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

# (c) 2012, Daniel Hokka Zakrisson <daniel@hozac.com>
# (c) 2014, Ahti Kitsik <ak@ahtik.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/>.

ANSIBLE_METADATA = {'status': ['preview'],
                    'supported_by': 'core',
                    'version': '1.0'}

DOCUMENTATION = """
---
module: lineinfile
author:
    - "Daniel Hokka Zakrissoni (@dhozac)"
    - "Ahti Kitsik (@ahtik)"
extends_documentation_fragment:
    - files
    - validate
short_description: Ensure a particular line is in a file, or replace an
                   existing line using a back-referenced regular expression.
description:
  - This module will search a file for a line, and ensure that it is present or absent.
  - This is primarily useful when you want to change a single line in
    a file only. See the M(replace) module if you want to change
    multiple, similar lines or check M(blockinfile) if you want to insert/update/remove a block of lines in a file.
    For other cases, see the M(copy) or M(template) modules.
version_added: "0.7"
options:
  dest:
    required: true
    aliases: [ name, destfile ]
    description:
      - The file to modify.
  regexp:
    required: false
    version_added: 1.7
    description:
      - The regular expression to look for in every line of the file. For
        C(state=present), the pattern to replace if found; only the last line
        found will be replaced. For C(state=absent), the pattern of the line
        to remove.  Uses Python regular expressions; see
        U(http://docs.python.org/2/library/re.html).
  state:
    required: false
    choices: [ present, absent ]
    default: "present"
    aliases: []
    description:
      - Whether the line should be there or not.
  line:
    required: false
    description:
      - Required for C(state=present). The line to insert/replace into the
        file. If C(backrefs) is set, may contain backreferences that will get
        expanded with the C(regexp) capture groups if the regexp matches.
  backrefs:
    required: false
    default: "no"
    choices: [ "yes", "no" ]
    version_added: "1.1"
    description:
      - Used with C(state=present). If set, line can contain backreferences
        (both positional and named) that will get populated if the C(regexp)
        matches. This flag changes the operation of the module slightly;
        C(insertbefore) and C(insertafter) will be ignored, and if the C(regexp)
        doesn't match anywhere in the file, the file will be left unchanged.
        If the C(regexp) does match, the last matching line will be replaced by
        the expanded line parameter.
  insertafter:
    required: false
    default: EOF
    description:
      - Used with C(state=present). If specified, the line will be inserted
        after the last match of specified regular expression. A special value is
        available; C(EOF) for inserting the line at the end of the file.
        If specified regular expression has no matches, EOF will be used instead.
        May not be used with C(backrefs).
    choices: [ 'EOF', '*regex*' ]
  insertbefore:
    required: false
    version_added: "1.1"
    description:
      - Used with C(state=present). If specified, the line will be inserted
        before the last match of specified regular expression. A value is
        available; C(BOF) for inserting the line at the beginning of the file.
        If specified regular expression has no matches, the line will be
        inserted at the end of the file.  May not be used with C(backrefs).
    choices: [ 'BOF', '*regex*' ]
  create:
    required: false
    choices: [ "yes", "no" ]
    default: "no"
    description:
      - Used with C(state=present). If specified, the file will be created
        if it does not already exist. By default it will fail if the file
        is missing.
  backup:
     required: false
     default: "no"
     choices: [ "yes", "no" ]
     description:
       - Create a backup file including the timestamp information so you can
         get the original file back if you somehow clobbered it incorrectly.
  others:
     description:
       - All arguments accepted by the M(file) module also work here.
     required: false
"""

EXAMPLES = r"""
- lineinfile:
    dest: /etc/selinux/config
    regexp: '^SELINUX='
    line: 'SELINUX=enforcing'

- lineinfile:
    dest: /etc/sudoers
    state: absent
    regexp: '^%wheel'

- lineinfile:
    dest: /etc/hosts
    regexp: '^127\.0\.0\.1'
    line: '127.0.0.1 localhost'
    owner: root
    group: root
    mode: 0644

- lineinfile:
    dest: /etc/httpd/conf/httpd.conf
    regexp: '^Listen '
    insertafter: '^#Listen '
    line: 'Listen 8080'

- lineinfile:
    dest: /etc/services
    regexp: '^# port for http'
    insertbefore: '^www.*80/tcp'
    line: '# port for http by default'

# Add a line to a file if it does not exist, without passing regexp
- lineinfile:
    dest: /tmp/testfile
    line: '192.168.1.99 foo.lab.net foo'

# Fully quoted because of the ': ' on the line. See the Gotchas in the YAML docs.
- lineinfile: "
    dest: /etc/sudoers
    state: present
    regexp: '^%wheel'
    line: '%wheel ALL=(ALL) NOPASSWD: ALL'

- lineinfile:
    dest: /opt/jboss-as/bin/standalone.conf
    regexp: '^(.*)Xms(\d+)m(.*)$'
    line: '\1Xms${xms}m\3'
    backrefs: yes

# Validate the sudoers file before saving
- lineinfile:
    dest: /etc/sudoers
    state: present
    regexp: '^%ADMIN ALL='
    line: '%ADMIN ALL=(ALL) NOPASSWD: ALL'
    validate: 'visudo -cf %s'
"""

import re
import os
import tempfile

# import module snippets
from ansible.module_utils.basic import AnsibleModule
from ansible.module_utils.six import b
from ansible.module_utils._text import to_bytes, to_native


def write_changes(module, b_lines, dest):

    tmpfd, tmpfile = tempfile.mkstemp()
    f = os.fdopen(tmpfd, 'wb')
    f.writelines(b_lines)
    f.close()

    validate = module.params.get('validate', None)
    valid = not validate
    if validate:
        if "%s" not in validate:
            module.fail_json(msg="validate must contain %%s: %s" % (validate))
        (rc, out, err) = module.run_command(to_bytes(validate % tmpfile, errors='surrogate_or_strict'))
        valid = rc == 0
        if rc != 0:
            module.fail_json(msg='failed to validate: '
                                 'rc:%s error:%s' % (rc, err))
    if valid:
        module.atomic_move(tmpfile,
                to_native(os.path.realpath(to_bytes(dest, errors='surrogate_or_strict')), errors='surrogate_or_strict'),
                unsafe_writes=module.params['unsafe_writes'])


def check_file_attrs(module, changed, message, diff):

    file_args = module.load_file_common_arguments(module.params)
    if module.set_fs_attributes_if_different(file_args, False, diff=diff):

        if changed:
            message += " and "
        changed = True
        message += "ownership, perms or SE linux context changed"

    return message, changed


def present(module, dest, regexp, line, insertafter, insertbefore, create,
            backup, backrefs):

    diff = {'before': '',
            'after': '',
            'before_header': '%s (content)' % dest,
            'after_header': '%s (content)' % dest}

    b_dest = to_bytes(dest, errors='surrogate_or_strict')
    if not os.path.exists(b_dest):
        if not create:
            module.fail_json(rc=257, msg='Destination %s does not exist !' % dest)
        b_destpath = os.path.dirname(b_dest)
        if not os.path.exists(b_destpath) and not module.check_mode:
            os.makedirs(b_destpath)
        b_lines = []
    else:
        f = open(b_dest, 'rb')
        b_lines = f.readlines()
        f.close()

    if module._diff:
        diff['before'] = to_native(b('').join(b_lines))

    if regexp is not None:
        bre_m = re.compile(to_bytes(regexp, errors='surrogate_or_strict'))

    if insertafter not in (None, 'BOF', 'EOF'):
        bre_ins = re.compile(to_bytes(insertafter, errors='surrogate_or_strict'))
    elif insertbefore not in (None, 'BOF'):
        bre_ins = re.compile(to_bytes(insertbefore, errors='surrogate_or_strict'))
    else:
        bre_ins = None

    # index[0] is the line num where regexp has been found
    # index[1] is the line num where insertafter/inserbefore has been found
    index = [-1, -1]
    m = None
    b_line = to_bytes(line, errors='surrogate_or_strict')
    for lineno, b_cur_line in enumerate(b_lines):
        if regexp is not None:
            match_found = bre_m.search(b_cur_line)
        else:
            match_found = b_line == b_cur_line.rstrip(b('\r\n'))
        if match_found:
            index[0] = lineno
            m = match_found
        elif bre_ins is not None and bre_ins.search(b_cur_line):
            if insertafter:
                # + 1 for the next line
                index[1] = lineno + 1
            if insertbefore:
                # + 1 for the previous line
                index[1] = lineno

    msg = ''
    changed = False
    # Regexp matched a line in the file
    b_linesep = to_bytes(os.linesep, errors='surrogate_or_strict')
    if index[0] != -1:
        if backrefs:
            b_new_line = m.expand(b_line)
        else:
            # Don't do backref expansion if not asked.
            b_new_line = b_line

        if not b_new_line.endswith(b_linesep):
            b_new_line += b_linesep

        if b_lines[index[0]] != b_new_line:
            b_lines[index[0]] = b_new_line
            msg = 'line replaced'
            changed = True
    elif backrefs:
        # Do absolutely nothing, since it's not safe generating the line
        # without the regexp matching to populate the backrefs.
        pass
    # Add it to the beginning of the file
    elif insertbefore == 'BOF' or insertafter == 'BOF':
        b_lines.insert(0, b_line + b_linesep)
        msg = 'line added'
        changed = True
    # Add it to the end of the file if requested or
    # if insertafter/insertbefore didn't match anything
    # (so default behaviour is to add at the end)
    elif insertafter == 'EOF' or index[1] == -1:

        # If the file is not empty then ensure there's a newline before the added line
        if len(b_lines) > 0 and not b_lines[-1][-1:] in (b('\n'), b('\r')):
            b_lines.append(b_linesep)

        b_lines.append(b_line + b_linesep)
        msg = 'line added'
        changed = True
    # insert* matched, but not the regexp
    else:
        b_lines.insert(index[1], b_line + b_linesep)
        msg = 'line added'
        changed = True

    if module._diff:
        diff['after'] = to_native(b('').join(b_lines))

    backupdest = ""
    if changed and not module.check_mode:
        if backup and os.path.exists(b_dest):
            backupdest = module.backup_local(dest)
        write_changes(module, b_lines, dest)

    if module.check_mode and not os.path.exists(b_dest):
        module.exit_json(changed=changed, msg=msg, backup=backupdest, diff=diff)

    attr_diff = {}
    msg, changed = check_file_attrs(module, changed, msg, attr_diff)

    attr_diff['before_header'] = '%s (file attributes)' % dest
    attr_diff['after_header'] = '%s (file attributes)' % dest

    difflist = [diff, attr_diff]
    module.exit_json(changed=changed, msg=msg, backup=backupdest, diff=difflist)


def absent(module, dest, regexp, line, backup):

    b_dest = to_bytes(dest, errors='surrogate_or_strict')
    if not os.path.exists(b_dest):
        module.exit_json(changed=False, msg="file not present")

    msg = ''
    diff = {'before': '',
            'after': '',
            'before_header': '%s (content)' % dest,
            'after_header': '%s (content)' % dest}

    f = open(b_dest, 'rb')
    b_lines = f.readlines()
    f.close()

    if module._diff:
        diff['before'] = to_native(b('').join(b_lines))

    if regexp is not None:
        bre_c = re.compile(to_bytes(regexp, errors='surrogate_or_strict'))
    found = []

    b_line = to_bytes(line, errors='surrogate_or_strict')
    def matcher(b_cur_line):
        if regexp is not None:
            match_found = bre_c.search(b_cur_line)
        else:
            match_found = b_line == b_cur_line.rstrip(b('\r\n'))
        if match_found:
            found.append(b_cur_line)
        return not match_found

    b_lines = [l for l in b_lines if matcher(l)]
    changed = len(found) > 0

    if module._diff:
        diff['after'] = to_native(b('').join(b_lines))

    backupdest = ""
    if changed and not module.check_mode:
        if backup:
            backupdest = module.backup_local(dest)
        write_changes(module, b_lines, dest)

    if changed:
        msg = "%s line(s) removed" % len(found)

    attr_diff = {}
    msg, changed = check_file_attrs(module, changed, msg, attr_diff)

    attr_diff['before_header'] = '%s (file attributes)' % dest
    attr_diff['after_header'] = '%s (file attributes)' % dest

    difflist = [diff, attr_diff]

    module.exit_json(changed=changed, found=len(found), msg=msg, backup=backupdest, diff=difflist)


def main():
    module = AnsibleModule(
        argument_spec=dict(
            dest=dict(required=True, aliases=['name', 'destfile'], type='path'),
            state=dict(default='present', choices=['absent', 'present']),
            regexp=dict(default=None),
            line=dict(aliases=['value']),
            insertafter=dict(default=None),
            insertbefore=dict(default=None),
            backrefs=dict(default=False, type='bool'),
            create=dict(default=False, type='bool'),
            backup=dict(default=False, type='bool'),
            validate=dict(default=None, type='str'),
        ),
        mutually_exclusive=[['insertbefore', 'insertafter']],
        add_file_common_args=True,
        supports_check_mode=True
    )

    params = module.params
    create = params['create']
    backup = params['backup']
    backrefs = params['backrefs']
    dest = params['dest']

    b_dest = to_bytes(dest, errors='surrogate_or_strict')
    if os.path.isdir(b_dest):
        module.fail_json(rc=256, msg='Destination %s is a directory !' % dest)

    if params['state'] == 'present':
        if backrefs and params['regexp'] is None:
            module.fail_json(msg='regexp= is required with backrefs=true')

        if params.get('line', None) is None:
            module.fail_json(msg='line= is required with state=present')

        # Deal with the insertafter default value manually, to avoid errors
        # because of the mutually_exclusive mechanism.
        ins_bef, ins_aft = params['insertbefore'], params['insertafter']
        if ins_bef is None and ins_aft is None:
            ins_aft = 'EOF'

        line = params['line']

        present(module, dest, params['regexp'], line,
                ins_aft, ins_bef, create, backup, backrefs)
    else:
        if params['regexp'] is None and params.get('line', None) is None:
            module.fail_json(msg='one of line= or regexp= is required with state=absent')

        absent(module, dest, params['regexp'], params.get('line', None), backup)

if __name__ == '__main__':
    main()