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

# (c) 2013, Jan-Piet Mens <jpmens () gmail.com>
#
# This file is part of Ansible
#
# Ansible is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# Ansible is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with Ansible.  If not, see <http://www.gnu.org/licenses/>.
#

DOCUMENTATION = '''
---
module: mqtt
short_description: Publish a message on an MQTT topic for the IoT
version_added: "1.2"
description:
   - Publish a message on an MQTT topic.
options:
  server:
    description:
      - MQTT broker address/name
    required: false
    default: localhost
  port:
    description:
      - MQTT broker port number
    required: false
    default: 1883
  username:
    description:
      - Username to authenticate against the broker.
    required: false
  password:
    description:
      - Password for C(username) to authenticate against the broker.
    required: false
  client_id:
    description:
      - MQTT client identifier
    required: false
    default: hostname + pid
  topic:
    description:
      - MQTT topic name
    required: true
    default: null
  payload:
    description:
      - Payload. The special string C("None") may be used to send a NULL
        (i.e. empty) payload which is useful to simply notify with the I(topic)
        or to clear previously retained messages.
    required: true
    default: null
  qos:
    description:
      - QoS (Quality of Service)
    required: false
    default: 0
    choices: [ "0", "1", "2" ]
  retain:
    description:
      - Setting this flag causes the broker to retain (i.e. keep) the message so that
        applications that subsequently subscribe to the topic can received the last
        retained message immediately.
    required: false
    default: False

# informational: requirements for nodes
requirements: [ mosquitto ]
notes:
 - This module requires a connection to an MQTT broker such as Mosquitto
   U(http://mosquitto.org) and the C(mosquitto) Python module (U(http://mosquitto.org/python)).
author: Jan-Piet Mens
'''

EXAMPLES = '''
local_action: mqtt
              topic=service/ansible/{{ ansible_hostname }}
              payload="Hello at {{ ansible_date_time.iso8601 }}"
              qos=0
              retain=false
              client_id=ans001
'''

# ===========================================
# MQTT module support methods.
#

HAS_MOSQUITTO = True
try:
    import socket
    import mosquitto
except ImportError:
    HAS_MOSQUITTO = False
import os

def publish(module, topic, payload, server='localhost', port='1883', qos='0',
        client_id='', retain=False, username=None, password=None):
    '''Open connection to MQTT broker and publish the topic'''

    mqttc = mosquitto.Mosquitto(client_id, clean_session=True)

    if username is not None and password is not None:
        mqttc.username_pw_set(username, password)

    rc = mqttc.connect(server, int(port), 5)
    if rc != 0:
        module.fail_json(msg="unable to connect to MQTT broker")

    mqttc.publish(topic, payload, int(qos), retain)
    rc = mqttc.loop()
    if rc != 0:
        module.fail_json(msg="unable to send to MQTT broker")

    mqttc.disconnect()


# ===========================================
# Main
#

def main():

    if not HAS_MOSQUITTO:
        module.fail_json(msg="mosquitto is not installed")


    module = AnsibleModule(
        argument_spec=dict(
            server = dict(default = 'localhost'),
            port = dict(default = 1883),
            topic = dict(required = True),
            payload = dict(required = True),
            client_id = dict(default = None),
            qos = dict(default="0", choices=["0", "1", "2"]),
            retain = dict(default='no', choices=BOOLEANS, type='bool'),
            username = dict(default = None),
            password = dict(default = None),
        ),
        supports_check_mode=True
    )

    server     = module.params["server"]
    port       = module.params["port"]
    topic      = module.params["topic"]
    payload    = module.params["payload"]
    client_id  = module.params["client_id"]
    qos        = module.params["qos"]
    retain     = module.params["retain"]
    username   = module.params["username"]
    password   = module.params["password"]

    if client_id is None:
        client_id = "%s_%s" % (socket.getfqdn(), os.getpid())

    if payload and payload == 'None':
        payload = None

    try:
        publish(module, topic, payload, server, port, qos, client_id, retain,
                username, password)
    except Exception, e:
        module.fail_json(msg="unable to publish to MQTT broker %s" % (e))

    module.exit_json(changed=True, topic=topic)

# this is magic, see lib/ansible/module_common.py
#<<INCLUDE_ANSIBLE_MODULE_COMMON>>
main()