#!/usr/bin/python
# -*- coding: utf-8 -*-

import subprocess, sys

def deb_size_map(iso_path):
    map = {} # package -> (version, size)
    isoinfo = subprocess.Popen(['isoinfo', '-lR', '-i', iso_path],
       stdout=subprocess.PIPE)
    out = isoinfo.communicate()[0]
    assert isoinfo.returncode == 0

    for l in out.splitlines():
        l = l.strip()
        if not l.endswith('.deb'):
            continue

        fields = l.split()
        size = int(fields[4])
        fname = fields[11]

        (pkg, version, _) = fname.split('_')
        map[pkg] = (version, size)

    return map

#
# main
#    

if len(sys.argv) != 3:
    print >> sys.stderr, 'Usage: %s <old iso> <new iso>' % sys.argv[0]
    sys.exit(1)

old_map = deb_size_map(sys.argv[1])
new_map = deb_size_map(sys.argv[2])

print '== Removed packages =='
sum = 0
for p, (v, s) in old_map.iteritems():
    if p not in new_map:
        print '%s (%.1f MB)' % (p, s / 1000000.)
        sum += s
print 'TOTAL: -%.1f MB' % (sum/1000000.)

sum = 0
print '\n== Added packages =='
for p, (v, s) in new_map.iteritems():
    if p not in old_map:
        print '%s (%.1f MB)' % (p, s / 1000000.)
        sum += s
print 'TOTAL: +%.1f MB' % (sum/1000000.)

print '\n== Changed packages =='
sum = 0
for p, (v, s) in old_map.iteritems():
    if p not in new_map:
        continue

    new_s = new_map[p][1]
    sum += new_s - s

    # only show differences > 100 kB to filter out noise
    if new_s - s > 100000:
        print '%s (Δ %.1f MB - %s: %.1f MB   %s: %.1f MB)' % (
        p, (new_s-s)/1000000., v, s/1000000., new_map[p][0], new_s/1000000.)

print 'TOTAL difference: %.1f MB' % (sum/1000000.)