#!perl

use IO::File;

my $descriptive = 0;
my $lhfile = shift @ARGV;

if ($lhfile eq "--desc") {
    $descriptive = 1;
    $lhfile = shift @ARGV;
}

my $rhfile = shift @ARGV;

if (!defined $rhfile) {
    die qq(Syntax:

	./cmp_cmds.pl [--desc] orig_mod_cmds_output new_mod_cmds_output

	where --desc will include changes in directives' descriptions.
);
}

my %cmdhash;

my ($hdr, $mod, $cmd, $ctx, $desc);

my $fl = new IO::File $lhfile, "r" || die "Could not read ".$rhfile;
while (($hdr = <$fl>) && ($cntx = <$fl>) && ($desc = <$fl>)) {
    chomp $hdr;  chomp $cntx;  chomp $desc;
    ($mod, $cmd) = split "::", $hdr;
    if (defined $cmdhash{$cmd}{lmod}) {
        $mod = $cmdhash{$cmd}{lmod}.",".$mod;
    }
    $cmdhash{$cmd} = {
        cmd => $cmd,
        lmod => $mod,
        lcntx => $cntx,
        ldesc => $desc, };
}
undef $fl;       

my $fl = new IO::File $rhfile, "r" || die "Could not read ".$rhfile;
while (($hdr = <$fl>) && ($cntx = <$fl>) && ($desc = <$fl>)) {
    chomp $hdr;  chomp $cntx;  chomp $desc;
    ($mod, $cmd) = split "::", $hdr;
    if (defined $cmdhash{$cmd}{rmod}) {
        $mod = $cmdhash{$cmd}{rmod}.",".$mod;
    }
    if (defined $cmdhash{$cmd}{lmod}) {
        $cmdhash{$cmd} = {
            cmd => $cmd,
            rmod => $mod,
            rcntx => $cntx,
            rdesc => $desc,
            lmod => $cmdhash{$cmd}{lmod},
            lcntx => $cmdhash{$cmd}{lcntx},
            ldesc => $cmdhash{$cmd}{ldesc}, };
    }
    else {
        $cmdhash{$cmd} = {
            cmd => $cmd,
            rmod => $mod,
            rcntx => $cntx,
            rdesc => $desc, };
    }
}
undef $fl;       

my @cmdkeys = sort keys %cmdhash;    

foreach $cmd (@cmdkeys) {
    if (!defined $cmdhash{$cmd}{lmod}) {
        $rhonly{$cmd} = $cmdhash{$cmd};
        print $cmd." introduced in ".$cmdhash{$cmd}{rmod}."\n";
    }
    elsif (!defined $cmdhash{$cmd}{rmod}) {
        $lhonly{$cmd} = $cmdhash{$cmd};
        print $cmd." deprecated from ".$cmdhash{$cmd}{lmod}."\n";
    }
    else {
	if ($cmdhash{$cmd}{lmod} ne $cmdhash{$cmd}{rmod}) {
            print $cmd." moved from ".$cmdhash{$cmd}{lmod}." to ".$cmdhash{$cmd}{rmod}."\n"
        }
	if ($cmdhash{$cmd}{lcntx} ne $cmdhash{$cmd}{rcntx}) {
            print $cmd." options changed\n..from ".$cmdhash{$cmd}{lcntx}."\n....to ".$cmdhash{$cmd}{rcntx}."\n"
        }
	if ($descriptive && ($cmdhash{$cmd}{ldesc} ne $cmdhash{$cmd}{rdesc})) {
            print $cmd." description changed\n..from ".$cmdhash{$cmd}{ldesc}."\n....to ".$cmdhash{$cmd}{rdesc}."\n"
        }
    }
}