#!/usr/bin/python -tt

# remove requested pkg and any pkg which it (and only it depends on)

# for each pkg in remove state
#  traverse their requirements
#  if the installed pkg they require is not required by anything that's not already in the 
#  transaction set marked as 'remove' then mark them for removal.

import yum
from yum.constants import *
import yum.misc
import sys

__requires_cache = {}

def requires_this_package(rpmsack, pkg):
    if __requires_cache.has_key(pkg):
        return __requires_cache[pkg]
        
    requirers = {}
    for prov in pkg.provides:
        for req_pkg in rpmsack.getRequires(prov[0], prov[1], prov[2]):
            if req_pkg == pkg:
                continue
            requirers[req_pkg.pkgtup] = 1
    for prov in pkg.filelist + pkg.dirlist + pkg.ghostlist:
        for req_pkg in rpmsack.getRequires(prov):
            if req_pkg == pkg:
                continue
            requirers[req_pkg.pkgtup] = 1

    __requires_cache[pkg] = requirers.keys()
    return requirers.keys()
                  
remove_pkg = sys.argv[1]
ignore_list = ['glibc', 'bash', 'kernel', 'libgcc']

my = yum.YumBase()
print 'remove %s' % remove_pkg
my.remove(pattern=remove_pkg)
oldlen = 0
while oldlen != len(my.tsInfo):
    oldlen = len(my.tsInfo)
    for txmbr in my.tsInfo.getMembersWithState(output_states=TS_REMOVE_STATES):
        for req in txmbr.po.requires:
            if req[0].startswith('rpmlib('):
                continue
            for pkg in my.rpmdb.getProvides(req[0], req[1], req[2]):
                if pkg.pkgtup in [ txmbr.po.pkgtup for txmbr in my.tsInfo.getMembersWithState(output_states=TS_REMOVE_STATES) ]:
                    continue # skip ones already marked for remove, kinda pointless
                if pkg.name in ignore_list: # there are some pkgs which are NEVER going to be leafremovals
                    continue
                non_removed_requires = []
                for req_pkgtup in requires_this_package(my.rpmdb, pkg):
                    pkgtups = [ txmbr.po.pkgtup for txmbr in my.tsInfo.getMembersWithState(output_states=TS_REMOVE_STATES) ]
                    if req_pkgtup not in pkgtups:
                        non_removed_requires.append(req_pkgtup)

                if not non_removed_requires:
                    print 'removing %s b/c it is not required by anything else' % pkg
                    my.remove(pkg)

my.buildTransaction()
#my.processTransaction()
for pkg in my.tsInfo:
    print pkg