var redis = require("redis");
var util = require('util');
var EventEmitter = require('events').EventEmitter;
var exec = require('child_process').exec;

var redisprefix = "ippoll:";

var IpPoll = function(switchaddr, hostsaddr) {
    var self = this;

    var redisClient = redis.createClient();
    var regexp = /\(([0-9]+) hosts* up\)/;
    var nmap = "nmap -n -sP -T4 ";

    redisClient.on("connect", function () {
        console.log("connected to redis");
        self.emit('ready');
    });

    this.pollCount = function() {
        exec(nmap + "--min-hostgroup 10 " + hostsaddr, function (error, stdout, stderr) {
            if(error == null) {
                var matches = regexp.exec(stdout);
                if(matches != null && matches.length == 2) {
                    var time = Date.now();

                    redisClient.zremrangebyscore(redisprefix + 'onlinecount', "-inf", time - 7*24*60*1000);

                    var num = matches[1];

                    redisClient.zadd(redisprefix + 'onlinecount', time, time + "|" + num, function() {
                        self.emit('doneCount', parseInt(num));
                    });
                }
            }
        });
    };

    this.pollState = function() {
        exec(nmap + switchaddr, function (error, stdout, stderr) {
            if(error == null) {
                var matches = regexp.exec(stdout);
                if(matches != null && matches.length == 2) {
                    self.emit('doneState', matches[1] == "1");
                }
            } else {
                self.emit('doneState', "unknown");
            }
        });
    };

    this.getHistory = function(start, end, callback) {

        redisClient.zrangebyscore(redisprefix + 'onlinecount', "-inf", "+inf", function(err, replies) {
            var data = [];

            replies.forEach(function (reply, i) {
                var line = reply.split('|');
                data.push( { at: moment(parseInt(line[0])).format(), value: line[1] });
            });

            callback(data);
        });
    };
};

util.inherits(IpPoll, EventEmitter);

module.exports = IpPoll;