/**
 * 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 mqtt = require("./mqtt");
var settings = require(process.env.NODE_RED_HOME+"/red/red").settings;

util.log("[warn] nodes/core/io/lib/mqttConnectionPool.js is deprecated and will be removed in a future release of Node-RED. Please report this usage to the Node-RED mailing list.");

var connections = {};

function matchTopic(ts,t) {
    if (ts == "#") {
        return true;
    }
    var re = new RegExp("^"+ts.replace(/([\[\]\?\(\)\\\\$\^\*\.|])/g,"\\$1").replace(/\+/g,"[^/]+").replace(/\/#$/,"(\/.*)?")+"$");
    return re.test(t);
}

module.exports = {
    get: function(broker,port,clientid,username,password,will) {
        var id = "["+(username||"")+":"+(password||"")+"]["+(clientid||"")+"]@"+broker+":"+port;
        if (!connections[id]) {
            connections[id] = function() {
                var uid = (1+Math.random()*4294967295).toString(16);
                var client = mqtt.createClient(port,broker);
                client.uid = uid;
                client.setMaxListeners(0);
                var options = {keepalive:15};
                options.clientId = clientid || 'mqtt_' + (1+Math.random()*4294967295).toString(16);
                options.username = username;
                options.password = password;
                options.will = will;
                var queue = [];
                var subscriptions = {};
                var connecting = false;
                var obj = {
                    _instances: 0,
                    publish: function(msg) {
                        if (client.isConnected()) {
                            client.publish(msg.topic,msg.payload,msg.qos,msg.retain);
                        } else {
                            if (!connecting) {
                                connecting = true;
                                client.connect(options);
                            }
                            queue.push(msg);
                        }
                    },
                    subscribe: function(topic,qos,callback,ref) {
                        ref = ref||0;
                        subscriptions[topic] = subscriptions[topic]||{};

                        var sub = {
                            topic:topic,
                            qos:qos,
                            handler:function(mtopic,mpayload,mqos,mretain) {
                                if (matchTopic(topic,mtopic)) {
                                    callback(mtopic,mpayload,mqos,mretain);
                                }
                            },
                            ref: ref
                        };
                        subscriptions[topic][ref] = sub;
                        client.on('message',sub.handler);
                        if (client.isConnected()) {
                            client.subscribe(topic,qos);
                        }
                    },
                    unsubscribe: function(topic,ref) {
                        ref = ref||0;
                        var sub = subscriptions[topic];
                        if (sub) {
                            if (sub[ref]) {
                                client.removeListener('message',sub[ref].handler);
                                delete sub[ref];
                            }
                            if (Object.keys(sub).length == 0) {
                                delete subscriptions[topic];
                                client.unsubscribe(topic);
                            }
                        }
                    },
                    on: function(a,b){
                        client.on(a,b);
                    },
                    once: function(a,b){
                        client.once(a,b);
                    },
                    connect: function() {
                        if (client && !client.isConnected() && !connecting) {
                            connecting = true;
                            client.connect(options);
                        }
                    },
                    disconnect: function(ref) {

                        this._instances -= 1;
                        if (this._instances == 0) {
                            client.disconnect();
                            client = null;
                            delete connections[id];
                        }
                    },
                    isConnected: function() {
                        return client.isConnected();
                    }
                };
                client.on('connect',function() {
                        if (client) {
                            util.log('[mqtt] ['+uid+'] connected to broker tcp://'+broker+':'+port);
                            connecting = false;
                            for (var s in subscriptions) {
                                var topic = s;
                                var qos = 0;
                                for (var r in subscriptions[s]) {
                                    qos = Math.max(qos,subscriptions[s][r].qos);
                                }
                                client.subscribe(topic,qos);
                            }
                            //console.log("connected - publishing",queue.length,"messages");
                            while(queue.length) {
                                var msg = queue.shift();
                                //console.log(msg);
                                client.publish(msg.topic,msg.payload,msg.qos,msg.retain);
                            }
                        }
                });
                client.on('connectionlost', function(err) {
                        util.log('[mqtt] ['+uid+'] connection lost to broker tcp://'+broker+':'+port);
                        connecting = false;
                        setTimeout(function() {
                            obj.connect();
                        }, settings.mqttReconnectTime||5000);
                });
                client.on('disconnect', function() {
                        connecting = false;
                        util.log('[mqtt] ['+uid+'] disconnected from broker tcp://'+broker+':'+port);
                });

                return obj
            }();
        }
        connections[id]._instances += 1;
        return connections[id];
    }
};