#!/usr/bin/python
# -*- coding: utf-8 -*-

# (c) 2012, Michael DeHaan <michael.dehaan@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/>.

import os
import shutil
import time

def main():

    module = AnsibleModule(
        # not checking because of daisy chain to file module
        check_invalid_arguments = False,
        argument_spec = dict(
            src=dict(required=True),
            dest=dict(required=True),
            backup=dict(default=False, choices=BOOLEANS),
        )
    )

    src  = os.path.expanduser(module.params['src'])
    dest = os.path.expanduser(module.params['dest'])
    backup = module.boolean(module.params.get('backup', False))
    
    if not os.path.exists(src):
        module.fail_json(msg="Source %s failed to transfer" % (src))
    if not os.access(src, os.R_OK):
        module.fail_json(msg="Source %s not readable" % (src))

    md5sum_src = module.md5(src)
    md5sum_dest = None

    if os.path.exists(dest):
        if not os.access(dest, os.W_OK):
            module.fail_json(msg="Destination %s not writable" % (dest))
        if not os.access(dest, os.R_OK):
            module.fail_json(msg="Destination %s not readable" % (dest))
        # Allow dest to be directory without compromising md5 check
        if (os.path.isdir(dest)):
            module.fail_json(msg="Destination %s cannot be a directory" % (dest))
        md5sum_dest = module.md5(dest)
    else:
        if not os.access(os.path.dirname(dest), os.W_OK):
            module.fail_json(msg="Destination %s not writable" % (os.path.dirname(dest)))

    backup_file = None
    if md5sum_src != md5sum_dest:
        try:
            if backup:
                if os.path.exists(dest):
                    backup_file = module.backup_local(dest)
            #TODO:pid + epoch should avoid most collisions, hostname/mac for those using nfs?
            # might be an issue with exceeding path length
            dest_tmp = "%s.%s.%s.tmp" % (dest,os.getpid(),time.gmtime())
            shutil.copyfile(src, dest_tmp)
            shutil.move(dest_tmp, dest)
        except shutil.Error:
            module.fail_json(msg="failed to copy: %s and %s are the same" % (src, dest))
        except IOError:
            module.fail_json(msg="failed to copy: %s to %s" % (src, dest))
        changed = True
    else:
        changed = False

    res_args = {
        'dest':dest,
        'src':src,
        'md5sum':md5sum_src,
        'changed':changed
    }
    if backup_file:
        res_args['backup_file'] = backup_file
        
    module.exit_json(**res_args)

# this is magic, see lib/ansible/module_common.py
#<<INCLUDE_ANSIBLE_MODULE_COMMON>>
main()