#!/usr/bin/env python
# Copyright (C) 2005 Vittorio Palmisano <redclay at email dot it>
#
# 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 2
# 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, write to the Free Software
# Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
#
'''apt-history 0.1
Usage: apt-history [command] [options]
	
Commands:
  log  - log the current packages status
  show - shows the history for installed, removed,
         and upgraded packages.
  show install|remove|upgrade - shows only installed,
         removed or upgraded packages
  clean - clean log informations

Options:
  --help, -h - shows this help
'''
import os, sys, cPickle, time, getopt
import apt_pkg

class Status:
	'''dpkg status file'''
	def __init__(self, tagfile='/var/lib/dpkg/status'):
		'''Init of the status informations'''
		apt_pkg.InitSystem()
		self._parse = apt_pkg.ParseTagFile(open(tagfile));
		self.status = {}
		while self._parse.Step() == 1:
			offset = self._parse.Offset() - self._parse.Section.Bytes() - 1
			self.status[self._parse.Section.get('Package')] = offset

	def get(self, name, field):
		'''Get `field' from status for package `name' '''
		try:
			self._parse.Jump(self.status[name])
			return self._parse.Section.get(field, '')
		except KeyError:
			return ''
	
	def get_version(self, name):
		'''Get the version of package `name' '''
		return self.get(name, 'Version')
	
	def get_status(self, name):
		'''Get the status of package `name' '''
		return self.get(name, 'Status')

prefix= '/var/log/apt-history'
status_file = os.path.join(prefix, 'status')
log_file = os.path.join(prefix, 'log')

def save_status(s):
	p = {}
	for name in s.status.iterkeys():
		p[name] = (s.get_version(name), s.get_status(name))
	cPickle.dump(p, open(status_file, 'w'))

def get_changes(old_status, new_status):
	changes = {'install': [], 'remove': [], 'upgrade': []}
	for pkg_name in new_status.status.iterkeys():
		pkg_status = new_status.get_status(pkg_name)
		pkg_version = new_status.get_version(pkg_name)
		
		if not pkg_name in old_status:
			if 'install ok installed' in pkg_status:
				changes['install'].append((pkg_name, pkg_version))
		elif pkg_status != old_status[pkg_name][1]:
			if 'install ok installed' in pkg_status:
				changes['install'].append((pkg_name, pkg_version))
			elif 'purge ok not-installed' in pkg_status:
				changes['remove'].append((pkg_name, pkg_version))
		elif pkg_version != old_status[pkg_name][0]:
			changes['upgrade'].append((pkg_name, pkg_version, old_status[pkg_name][0]))
	return changes

def do_log():
	try:
		old_status = cPickle.load(open(status_file))
		log = cPickle.load(open(log_file))
	except:
		do_init_log()
		return
	
	new_status = Status()
	changes = get_changes(old_status, new_status)
	date = time.strftime('%Y-%m-%d %H:%M:%S', time.gmtime())
	log.append((date, changes))
	cPickle.dump(log, open(log_file, 'wa'))
	print 'Saving new apt-history status...'
	save_status(new_status)

def do_init_log():
	date = time.strftime('%Y-%m-%d %H:%M:%S', time.gmtime())
	log = [(date, dict(install=[], upgrade=[], remove=[]))]
	cPickle.dump(log, open(log_file, 'w'))
	new_status = Status()
	save_status(new_status)

def do_show(args=[]):
	print_str = '%(date)s: %(action)-8s %(name)-40s '
	def print_fields(date, entry, action):
		info = {'date': date, 'action': action}
		for fields in entry[action]:
			if action == 'upgrade':
				info['name'] = '%-30s' %(fields[0]+'='+fields[2])
				info['new_v'] = fields[1]
				print (print_str+'%(new_v)s') %info
			else:
				info['name'] = fields[0]
				info['new_v'] = fields[1]
				print (print_str+'%(new_v)s') %info

	try: log = cPickle.load(open(log_file))
	except:	log = []
		
	if len(args):
		actions = []
		for action in args:
			if action in ['install', 'remove', 'upgrade']:
				actions.append(action)
	else: actions = ['install', 'remove', 'upgrade']
	for date, log_entry in log:
		for action in actions:
			print_fields(date, log_entry, action)
	
def usage():
	print __doc__

def main():
	try:
		assert sys.argv[1] in ('log', 'show', 'clean')
	except:
		usage()
		sys.exit(-1)

	try:
		opts, args = getopt.getopt(sys.argv[1:], 'h', ['help'])
	except getopt.GetoptError:
		usage()
		sys.exit(-1) 

	for o, a in opts:
		if o in ('-h', '--help'):
			usage()
			sys.exit(0)

	if not os.path.exists(prefix):
		try:
			os.mkdir(prefix)
			do_init_log()
		except OSError, e:
			print e
			sys.exit(-1)
	
	if sys.argv[1] == 'log':
		do_log()
	elif sys.argv[1] == 'show':
		do_show(args[1:])
	elif sys.argv[1] == 'clean':
		do_init_log()
	sys.exit(0)
	
if __name__ == '__main__':
	main()