#!/usr/bin/python

# (c) 2012, Stephen Fromm <sfromm@gmail.com>
#
# This file is part of Ansible
#
# Ansible 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.
#
# Ansible 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 Ansible.  If not, see <http://www.gnu.org/licenses/>.

try:
    import json
except ImportError:
    import simplejson as json
import os
import os.path
import sys
import shlex
import shutil
import syslog
import tempfile

try:
    import hashlib
    HAVE_HASHLIB=True
except ImportError:
    import md5
    HAVE_HASHLIB=False

# Since hashlib is only available in 2.5 and onwards, this module
# uses md5 which is available in 2.4.

# ===========================================
# Support methods

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 assemble_from_fragments(path):
    ''' assemble a file from a directory of fragments '''
    assembled = []
    for f in sorted(os.listdir(path)):
        fragment = "%s/%s" % (path, f)
        if os.path.isfile(fragment):
            assembled.append(file(fragment).read())
    return "".join(assembled)

def write_temp_file(data):
    fd, path = tempfile.mkstemp()
    os.write(fd, data)
    os.close(fd)
    return path

def md5(filename):
     ''' compute md5sum, return None if file is not present '''
     if not os.path.exists(filename):
         return None
     if HAVE_HASHLIB:
         return hashlib.md5(file(filename).read()).hexdigest()
     else:
         return md5.new(file(filename).read()).hexdigest()

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

if len(sys.argv) == 1:
   fail_json(msg="the assemble module requires arguments (-a)")

argfile = sys.argv[1]
if not os.path.exists(argfile):
   fail_json(msg="Argument file not found")

args = open(argfile, 'r').read()
items = shlex.split(args)
syslog.openlog('ansible-%s' % os.path.basename(__file__))
syslog.syslog(syslog.LOG_NOTICE, 'Invoked with %s' % args)

if not len(items):
   fail_json(msg="the assemble module requires arguments (-a)")

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

changed = False
pathmd5 = None
destmd5 = None
src  = params.get('src', None)
dest = params.get('dest', None)

if src:
    src = os.path.expanduser(src)
if dest:
    dest = os.path.expanduser(dest)

if not os.path.exists(src):
    fail_json(msg="Source (%s) does not exist" % src)

if not os.path.isdir(src):
    fail_json(msg="Source (%s) is not a directory" % src)

path = write_temp_file(assemble_from_fragments(src))
pathmd5 = md5(path)

if os.path.exists(dest):
    destmd5 = md5(dest)

if pathmd5 != destmd5:
    shutil.copy(path, dest)
    changed = True

exit_json(md5sum=pathmd5, changed=changed)