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

# Copyright: (c) 2012, Stephen Fromm <sfromm@gmail.com>
# Copyright: (c) 2016, Toshio Kuratomi <tkuratomi@ansible.com>
# Copyright: (c) 2017, Ansible Project
# GNU General Public License v3.0+ (see COPYING or https://www.gnu.org/licenses/gpl-3.0.txt)

from __future__ import absolute_import, division, print_function
__metaclass__ = type

ANSIBLE_METADATA = {'metadata_version': '1.1',
                    'status': ['stableinterface'],
                    'supported_by': 'core'}

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. C(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
  dest:
    description:
      - A file to create using the concatenation of all of the source files.
    required: true
  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.
    type: bool
    default: 'no'
  delimiter:
    description:
      - A delimiter to separate the file contents.
    version_added: "1.4"
  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.
    type: bool
    default: 'yes'
    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).
  ignore_hidden:
    description:
      - A boolean that controls if files that start with a '.' will be included or not.
    type: bool
    default: 'no'
    version_added: "2.0"
  validate:
    description:
      - The validation command to run before copying into place.  The path to the file to
        validate is passed in via '%s' which must be present as in the sshd example below.
        The command is passed securely so shell features like expansion and pipes won't work.
    version_added: "2.0"
author:
- Stephen Fromm (@sfromm)
extends_documentation_fragment:
    - files
    - decrypt
'''

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 ###'

# Copy a new "sshd_config" file into place, after passing validation with sshd
- assemble:
    src: /etc/ssh/conf.d/
    dest: /etc/ssh/sshd_config
    validate: '/usr/sbin/sshd -t -f %s'
'''

import codecs
import os
import re
import tempfile

from ansible.module_utils.basic import AnsibleModule
from ansible.module_utils.six import b
from ansible.module_utils._text import to_native


def assemble_from_fragments(src_path, delimiter=None, compiled_regexp=None, ignore_hidden=False, tmpdir=None):
    ''' assemble a file from a directory of fragments '''
    tmpfd, temp_path = tempfile.mkstemp(dir=tmpdir)
    tmp = os.fdopen(tmpfd, 'wb')
    delimit_me = False
    add_newline = False

    for f in sorted(os.listdir(src_path)):
        if compiled_regexp and not compiled_regexp.search(f):
            continue
        fragment = os.path.join(src_path, f)
        if not os.path.isfile(fragment) or (ignore_hidden and os.path.basename(fragment).startswith('.')):
            continue
        fragment_content = open(fragment, 'rb').read()

        # always put a newline between fragments if the previous fragment didn't end with a newline.
        if add_newline:
            tmp.write(b('\n'))

        # delimiters should only appear between fragments
        if delimit_me:
            if delimiter:
                # un-escape anything like newlines
                delimiter = codecs.escape_decode(delimiter)[0]
                tmp.write(delimiter)
                # always make sure there's a newline after the
                # delimiter, so lines don't run together
                if delimiter[-1] != b('\n'):
                    tmp.write(b('\n'))

        tmp.write(fragment_content)
        delimit_me = True
        if fragment_content.endswith(b('\n')):
            add_newline = False
        else:
            add_newline = True

    tmp.close()
    return temp_path


def cleanup(path, result=None):
    # cleanup just in case
    if os.path.exists(path):
        try:
            os.remove(path)
        except (IOError, OSError) as e:
            # don't error on possible race conditions, but keep warning
            if result is not None:
                result['warnings'] = ['Unable to remove temp file (%s): %s' % (path, to_native(e))]


def main():

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

    changed = False
    path_hash = None
    dest_hash = None
    src = module.params['src']
    dest = module.params['dest']
    backup = module.params['backup']
    delimiter = module.params['delimiter']
    regexp = module.params['regexp']
    compiled_regexp = None
    ignore_hidden = module.params['ignore_hidden']
    validate = module.params.get('validate', None)

    result = dict(src=src, dest=dest)
    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 is not None:
        try:
            compiled_regexp = re.compile(regexp)
        except re.error as e:
            module.fail_json(msg="Invalid Regexp (%s) in \"%s\"" % (to_native(e), regexp))

    if validate and "%s" not in validate:
        module.fail_json(msg="validate must contain %%s: %s" % validate)

    path = assemble_from_fragments(src, delimiter, compiled_regexp, ignore_hidden, module.tmpdir)
    path_hash = module.sha1(path)
    result['checksum'] = path_hash

    # Backwards compat.  This won't return data if FIPS mode is active
    try:
        pathmd5 = module.md5(path)
    except ValueError:
        pathmd5 = None
    result['md5sum'] = pathmd5

    if os.path.exists(dest):
        dest_hash = module.sha1(dest)

    if path_hash != dest_hash:
        if validate:
            (rc, out, err) = module.run_command(validate % path)
            result['validation'] = dict(rc=rc, stdout=out, stderr=err)
            if rc != 0:
                cleanup(path)
                module.fail_json(msg="failed to validate: rc:%s error:%s" % (rc, err))
        if backup and dest_hash is not None:
            result['backup_file'] = module.backup_local(dest)

        module.atomic_move(path, dest, unsafe_writes=module.params['unsafe_writes'])
        changed = True

    cleanup(path, result)

    # handle file permissions
    file_args = module.load_file_common_arguments(module.params)
    result['changed'] = module.set_fs_attributes_if_different(file_args, changed)

    # Mission complete
    result['msg'] = "OK"
    module.exit_json(**result)


if __name__ == '__main__':
    main()
