#!/usr/bin/python -tt
# (c) 2012, Flowroute LLC
# Written by Matthew Williams <matthew@flowroute.com>
# Based on yum module written by Seth Vidal <skvidal at fedoraproject.org>
#
# This module 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 3 of the License, or
# (at your option) any later version.
#
# This software 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 software.  If not, see <http://www.gnu.org/licenses/>.
#

try:
    import json
except ImportError:
    import simplejson as json
import os
import sys
import apt
import shlex
import subprocess
import traceback

APT = "/usr/bin/apt-get"

def debug(msg):
    # ansible ignores stderr, so it's safe to use for debug
    print >>sys.stderr, msg
    #pass
    
def exit_json(rc=0, **kwargs):
    print json.dumps(kwargs)
    sys.exit(rc)

def fail_json(**kwargs):
    kwargs['failed'] = True
    exit_json(rc=1, **kwargs)

def run_apt(command):
    debug(command)
    try:
        cmd = subprocess.Popen(command, shell=True, 
            stdout=subprocess.PIPE, stderr=subprocess.PIPE)
        out, err = cmd.communicate()
    except (OSError, IOError), e:
        rc = 1
        err = str(e)
        out = ''
    except:
        rc = 1
        err = traceback.format_exc()
        out = ''

        if out is None:
           out = ''
        if err is None:
           err = ''
    else:
        rc = cmd.returncode
        
    debug(err)
    return rc, out, err

def get_cache():
    # TODO: Only update the cache if it's old.
    cache = apt.Cache()
    cache.update()
    cache.open(None)
    return cache

def package_installed(pkgspec):
    cache = get_cache()
    try:
       pkg = cache[pkgspec]
    except:
        fail_json(msg="No package matching '%s' is available" % pkgspec)
    return bool(pkg.is_installed)

def install(pkgspec):
    installed = package_installed(pkgspec)
    debug("installed: %d" % installed)
    if installed:
        return False
    else:
        cmd = "%s -q -y install '%s'" % (APT, pkgspec)
        rc, out, err = run_apt(cmd)
        # TODO: Ensure the package was really installed.
        return True

def remove(pkgspec):
    installed = package_installed(pkgspec)
    debug("installed: %d" % installed)
    if not installed:
        return False
    else:
        cmd = "%s -q -y remove '%s'" % (APT, pkgspec)
        rc, out, err = run_apt(cmd)
        # TODO: Ensure the package was really removed.
        return True
    
def update(args):
    # TODO: generic update routine 
    pass

def remove_only(pkgspec):
    # TODO: remove this pkg and only this pkg - fail if it will require more to remove
    pass

# ===========================================

if not os.path.exists(APT):
   fail_json(msg="Cannot find apt-get")

argfile = sys.argv[1]
args    = open(argfile, 'r').read()
items   = shlex.split(args)

if not len(items):
    fail_json(msg='the module requires arguments -a')
    sys.exit(1)

params = {}
for x in items:
    (k, v) = x.split("=")
    params[k] = v

state   = params.get('state','installed')
package = params.get('pkg', None)

if state not in ['installed', 'removed']:
    fail_json(msg='invalid state')
if package is None:
    fail_json(msg='pkg is required')

if state == 'installed':
    changed = install(package)
elif state == 'removed':
    changed = remove(package)
exit_json(changed=changed)