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('onlinecount', "-inf", time - 7*24*60*1000);

					var num = matches[1];

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