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

# (c) 2016 Michael Gruener <michael.gruener@chaosmoon.net>
# 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 = '''
---
module: acme_certificate
author: "Michael Gruener (@mgruener)"
version_added: "2.2"
short_description: Create SSL/TLS certificates with the ACME protocol
description:
   - "Create and renew SSL/TLS certificates with a CA supporting the
      L(ACME protocol,https://tools.ietf.org/html/rfc8555),
      such as L(Let's Encrypt,https://letsencrypt.org/) or
      L(Buypass,https://www.buypass.com/). The current implementation
      supports the C(http-01), C(dns-01) and C(tls-alpn-01) challenges."
   - "To use this module, it has to be executed twice. Either as two
      different tasks in the same run or during two runs. Note that the output
      of the first run needs to be recorded and passed to the second run as the
      module argument C(data)."
   - "Between these two tasks you have to fulfill the required steps for the
      chosen challenge by whatever means necessary. For C(http-01) that means
      creating the necessary challenge file on the destination webserver. For
      C(dns-01) the necessary dns record has to be created. For C(tls-alpn-01)
      the necessary certificate has to be created and served.
      It is I(not) the responsibility of this module to perform these steps."
   - "For details on how to fulfill these challenges, you might have to read through
      L(the main ACME specification,https://tools.ietf.org/html/rfc8555#section-8)
      and the L(TLS-ALPN-01 specification,https://www.rfc-editor.org/rfc/rfc8737.html#section-3).
      Also, consider the examples provided for this module."
   - "The module includes experimental support for IP identifiers according to
      the L(RFC 8738,https://www.rfc-editor.org/rfc/rfc8738.html)."
notes:
   - "At least one of C(dest) and C(fullchain_dest) must be specified."
   - "This module includes basic account management functionality.
      If you want to have more control over your ACME account, use the M(acme_account)
      module and disable account management for this module using the C(modify_account)
      option."
   - "This module was called C(letsencrypt) before Ansible 2.6. The usage
      did not change."
seealso:
  - name: The Let's Encrypt documentation
    description: Documentation for the Let's Encrypt Certification Authority.
                 Provides useful information for example on rate limits.
    link: https://letsencrypt.org/docs/
  - name: Buypass Go SSL
    description: Documentation for the Buypass Certification Authority.
                 Provides useful information for example on rate limits.
    link: https://www.buypass.com/ssl/products/acme
  - name: Automatic Certificate Management Environment (ACME)
    description: The specification of the ACME protocol (RFC 8555).
    link: https://tools.ietf.org/html/rfc8555
  - name: ACME TLS ALPN Challenge Extension
    description: The specification of the C(tls-alpn-01) challenge (RFC 8737).
    link: https://www.rfc-editor.org/rfc/rfc8737.html-05
  - module: acme_challenge_cert_helper
    description: Helps preparing C(tls-alpn-01) challenges.
  - module: openssl_privatekey
    description: Can be used to create private keys (both for certificates and accounts).
  - module: openssl_csr
    description: Can be used to create a Certificate Signing Request (CSR).
  - module: certificate_complete_chain
    description: Allows to find the root certificate for the returned fullchain.
  - module: acme_certificate_revoke
    description: Allows to revoke certificates.
  - module: acme_account
    description: Allows to create, modify or delete an ACME account.
  - module: acme_inspect
    description: Allows to debug problems.
extends_documentation_fragment:
  - acme
options:
  account_email:
    description:
      - "The email address associated with this account."
      - "It will be used for certificate expiration warnings."
      - "Note that when C(modify_account) is not set to C(no) and you also
         used the M(acme_account) module to specify more than one contact
         for your account, this module will update your account and restrict
         it to the (at most one) contact email address specified here."
    type: str
  agreement:
    description:
      - "URI to a terms of service document you agree to when using the
         ACME v1 service at C(acme_directory)."
      - Default is latest gathered from C(acme_directory) URL.
      - This option will only be used when C(acme_version) is 1.
    type: str
  terms_agreed:
    description:
      - "Boolean indicating whether you agree to the terms of service document."
      - "ACME servers can require this to be true."
      - This option will only be used when C(acme_version) is not 1.
    type: bool
    default: no
    version_added: "2.5"
  modify_account:
    description:
      - "Boolean indicating whether the module should create the account if
         necessary, and update its contact data."
      - "Set to C(no) if you want to use the M(acme_account) module to manage
         your account instead, and to avoid accidental creation of a new account
         using an old key if you changed the account key with M(acme_account)."
      - "If set to C(no), C(terms_agreed) and C(account_email) are ignored."
    type: bool
    default: yes
    version_added: "2.6"
  challenge:
    description: The challenge to be performed.
    type: str
    default: 'http-01'
    choices: [ 'http-01', 'dns-01', 'tls-alpn-01' ]
  csr:
    description:
      - "File containing the CSR for the new certificate."
      - "Can be created with C(openssl req ...)."
      - "The CSR may contain multiple Subject Alternate Names, but each one
         will lead to an individual challenge that must be fulfilled for the
         CSR to be signed."
      - "I(Note): the private key used to create the CSR I(must not) be the
         account key. This is a bad idea from a security point of view, and
         the CA should not accept the CSR. The ACME server should return an
         error in this case."
    type: path
    required: true
    aliases: ['src']
  data:
    description:
      - "The data to validate ongoing challenges. This must be specified for
         the second run of the module only."
      - "The value that must be used here will be provided by a previous use
         of this module. See the examples for more details."
      - "Note that for ACME v2, only the C(order_uri) entry of C(data) will
         be used. For ACME v1, C(data) must be non-empty to indicate the
         second stage is active; all needed data will be taken from the
         CSR."
      - "I(Note): the C(data) option was marked as C(no_log) up to
         Ansible 2.5. From Ansible 2.6 on, it is no longer marked this way
         as it causes error messages to be come unusable, and C(data) does
         not contain any information which can be used without having
         access to the account key or which are not public anyway."
    type: dict
  dest:
    description:
      - "The destination file for the certificate."
      - "Required if C(fullchain_dest) is not specified."
    type: path
    aliases: ['cert']
  fullchain_dest:
    description:
      - "The destination file for the full chain (i.e. certificate followed
         by chain of intermediate certificates)."
      - "Required if C(dest) is not specified."
    type: path
    version_added: 2.5
    aliases: ['fullchain']
  chain_dest:
    description:
      - If specified, the intermediate certificate will be written to this file.
    type: path
    version_added: 2.5
    aliases: ['chain']
  remaining_days:
    description:
      - "The number of days the certificate must have left being valid.
         If C(cert_days < remaining_days), then it will be renewed.
         If the certificate is not renewed, module return values will not
         include C(challenge_data)."
      - "To make sure that the certificate is renewed in any case, you can
         use the C(force) option."
    type: int
    default: 10
  deactivate_authzs:
    description:
      - "Deactivate authentication objects (authz) after issuing a certificate,
         or when issuing the certificate failed."
      - "Authentication objects are bound to an account key and remain valid
         for a certain amount of time, and can be used to issue certificates
         without having to re-authenticate the domain. This can be a security
         concern."
    type: bool
    default: no
    version_added: 2.6
  force:
    description:
      - Enforces the execution of the challenge and validation, even if an
        existing certificate is still valid for more than C(remaining_days).
      - This is especially helpful when having an updated CSR e.g. with
        additional domains for which a new certificate is desired.
    type: bool
    default: no
    version_added: 2.6
  retrieve_all_alternates:
    description:
      - "When set to C(yes), will retrieve all alternate chains offered by the ACME CA.
         These will not be written to disk, but will be returned together with the main
         chain as C(all_chains). See the documentation for the C(all_chains) return
         value for details."
    type: bool
    default: no
    version_added: "2.9"
'''

EXAMPLES = r'''
### Example with HTTP challenge ###

- name: Create a challenge for sample.com using a account key from a variable.
  acme_certificate:
    account_key_content: "{{ account_private_key }}"
    csr: /etc/pki/cert/csr/sample.com.csr
    dest: /etc/httpd/ssl/sample.com.crt
  register: sample_com_challenge

# Alternative first step:
- name: Create a challenge for sample.com using a account key from hashi vault.
  acme_certificate:
    account_key_content: "{{ lookup('hashi_vault', 'secret=secret/account_private_key:value') }}"
    csr: /etc/pki/cert/csr/sample.com.csr
    fullchain_dest: /etc/httpd/ssl/sample.com-fullchain.crt
  register: sample_com_challenge

# Alternative first step:
- name: Create a challenge for sample.com using a account key file.
  acme_certificate:
    account_key_src: /etc/pki/cert/private/account.key
    csr: /etc/pki/cert/csr/sample.com.csr
    dest: /etc/httpd/ssl/sample.com.crt
    fullchain_dest: /etc/httpd/ssl/sample.com-fullchain.crt
  register: sample_com_challenge

# perform the necessary steps to fulfill the challenge
# for example:
#
# - copy:
#     dest: /var/www/html/{{ sample_com_challenge['challenge_data']['sample.com']['http-01']['resource'] }}
#     content: "{{ sample_com_challenge['challenge_data']['sample.com']['http-01']['resource_value'] }}"
#     when: sample_com_challenge is changed and 'sample.com' in sample_com_challenge['challenge_data']
#
# Alternative way:
#
# - copy:
#     dest: /var/www/{{ item.key }}/{{ item.value['http-01']['resource'] }}
#     content: "{{ item.value['http-01']['resource_value'] }}"
#   loop: "{{ sample_com_challenge.challenge_data | dictsort }}"
#   when: sample_com_challenge is changed

- name: Let the challenge be validated and retrieve the cert and intermediate certificate
  acme_certificate:
    account_key_src: /etc/pki/cert/private/account.key
    csr: /etc/pki/cert/csr/sample.com.csr
    dest: /etc/httpd/ssl/sample.com.crt
    fullchain_dest: /etc/httpd/ssl/sample.com-fullchain.crt
    chain_dest: /etc/httpd/ssl/sample.com-intermediate.crt
    data: "{{ sample_com_challenge }}"

### Example with DNS challenge against production ACME server ###

- name: Create a challenge for sample.com using a account key file.
  acme_certificate:
    account_key_src: /etc/pki/cert/private/account.key
    account_email: myself@sample.com
    src: /etc/pki/cert/csr/sample.com.csr
    cert: /etc/httpd/ssl/sample.com.crt
    challenge: dns-01
    acme_directory: https://acme-v01.api.letsencrypt.org/directory
    # Renew if the certificate is at least 30 days old
    remaining_days: 60
  register: sample_com_challenge

# perform the necessary steps to fulfill the challenge
# for example:
#
# - route53:
#     zone: sample.com
#     record: "{{ sample_com_challenge.challenge_data['sample.com']['dns-01'].record }}"
#     type: TXT
#     ttl: 60
#     state: present
#     wait: yes
#     # Note: route53 requires TXT entries to be enclosed in quotes
#     value: "{{ sample_com_challenge.challenge_data['sample.com']['dns-01'].resource_value | regex_replace('^(.*)$', '\"\\1\"') }}"
#   when: sample_com_challenge is changed and 'sample.com' in sample_com_challenge.challenge_data
#
# Alternative way:
#
# - route53:
#     zone: sample.com
#     record: "{{ item.key }}"
#     type: TXT
#     ttl: 60
#     state: present
#     wait: yes
#     # Note: item.value is a list of TXT entries, and route53
#     # requires every entry to be enclosed in quotes
#     value: "{{ item.value | map('regex_replace', '^(.*)$', '\"\\1\"' ) | list }}"
#   loop: "{{ sample_com_challenge.challenge_data_dns | dictsort }}"
#   when: sample_com_challenge is changed

- name: Let the challenge be validated and retrieve the cert and intermediate certificate
  acme_certificate:
    account_key_src: /etc/pki/cert/private/account.key
    account_email: myself@sample.com
    src: /etc/pki/cert/csr/sample.com.csr
    cert: /etc/httpd/ssl/sample.com.crt
    fullchain: /etc/httpd/ssl/sample.com-fullchain.crt
    chain: /etc/httpd/ssl/sample.com-intermediate.crt
    challenge: dns-01
    acme_directory: https://acme-v01.api.letsencrypt.org/directory
    remaining_days: 60
    data: "{{ sample_com_challenge }}"
  when: sample_com_challenge is changed
'''

RETURN = '''
cert_days:
  description: The number of days the certificate remains valid.
  returned: success
  type: int
challenge_data:
  description:
    - Per identifier / challenge type challenge data.
    - Since Ansible 2.8.5, only challenges which are not yet valid are returned.
  returned: changed
  type: list
  elements: dict
  contains:
    resource:
      description: The challenge resource that must be created for validation.
      returned: changed
      type: str
      sample: .well-known/acme-challenge/evaGxfADs6pSRb2LAv9IZf17Dt3juxGJ-PCt92wr-oA
    resource_original:
      description:
        - The original challenge resource including type identifier for C(tls-alpn-01)
          challenges.
      returned: changed and challenge is C(tls-alpn-01)
      type: str
      sample: DNS:example.com
      version_added: "2.8"
    resource_value:
      description:
        - The value the resource has to produce for the validation.
        - For C(http-01) and C(dns-01) challenges, the value can be used as-is.
        - "For C(tls-alpn-01) challenges, note that this return value contains a
           Base64 encoded version of the correct binary blob which has to be put
           into the acmeValidation x509 extension; see
           U(https://www.rfc-editor.org/rfc/rfc8737.html#section-3)
           for details. To do this, you might need the C(b64decode) Jinja filter
           to extract the binary blob from this return value."
      returned: changed
      type: str
      sample: IlirfxKKXA...17Dt3juxGJ-PCt92wr-oA
    record:
      description: The full DNS record's name for the challenge.
      returned: changed and challenge is C(dns-01)
      type: str
      sample: _acme-challenge.example.com
      version_added: "2.5"
challenge_data_dns:
  description:
    - List of TXT values per DNS record, in case challenge is C(dns-01).
    - Since Ansible 2.8.5, only challenges which are not yet valid are returned.
  returned: changed
  type: dict
  version_added: "2.5"
authorizations:
  description:
    - ACME authorization data.
    - Maps an identifier to ACME authorization objects. See U(https://tools.ietf.org/html/rfc8555#section-7.1.4).
  returned: changed
  type: dict
  sample: '{"example.com":{...}}'
order_uri:
  description: ACME order URI.
  returned: changed
  type: str
  version_added: "2.5"
finalization_uri:
  description: ACME finalization URI.
  returned: changed
  type: str
  version_added: "2.5"
account_uri:
  description: ACME account URI.
  returned: changed
  type: str
  version_added: "2.5"
all_chains:
  description:
    - When I(retrieve_all_alternates) is set to C(yes), the module will query the ACME server
      for alternate chains. This return value will contain a list of all chains returned,
      the first entry being the main chain returned by the server.
    - See L(Section 7.4.2 of RFC8555,https://tools.ietf.org/html/rfc8555#section-7.4.2) for details.
  returned: when certificate was retrieved and I(retrieve_all_alternates) is set to C(yes)
  type: list
  elements: dict
  contains:
    cert:
      description:
        - The leaf certificate itself, in PEM format.
      type: str
      returned: always
    chain:
      description:
        - The certificate chain, excluding the root, as concatenated PEM certificates.
      type: str
      returned: always
    full_chain:
      description:
        - The certificate chain, excluding the root, but including the leaf certificate,
          as concatenated PEM certificates.
      type: str
      returned: always
'''

from ansible.module_utils.acme import (
    ModuleFailException,
    write_file, nopad_b64, pem_to_der,
    ACMEAccount,
    HAS_CURRENT_CRYPTOGRAPHY,
    cryptography_get_csr_identifiers,
    openssl_get_csr_identifiers,
    cryptography_get_cert_days,
    set_crypto_backend,
    process_links,
)

import base64
import hashlib
import locale
import os
import re
import textwrap
import time
import urllib
from datetime import datetime

from ansible.module_utils.basic import AnsibleModule
from ansible.module_utils._text import to_bytes
from ansible.module_utils.compat import ipaddress as compat_ipaddress


def get_cert_days(module, cert_file):
    '''
    Return the days the certificate in cert_file remains valid and -1
    if the file was not found. If cert_file contains more than one
    certificate, only the first one will be considered.
    '''
    if HAS_CURRENT_CRYPTOGRAPHY:
        return cryptography_get_cert_days(module, cert_file)
    if not os.path.exists(cert_file):
        return -1

    openssl_bin = module.get_bin_path('openssl', True)
    openssl_cert_cmd = [openssl_bin, "x509", "-in", cert_file, "-noout", "-text"]
    dummy, out, dummy = module.run_command(openssl_cert_cmd, check_rc=True, encoding=None)
    try:
        not_after_str = re.search(r"\s+Not After\s*:\s+(.*)", out.decode('utf8')).group(1)
        not_after = datetime.fromtimestamp(time.mktime(time.strptime(not_after_str, '%b %d %H:%M:%S %Y %Z')))
    except AttributeError:
        raise ModuleFailException("No 'Not after' date found in {0}".format(cert_file))
    except ValueError:
        raise ModuleFailException("Failed to parse 'Not after' date of {0}".format(cert_file))
    now = datetime.utcnow()
    return (not_after - now).days


class ACMEClient(object):
    '''
    ACME client class. Uses an ACME account object and a CSR to
    start and validate ACME challenges and download the respective
    certificates.
    '''

    def __init__(self, module):
        self.module = module
        self.version = module.params['acme_version']
        self.challenge = module.params['challenge']
        self.csr = module.params['csr']
        self.dest = module.params.get('dest')
        self.fullchain_dest = module.params.get('fullchain_dest')
        self.chain_dest = module.params.get('chain_dest')
        self.account = ACMEAccount(module)
        self.directory = self.account.directory
        self.data = module.params['data']
        self.authorizations = None
        self.cert_days = -1
        self.order_uri = self.data.get('order_uri') if self.data else None
        self.finalize_uri = None

        # Make sure account exists
        modify_account = module.params['modify_account']
        if modify_account or self.version > 1:
            contact = []
            if module.params['account_email']:
                contact.append('mailto:' + module.params['account_email'])
            created, account_data = self.account.setup_account(
                contact,
                agreement=module.params.get('agreement'),
                terms_agreed=module.params.get('terms_agreed'),
                allow_creation=modify_account,
            )
            if account_data is None:
                raise ModuleFailException(msg='Account does not exist or is deactivated.')
            updated = False
            if not created and account_data and modify_account:
                updated, account_data = self.account.update_account(account_data, contact)
            self.changed = created or updated
        else:
            # This happens if modify_account is False and the ACME v1
            # protocol is used. In this case, we do not call setup_account()
            # to avoid accidental creation of an account. This is OK
            # since for ACME v1, the account URI is not needed to send a
            # signed ACME request.
            pass

        if not os.path.exists(self.csr):
            raise ModuleFailException("CSR %s not found" % (self.csr))

        self._openssl_bin = module.get_bin_path('openssl', True)

        # Extract list of identifiers from CSR
        self.identifiers = self._get_csr_identifiers()

    def _get_csr_identifiers(self):
        '''
        Parse the CSR and return the list of requested identifiers
        '''
        if HAS_CURRENT_CRYPTOGRAPHY:
            return cryptography_get_csr_identifiers(self.module, self.csr)
        else:
            return openssl_get_csr_identifiers(self._openssl_bin, self.module, self.csr)

    def _add_or_update_auth(self, identifier_type, identifier, auth):
        '''
        Add or update the given authorization in the global authorizations list.
        Return True if the auth was updated/added and False if no change was
        necessary.
        '''
        if self.authorizations.get(identifier_type + ':' + identifier) == auth:
            return False
        self.authorizations[identifier_type + ':' + identifier] = auth
        return True

    def _new_authz_v1(self, identifier_type, identifier):
        '''
        Create a new authorization for the given identifier.
        Return the authorization object of the new authorization
        https://tools.ietf.org/html/draft-ietf-acme-acme-02#section-6.4
        '''
        new_authz = {
            "resource": "new-authz",
            "identifier": {"type": identifier_type, "value": identifier},
        }

        result, info = self.account.send_signed_request(self.directory['new-authz'], new_authz)
        if info['status'] not in [200, 201]:
            raise ModuleFailException("Error requesting challenges: CODE: {0} RESULT: {1}".format(info['status'], result))
        else:
            result['uri'] = info['location']
            return result

    def _get_challenge_data(self, auth, identifier_type, identifier):
        '''
        Returns a dict with the data for all proposed (and supported) challenges
        of the given authorization.
        '''

        data = {}
        # no need to choose a specific challenge here as this module
        # is not responsible for fulfilling the challenges. Calculate
        # and return the required information for each challenge.
        for challenge in auth['challenges']:
            challenge_type = challenge['type']
            token = re.sub(r"[^A-Za-z0-9_\-]", "_", challenge['token'])
            keyauthorization = self.account.get_keyauthorization(token)

            if challenge_type == 'http-01':
                # https://tools.ietf.org/html/rfc8555#section-8.3
                resource = '.well-known/acme-challenge/' + token
                data[challenge_type] = {'resource': resource, 'resource_value': keyauthorization}
            elif challenge_type == 'dns-01':
                if identifier_type != 'dns':
                    continue
                # https://tools.ietf.org/html/rfc8555#section-8.4
                resource = '_acme-challenge'
                value = nopad_b64(hashlib.sha256(to_bytes(keyauthorization)).digest())
                record = (resource + identifier[1:]) if identifier.startswith('*.') else (resource + '.' + identifier)
                data[challenge_type] = {'resource': resource, 'resource_value': value, 'record': record}
            elif challenge_type == 'tls-alpn-01':
                # https://www.rfc-editor.org/rfc/rfc8737.html#section-3
                if identifier_type == 'ip':
                    # IPv4/IPv6 address: use reverse mapping (RFC1034, RFC3596)
                    resource = compat_ipaddress.ip_address(identifier).reverse_pointer
                    if not resource.endswith('.'):
                        resource += '.'
                else:
                    resource = identifier
                value = base64.b64encode(hashlib.sha256(to_bytes(keyauthorization)).digest())
                data[challenge_type] = {'resource': resource, 'resource_original': identifier_type + ':' + identifier, 'resource_value': value}
            else:
                continue

        return data

    def _fail_challenge(self, identifier_type, identifier, auth, error):
        '''
        Aborts with a specific error for a challenge.
        '''
        error_details = ''
        # multiple challenges could have failed at this point, gather error
        # details for all of them before failing
        for challenge in auth['challenges']:
            if challenge['status'] == 'invalid':
                error_details += ' CHALLENGE: {0}'.format(challenge['type'])
                if 'error' in challenge:
                    error_details += ' DETAILS: {0};'.format(challenge['error']['detail'])
                else:
                    error_details += ';'
        raise ModuleFailException("{0}: {1}".format(error.format(identifier_type + ':' + identifier), error_details))

    def _validate_challenges(self, identifier_type, identifier, auth):
        '''
        Validate the authorization provided in the auth dict. Returns True
        when the validation was successful and False when it was not.
        '''
        for challenge in auth['challenges']:
            if self.challenge != challenge['type']:
                continue

            uri = challenge['uri'] if self.version == 1 else challenge['url']

            challenge_response = {}
            if self.version == 1:
                token = re.sub(r"[^A-Za-z0-9_\-]", "_", challenge['token'])
                keyauthorization = self.account.get_keyauthorization(token)
                challenge_response["resource"] = "challenge"
                challenge_response["keyAuthorization"] = keyauthorization
                challenge_response["type"] = self.challenge
            result, info = self.account.send_signed_request(uri, challenge_response)
            if info['status'] not in [200, 202]:
                raise ModuleFailException("Error validating challenge: CODE: {0} RESULT: {1}".format(info['status'], result))

        status = ''

        while status not in ['valid', 'invalid', 'revoked']:
            result, dummy = self.account.get_request(auth['uri'])
            result['uri'] = auth['uri']
            if self._add_or_update_auth(identifier_type, identifier, result):
                self.changed = True
            # https://tools.ietf.org/html/draft-ietf-acme-acme-02#section-6.1.2
            # "status (required, string): ...
            # If this field is missing, then the default value is "pending"."
            if self.version == 1 and 'status' not in result:
                status = 'pending'
            else:
                status = result['status']
            time.sleep(2)

        if status == 'invalid':
            self._fail_challenge(identifier_type, identifier, result, 'Authorization for {0} returned invalid')

        return status == 'valid'

    def _finalize_cert(self):
        '''
        Create a new certificate based on the csr.
        Return the certificate object as dict
        https://tools.ietf.org/html/rfc8555#section-7.4
        '''
        csr = pem_to_der(self.csr)
        new_cert = {
            "csr": nopad_b64(csr),
        }
        result, info = self.account.send_signed_request(self.finalize_uri, new_cert)
        if info['status'] not in [200]:
            raise ModuleFailException("Error new cert: CODE: {0} RESULT: {1}".format(info['status'], result))

        status = result['status']
        while status not in ['valid', 'invalid']:
            time.sleep(2)
            result, dummy = self.account.get_request(self.order_uri)
            status = result['status']

        if status != 'valid':
            raise ModuleFailException("Error new cert: CODE: {0} STATUS: {1} RESULT: {2}".format(info['status'], status, result))

        return result['certificate']

    def _der_to_pem(self, der_cert):
        '''
        Convert the DER format certificate in der_cert to a PEM format
        certificate and return it.
        '''
        return """-----BEGIN CERTIFICATE-----\n{0}\n-----END CERTIFICATE-----\n""".format(
            "\n".join(textwrap.wrap(base64.b64encode(der_cert).decode('utf8'), 64)))

    def _download_cert(self, url):
        '''
        Download and parse the certificate chain.
        https://tools.ietf.org/html/rfc8555#section-7.4.2
        '''
        content, info = self.account.get_request(url, parse_json_result=False, headers={'Accept': 'application/pem-certificate-chain'})

        if not content or not info['content-type'].startswith('application/pem-certificate-chain'):
            raise ModuleFailException("Cannot download certificate chain from {0}: {1} (headers: {2})".format(url, content, info))

        cert = None
        chain = []

        # Parse data
        lines = content.decode('utf-8').splitlines(True)
        current = []
        for line in lines:
            if line.strip():
                current.append(line)
            if line.startswith('-----END CERTIFICATE-----'):
                if cert is None:
                    cert = ''.join(current)
                else:
                    chain.append(''.join(current))
                current = []

        alternates = []

        def f(link, relation):
            if relation == 'up':
                # Process link-up headers if there was no chain in reply
                if not chain:
                    chain_result, chain_info = self.account.get_request(link, parse_json_result=False)
                    if chain_info['status'] in [200, 201]:
                        chain.append(self._der_to_pem(chain_result))
            elif relation == 'alternate':
                alternates.append(link)

        process_links(info, f)

        if cert is None or current:
            raise ModuleFailException("Failed to parse certificate chain download from {0}: {1} (headers: {2})".format(url, content, info))
        return {'cert': cert, 'chain': chain, 'alternates': alternates}

    def _new_cert_v1(self):
        '''
        Create a new certificate based on the CSR (ACME v1 protocol).
        Return the certificate object as dict
        https://tools.ietf.org/html/draft-ietf-acme-acme-02#section-6.5
        '''
        csr = pem_to_der(self.csr)
        new_cert = {
            "resource": "new-cert",
            "csr": nopad_b64(csr),
        }
        result, info = self.account.send_signed_request(self.directory['new-cert'], new_cert)

        chain = []

        def f(link, relation):
            if relation == 'up':
                chain_result, chain_info = self.account.get_request(link, parse_json_result=False)
                if chain_info['status'] in [200, 201]:
                    del chain[:]
                    chain.append(self._der_to_pem(chain_result))

        process_links(info, f)

        if info['status'] not in [200, 201]:
            raise ModuleFailException("Error new cert: CODE: {0} RESULT: {1}".format(info['status'], result))
        else:
            return {'cert': self._der_to_pem(result), 'uri': info['location'], 'chain': chain}

    def _new_order_v2(self):
        '''
        Start a new certificate order (ACME v2 protocol).
        https://tools.ietf.org/html/rfc8555#section-7.4
        '''
        identifiers = []
        for identifier_type, identifier in self.identifiers:
            identifiers.append({
                'type': identifier_type,
                'value': identifier,
            })
        new_order = {
            "identifiers": identifiers
        }
        result, info = self.account.send_signed_request(self.directory['newOrder'], new_order)

        if info['status'] not in [201]:
            raise ModuleFailException("Error new order: CODE: {0} RESULT: {1}".format(info['status'], result))

        for auth_uri in result['authorizations']:
            auth_data, dummy = self.account.get_request(auth_uri)
            auth_data['uri'] = auth_uri
            identifier_type = auth_data['identifier']['type']
            identifier = auth_data['identifier']['value']
            if auth_data.get('wildcard', False):
                identifier = '*.{0}'.format(identifier)
            self.authorizations[identifier_type + ':' + identifier] = auth_data

        self.order_uri = info['location']
        self.finalize_uri = result['finalize']

    def is_first_step(self):
        '''
        Return True if this is the first execution of this module, i.e. if a
        sufficient data object from a first run has not been provided.
        '''
        if self.data is None:
            return True
        if self.version == 1:
            # As soon as self.data is a non-empty object, we are in the second stage.
            return not self.data
        else:
            # We are in the second stage if data.order_uri is given (which has been
            # stored in self.order_uri by the constructor).
            return self.order_uri is None

    def start_challenges(self):
        '''
        Create new authorizations for all identifiers of the CSR,
        respectively start a new order for ACME v2.
        '''
        self.authorizations = {}
        if self.version == 1:
            for identifier_type, identifier in self.identifiers:
                if identifier_type != 'dns':
                    raise ModuleFailException('ACME v1 only supports DNS identifiers!')
            for identifier_type, identifier in self.identifiers:
                new_auth = self._new_authz_v1(identifier_type, identifier)
                self._add_or_update_auth(identifier_type, identifier, new_auth)
        else:
            self._new_order_v2()
        self.changed = True

    def get_challenges_data(self):
        '''
        Get challenge details for the chosen challenge type.
        Return a tuple of generic challenge details, and specialized DNS challenge details.
        '''
        # Get general challenge data
        data = {}
        for type_identifier, auth in self.authorizations.items():
            identifier_type, identifier = type_identifier.split(':', 1)
            auth = self.authorizations[type_identifier]
            # Skip valid authentications: their challenges are already valid
            # and do not need to be returned
            if auth['status'] == 'valid':
                continue
            # We drop the type from the key to preserve backwards compatibility
            data[identifier] = self._get_challenge_data(auth, identifier_type, identifier)
        # Get DNS challenge data
        data_dns = {}
        if self.challenge == 'dns-01':
            for identifier, challenges in data.items():
                if self.challenge in challenges:
                    values = data_dns.get(challenges[self.challenge]['record'])
                    if values is None:
                        values = []
                        data_dns[challenges[self.challenge]['record']] = values
                    values.append(challenges[self.challenge]['resource_value'])
        return data, data_dns

    def finish_challenges(self):
        '''
        Verify challenges for all identifiers of the CSR.
        '''
        self.authorizations = {}

        # Step 1: obtain challenge information
        if self.version == 1:
            # For ACME v1, we attempt to create new authzs. Existing ones
            # will be returned instead.
            for identifier_type, identifier in self.identifiers:
                new_auth = self._new_authz_v1(identifier_type, identifier)
                self._add_or_update_auth(identifier_type, identifier, new_auth)
        else:
            # For ACME v2, we obtain the order object by fetching the
            # order URI, and extract the information from there.
            result, info = self.account.get_request(self.order_uri)

            if not result:
                raise ModuleFailException("Cannot download order from {0}: {1} (headers: {2})".format(self.order_uri, result, info))

            if info['status'] not in [200]:
                raise ModuleFailException("Error on downloading order: CODE: {0} RESULT: {1}".format(info['status'], result))

            for auth_uri in result['authorizations']:
                auth_data, dummy = self.account.get_request(auth_uri)
                auth_data['uri'] = auth_uri
                identifier_type = auth_data['identifier']['type']
                identifier = auth_data['identifier']['value']
                if auth_data.get('wildcard', False):
                    identifier = '*.{0}'.format(identifier)
                self.authorizations[identifier_type + ':' + identifier] = auth_data

            self.finalize_uri = result['finalize']

        # Step 2: validate challenges
        for type_identifier, auth in self.authorizations.items():
            if auth['status'] == 'pending':
                identifier_type, identifier = type_identifier.split(':', 1)
                self._validate_challenges(identifier_type, identifier, auth)

    def get_certificate(self):
        '''
        Request a new certificate and write it to the destination file.
        First verifies whether all authorizations are valid; if not, aborts
        with an error.
        '''
        for identifier_type, identifier in self.identifiers:
            auth = self.authorizations.get(identifier_type + ':' + identifier)
            if auth is None:
                raise ModuleFailException('Found no authorization information for "{0}"!'.format(identifier_type + ':' + identifier))
            if 'status' not in auth:
                self._fail_challenge(identifier_type, identifier, auth, 'Authorization for {0} returned no status')
            if auth['status'] != 'valid':
                self._fail_challenge(identifier_type, identifier, auth, 'Authorization for {0} returned status ' + str(auth['status']))

        if self.version == 1:
            cert = self._new_cert_v1()
        else:
            cert_uri = self._finalize_cert()
            cert = self._download_cert(cert_uri)
            if self.module.params['retrieve_all_alternates']:
                alternate_chains = []
                for alternate in cert['alternates']:
                    try:
                        alt_cert = self._download_cert(alternate)
                    except ModuleFailException as e:
                        self.module.warn('Error while downloading alternative certificate {0}: {1}'.format(alternate, e))
                        continue
                    alternate_chains.append(alt_cert)
                self.all_chains = []

                def _append_all_chains(cert_data):
                    self.all_chains.append(dict(
                        cert=cert_data['cert'].encode('utf8'),
                        chain=("\n".join(cert_data.get('chain', []))).encode('utf8'),
                        full_chain=(cert_data['cert'] + "\n".join(cert_data.get('chain', []))).encode('utf8'),
                    ))

                _append_all_chains(cert)
                for alt_chain in alternate_chains:
                    _append_all_chains(alt_chain)

        if cert['cert'] is not None:
            pem_cert = cert['cert']

            chain = [link for link in cert.get('chain', [])]

            if self.dest and write_file(self.module, self.dest, pem_cert.encode('utf8')):
                self.cert_days = get_cert_days(self.module, self.dest)
                self.changed = True

            if self.fullchain_dest and write_file(self.module, self.fullchain_dest, (pem_cert + "\n".join(chain)).encode('utf8')):
                self.cert_days = get_cert_days(self.module, self.fullchain_dest)
                self.changed = True

            if self.chain_dest and write_file(self.module, self.chain_dest, ("\n".join(chain)).encode('utf8')):
                self.changed = True

    def deactivate_authzs(self):
        '''
        Deactivates all valid authz's. Does not raise exceptions.
        https://community.letsencrypt.org/t/authorization-deactivation/19860/2
        https://tools.ietf.org/html/rfc8555#section-7.5.2
        '''
        authz_deactivate = {
            'status': 'deactivated'
        }
        if self.version == 1:
            authz_deactivate['resource'] = 'authz'
        if self.authorizations:
            for identifier_type, identifier in self.identifiers:
                auth = self.authorizations.get(identifier_type + ':' + identifier)
                if auth is None or auth.get('status') != 'valid':
                    continue
                try:
                    result, info = self.account.send_signed_request(auth['uri'], authz_deactivate)
                    if 200 <= info['status'] < 300 and result.get('status') == 'deactivated':
                        auth['status'] = 'deactivated'
                except Exception as dummy:
                    # Ignore errors on deactivating authzs
                    pass
                if auth.get('status') != 'deactivated':
                    self.module.warn(warning='Could not deactivate authz object {0}.'.format(auth['uri']))


def main():
    module = AnsibleModule(
        argument_spec=dict(
            account_key_src=dict(type='path', aliases=['account_key']),
            account_key_content=dict(type='str', no_log=True),
            account_uri=dict(type='str'),
            modify_account=dict(type='bool', default=True),
            acme_directory=dict(type='str', default='https://acme-staging.api.letsencrypt.org/directory'),
            acme_version=dict(type='int', default=1, choices=[1, 2]),
            validate_certs=dict(default=True, type='bool'),
            account_email=dict(type='str'),
            agreement=dict(type='str'),
            terms_agreed=dict(type='bool', default=False),
            challenge=dict(type='str', default='http-01', choices=['http-01', 'dns-01', 'tls-alpn-01']),
            csr=dict(type='path', required=True, aliases=['src']),
            data=dict(type='dict'),
            dest=dict(type='path', aliases=['cert']),
            fullchain_dest=dict(type='path', aliases=['fullchain']),
            chain_dest=dict(type='path', aliases=['chain']),
            remaining_days=dict(type='int', default=10),
            deactivate_authzs=dict(type='bool', default=False),
            force=dict(type='bool', default=False),
            retrieve_all_alternates=dict(type='bool', default=False),
            select_crypto_backend=dict(type='str', default='auto', choices=['auto', 'openssl', 'cryptography']),
        ),
        required_one_of=(
            ['account_key_src', 'account_key_content'],
            ['dest', 'fullchain_dest'],
        ),
        mutually_exclusive=(
            ['account_key_src', 'account_key_content'],
        ),
        supports_check_mode=True,
    )
    if module._name == 'letsencrypt':
        module.deprecate("The 'letsencrypt' module is being renamed 'acme_certificate'", version='2.10')
    set_crypto_backend(module)

    # AnsibleModule() changes the locale, so change it back to C because we rely on time.strptime() when parsing certificate dates.
    module.run_command_environ_update = dict(LANG='C', LC_ALL='C', LC_MESSAGES='C', LC_CTYPE='C')
    locale.setlocale(locale.LC_ALL, 'C')

    if not module.params.get('validate_certs'):
        module.warn(warning='Disabling certificate validation for communications with ACME endpoint. ' +
                            'This should only be done for testing against a local ACME server for ' +
                            'development purposes, but *never* for production purposes.')

    try:
        if module.params.get('dest'):
            cert_days = get_cert_days(module, module.params['dest'])
        else:
            cert_days = get_cert_days(module, module.params['fullchain_dest'])

        if module.params['force'] or cert_days < module.params['remaining_days']:
            # If checkmode is active, base the changed state solely on the status
            # of the certificate file as all other actions (accessing an account, checking
            # the authorization status...) would lead to potential changes of the current
            # state
            if module.check_mode:
                module.exit_json(changed=True, authorizations={}, challenge_data={}, cert_days=cert_days)
            else:
                client = ACMEClient(module)
                client.cert_days = cert_days
                other = dict()
                if client.is_first_step():
                    # First run: start challenges / start new order
                    client.start_challenges()
                else:
                    # Second run: finish challenges, and get certificate
                    try:
                        client.finish_challenges()
                        client.get_certificate()
                        if module.params['retrieve_all_alternates']:
                            other['all_chains'] = client.all_chains
                    finally:
                        if module.params['deactivate_authzs']:
                            client.deactivate_authzs()
                data, data_dns = client.get_challenges_data()
                auths = dict()
                for k, v in client.authorizations.items():
                    # Remove "type:" from key
                    auths[k.split(':', 1)[1]] = v
                module.exit_json(
                    changed=client.changed,
                    authorizations=auths,
                    finalize_uri=client.finalize_uri,
                    order_uri=client.order_uri,
                    account_uri=client.account.uri,
                    challenge_data=data,
                    challenge_data_dns=data_dns,
                    cert_days=client.cert_days,
                    **other
                )
        else:
            module.exit_json(changed=False, cert_days=cert_days)
    except ModuleFailException as e:
        e.do_fail(module)


if __name__ == '__main__':
    main()
