text: /**
   * Copyright JS Foundation and other contributors, http://js.foundation
   *
   * Licensed 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://www.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 util = require("util");
  var EventEmitter = require("events").EventEmitter;
  
  var redUtil = require("@node-red/util").util;
  var Log = require("@node-red/util").log;
  var context = require("./context");
  var flows = require("./flows");
  
  const NOOP_SEND = function() {}
  
  /**
   * The Node object is the heart of a Node-RED flow. It is the object that all
   * nodes extend.
   *
   * The Node object itself inherits from EventEmitter, although it provides
   * custom implementations of some of the EE functions in order to handle
   * `input` and `close` events properly.
   */
  function Node(n) {
      this.id = n.id;
      this.type = n.type;
      this.z = n.z;
      this._closeCallbacks = [];
      this._inputCallback = null;
      this._inputCallbacks = null;
  
      if (n.name) {
          this.name = n.name;
      }
      if (n._alias) {
          this._alias = n._alias;
      }
      if (n._flow) {
          // Make this a non-enumerable property as it may cause
          // circular references. Any existing code that tries to JSON serialise
          // the object (such as dashboard) will not like circular refs
          // The value must still be writable in the case that a node does:
          //     Object.assign(this,config)
          // as part of its constructure - config._flow will overwrite this._flow
          // which we can tolerate as they are the same object.
          Object.defineProperty(this,'_flow', {value: n._flow, enumerable: false, writable: true })
          this._asyncDelivery = n._flow.asyncMessageDelivery;
      }
      if (this._asyncDelivery === undefined) {
          this._asyncDelivery = true;
      }
      this.updateWires(n.wires);
  }
  
  util.inherits(Node, EventEmitter);
  
  /**
   * Update the wiring configuration for this node.
   *
   * We try to optimise the message handling path. To do this there are three
   * cases to consider:
   *  1. this node is wired to nothing. In this case we replace node.send with a
   *     NO-OP function.
   *  2. this node is wired to one other node. In this case we set `this._wire`
   *     as a reference to the node it is wired to. This means we avoid unnecessary
   *     iterations over what would otherwise be a 1-element array.
   *  3. this node is wired to multiple things. The normal node.send processing of
   *     this.wires applies.
   *
   * @param  {array} wires the new wiring configuration
   */
  Node.prototype.updateWires = function(wires) {
      //console.log("UPDATE",this.id);
      this.wires = wires || [];
      delete this._wire;
  
      var wc = 0;
      this.wires.forEach(function(w) {
          wc+=w.length;
      });
      this._wireCount = wc;
      if (wc === 0) {
          // With nothing wired to the node, no-op send
          this.send = NOOP_SEND
      } else {
          this.send = Node.prototype.send;
          if (this.wires.length === 1 && this.wires[0].length === 1) {
              // Single wire, so we can shortcut the send when
              // a single message is sent
              this._wire = this.wires[0][0];
          }
      }
  
  }
  /**
   * Get the context object for this node.
   *
   * As most nodes do not use context, this is a lazy function that will only
   * create a context instance for the node if it is needed.
   * @return {object} the context object
   */
  Node.prototype.context = function() {
      if (!this._context) {
          this._context = context.get(this._alias||this.id,this.z);
      }
      return this._context;
  }
  
  /**
   * Handle the complete event for a message
   *
   * @param  {object} msg  The message that has completed
   * @param  {error} error (optional) an error hit whilst handling the message
   */
  Node.prototype._complete = function(msg,error) {
      if (error) {
          // For now, delegate this to this.error
          // But at some point, the timeout handling will need to know about
          // this as well.
          this.error(error,msg);
      } else {
          this._flow.handleComplete(this,msg);
      }
  }
  
  /**
   * An internal reference to the original EventEmitter.on() function
   */
  Node.prototype._on = Node.prototype.on;
  
  /**
   * Register a callback function for a named event.
   * 'close' and 'input' events are handled locally, other events defer to EventEmitter.on()
   */
  Node.prototype.on = function(event, callback) {
      var node = this;
      if (event == "close") {
          this._closeCallbacks.push(callback);
      } else if (event === "input") {
          if (this._inputCallback) {
              this._inputCallbacks = [this._inputCallback, callback];
              this._inputCallback = null;
          } else if (this._inputCallbacks) {
              this._inputCallbacks.push(callback);
          } else {
              this._inputCallback = callback;
          }
      } else {
          this._on(event, callback);
      }
  };
  
  /**
   * An internal reference to the original EventEmitter.emit() function
   */
  Node.prototype._emit = Node.prototype.emit;
  
  /**
   * Emit an event to all registered listeners.
   */
  Node.prototype.emit = function(event, ...args) {
      var node = this;
      if (event === "input") {
          // When Pluggable Message Routing arrives, this will be called from
          // that and will already be sync/async depending on the router.
          if (this._asyncDelivery) {
              setImmediate(function() {
                  node._emitInput.apply(node,args);
              });
          } else {
              this._emitInput.apply(this,args);
          }
      } else {
          this._emit.apply(this,arguments);
      }
  }
  
  /**
   * Handle the 'input' event.
   *
   * This will call all registered handlers for the 'input' event.
   */
  Node.prototype._emitInput = function(arg) {
      var node = this;
      if (node._inputCallback) {
          // Just one callback registered.
          try {
              node._inputCallback(
                  arg,
                  function() { node.send.apply(node,arguments) },
                  function(err) { node._complete(arg,err); }
              );
          } catch(err) {
              node.error(err,arg);
          }
      } else if (node._inputCallbacks) {
          // Multiple callbacks registered. Call each one, tracking eventual completion
          var c = node._inputCallbacks.length;
          for (var i=0;i<c;i++) {
              var cb = node._inputCallbacks[i];
              if (cb.length === 2) {
                  c++;
              }
              try {
                  node._inputCallbacks[i](
                      arg,
                      function() { node.send.apply(node,arguments) },
                      function(err) {
                          c--;
                          if (c === 0) {
                              node._complete(arg,err);
                          }
                      }
                  );
              } catch(err) {
                  node.error(err,msg);
              }
          }
      }
  }
  
  /**
   * An internal reference to the original EventEmitter.removeListener() function
   */
  Node.prototype._removeListener = Node.prototype.removeListener;
  
  /**
   * Remove a listener for an event
   */
  Node.prototype.removeListener = function(name, listener) {
      var index;
      if (name === "input") {
          if (this._inputCallback && this._inputCallback === listener) {
              // Removing the only callback
              this._inputCallback = null;
          } else if (this._inputCallbacks) {
              // Removing one of many callbacks
              index = this._inputCallbacks.indexOf(listener);
              if (index > -1) {
                  this._inputCallbacks.splice(index,1);
              }
              // Check if we can optimise back to a single callback
              if (this._inputCallbacks.length === 1) {
                  this._inputCallback = this._inputCallbacks[0];
                  this._inputCallbacks = null;
              }
          }
      } else if (name === "close") {
          index = this._closeCallbacks.indexOf(listener);
          if (index > -1) {
              this._closeCallbacks.splice(index,1);
          }
      } else {
          this._removeListener(name, listener);
      }
  }
  
  /**
   * An internal reference to the original EventEmitter.removeAllListeners() function
   */
  Node.prototype._removeAllListeners = Node.prototype.removeAllListeners;
  
  /**
   * Remove all listeners for an event
   */
  Node.prototype.removeAllListeners = function(name) {
      if (name === "input") {
          this._inputCallback = null;
          this._inputCallbacks = null;
      } else if (name === "close") {
          this._closeCallbacks = [];
      } else {
          this._removeAllListeners(name);
      }
  }
  
  /**
   * Called when the node is being stopped
   * @param  {boolean} removed Whether the node has been removed, or just being stopped
   * @return {Promise} resolves when the node has closed
   */
  Node.prototype.close = function(removed) {
      //console.log(this.type,this.id,removed);
      var promises = [];
      var node = this;
      // Call all registered close callbacks.
      for (var i=0;i<this._closeCallbacks.length;i++) {
          var callback = this._closeCallbacks[i];
          if (callback.length > 0) {
              // The callback takes a 'done' callback and (maybe) the removed flag
              promises.push(
                  new Promise((resolve) => {
                      try {
                          var args = [];
                          if (callback.length === 2) {
                              // The listener expects the removed flag
                              args.push(!!removed);
                          }
                          args.push(() => {
                              resolve();
                          });
                          callback.apply(node, args);
                      } catch(err) {
                          // TODO: error thrown in node async close callback
                          // We've never logged this properly.
                          resolve();
                      }
                  })
              );
          } else {
              // No done callback so handle synchronously
              try {
                  callback.call(node);
              } catch(err) {
                  // TODO: error thrown in node sync close callback
                  // We've never logged this properly.
              }
          }
      }
      if (promises.length > 0) {
          return Promise.all(promises).then(function() {
              if (this._context) {
                 return context.delete(this._alias||this.id,this.z);
              }
          });
      } else {
          if (this._context) {
              return context.delete(this._alias||this.id,this.z);
          }
          return Promise.resolve();
      }
  };
  
  /**
   * Send a message to the nodes wired.
   *
   *
   * @param  {object} msg A message or array of messages to send
   */
  Node.prototype.send = function(msg) {
      var msgSent = false;
      var node;
  
      if (msg === null || typeof msg === "undefined") {
          return;
      } else if (!util.isArray(msg)) {
          if (this._wire) {
              // A single message and a single wire on output 0
              // TODO: pre-load flows.get calls - cannot do in constructor
              //       as not all nodes are defined at that point
              if (!msg._msgid) {
                  msg._msgid = redUtil.generateId();
              }
              this.metric("send",msg);
              node = this._flow.getNode(this._wire);
              /* istanbul ignore else */
              if (node) {
                  node.receive(msg);
              }
              return;
          } else {
              msg = [msg];
          }
      }
  
      var numOutputs = this.wires.length;
  
      // Build a list of send events so that all cloning is done before
      // any calls to node.receive
      var sendEvents = [];
  
      var sentMessageId = null;
  
      // for each output of node eg. [msgs to output 0, msgs to output 1, ...]
      for (var i = 0; i < numOutputs; i++) {
          var wires = this.wires[i]; // wires leaving output i
          /* istanbul ignore else */
          if (i < msg.length) {
              var msgs = msg[i]; // msgs going to output i
              if (msgs !== null && typeof msgs !== "undefined") {
                  if (!util.isArray(msgs)) {
                      msgs = [msgs];
                  }
                  var k = 0;
                  // for each recipent node of that output
                  for (var j = 0; j < wires.length; j++) {
                      node = this._flow.getNode(wires[j]); // node at end of wire j
                      if (node) {
                          // for each msg to send eg. [[m1, m2, ...], ...]
                          for (k = 0; k < msgs.length; k++) {
                              var m = msgs[k];
                              if (m !== null && m !== undefined) {
                                  /* istanbul ignore else */
                                  if (!sentMessageId) {
                                      sentMessageId = m._msgid;
                                  }
                                  if (msgSent) {
                                      var clonedmsg = redUtil.cloneMessage(m);
                                      sendEvents.push({n:node,m:clonedmsg});
                                  } else {
                                      sendEvents.push({n:node,m:m});
                                      msgSent = true;
                                  }
                              }
                          }
                      }
                  }
              }
          }
      }
      /* istanbul ignore else */
      if (!sentMessageId) {
          sentMessageId = redUtil.generateId();
      }
      this.metric("send",{_msgid:sentMessageId});
  
      for (i=0;i<sendEvents.length;i++) {
          var ev = sendEvents[i];
          /* istanbul ignore else */
          if (!ev.m._msgid) {
              ev.m._msgid = sentMessageId;
          }
          ev.n.receive(ev.m);
      }
  };
  
  /**
   * Receive a message.
   *
   * This will emit the `input` event with the provided message.
   * As of 1.0, this will return *before* any 'input' callback handler is invoked.
   */
  Node.prototype.receive = function(msg) {
      if (!msg) {
          msg = {};
      }
      if (!msg._msgid) {
          msg._msgid = redUtil.generateId();
      }
      this.metric("receive",msg);
      this.emit("input",msg);
  };
  
  function log_helper(self, level, msg) {
      var o = {
          level: level,
          id: self.id,
          type: self.type,
          msg: msg
      };
      if (self._alias) {
          o._alias = self._alias;
      }
      if (self.z) {
          o.z = self.z;
      }
      if (self.name) {
          o.name = self.name;
      }
      Log.log(o);
  }
  /**
   * Log an INFO level message
   */
  Node.prototype.log = function(msg) {
      log_helper(this, Log.INFO, msg);
  };
  
  /**
   * Log a WARN level message
   */
  Node.prototype.warn = function(msg) {
      log_helper(this, Log.WARN, msg);
  };
  
  /**
   * Log an ERROR level message
   */
  Node.prototype.error = function(logMessage,msg) {
      if (typeof logMessage != 'boolean') {
          logMessage = logMessage || "";
      }
      var handled = false;
      if (msg && typeof msg === 'object') {
          handled = this._flow.handleError(this,logMessage,msg);
      }
      if (!handled) {
          log_helper(this, Log.ERROR, logMessage);
      }
  };
  
  /**
   * Log an DEBUG level message
   */
  Node.prototype.debug = function(msg) {
      log_helper(this, Log.DEBUG, msg);
  }
  
  /**
   * Log an TRACE level message
   */
  Node.prototype.trace = function(msg) {
      log_helper(this, Log.TRACE, msg);
  }
  
  /**
   * Log a metric event.
   * If called with no args, returns whether metric collection is enabled
   */
  Node.prototype.metric = function(eventname, msg, metricValue) {
      if (typeof eventname === "undefined") {
          return Log.metric();
      }
      var metrics = {};
      metrics.level = Log.METRIC;
      metrics.nodeid = this.id;
      metrics.event = "node."+this.type+"."+eventname;
      metrics.msgid = msg._msgid;
      metrics.value = metricValue;
      Log.log(metrics);
  }
  
  /**
   * Set the node's status object
   *
   * status: { fill:"red|green", shape:"dot|ring", text:"blah" }
   * or
   * status: "simple text status"
   */
  Node.prototype.status = function(status) {
      switch (typeof status) {
          case "string":
          case "number":
          case "boolean":
              status = {text:""+status}
      }
      this._flow.handleStatus(this,status);
  };
  
  module.exports = Node;
  