#! /usr/bin/python -tt

import os
from os.path import basename
import sys
import glob
from subprocess import call

apply_delta = "/usr/bin/applydeltarpm"

if len(sys.argv) < 3:
    print >>sys.stderr, "\
 Usage: delta-rpm-dir <drpm-dir> <rpm-dir>..."
    sys.exit(1)

# print "Doing delta checks for:", sys.argv[1:]
for delta_path_fname in glob.glob(sys.argv[1] + '/*.drpm'):
    # drpms are of the form: <name>-<old-vr>_<new-vr>.<arch>.drpm
    #  rpms are of the form: <name>-<vr>.<arch>.rpm
    fname = basename(delta_path_fname)
    fname = fname[:-len('.drpm')]
    fname, arch = fname.rsplit('.', 1)
    name, old_v, fname, new_r  = fname.rsplit('-', 3)
    # _ doesn't seem to be used in versions/releases, but if it is it just means
    # we won't be able to delta that pkg.
    old_r, new_v = fname.split('_', 1)

    old_fname = "%s-%s-%s.%s.rpm" % (name, old_v, old_r, arch)
    new_fname = "%s-%s-%s.%s.rpm" % (name, new_v, new_r, arch)

    new_path_fname = sys.argv[2] + '/' + new_fname
    if os.path.exists(new_path_fname):
        continue

    for dname in sys.argv[2:]:
        old_path_fname = dname + '/' + old_fname
        if not os.path.exists(old_path_fname):
            continue

        print "Applying Delta:", basename(old_path_fname), "=>"
        print "               ", basename(new_path_fname)
        call([apply_delta, '-a', arch,
              '-r', old_path_fname, delta_path_fname, new_path_fname])
        break