#!/usr/bin/perl
#
# diff two KiCad eeschema Postscript files. Removals are red, additions are
# green.
#

if (@ARGV != 2) {
    print STDERR "usage: $0 (file_a.ps|file_a.gz) (file_b.ps|file_b.gz)\n";
    exit(1);
}

if ($ARGV[0] =~ /\.gz$/) {
    open(A, "zcat '$ARGV[0]' |") || die "popen: $!";
} else {
    open(A, $ARGV[0]) || die "$ARGV[0]: $!";
}

if ($ARGV[1] =~ /\.gz$/) {
    open(B, "zcat '$ARGV[1]' |") || die "popen: $!";
} else {
    open(B, $ARGV[0]) || die "$ARGV[1]: $!";
}

($pa, $pb) = (1, 1);
while (<A>) {
    push(@a, $_);
    $pa++ if /showpage/;
    $a{"$pa:$_"} = 1;
}

while (<B>) {
    push(@b, $_);
    $pb++ if /showpage/;
    $b{"$pb:$_"} = 1;
}

($pa, $pb) = (1, 1);
while (@a && @b) {
    while (@a) {
	$a = shift @a;
	$pa++ if $a =~ /showpage/;
	last if $a =~ /cleartomark end/;
	$diff = !$b{"$pa:$a"} && $a !~ /^%/;
	if ($diff) {
	    print "1 0 0 setrgbcolor\n";
	}
	print $a;
	if ($diff) {
	    print "0 0 0 setrgbcolor\n";
	}
    }
    undef $q;
    while (@b) {
	$b = shift @b;
	next if $b =~ /^%/;
	$pb++ if $b =~ /showpage/;
	next if $b =~ /showpage/;
	next if $b =~ /gsave mark/;
	last if $b =~ /cleartomark end/;
	if ($b =~ /^[Qq]/) {
	     $q .= $b;
	     next;
	}
	if (!$a{"$pb:$b"}) {
	    print $q if defined $q;
	    undef $q;
	    # need to set the color before each line
	    print "0 0.7 0 setrgbcolor\n";
	    print $b;
	}
    }
    print "0 0 0 setrgbcolor\n";
    print $b;
}
print "1 0 0 setrgbcolor\n";
print join("\n", @a);
print "0 0.7 0 setrgbcolor\n";
print join("\n", @b);