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

# Copyright 2014, Red Hat, Inc.
#     Tim Bielawa <tbielawa@redhat.com>
#     Magnus Hedemark <mhedemar@redhat.com>
# Copyright 2017, Dag Wieers <dag@wieers.com>

# 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': ['preview'],
                    'supported_by': 'community'}

DOCUMENTATION = r'''
---
module: xml
short_description: Manage bits and pieces of XML files or strings
description:
- A CRUD-like interface to managing bits of XML files.
- You might also be interested in a brief tutorial from U(http://www.w3schools.com/xpath/)
  and U(https://developer.mozilla.org/en-US/docs/Web/XPath).
version_added: '2.4'
options:
  path:
    description:
    - Path to the file to operate on. File must exist ahead of time.
    - This parameter is required, unless C(xmlstring) is given.
    required: yes
    aliases: [ dest, file ]
  xmlstring:
    description:
    - A string containing XML on which to operate.
    - This parameter is required, unless C(path) is given.
    required: yes
  xpath:
    description:
    - A valid XPath expression describing the item(s) you want to manipulate.
    - Operates on the document root, C(/), by default.
    default: /
  namespaces:
    description:
    - The namespace C(prefix:uri) mapping for the XPath expression.
    - Needs to be a C(dict), not a C(list) of items.
  state:
    description:
    - Set or remove an xpath selection (node(s), attribute(s)).
    default: present
    choices: [ absent, present ]
    aliases: [ ensure ]
  attribute:
    description:
    - The attribute to select when using parameter C(value).
    - This is a string, not prepended with C(@).
  value:
    description:
    - Desired state of the selected attribute.
    - Either a string, or to unset a value, the Python C(None) keyword (YAML Equivalent, C(null)).
    - Elements default to no value (but present).
    - Attributes default to an empty string.
  add_children:
    description:
    - Add additional child-element(s) to a selected element for a given C(xpath).
    - Child elements must be given in a list and each item may be either a string
      (eg. C(children=ansible) to add an empty C(<ansible/>) child element),
      or a hash where the key is an element name and the value is the element value.
    - This parameter requires C(xpath) to be set.
  set_children:
    description:
    - Set the child-element(s) of a selected element for a given C(xpath).
    - Removes any existing children.
    - Child elements must be specified as in C(add_children).
    - This parameter requires C(xpath) to be set.
  count:
    description:
    - Search for a given C(xpath) and provide the count of any matches.
    - This parameter requires C(xpath) to be set.
    type: bool
    default: 'no'
  print_match:
    description:
    - Search for a given C(xpath) and print out any matches.
    - This parameter requires C(xpath) to be set.
    type: bool
    default: 'no'
  pretty_print:
    description:
    - Pretty print XML output.
    type: bool
    default: 'no'
  content:
    description:
    - Search for a given C(xpath) and get content.
    - This parameter requires C(xpath) to be set.
    choices: [ attribute, text ]
  input_type:
    description:
    - Type of input for C(add_children) and C(set_children).
    choices: [ xml, yaml ]
    default: yaml
  backup:
    description:
      - Create a backup file including the timestamp information so you can get
        the original file back if you somehow clobbered it incorrectly.
    type: bool
    default: 'no'
requirements:
- lxml >= 2.3.0
notes:
- Use the C(--check) and C(--diff) options when testing your expressions.
- The diff output is automatically pretty-printed, so may not reflect the actual file content, only the file structure.
- This module does not handle complicated xpath expressions, so limit xpath selectors to simple expressions.
- Beware that in case your XML elements are namespaced, you need to use the C(namespaces) parameter.
- Namespaces prefix should be used for all children of an element where namespace is defined, unless another namespace is defined for them.
- More information about this module is available from the community wiki at U(https://github.com/ansible/community/wiki/Module:-xml)
author:
- Tim Bielawa (@tbielawa)
- Magnus Hedemark (@magnus919)
- Dag Wieers (@dagwieers)
'''

EXAMPLES = r'''
- name: Remove the subjective attribute of the rating element
  xml:
    path: /foo/bar.xml
    xpath: /business/rating/@subjective
    state: absent

- name: Set the rating to 11
  xml:
    path: /foo/bar.xml
    xpath: /business/rating
    value: 11

# Retrieve and display the number of nodes
- name: Get count of beers nodes
  xml:
    path: /foo/bar.xml
    xpath: /business/beers/beer
    count: yes
  register: hits

- debug:
    var: hits.count

- name: Add a phonenumber element to the business element
  xml:
    path: /foo/bar.xml
    xpath: /business/phonenumber
    value: 555-555-1234

- name: Add several more beers to the beers element
  xml:
    path: /foo/bar.xml
    xpath: /business/beers
    add_children:
    - beer: Old Rasputin
    - beer: Old Motor Oil
    - beer: Old Curmudgeon

- name: Add a validxhtml element to the website element
  xml:
    path: /foo/bar.xml
    xpath: /business/website/validxhtml

- name: Add an empty validatedon attribute to the validxhtml element
  xml:
    path: /foo/bar.xml
    xpath: /business/website/validxhtml/@validatedon

- name: Add or modify an attribute, add element if needed
  xml:
    path: /foo/bar.xml
    xpath: /business/website/validxhtml
    attribute: validatedon
    value: 1976-08-05

# How to read an attrribute value and access it in Ansible
- name: Read attribute value
  xml:
    path: /foo/bar.xml
    xpath: /business/website/validxhtml
    content: attribute
    attribute: validatedon
  register: xmlresp

- name: Show attribute value
  debug:
    var: xmlresp.matches[0].validxhtml.validatedon

- name: Remove all children from the website element (option 1)
  xml:
    path: /foo/bar.xml
    xpath: /business/website/*
    state: absent

- name: Remove all children from the website element (option 2)
  xml:
    path: /foo/bar.xml
    xpath: /business/website
    children: []

# In case of namespaces, like in below XML, they have to be explicitely stated
# NOTE: there's the prefix "x" in front of the "bar", too
#<?xml version='1.0' encoding='UTF-8'?>
#<foo xmlns="http://x.test" xmlns:attr="http://z.test">
#  <bar>
#    <baz xmlns="http://y.test" attr:my_namespaced_attribute="true" />
#  </bar>
#</foo>

- name: Set namespaced '/x:foo/x:bar/y:baz/@z:my_namespaced_attribute' to 'false'
  xml:
    path: foo.xml
    xpath: /x:foo/x:bar/y:baz
    namespaces:
      x: http://x.test
      y: http://y.test
      z: http://z.test
    attribute: z:my_namespaced_attribute
    value: 'false'
'''

RETURN = r'''
actions:
    description: A dictionary with the original xpath, namespaces and state.
    type: dict
    returned: success
    sample: {xpath: xpath, namespaces: [namespace1, namespace2], state=present}
backup_file:
    description: The name of the backup file that was created
    type: str
    returned: when backup=yes
    sample: /path/to/file.xml.1942.2017-08-24@14:16:01~
count:
    description: The count of xpath matches.
    type: int
    returned: when parameter 'count' is set
    sample: 2
matches:
    description: The xpath matches found.
    type: list
    returned: when parameter 'print_match' is set
msg:
    description: A message related to the performed action(s).
    type: string
    returned: always
xmlstring:
    description: An XML string of the resulting output.
    type: string
    returned: when parameter 'xmlstring' is set
'''

import copy
import json
import os
import re
import traceback

from collections import MutableMapping
from distutils.version import LooseVersion
from io import BytesIO

try:
    from lxml import etree, objectify
    HAS_LXML = True
except ImportError:
    HAS_LXML = False

from ansible.module_utils.basic import AnsibleModule, json_dict_bytes_to_unicode
from ansible.module_utils.six import iteritems, string_types
from ansible.module_utils._text import to_bytes, to_native

_IDENT = "[a-zA-Z-][a-zA-Z0-9_\-\.]*"
_NSIDENT = _IDENT + "|" + _IDENT + ":" + _IDENT
# Note: we can't reasonably support the 'if you need to put both ' and " in a string, concatenate
# strings wrapped by the other delimiter' XPath trick, especially as simple XPath.
_XPSTR = "('(?:.*)'|\"(?:.*)\")"

_RE_SPLITSIMPLELAST = re.compile("^(.*)/(" + _NSIDENT + ")$")
_RE_SPLITSIMPLELASTEQVALUE = re.compile("^(.*)/(" + _NSIDENT + ")/text\\(\\)=" + _XPSTR + "$")
_RE_SPLITSIMPLEATTRLAST = re.compile("^(.*)/(@(?:" + _NSIDENT + "))$")
_RE_SPLITSIMPLEATTRLASTEQVALUE = re.compile("^(.*)/(@(?:" + _NSIDENT + "))=" + _XPSTR + "$")
_RE_SPLITSUBLAST = re.compile("^(.*)/(" + _NSIDENT + ")\\[(.*)\\]$")
_RE_SPLITONLYEQVALUE = re.compile("^(.*)/text\\(\\)=" + _XPSTR + "$")


def has_changed(doc):
    orig_obj = etree.tostring(objectify.fromstring(etree.tostring(orig_doc)))
    obj = etree.tostring(objectify.fromstring(etree.tostring(doc)))
    return (orig_obj != obj)


def do_print_match(module, tree, xpath, namespaces):
    match = tree.xpath(xpath, namespaces=namespaces)
    match_xpaths = []
    for m in match:
        match_xpaths.append(tree.getpath(m))
    match_str = json.dumps(match_xpaths)
    msg = "selector '%s' match: %s" % (xpath, match_str)
    finish(module, tree, xpath, namespaces, changed=False, msg=msg)


def count_nodes(module, tree, xpath, namespaces):
    """ Return the count of nodes matching the xpath """
    hits = tree.xpath("count(/%s)" % xpath, namespaces=namespaces)
    msg = "found %d nodes" % hits
    finish(module, tree, xpath, namespaces, changed=False, msg=msg, hitcount=int(hits))


def is_node(tree, xpath, namespaces):
    """ Test if a given xpath matches anything and if that match is a node.

    For now we just assume you're only searching for one specific thing."""
    if xpath_matches(tree, xpath, namespaces):
        # OK, it found something
        match = tree.xpath(xpath, namespaces=namespaces)
        if isinstance(match[0], etree._Element):
            return True

    return False


def is_attribute(tree, xpath, namespaces):
    """ Test if a given xpath matches and that match is an attribute

    An xpath attribute search will only match one item"""
    if xpath_matches(tree, xpath, namespaces):
        match = tree.xpath(xpath, namespaces=namespaces)
        if isinstance(match[0], etree._ElementStringResult):
            return True
        elif isinstance(match[0], etree._ElementUnicodeResult):
            return True
    return False


def xpath_matches(tree, xpath, namespaces):
    """ Test if a node exists """
    if tree.xpath(xpath, namespaces=namespaces):
        return True
    return False


def delete_xpath_target(module, tree, xpath, namespaces):
    """ Delete an attribute or element from a tree """
    try:
        for result in tree.xpath(xpath, namespaces=namespaces):
            # Get the xpath for this result
            if is_attribute(tree, xpath, namespaces):
                # Delete an attribute
                parent = result.getparent()
                # Pop this attribute match out of the parent
                # node's 'attrib' dict by using this match's
                # 'attrname' attribute for the key
                parent.attrib.pop(result.attrname)
            elif is_node(tree, xpath, namespaces):
                # Delete an element
                result.getparent().remove(result)
            else:
                raise Exception("Impossible error")
    except Exception as e:
        module.fail_json(msg="Couldn't delete xpath target: %s (%s)" % (xpath, e))
    else:
        finish(module, tree, xpath, namespaces, changed=True)


def replace_children_of(children, match):
    for element in match.getchildren():
        match.remove(element)
    match.extend(children)


def set_target_children_inner(module, tree, xpath, namespaces, children, in_type):
    matches = tree.xpath(xpath, namespaces=namespaces)

    # Create a list of our new children
    children = children_to_nodes(module, children, in_type)
    children_as_string = [etree.tostring(c) for c in children]

    changed = False

    # xpaths always return matches as a list, so....
    for match in matches:
        # Check if elements differ
        if len(match.getchildren()) == len(children):
            for idx, element in enumerate(match.getchildren()):
                if etree.tostring(element) != children_as_string[idx]:
                    replace_children_of(children, match)
                    changed = True
                    break
        else:
            replace_children_of(children, match)
            changed = True

    return changed


def set_target_children(module, tree, xpath, namespaces, children, in_type):
    changed = set_target_children_inner(module, tree, xpath, namespaces, children, in_type)
    # Write it out
    finish(module, tree, xpath, namespaces, changed=changed)


def add_target_children(module, tree, xpath, namespaces, children, in_type):
    if is_node(tree, xpath, namespaces):
        new_kids = children_to_nodes(module, children, in_type)
        for node in tree.xpath(xpath, namespaces=namespaces):
            node.extend(new_kids)
        finish(module, tree, xpath, namespaces, changed=True)
    else:
        finish(module, tree, xpath, namespaces)


def _extract_xpstr(g):
    return g[1:-1]


def split_xpath_last(xpath):
    """split an XPath of the form /foo/bar/baz into /foo/bar and baz"""
    xpath = xpath.strip()
    m = _RE_SPLITSIMPLELAST.match(xpath)
    if m:
        # requesting an element to exist
        return (m.group(1), [(m.group(2), None)])
    m = _RE_SPLITSIMPLELASTEQVALUE.match(xpath)
    if m:
        # requesting an element to exist with an inner text
        return (m.group(1), [(m.group(2), _extract_xpstr(m.group(3)))])

    m = _RE_SPLITSIMPLEATTRLAST.match(xpath)
    if m:
        # requesting an attribute to exist
        return (m.group(1), [(m.group(2), None)])
    m = _RE_SPLITSIMPLEATTRLASTEQVALUE.match(xpath)
    if m:
        # requesting an attribute to exist with a value
        return (m.group(1), [(m.group(2), _extract_xpstr(m.group(3)))])

    m = _RE_SPLITSUBLAST.match(xpath)
    if m:
        content = [x.strip() for x in m.group(3).split(" and ")]
        return (m.group(1), [('/' + m.group(2), content)])

    m = _RE_SPLITONLYEQVALUE.match(xpath)
    if m:
        # requesting a change of inner text
        return (m.group(1), [("", _extract_xpstr(m.group(2)))])
    return (xpath, [])


def nsnameToClark(name, namespaces):
    if ":" in name:
        (nsname, rawname) = name.split(":")
        # return "{{%s}}%s" % (namespaces[nsname], rawname)
        return "{{{0}}}{1}".format(namespaces[nsname], rawname)
    else:
        # no namespace name here
        return name


def check_or_make_target(module, tree, xpath, namespaces):
    (inner_xpath, changes) = split_xpath_last(xpath)
    if (inner_xpath == xpath) or (changes is None):
        module.fail_json(msg="Can't process Xpath %s in order to spawn nodes! tree is %s" %
                             (xpath, etree.tostring(tree, pretty_print=True)))
        return False

    changed = False

    if not is_node(tree, inner_xpath, namespaces):
        changed = check_or_make_target(module, tree, inner_xpath, namespaces)

    # we test again after calling check_or_make_target
    if is_node(tree, inner_xpath, namespaces) and changes:
        for (eoa, eoa_value) in changes:
            if eoa and eoa[0] != '@' and eoa[0] != '/':
                # implicitly creating an element
                new_kids = children_to_nodes(module, [nsnameToClark(eoa, namespaces)], "yaml")
                if eoa_value:
                    for nk in new_kids:
                        nk.text = eoa_value

                for node in tree.xpath(inner_xpath, namespaces=namespaces):
                    node.extend(new_kids)
                    changed = True
                # module.fail_json(msg="now tree=%s" % etree.tostring(tree, pretty_print=True))
            elif eoa and eoa[0] == '/':
                element = eoa[1:]
                new_kids = children_to_nodes(module, [nsnameToClark(element, namespaces)], "yaml")
                for node in tree.xpath(inner_xpath, namespaces=namespaces):
                    node.extend(new_kids)
                    for nk in new_kids:
                        for subexpr in eoa_value:
                            # module.fail_json(msg="element=%s subexpr=%s node=%s now tree=%s" %
                            #                      (element, subexpr, etree.tostring(node, pretty_print=True), etree.tostring(tree, pretty_print=True))
                            check_or_make_target(module, nk, "./" + subexpr, namespaces)
                    changed = True

                # module.fail_json(msg="now tree=%s" % etree.tostring(tree, pretty_print=True))
            elif eoa == "":
                for node in tree.xpath(inner_xpath, namespaces=namespaces):
                    if (node.text != eoa_value):
                        node.text = eoa_value
                        changed = True

            elif eoa and eoa[0] == '@':
                attribute = nsnameToClark(eoa[1:], namespaces)

                for element in tree.xpath(inner_xpath, namespaces=namespaces):
                    changing = (attribute not in element.attrib or element.attrib[attribute] != eoa_value)

                    if changing:
                        changed = changed or changing
                        if eoa_value is None:
                            value = ""
                        else:
                            value = eoa_value
                        element.attrib[attribute] = value

                    # module.fail_json(msg="arf %s changing=%s as curval=%s changed tree=%s" %
                    #       (xpath, changing, etree.tostring(tree, changing, element[attribute], pretty_print=True)))

            else:
                module.fail_json(msg="unknown tree transformation=%s" % etree.tostring(tree, pretty_print=True))

    return changed


def ensure_xpath_exists(module, tree, xpath, namespaces):
    changed = False

    if not is_node(tree, xpath, namespaces):
        changed = check_or_make_target(module, tree, xpath, namespaces)

    finish(module, tree, xpath, namespaces, changed)


def set_target_inner(module, tree, xpath, namespaces, attribute, value):
    changed = False

    try:
        if not is_node(tree, xpath, namespaces):
            changed = check_or_make_target(module, tree, xpath, namespaces)
    except Exception as e:
        module.fail_json(msg="Xpath %s causes a failure: %s\n  -- tree is %s" %
                             (xpath, e, etree.tostring(tree, pretty_print=True)), exception=traceback.format_exc(e))

    if not is_node(tree, xpath, namespaces):
        module.fail_json(msg="Xpath %s does not reference a node! tree is %s" %
                             (xpath, etree.tostring(tree, pretty_print=True)))

    for element in tree.xpath(xpath, namespaces=namespaces):
        if not attribute:
            changed = changed or (element.text != value)
            if element.text != value:
                element.text = value
        else:
            changed = changed or (element.get(attribute) != value)
            if ":" in attribute:
                attr_ns, attr_name = attribute.split(":")
                # attribute = "{{%s}}%s" % (namespaces[attr_ns], attr_name)
                attribute = "{{{0}}}{1}".format(namespaces[attr_ns], attr_name)
            if element.get(attribute) != value:
                element.set(attribute, value)

    return changed


def set_target(module, tree, xpath, namespaces, attribute, value):
    changed = set_target_inner(module, tree, xpath, namespaces, attribute, value)
    finish(module, tree, xpath, namespaces, changed)


def get_element_text(module, tree, xpath, namespaces):
    if not is_node(tree, xpath, namespaces):
        module.fail_json(msg="Xpath %s does not reference a node!" % xpath)

    elements = []
    for element in tree.xpath(xpath, namespaces=namespaces):
        elements.append({element.tag: element.text})

    finish(module, tree, xpath, namespaces, changed=False, msg=len(elements), hitcount=len(elements), matches=elements)


def get_element_attr(module, tree, xpath, namespaces):
    if not is_node(tree, xpath, namespaces):
        module.fail_json(msg="Xpath %s does not reference a node!" % xpath)

    elements = []
    for element in tree.xpath(xpath, namespaces=namespaces):
        child = {}
        for key in element.keys():
            value = element.get(key)
            child.update({key: value})
        elements.append({element.tag: child})

    finish(module, tree, xpath, namespaces, changed=False, msg=len(elements), hitcount=len(elements), matches=elements)


def child_to_element(module, child, in_type):
    if in_type == 'xml':
        infile = BytesIO(to_bytes(child, errors='surrogate_or_strict'))

        try:
            parser = etree.XMLParser()
            node = etree.parse(infile, parser)
            return node.getroot()
        except etree.XMLSyntaxError as e:
            module.fail_json(msg="Error while parsing child element: %s" % e)
    elif in_type == 'yaml':
        if isinstance(child, string_types):
            return etree.Element(child)
        elif isinstance(child, MutableMapping):
            if len(child) > 1:
                module.fail_json(msg="Can only create children from hashes with one key")

            (key, value) = next(iteritems(child))
            if isinstance(value, MutableMapping):
                children = value.pop('_', None)

                node = etree.Element(key, value)

                if children is not None:
                    if not isinstance(children, list):
                        module.fail_json(msg="Invalid children type: %s, must be list." % type(children))

                    subnodes = children_to_nodes(module, children)
                    node.extend(subnodes)
            else:
                node = etree.Element(key)
                node.text = value
            return node
        else:
            module.fail_json(msg="Invalid child type: %s. Children must be either strings or hashes." % type(child))
    else:
        module.fail_json(msg="Invalid child input type: %s. Type must be either xml or yaml." % in_type)


def children_to_nodes(module=None, children=[], type='yaml'):
    """turn a str/hash/list of str&hash into a list of elements"""
    return [child_to_element(module, child, type) for child in children]


def make_pretty(module, tree):
    xml_string = etree.tostring(tree, xml_declaration=True, encoding='UTF-8', pretty_print=module.params['pretty_print'])

    result = dict(
        changed=False,
    )

    if module.params['path']:
        xml_file = module.params['path']
        with open(xml_file, 'rb') as xml_content:
            if xml_string != xml_content.read():
                result['changed'] = True
                if not module.check_mode:
                    if module.params['backup']:
                        result['backup_file'] = module.backup_local(module.params['path'])
                    tree.write(xml_file, xml_declaration=True, encoding='UTF-8', pretty_print=module.params['pretty_print'])

    elif module.params['xmlstring']:
        result['xmlstring'] = xml_string
        # NOTE: Modifying a string is not considered a change !
        if xml_string != module.params['xmlstring']:
            result['changed'] = True

    module.exit_json(**result)


def finish(module, tree, xpath, namespaces, changed=False, msg='', hitcount=0, matches=tuple()):

    result = dict(
        actions=dict(
            xpath=xpath,
            namespaces=namespaces,
            state=module.params['state']
        ),
        changed=has_changed(tree),
    )

    if module.params['count'] or hitcount:
        result['count'] = hitcount

    if module.params['print_match'] or matches:
        result['matches'] = matches

    if msg:
        result['msg'] = msg

    if result['changed']:
        if module._diff:
            result['diff'] = dict(
                before=etree.tostring(orig_doc, xml_declaration=True, encoding='UTF-8', pretty_print=True),
                after=etree.tostring(tree, xml_declaration=True, encoding='UTF-8', pretty_print=True),
            )

        if module.params['path'] and not module.check_mode:
            if module.params['backup']:
                result['backup_file'] = module.backup_local(module.params['path'])
            tree.write(module.params['path'], xml_declaration=True, encoding='UTF-8', pretty_print=module.params['pretty_print'])

    if module.params['xmlstring']:
        result['xmlstring'] = etree.tostring(tree, xml_declaration=True, encoding='UTF-8', pretty_print=module.params['pretty_print'])

    module.exit_json(**result)


def main():
    module = AnsibleModule(
        argument_spec=dict(
            path=dict(type='path', aliases=['dest', 'file']),
            xmlstring=dict(type='str'),
            xpath=dict(type='str'),
            namespaces=dict(type='dict', default={}),
            state=dict(type='str', default='present', choices=['absent', 'present'], aliases=['ensure']),
            value=dict(type='raw'),
            attribute=dict(type='raw'),
            add_children=dict(type='list'),
            set_children=dict(type='list'),
            count=dict(type='bool', default=False),
            print_match=dict(type='bool', default=False),
            pretty_print=dict(type='bool', default=False),
            content=dict(type='str', choices=['attribute', 'text']),
            input_type=dict(type='str', default='yaml', choices=['xml', 'yaml']),
            backup=dict(type='bool', default=False),
        ),
        supports_check_mode=True,
        # TODO: Implement this as soon as #28662 (required_by functionality) is merged
        # required_by=dict(
        #    add_children=['xpath'],
        #    attribute=['value'],
        #    set_children=['xpath'],
        #    value=['xpath'],
        # ),
        required_if=[
            ['content', 'attribute', ['xpath']],
            ['content', 'text', ['xpath']],
            ['count', True, ['xpath']],
            ['print_match', True, ['xpath']],
        ],
        required_one_of=[
            ['path', 'xmlstring'],
            ['add_children', 'content', 'count', 'pretty_print', 'print_match', 'set_children', 'value'],
        ],
        mutually_exclusive=[
            ['add_children', 'content', 'count', 'print_match', 'set_children', 'value'],
            ['path', 'xmlstring'],
        ],
    )

    xml_file = module.params['path']
    xml_string = module.params['xmlstring']
    xpath = module.params['xpath']
    namespaces = module.params['namespaces']
    state = module.params['state']
    value = json_dict_bytes_to_unicode(module.params['value'])
    attribute = module.params['attribute']
    set_children = json_dict_bytes_to_unicode(module.params['set_children'])
    add_children = json_dict_bytes_to_unicode(module.params['add_children'])
    pretty_print = module.params['pretty_print']
    content = module.params['content']
    input_type = module.params['input_type']
    print_match = module.params['print_match']
    count = module.params['count']
    backup = module.params['backup']

    # Check if we have lxml 2.3.0 or newer installed
    if not HAS_LXML:
        module.fail_json(msg='The xml ansible module requires the lxml python library installed on the managed machine')
    elif LooseVersion('.'.join(to_native(f) for f in etree.LXML_VERSION)) < LooseVersion('2.3.0'):
        module.fail_json(msg='The xml ansible module requires lxml 2.3.0 or newer installed on the managed machine')
    elif LooseVersion('.'.join(to_native(f) for f in etree.LXML_VERSION)) < LooseVersion('3.0.0'):
        module.warn('Using lxml version lower than 3.0.0 does not guarantee predictable element attribute order.')

    # Check if the file exists
    if xml_string:
        infile = BytesIO(to_bytes(xml_string, errors='surrogate_or_strict'))
    elif os.path.isfile(xml_file):
        infile = open(xml_file, 'rb')
    else:
        module.fail_json(msg="The target XML source '%s' does not exist." % xml_file)

    # Parse and evaluate xpath expression
    if xpath is not None:
        try:
            etree.XPath(xpath)
        except etree.XPathSyntaxError as e:
            module.fail_json(msg="Syntax error in xpath expression: %s (%s)" % (xpath, e))
        except etree.XPathEvalError as e:
            module.fail_json(msg="Evaluation error in xpath expression: %s (%s)" % (xpath, e))

    # Try to parse in the target XML file
    try:
        parser = etree.XMLParser(remove_blank_text=pretty_print)
        doc = etree.parse(infile, parser)
    except etree.XMLSyntaxError as e:
        module.fail_json(msg="Error while parsing document: %s (%s)" % (xml_file or 'xml_string', e))

    # Ensure we have the original copy to compare
    global orig_doc
    orig_doc = copy.deepcopy(doc)

    if print_match:
        do_print_match(module, doc, xpath, namespaces)

    if count:
        count_nodes(module, doc, xpath, namespaces)

    if content == 'attribute':
        get_element_attr(module, doc, xpath, namespaces)
    elif content == 'text':
        get_element_text(module, doc, xpath, namespaces)

    # File exists:
    if state == 'absent':
        # - absent: delete xpath target
        delete_xpath_target(module, doc, xpath, namespaces)

    # - present: carry on

    # children && value both set?: should have already aborted by now
    # add_children && set_children both set?: should have already aborted by now

    # set_children set?
    if set_children:
        set_target_children(module, doc, xpath, namespaces, set_children, input_type)

    # add_children set?
    if add_children:
        add_target_children(module, doc, xpath, namespaces, add_children, input_type)

    # No?: Carry on

    # Is the xpath target an attribute selector?
    if value is not None:
        set_target(module, doc, xpath, namespaces, attribute, value)

    # If an xpath was provided, we need to do something with the data
    if xpath is not None:
        ensure_xpath_exists(module, doc, xpath, namespaces)

    # Otherwise only reformat the xml data?
    if pretty_print:
        make_pretty(module, doc)

    module.fail_json(msg="Don't know what to do")


if __name__ == '__main__':
    main()
