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

# (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/>.

import os
import os.path
import shutil
import tempfile
import re

DOCUMENTATION = '''
---
module: assemble
short_description: Assembles a configuration file from fragments
description:
     - Assembles a configuration file from fragments. Often a particular
       program will take a single configuration file and does not support a
       C(conf.d) style structure where it is easy to build up the configuration
       from multiple sources. M(assemble) will take a directory of files that can be
       local or have already been transferred to the system, and concatenate them
       together to produce a destination file. Files are assembled in string sorting order.
       Puppet calls this idea I(fragments).
version_added: "0.5"
options:
  src:
    description:
      - An already existing directory full of source files.
    required: true
    default: null
    aliases: []
  dest:
    description:
      - A file to create using the concatenation of all of the source files.
    required: true
    default: null
  backup:
    description:
      - Create a backup file (if C(yes)), including the timestamp information so
        you can get the original file back if you somehow clobbered it
        incorrectly.
    required: false
    choices: [ "yes", "no" ]
    default: "no"
  delimiter:
    description:
      - A delimiter to seperate the file contents.
    version_added: "1.4"
    required: false
    default: null
  remote_src:
    description:
      - If False, it will search for src at originating/master machine, if True it will
        go to the remote/target machine for the src. Default is True.
    choices: [ "True", "False" ]
    required: false
    default: "True"
    version_added: "1.4"
  regexp:
    description:
      - Assemble files only if C(regex) matches the filename. If not set,
        all files are assembled. All "\" (backslash) must be escaped as
        "\\\\" to comply yaml syntax. Uses Python regular expressions; see
        U(http://docs.python.org/2/library/re.html).
    required: false
    default: null
  others:
    description:
      - all arguments accepted by the M(file) module also work here
    required: false
author: Stephen Fromm
'''

EXAMPLES = '''
# Example from Ansible Playbooks
- assemble: src=/etc/someapp/fragments dest=/etc/someapp/someapp.conf

# When a delimiter is specified, it will be inserted in between each fragment
- assemble: src=/etc/someapp/fragments dest=/etc/someapp/someapp.conf delimiter='### START FRAGMENT ###'
'''

# ===========================================
# Support method

def assemble_from_fragments(src_path, delimiter=None, compiled_regexp=None):
    ''' assemble a file from a directory of fragments '''
    tmpfd, temp_path = tempfile.mkstemp()
    tmp = os.fdopen(tmpfd,'w')
    delimit_me = False
    for f in sorted(os.listdir(src_path)):
        if compiled_regexp and not compiled_regexp.search(f):
            continue
        fragment = "%s/%s" % (src_path, f)
        if delimit_me and delimiter:
            # un-escape anything like newlines
            delimiter = delimiter.decode('unicode-escape')
            tmp.write(delimiter)
            # always make sure there's a newline after the 
            # delimiter, so lines don't run together
            if delimiter[-1] != '\n':
                tmp.write('\n')
        if os.path.isfile(fragment):
            tmp.write(file(fragment).read())
        delimit_me = True
    tmp.close()
    return temp_path

# ==============================================================
# main

def main():

    module = AnsibleModule(
        # not checking because of daisy chain to file module
        argument_spec = dict(
            src = dict(required=True),
            delimiter = dict(required=False),
            dest = dict(required=True),
            backup=dict(default=False, type='bool'),
            remote_src=dict(default=False, type='bool'),
            regexp = dict(required=False),
        ),
        add_file_common_args=True
    )

    changed   = False
    pathmd5   = None
    destmd5   = None
    src       = os.path.expanduser(module.params['src'])
    dest      = os.path.expanduser(module.params['dest'])
    backup    = module.params['backup']
    delimiter = module.params['delimiter']
    regexp    = module.params['regexp']
    compiled_regexp = None

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

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

    if regexp != None:
        try:
            compiled_regexp = re.compile(regexp)
        except re.error, e:
            module.fail_json(msg="Invalid Regexp (%s) in \"%s\"" % (e, regexp))

    path = assemble_from_fragments(src, delimiter, compiled_regexp)
    pathmd5 = module.md5(path)

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

    if pathmd5 != destmd5:
        if backup and destmd5 is not None:
            module.backup_local(dest)
        shutil.copy(path, dest)
        changed = True

    os.remove(path)

    file_args = module.load_file_common_arguments(module.params)
    changed = module.set_file_attributes_if_different(file_args, changed)
    # Mission complete
    module.exit_json(src=src, dest=dest, md5sum=pathmd5, changed=changed, msg="OK")

# import module snippets
from ansible.module_utils.basic import *

main()