#!/usr/bin/perl
use strict;
use warnings;
use Digest::MD5;
package infobomb;

################ MAIN ################ 
$ARGV[0] or die "Usage: $0 config_file.conf\n";

# read config file
%infobomb::config = ();
read_configuration($ARGV[0]);
check_configuration();
my $filename_base = "[$infobomb::config{project}]-[$infobomb::config{location}]-[$infobomb::config{'sensor-type'}]-[$infobomb::config{sn}]-[data]";
$infobomb::config{'state_file'} = "$infobomb::config{'data-path'}/$filename_base.state";
$infobomb::config{'readings_log'} = "$infobomb::config{'data-path'}/$filename_base.csv";

############### CONFIGURATION ################ 

# client ssh/scp absolute paths 
$infobomb::ssh = "/usr/sbin/ssh";
$infobomb::scp = "/usr/sbin/scp";

# client identity file absolute path (ssh public key)
$infobomb::identity_file = "/root/.ssh/pmp3_rsa";

# TODO: figure out why this doesn't get set by .bashrc or .bash_profile on host
# special environment variables to set on host
#$infobomb::host_export = "export DJANGO_SETTINGS_MODULE=infobomb.settings; export PYTHONPATH=/home/infobomb;";

# user and host of running infobomb instance
$infobomb::user = "infobomb";
$infobomb::host = "stewie.cs.earlham.edu";

# absolute path to infobomb checkout on host
#$infobomb::host_path = "/home/infobomb/infobomb/";
$infobomb::host_data = "/home/infobomb/data/";

$infobomb::ssh = "$infobomb::ssh -i $infobomb::identity_file";
$infobomb::scp = "$infobomb::scp -i $infobomb::identity_file";
#$infobomb::check_transactions = "$infobomb::host_path/dataparser/check_transactions.py";

############### MAIN ################ 

# poll sensor, record reading
my ($reading, $state);

$state = read_state();

++$state;
record_state($state);

$reading = poll($infobomb::config{'run'});
if ($reading ne 'INVALID') {
    record_reading($infobomb::config{'readings_log'}, $reading);
} else {
    ErrorEvent("alert", "Sensor returned non-numeric value.");
}

print "state: $state\n";

if ($state >= $infobomb::config{'readings_per_file'}) {
    my $date = time;
    $state = 0;
    record_state($state);

    system("mv $infobomb::config{readings_log} $infobomb::config{'data-path'}/$filename_base-[$date].csv");
    create_checksum_file("$infobomb::config{'data-path'}/$filename_base-[$date].csv");
    
    delete_or_send_transactions();
}

############### SUBS ################ 

sub delete_or_send_transactions {
    my $filelist = `ls $infobomb::config{'data-path'} | grep csv | grep -v md5`;
    my @files = split("\n",$filelist);
    
    # go through each file in the data-path directory
    foreach my $file (@files) {
	
	# parse filename for project details
	my ($project, $location, $sensor_type, $sn, $type, $time) = ( $file =~ /\[([^\[\]]*)\]/g );
	
	# check to see if file is our project	
	if ( ($infobomb::config{'project'} eq $project) &&
	     ($infobomb::config{'location'} eq $location) &&
	     ($infobomb::config{'sensor-type'} eq $sensor_type) &&
	     ($infobomb::config{'sn'} eq $sn)) {	
	    
	    if ($time < (time - 1209600)) {
		
		# file is older than 2 weeks, remove it
		system("rm -f $infobomb::config{'data-path'}/$file $infobomb::config{'data-path'}/$file.md5");
		
	    } else {

		#contact server to see if transaction exists in infobomb database	
                #my $trans = `$infobomb::ssh $infobomb::user\@$infobomb::host \"$infobomb::host_export $infobomb::check_transactions $file\"`;
		my $download = "wget -q http://stewie.cs.earlham.edu:8000/transaction/$file -O  $infobomb::config{'data-path'}/datacheck/$file";
		system("$download");
		my $contents = `cat $infobomb::config{'data-path'}/datacheck/$file`;
		
                #if ( $trans =~ /EXISTS/ ) {
		if ( $contents =~ /EXISTS/ ) {
		    
		    # transaction exists, remove the file	
		    print "Transaction completed. Deleting file\n";
		    system("rm -f $infobomb::config{'data-path'}/$file $infobomb::config{'data-path'}/$file.md5");	
		    
		} else {
		    
		    # transaction doesn't exist, transfer file to server	
		    print "Starting transaction\n";
		    system("$infobomb::scp $infobomb::config{'data-path'}/$file $infobomb::config{'data-path'}/$file.md5 $infobomb::user\@$infobomb::host:$infobomb::host_data");
		}
		# delete data check file
		system("rm -f $infobomb::config{'data-path'}/datacheck/$file");
	    }
	}
    }
}

sub read_state {
    record_state(0) unless (-e $infobomb::config{state_file});
    open (STATE, $infobomb::config{state_file} ) or ErrorEvent("alert","Failed to open state file");
    
    my $state = <STATE>;
    if (!$state) {
	$state = 0;
    }
    
    close STATE;
    return $state;
}

sub record_state {
    my ($state) = @_;
    
    open (STATE, ">$infobomb::config{state_file}") or ErrorEvent("alert","Failed to write state file");
    
    print STATE $state;
    close STATE;
}

sub read_configuration {
    my ($config_file) = @_;
    my $line;
    
    open (CONFIGFILE, $config_file) or ErrorEvent("alert","Failed to open infobomb::config file");
    
    while ($line = <CONFIGFILE>) {
	if ($line =~ /^([^=]+)=(.*)/) {
	    my ($config_name, $config_val) = ($1, $2);
	    $infobomb::config{$config_name} = $config_val;
	}
    }
    
    close CONFIGFILE;
}

sub poll {
    my ($run) = @_;
    my ($time, $output);
    
    $time = time;
	
    $output = `$run`;
    chomp $output;
    
    if ( $output =~ /^-?(?:\d+(?:\.\d*)?|\.\d+)$/ ) {
	return "$time,$output";
    } else {
	return "INVALID";
    }
}

sub record_reading {
    my ($log, $reading) = @_;
    
    open (LOG, ">>$log") or ErrorEvent("alert","Failed to write log file");
    print LOG "$reading\n";
    close LOG;
}


sub check_configuration {
    my @keys = qw( project location sensor-type sn readings_per_file run data-path );
    foreach my $key (@keys) {
	if (not $infobomb::config{$key}) {
	    print "Alert: $key is undefined in infobomb::configuration file.\n";	
	    die;
	}
    }
    
    # check for arguments associated with run command
    # i.e. ./poll_sensor --type=temperature
    my @run_args = split(/ /, $infobomb::config{'run'});
    my $path = $run_args[0]; 
    
    ErrorEvent("alert", "Failed to open sensor script/binary") unless (-e $path);
    ErrorEvent("alert", "Failed to open data-path.") unless (-e $infobomb::config{'data-path'});
}

sub ErrorEvent {
    my ( $type, $message ) = @_;
    my $time = time;
    my $filename = "$infobomb::config{'data-path'}/[$infobomb::config{project}]-[$infobomb::config{location}]-[$infobomb::config{'sensor-type'}]-[$infobomb::config{sn}]-[$type]-[$time].csv";
    print "$type: $message\n";
    open(LOG, ">>$filename") or die "Failed to open error file";
    print LOG $message;
    close LOG;
    
    create_checksum_file_or_die($filename);
    
    if ($type eq 'alert') {
	die;
    }
}

sub create_checksum_file_or_die {
    my ($filename) = @_;
    open(DATAF, $filename) or die "Failed to open data file.";
    binmode(DATAF);
    
    open(CSF, ">>$filename.md5") or die "Failed to open checksum file.";
    
    print CSF Digest::MD5->new->addfile(*DATAF)->hexdigest;
    
    close CSF;
    close DATAF;
}

sub create_checksum_file {
    my ($filename) = @_;
    open(DATAF, $filename) or ErrorEvent("alert","Failed to open data file.");
    binmode(DATAF);	
    
    open(CSF, ">>$filename.md5") or ErrorEvent("alert","Failed to open checksum file.");
    
    print CSF Digest::MD5->new->addfile(*DATAF)->hexdigest;
    
    close CSF;
    close DATAF;
}