#!/usr/bin/env perl

use strict;
use File::Path;
use XML::Parser;

die("Usage: $0 maven-repo group-id package-name\n") if @ARGV < 3;

my ($repo, $group_id, $pkg_name) = @ARGV;
my $group_path = $group_id; $group_path =~ s/\./\//;
my $portdir = ".";
my $group_desc = "High Energy Physics Java library";

my $proto_ebuild = `cat $portdir/maven-proto.ebuild` or die;

my (@deps, @portage_dep_atoms, @portage_env_pkgs);
warn "$0: parsing $pkg_name\n";

my @versions;
my $pkg_parser = new XML::Parser(Style=>'Tree');
my $pkg_tree = $pkg_parser->parse(scalar(`wget -q -O - $repo/$group_path/$pkg_name/maven-metadata.xml`));
foreach my $i (0..$#{$pkg_tree->[1]}) {
	next if $pkg_tree->[1]->[$i] ne 'versioning';
	my @v = @{$pkg_tree->[1]->[$i+1]};
	foreach my $j (0..$#v) {
		next if $v[$j] ne 'versions';
		my @vers = @{$v[$j+1]};
		foreach my $k (0..$#vers) {
			next if $vers[$k] ne 'version';
			my $version = $vers[$k+1]->[2];
			@versions = ($version) if $version =~ /^(\d\.)+\d$/;
		}
	}
}

foreach my $version (@versions) {
	my ($pkg_desc, $pkg_url);
	my $parser = new XML::Parser(Style=>'Tree');
	my $tree = $parser->parse(scalar(`wget -q -O - $repo/$group_path/$pkg_name/$version/$pkg_name-$version.pom`));
	foreach my $i (0..$#{$tree->[1]}) {
		if ($tree->[1]->[$i] eq 'description') {
			$pkg_desc = $tree->[1]->[$i+1]->[2];
		} elsif ($tree->[1]->[$i] eq 'url') {
			$pkg_url = $tree->[1]->[$i+1]->[2];
		}
		next if $tree->[1]->[$i] ne 'dependencies';
		my @d = @{$tree->[1]->[$i+1]};
		foreach my $j (0..$#d) {
			next if $d[$j] ne 'dependency';
			my @dep = @{$d[$j+1]};
			my %dep_info;
			foreach my $k (0..$#dep) {
				next if $dep[$k] !~ /groupId|artifactId|version/;
				my $value = $dep[$k+1]->[2];
				$dep_info{$dep[$k]} = $value;
			}
			push(@deps, \%dep_info);
		}
	}

	print "$pkg_name-$version:\n";
	foreach my $dep (@deps) {
		my ($portage_atom, $env_pkg);
		if ($$dep{artifactId} eq 'kxml2') {
			$portage_atom = '>=dev-java/kxml-2.3.0'; $env_pkg = 'kxml';
		} elsif ($$dep{artifactId} eq 'cernlib') {
			$portage_atom = 'sci-physics/cernlib'; # needs runtime testing with higher cernlib version
		} elsif ($$dep{artifactId} eq 'aida') {
			$portage_atom = 'dev-java/hep-aida'; $env_pkg = 'aida';
		} elsif ($$dep{artifactId} =~ /^(openide-lookup|pawdemo|JAS|jas-plotter|rowwise)$/) {
			$portage_atom = 'dev-java/freehep-misc-deps'; $env_pkg = 'freehep-misc-deps';
		} elsif ($$dep{artifactId} eq 'cernlib') {
			$portage_atom = 'sci-physics/cernlib';
		} elsif ($$dep{groupId} =~ /^(org.freehep|junit|commons-codec|jdom|bcel|org.apache.bcel|org.codehaus.plexus|org.apache.maven)$/) {
			if ($$dep{artifactId} ne 'fortran') {
				$portage_atom = "dev-java/$$dep{artifactId}";
				$portage_atom = ">=$portage_atom-$$dep{version}" if $$dep{version};
				$env_pkg = $$dep{artifactId} if $$dep{artifactId} =~ /^(junit|bcel|commons-codec)$/ or $$dep{groupId} =~ /^(org.freehep)$/;
				$env_pkg = 'jdom-1.0' if $$dep{artifactId} eq 'jdom';
			}
		}

		push(@portage_dep_atoms, $portage_atom) if $portage_atom;
		push(@portage_env_pkgs, $env_pkg) if $env_pkg;
		warn "\tUNRESOLVED: $$dep{groupId}\t$$dep{artifactId}\t$$dep{version}\n" unless $portage_atom;
	}

	# freehep internal dependency matrix is incomplete. stupid.
	if ($pkg_name eq 'freehep-export') {
		push(@portage_dep_atoms, 'dev-java/freehep-util');
		push(@portage_env_pkgs, 'freehep-util');
	} elsif ($pkg_name eq 'freehep-graphicsio') {
		push(@portage_dep_atoms, 'dev-java/freehep-util');
		push(@portage_env_pkgs, 'freehep-util');
		push(@portage_dep_atoms, 'dev-java/freehep-swing');
		push(@portage_env_pkgs, 'freehep-swing');
	} elsif ($pkg_name =~ /^freehep-graphicsio-(tests|java|ps|pdf)$/) {
		(push(@portage_dep_atoms, "dev-java/$_"),
			push(@portage_env_pkgs, $_))
			for qw(freehep-util freehep-swing freehep-graphics2d freehep-io freehep-export);
	}

	print "\t".join("\n\t", @portage_dep_atoms)."\n";

	$proto_ebuild =~ s/DESCRIPTION=".*?"/DESCRIPTION="$group_desc - $pkg_desc"/s;
	$proto_ebuild =~ s/HOMEPAGE=".*?"/HOMEPAGE="$pkg_url"/s;
	my $deps_string = join("\n\t", @portage_dep_atoms);
	$proto_ebuild =~ s/CDEPEND=".*?"/CDEPEND="$deps_string"/s;
	my $env_pkgs_string = join(",", @portage_env_pkgs);
	$proto_ebuild =~ s/JAVA_GENTOO_CLASSPATH=".*?"/JAVA_GENTOO_CLASSPATH="$env_pkgs_string"/s;
	$proto_ebuild =~ s/GROUP_ID=".*?"/GROUP_ID="$group_id"/s;
	$proto_ebuild =~ s/MAVEN2_REPOSITORIES=".*?"/MAVEN2_REPOSITORIES="$repo"/s;

	mkdir "$portdir/$pkg_name";
	open(OUT, '>', "$portdir/$pkg_name/$pkg_name-$version.ebuild") or die;
	print OUT $proto_ebuild;
	close OUT;
	system("ebuild $portdir/$pkg_name/$pkg_name-$version.ebuild digest"); die if $?;
}

warn "Ebuild generated ;)\n";