#!/usr/bin/perl
#
#   archive-month.pl
#
#   Purpose:
#       Combine all last months log files into one file.
#
##############
use strict;
use warnings;

use File::Basename;
use Getopt::Std;

use vars qw($Ver $Year $Month $opt_d $opt_f $opt_h $opt_v);
$Ver = "0.1.2";

my $GZIP    =   "/usr/bin/gzip -9";
my $GCAT    =   "/usr/bin/gzcat";
my $GTEST=  "/usr/bin/gzip -t";

my $RM  =   "/usr/bin/rm";
my $CP  =   "/usr/bin/cp";
my $MV  =   "/usr/bin/mv";

sub Usage {
print <<USAGE;

  Usage: $0 [-hv] [-d directory] -f base-filename
     -f <required> base filename for files to archive into monthly file
    Options:
      -d directory to cd into; where target files are located
      -h print this message
      -v print version which is $Ver

USAGE
}

###############################################
#allow options to be intermixed with filenames
###############################################
    {
        my @hold;
        while(@ARGV) {
            #if it doesn't start with a '-', assume it's not an cmd line option
            while($ARGV[0] =~ /^[^\-]/) { 
                push @hold, shift @ARGV;
            }
            getopts('d:f:hv');
        }
        @ARGV=@hold;
    }

###############################################

    if( $opt_v ) {
        print "  $0 version $Ver\n"; 
        exit 0;
    }

    if( $opt_h ) {
        &Usage;
        exit 0;
    }

    if(! defined $opt_f) {
        print "  Must have basefile name of zipped logs\n";
        &Usage;
        exit 1;
    }

#######################################################################
# Beginning of Program
#######################################################################

    my ($date,$time) = SetTime();
    print "Monthly archive started at $date $time\n\n";

    #
    # The month is zero based, so this month is $mon+1, last month is $mon
    # unless $mon=0, in which case last month is $mon+12
    #
    my $lastmonth;

    if($Month==0) {
        $lastmonth = sprintf("%04d%02d",$Year-1,$Month+12);
    } else {
        $lastmonth = sprintf("%04d%02d",$Year,$Month);
    }

    if($opt_d ne '') {
        chdir $opt_d or die "Can't cd into $opt_d: <$!>\n";
    }

    if ( -e "$opt_f.$lastmonth.gz" || -e "$opt_f.$lastmonth" ) {
        die "Archive for $opt_f.$lastmonth already exists!\n";
    }

    {
        my @junk = glob "$opt_f.$lastmonth??.gz";
        if (scalar (@junk) == 0) {
            print join "", `ls -alF $opt_f.*.gz`;
            die "No files matching $opt_f.$lastmonth??.gz to archive\n";
        }
    }

    dosystem("$GCAT $opt_f.$lastmonth??.gz | $GZIP > $opt_f.$lastmonth.gz");

    if ( -z "$opt_f.$lastmonth.gz" ) {
        dosystem("$RM $opt_f.$lastmonth.gz");
        die "Archive was empty - removed\n";
    }

    if(dosystem("$GTEST $opt_f.$lastmonth.gz") != 0) {
        dosystem("$RM $opt_f.$lastmonth.gz");
        die "Archive was corrupt - removed\n";
    }

    dosystem("$RM $opt_f.$lastmonth??.gz");

    if($Month==0) {
        my $lastyear = sprintf("%04d",$Year-1);
        mkdir $lastyear, 755;
        dosystem("$MV $opt_f.$lastyear* $lastyear");
    }

######################################################################


    ($date,$time) = SetTime();
    print "\nMonthly archive finished at $time\n";

exit;

sub dosystem {

    my $rc = system(@_) & 0xFFFF;

    if ($rc == 0) { return $rc; }

    if ($rc == 0xff00 ) {
        print "Command <@_> failed: $!\n";
        exit 1;
    }

    if ($rc > 0x80) {
        $rc >>= 8;
        print "Command <@_> ran with exit code $rc\n";
        return $rc;
    }

    if ($rc & 0x80) {
        printf "Core dumped from signal %d\n", $rc & 0x7F;
        exit 2;
    } else {
        printf "Interrupted by signal %d\n", $rc & 0x7F;
        exit 3;
    }

    die "Should never be able to get here, \$rc was <$rc>\n System error, if any, was <$!>\n";
}

#######################################################################
# Set time variables to current time.
#######################################################################
sub SetTime {
    my ($sec,$min,$hr,$mday,$mon,$yr,$wday,$yday,$isdst) = localtime(time());

    my $date = sprintf("%04d%02d%02d",$yr+1900,$mon+1,$mday);
    my $time = sprintf("%02d:%02d:%02d",$hr,$min,$sec);

    #Side effects, I need the year and the month for other stuff, set the 
    #global variables to the appropriate values
    $Year = $yr + 1900;
    $Month = $mon;

    return ($date, $time);
}