# Copyright:
# Moshe Zadka (c) 2002
# Canonical Ltd. (c) 2005 (DebconfCommunicator)
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
# 1. Redistributions of source code must retain the above copyright
# notice, this list of conditions and the following disclaimer.
# 2. Redistributions in binary form must reproduce the above copyright
# notice, this list of conditions and the following disclaimer in the
# documentation and/or other materials provided with the distribution.
#
# THIS SOFTWARE IS PROVIDED BY AUTHORS AND CONTRIBUTORS ``AS IS'' AND
# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
# ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
# OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
# SUCH DAMAGE.

from __future__ import print_function

import sys, os
import errno
import re
import subprocess
import fcntl

class DebconfError(Exception):
pass

LOW, MEDIUM, HIGH, CRITICAL = 'low', 'medium', 'high', 'critical'

class Debconf:

def __init__(self, title=None, read=None, write=None):
for command in ('capb set reset title input beginblock endblock go get'
' register unregister subst fset fget previous_module'
' visible purge metaget exist version settitle'
' info progress data').split():
self.setCommand(command)
self.read = read or sys.stdin
self.write = write or sys.stdout
sys.stdout = sys.stderr
self.setUp(title)

def setUp(self, title):
self.version = self.version(2)
if self.version[:2] != '2.':
raise DebconfError(256, "wrong version: %s" % self.version)
self.capabilities = self.capb().split()
if title:
self.title(title)

def setCommand(self, command):
setattr(self, command,
lambda *args, **kw: self.command(command, *args, **kw))

def command(self, command, *params):
command = command.upper()
self.write.write("%s %s\n" % (command, ' '.join(map(str, params))))
self.write.flush()

while True:
try:
resp = self.read.readline().rstrip('\n')
break
except IOError as e:
if e.errno == errno.EINTR:
continue
else:
raise

if ' ' in resp:
status, data = resp.split(' ', 1)
else:
status, data = resp, ''
status = int(status)
if status == 0:
return data
elif status == 1: # unescaped data
unescaped = ''
for chunk in re.split(r'(\\.)', data):
if chunk.startswith('\\') and len(chunk) == 2:
if chunk[1] == 'n':
unescaped += '\n'
else:
unescaped += chunk[1]
else:
unescaped += chunk
return unescaped
else:
raise DebconfError(status, data)

def stop(self):
self.write.write('STOP\n')
self.write.flush()

def forceInput(self, priority, question):
try:
self.input(priority, question)
return 1
except DebconfError as e:
if e.args[0] != 30:
raise
return 0

def getBoolean(self, question):
result = self.get(question)
return result == 'true'

def getString(self, question):
return self.get(question)


class DebconfCommunicator(Debconf, object):
def __init__(self, owner, title=None, cloexec=False):
args = ['debconf-communicate', '-fnoninteractive', owner]
self.dccomm = subprocess.Popen(
args, stdin=subprocess.PIPE, stdout=subprocess.PIPE,
close_fds=True, universal_newlines=True)
super(DebconfCommunicator, self).__init__(title=title,
read=self.dccomm.stdout,
write=self.dccomm.stdin)
if cloexec:
fcntl.fcntl(self.read.fileno(), fcntl.F_SETFD, fcntl.FD_CLOEXEC)
fcntl.fcntl(self.write.fileno(), fcntl.F_SETFD, fcntl.FD_CLOEXEC)

def shutdown(self):
if self.dccomm is not None:
self.dccomm.stdin.close()
self.dccomm.stdout.close()
self.dccomm.wait()
self.dccomm = None

# Don't rely on this; call .shutdown() explicitly.
def __del__(self):
try:
self.shutdown()
except AttributeError:
pass


if ('DEBCONF_USE_CDEBCONF' in os.environ and
os.environ['DEBCONF_USE_CDEBCONF'] != ''):
_frontEndProgram = '/usr/lib/cdebconf/debconf'
else:
_frontEndProgram = '/usr/share/debconf/frontend'

def runFrontEnd():
if 'DEBIAN_HAS_FRONTEND' not in os.environ:
os.environ['PERL_DL_NONLAZY']='1'
os.execv(_frontEndProgram, [_frontEndProgram, sys.executable]+sys.argv)


if __name__ == '__main__':
runFrontEnd()
db = Debconf()
db.forceInput(CRITICAL, 'bsdmainutils/calendar_lib_is_not_empty')
db.go()
less = db.getBoolean('less/add_mime_handler')
aptlc = db.getString('apt-listchanges/email-address')
db.stop()
print(db.version)
print(db.capabilities)
print(less)
print(aptlc)