// https://github.com/ben-bradley/ping-lite/blob/master/ping-lite.js
// Fixed on Windows

var spawn = require('child_process').spawn,
    events = require('events'),
    fs = require('fs'),
    WIN = /^win/.test(process.platform),
    LIN = /^linux/.test(process.platform),
    MAC = /^darwin/.test(process.platform);

module.exports = Ping;

function Ping(host, options) {
    if (!host)
        throw new Error('You must specify a host to ping!');

    this._host = host;
    this._options = options = (options || {});

    events.EventEmitter.call(this);

    if (WIN) {
        this._bin = 'c:/windows/system32/ping.exe';
        this._args = (options.args) ? options.args : [ '-n', '1', '-w', '5000', host ];
        this._regmatch = /[><=]([0-9.]+?)ms/;
    }
    else if (LIN) {
        this._bin = '/bin/ping';
        this._args = (options.args) ? options.args : [ '-n', '-w', '2', '-c', '1', host ];
        this._regmatch = /=([0-9.]+?) ms/; // need to verify this
    }
    else if (MAC) {
        this._bin = '/sbin/ping';
        this._args = (options.args) ? options.args : [ '-n', '-t', '2', '-c', '1', host ];
        this._regmatch = /=([0-9.]+?) ms/;
    }
    else {
        throw new Error('Could not detect your ping binary.');
    }

    if (!fs.existsSync(this._bin))
        throw new Error('Could not detect '+this._bin+' on your system');

    this._i = 0;

    return this;
}

Ping.prototype.__proto__ = events.EventEmitter.prototype;

// SEND A PING
// ===========
Ping.prototype.send = function(callback) {
    var self = this;
    callback = callback || function(err, ms) {
        if (err) return self.emit('error', err);
        else     return self.emit('result', ms);
    };

    var _ended, _exited, _errored;

    this._ping = spawn(this._bin, this._args); // spawn the binary

    this._ping.on('error', function(err) { // handle binary errors
        _errored = true;
        callback(err);
    });

    this._ping.stdout.on('data', function(data) { // log stdout
        this._stdout = (this._stdout || '') + data;
    });

    this._ping.stdout.on('end', function() {
        _ended = true;
        if (_exited && !_errored) onEnd.call(self._ping);
    });

    this._ping.stderr.on('data', function(data) { // log stderr
        this._stderr = (this._stderr || '') + data;
    });

    this._ping.on('exit', function(code) { // handle complete
        _exited = true;
        if (_ended && !_errored) onEnd.call(self._ping);
    });

    function onEnd() {
        var stdout = this.stdout._stdout,
            stderr = this.stderr._stderr,
            ms;

        if (stderr)
            return callback(new Error(stderr));
        else if (!stdout)
            return callback(new Error('No stdout detected'));

        ms = stdout.match(self._regmatch); // parse out the ##ms response
        ms = (ms && ms[1]) ? Number(ms[1]) : ms;

        callback(null, ms);
    }
};

// CALL Ping#send(callback) ON A TIMER
// ===================================
Ping.prototype.start = function(callback) {
    var self = this;
    this._i = setInterval(function() {
        self.send(callback);
    }, (self._options.interval || 5000));
    self.send(callback);
};

// STOP SENDING PINGS
// ==================
Ping.prototype.stop = function() {
    clearInterval(this._i);
};