#!/usr/bin/python

###############################################################################
# purge-old-rpms.py 1.0                                                       #
# Purges old RPM packages from given directories.                             #
# http://juliano.info/en/Projects/Purge_old_RPMs                              #
###############################################################################
#   Author: Juliano F. Ravasi < dev at juliano info >                         #
#  Version: 1.0 (Sep 8, 2007)                                                 #
# Language: Python 2.5                                                        #
#  License: GNU General Public License v3                                     #
###############################################################################

###############################################################################
#                  Copyright (C) 2007 - Juliano F. Ravasi                     #
###############################################################################
#                                                                             #
#   This program is free software: you can redistribute it and/or modify      #
#   it under the terms of the GNU General Public License as published by      #
#   the Free Software Foundation, either version 3 of the License, or         #
#   (at your option) any later version.                                       #
#                                                                             #
#   This program is distributed in the hope that it will be useful,           #
#   but WITHOUT ANY WARRANTY; without even the implied warranty of            #
#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the             #
#   GNU General Public License for more details.                              #
#                                                                             #
#   You should have received a copy of the GNU General Public License         #
#   along with this program.  If not, see <http://www.gnu.org/licenses/>.     #
#                                                                             #
###############################################################################

import sys, os, re
from dircache import listdir
from fnmatch import fnmatch
from distutils import version
from optparse import OptionParser

rpm_re = re.compile('([\\w_.-]+?)-(\\d[\\w.]*)-(\\d[\\w.]*?)\\.([\\w_]+)\\.rpm');
##                  "kernel-devel- 2.6.22.4   - 65.fc7        . i686      .rpm"
##                   |-----1----| |----2-----| |-----3-----|   |---4---|

def main(argv):
	parser = OptionParser(usage="Usage: %prog [options] directory...", version="%prog 1.0");
	parser.add_option("-v", "--verbose", action="store_true", dest="verbose", help="make output verbose")
	parser.add_option("-n", "--dry-run", action="store_true", dest="dryrun", help="don't actually delete anything")
	(options, args) = parser.parse_args(argv[1:])

	discard = []

	for arg in args:
		path = os.path.realpath(arg)

		if not os.access(path, os.W_OK) and not options.dryrun:
			raise IOError("Write access denied to %s." % (path))

		if options.verbose:
			print "Processing directory %s..." % (path)

		packages = {}
		files = listdir(path)

		for f in files:
			if not fnmatch(f, "*.rpm"):
				continue;

			m = rpm_re.match(f)
			if m:
				pfile = m.group(0)
				pname = m.group(1)
				pversion = m.group(2)
				prelease = m.group(3)
				parch = m.group(4)
				if not packages.has_key(pname):
					packages[pname] = []
				packages[pname].append({
					'version': pversion,
					'release': prelease,
					'arch': parch,
					'file': pfile})
			else:
				print "File '%s' doesn't match regular expression." % f

		names = packages.keys()
		names.sort()

		for name in names:
			if options.verbose:
				print "  Processing package '%s'..." % (name),

			ps = packages[name]
			if len(ps) < 2:
				if options.verbose:
					print "single version found, skipping."
				continue

			try:
				for p in ps:
					p['lver'] = version.StrictVersion(p['version'])
			except:
				for p in ps:
					p['lver'] = version.LooseVersion(p['version'])

			try:
				for p in ps:
					p['lrel'] = version.StrictVersion(p['release'])
			except:
				for p in ps:
					p['lrel'] = version.LooseVersion(p['release'])

			latest = None
			for p in ps:
				if not latest or p['lver'] > latest['lver'] or (p['lver'] == latest['lver'] and p['lrel'] > latest['lrel']):
					latest = p

			obsolete = [x for x in ps if x != latest]

			if options.verbose:
				print "latest: %s-%s" % (latest['version'], latest['release'])
				for ob in obsolete:
					print "    ..obsolete:", ob['file']

			discard += [path + os.path.sep + ob['file'] for ob in obsolete]

	if len(discard) > 0:
		print "Removing obsolete packages..."

		for fl in discard:
			print "  Removing '%s'." % (fl)

			if not options.dryrun:
				os.unlink(fl)
	else:
		print "Nothing to remove."

if __name__ == "__main__":
	main(sys.argv)