#! /usr/bin/perl -w

use strict;
use FileHandle;
use File::Spec;
use Digest::MD5;

my $system = "@SYSTEM@";

my $outdir = File::Spec->rel2abs($ARGV[0]);
my $netdir = File::Spec->rel2abs($ARGV[1]);

my %donetmpls = ();

sub fetchFile {
    my $loc = shift;

    if ($loc =~ /^([+\w\d\.\/-]+)$/) {
	return $1;
    } elsif ($loc =~ /^url\((.*)\)$/) {
	my $url = $1;
	$url =~ /\/([^\/]+)$/ || die "invalid url $url";
	my $fn = "$netdir/$1";
	if (! -f $fn) {
	    print "fetching $url...\n";
	    system "cd $netdir; wget --quiet -N $url";
	    if ($? != 0) {
		unlink($fn);
		die;
	    }
	}
	return $fn;
    } else {
	die "invalid file specified $loc";
    }
}

sub hashFile {
    my $file = shift;
    open FILE, "< $file" or die "cannot open $file";
    # !!! error checking
    my $hash = Digest::MD5->new->addfile(*FILE)->hexdigest;
    close FILE;
    return $hash;
}

sub convert {
    my $descr = shift;

    if (defined $donetmpls{$descr}) {
        return $donetmpls{$descr};
    }

    my ($x, $dir, $fn) = File::Spec->splitpath($descr);

    print "$descr\n";

    my $IN = new FileHandle;
    my $OUT = new FileHandle;
    my $tmpfile = "$outdir/$fn-tmp";
    open $IN, "< $descr" or die "cannot open $descr";
    open $OUT, "> $tmpfile" or die "cannot create $tmpfile";

    print $OUT "system : $system\n";

    while (<$IN>) {
        chomp;

        if (/^(\w+)\s*=\s*([^\#\s]*)\s*(\#.*)?$/) {
            my ($name, $loc) = ($1, $2);
            my $file = fetchFile($loc);
            $file = File::Spec->rel2abs($file, $dir);
	    my $hash = hashFile($file);
            print $OUT "$name = $hash\n";
        } elsif (/^(\w+)\s*<-\s*([+\w\d\.\/-]+)\s*(\#.*)?$/) {
            my $name = $1;
            my $file = $2;
            $file = File::Spec->rel2abs($file, $dir);
            $file = convert($file);
	    my $hash = hashFile($file);
            print $OUT "$name <- $hash\n";
        } else {
            print $OUT "$_\n";
        }
    }

    close $OUT;
    close $IN;

    my $hash = hashFile($tmpfile);

    my $outfile = "$outdir/$hash-$fn";
    rename($tmpfile, $outfile) or die "cannot rename $tmpfile to $outfile";

    $donetmpls{$descr} = $outfile;
    return $outfile;
}

for (my $i = 2; $i < scalar @ARGV; $i++) {
    convert(File::Spec->rel2abs($ARGV[$i]));
}