#!/usr/bin/perl
my @url_list = qw(http://www.xxxxx.de/
                  http://www.xxxxx.info/);
my $sleep_minutes = 1;
my $send_adress    = 'webservice@xxxxxxx.de';
my $notiy_adress_1 = 'office@xxxxxxxxx.de';
my $notiy_adress_2 = 'me@xxxxxxxxxxx.de';
my $mail_prog      = '/usr/sbin/sendmail -t';
my $base_dir       = '/home/xxxxxx/xxxxxxx';

#------------------ Run as daemon ---------------------------------#
#use Proc::Daemon;
#Proc::Daemon::Init;
#------------------------------------------------------------------#

use strict;
#use warnings;
#use diagnostics;
use LWP;
use LWP::UserAgent;
use Storable qw(lock_store lock_retrieve);
use File::Spec;
use FindBin;

sub send_notify_mail($$);
sub _get_file($);
my $emacs_neeed_this = {};

my $work_dir = $FindBin::Bin;

while(1){
    foreach my $url(@url_list){
        my $ua = LWP::UserAgent->new();
        $ua->agent("Server-Control/0.1, powered by KFSW");
        $ua->timeout(15);
        my $req = HTTP::Request->new(GET => $url);
        my $res = $ua->request($req);
        my $file = _get_file($url);
        my $data;
        if(-f $file){
            $data = lock_retrieve($file);
        }else{
            $data = {};
            $data->{'status'}       = 'offline';
            $data->{'off_notified'} = 'no';
            $data->{'on_notified'}  = 'no';
            $data->{'time'}         = time();
        }
        if($res->is_success){
            $data->{'status'} = 'online';
            $data->{'time'}   = time();
            unless($data->{'on_notified'} eq 'yes'){
                my $res = send_notify_mail($url,'online');
                if($res){
                    $data->{'on_notified'}  = 'yes';
                    $data->{'off_notified'} = 'no';
                }
            }
            print "$url Still running \n";
        }else{
            unless($data->{'off_notified'} eq 'yes'){
                my $res = send_notify_mail($url,'offline');
                if($res){
                    $data->{'off_notified'} = 'yes';
                    $data->{'on_notified'}  = 'no';
                }
            }
            $data->{'status'}       = 'offline';
            $data->{'time'}         = time();
            print "$url NOT running \n" . $res->status_line . "\n";
        }
        lock_store($data,$file);
    }
    sleep ($sleep_minutes * 60);
}

sub _get_file($){
    my $url = shift;
    $url =~ s/[^a-z0-9]/_/g;
    my $file = File::Spec->catfile($base_dir,'memory',$url);
    return $file;
}
sub send_notify_mail($$){
    my $url    = shift;
    my $status = shift;
    my $mail = 'From: ' . $send_adress . "\n";
    $mail .= 'To: ' . $notiy_adress_1 . "\n";
    $mail .= 'Cc: ' . $notiy_adress_2 . "\n";
    $mail .= 'Return-Path: ' . $send_adress .  "\n";
    $mail .= 'Reply-To: ' . $send_adress .  "\n";
    $mail .= 'Errors-To: ' . $send_adress .  "\n";
    $mail .= 'Subject: ' . $url . " is $status \n\n";
    $mail .= 'Hello!' .  "\n\n";
    $mail .= 'Date ' . scalar(gmtime()) . "GMT \n";
    $mail .= 'The HTTP-Server on ' . $url . " is " . $status . "\n\n";
    open(MAIL,"|$mail_prog") or die("open (MAIL,\"|$mail_prog\") failed\n $! \n");
    print MAIL "$mail\n";
    close(MAIL) or die("close(MAIL) failed\n $! \n");
    return 1;
}