      }
    });
    
    handlers.forEach(function (handler) {
      self.exceptionHandlers[handler.name] = handler;
    });
    
    this._hnames = Object.keys(self.exceptionHandlers);
      
    if (!this.catchExceptions) {
      this.catchExceptions = this._uncaughtException.bind(this);
      process.on('uncaughtException', this.catchExceptions);
    }
  };
  
  //
  // ### function unhandleExceptions () 
  // Removes any handlers to `uncaughtException` events
  // for the current process
  //
  Logger.prototype.unhandleExceptions = function () {
    var self = this;
    
    if (this.catchExceptions) {
      Object.keys(this.exceptionHandlers).forEach(function (name) {
        if (handler.close) {
          handler.close();
        }
      });
      
      this.exceptionHandlers = {};
      Object.keys(this.transports).forEach(function (name) {
        var transport = self.transports[name];
        if (transport.handleExceptions) {
          transport.handleExceptions = false;
        }
      })
      
      process.removeListener('uncaughtException', this.catchExceptions);
      this.catchExceptions = false;    
    }
  };
  
  //
  // ### function add (transport, [options])
  // #### @transport {Transport} Prototype of the Transport object to add.
  // #### @options {Object} **Optional** Options for the Transport to add.
  // #### @instance {Boolean} **Optional** Value indicating if `transport` is already instantiated.
  // Adds a transport of the specified type to this instance.
  //
  Logger.prototype.add = function (transport, options, created) {
    var instance = created ? transport : (new (transport)(options));
    
    if (!instance.name && !instance.log) {
      throw new Error('Unknown transport with no log() method');
    }
    else if (this.transports[instance.name]) {
      throw new Error('Transport already attached: ' + instance.name);
    }
    
    this.transports[instance.name] = instance;
    this._names = Object.keys(this.transports);
    
    //
    // Listen for the `error` event on the new Transport
    //
    instance._onError = this._onError.bind(this, instance)
    instance.on('error', instance._onError);
    
    //
    // If this transport has `handleExceptions` set to `true`
    // and we are not already handling exceptions, do so.
    //
    if (transport.handleExceptions && !this.catchExceptions) {
      this.handleExceptions();
    }
  
    return this;
  };
  
  //
  // ### function addRewriter (transport, [options])
  // #### @transport {Transport} Prototype of the Transport object to add.
  // #### @options {Object} **Optional** Options for the Transport to add.
  // #### @instance {Boolean} **Optional** Value indicating if `transport` is already instantiated.
  // Adds a transport of the specified type to this instance.
  //
  Logger.prototype.addRewriter = function(rewriter) {
    this.rewriters.push(rewriter);
  }
  
  //
  // ### function clear ()
  // Remove all transports from this instance
  //
  Logger.prototype.clear = function () {
    for (var name in this.transports) {
      this.remove({ name: name });
    }
  };
  
  //
  // ### function remove (transport) 
  // #### @transport {Transport} Transport to remove.
  // Removes a transport of the specified type from this instance.
  //
  Logger.prototype.remove = function (transport) {
    var name = transport.name || transport.prototype.name;
      
    if (!this.transports[name]) {
      throw new Error('Transport ' + name + ' not attached to this instance');
    }
    
    var instance = this.transports[name];
    delete this.transports[name];
    this._names = Object.keys(this.transports);
    
    if (instance.close) {
      instance.close();
    }
    
    instance.removeListener('error', instance._onError);
    return this;
  };
  
  var ProfileHandler = function (logger) {
    this.logger = logger;
  
    this.start = Date.now();
  
    this.done = function (msg) {
      var args, callback, meta;
      args     = Array.prototype.slice.call(arguments);
      callback = typeof args[args.length - 1] === 'function' ? args.pop() : null;
      meta     = typeof args[args.length - 1] === 'object' ? args.pop() : {};
     
      meta.duration = (Date.now()) - this.start + 'ms';
  
      return this.logger.info(msg, meta, callback);
    }
  }
  
  Logger.prototype.startTimer = function () {
    return new ProfileHandler(this);
  }
  
  //
  // ### function profile (id, [msg, meta, callback])
  // #### @id {string} Unique id of the profiler 
  // #### @msg {string} **Optional** Message to log
  // #### @meta {Object} **Optional** Additional metadata to attach
  // #### @callback {function} **Optional** Continuation to respond to when complete.
  // Tracks the time inbetween subsequent calls to this method
  // with the same `id` parameter. The second call to this method
  // will log the difference in milliseconds along with the message.
  //
  Logger.prototype.profile = function (id) {
    var now = Date.now(), then, args,
        msg, meta, callback;
    
    if (this.profilers[id]) {
      then = this.profilers[id];
      delete this.profilers[id];
      
      // Support variable arguments: msg, meta, callback
      args     = Array.prototype.slice.call(arguments);
      callback = typeof args[args.length - 1] === 'function' ? args.pop() : null;
      meta     = typeof args[args.length - 1] === 'object' ? args.pop() : {};
      msg      = args.length === 2 ? args[1] : id; 
      
      // Set the duration property of the metadata
      meta.duration = now - then + 'ms'; 
      return this.info(msg, meta, callback);
    }
    else {
      this.profilers[id] = now;
    }
    
    return this;
  };
  
  //
  // ### function setLevels (target)
  // #### @target {Object} Target levels to use on this instance
  // Sets the `target` levels specified on this instance.
  //
  Logger.prototype.setLevels = function (target) {
    return common.setLevels(this, this.levels, target);
  };
  
  //
  // ### function cli ()
  // Configures this instance to have the default
  // settings for command-line interfaces: no timestamp,
  // colors enabled, padded output, and additional levels.
  //
  Logger.prototype.cli = function () {
    this.padLevels = true;
    this.setLevels(config.cli.levels);
    config.addColors(config.cli.colors);
    
    if (this.transports.console) {
      this.transports.console.colorize = true;
      this.transports.console.timestamp = false;
    }
    
    return this;
  };
  
  //
  // ### @private function _uncaughtException (err) 
  // #### @err {Error} Error to handle
  // Logs all relevant information around the `err` and
  // exits the current process.
  //
  Logger.prototype._uncaughtException = function (err) {
    var self = this,
        responded = false,
        info = exception.getAllInfo(err),
        handlers = this._getExceptionHandlers(),
        timeout,
        doExit;
    
    //
    // Calculate if we should exit on this error
    //
    doExit = typeof this.exitOnError === 'function'
      ? this.exitOnError(err)
      : this.exitOnError;
    
    function logAndWait(transport, next) {
      transport.logException('uncaughtException', info, next);
    }
    
    function gracefulExit() {
      if (doExit && !responded) {
        //
        // Remark: Currently ignoring any exceptions from transports
        //         when catching uncaught exceptions.
        //
        clearTimeout(timeout);
        responded = true;
        process.exit(1);
      }
    }
    
    if (!handlers || handlers.length === 0) {
      return gracefulExit();
    }
    
    //
    // Log to all transports and allow the operation to take
    // only up to `3000ms`.
    //
    async.forEach(handlers, logAndWait, gracefulExit);
    if (doExit) {
      timeout = setTimeout(gracefulExit, 3000);
    }
  };
  
  //
  // ### @private function _getExceptionHandlers ()
  // Returns the list of transports and exceptionHandlers
  // for this instance.
  //
  Logger.prototype._getExceptionHandlers = function () {
    var self = this;
  
    return this._hnames.map(function (name) {
      return self.exceptionHandlers[name];
    }).concat(this._names.map(function (name) {
      return self.transports[name].handleExceptions && self.transports[name];
    })).filter(Boolean);
  };
  
  //
  // ### @private function _onError (transport, err)
  // #### @transport {Object} Transport on which the error occured
  // #### @err {Error} Error that occurred on the transport
  // Bubbles the error, `err`, that occured on the specified `transport`
  // up from this instance if `emitErrs` has been set.
  //
  Logger.prototype._onError = function (transport, err) {
    if (this.emitErrs) {
      this.emit('error', err, transport);
    }
  };
  