#!/usr/bin/python
#
# 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 = {'metadata_version': '1.0',
                    'status': ['preview'],
                    'supported_by': 'core'}


DOCUMENTATION = """
---
module: ios_vrf
version_added: "2.3"
author: "Peter Sprygada (@privateip)"
short_description: Manage the collection of VRF definitions on IOS devices
description:
  - This module provides declarative management of VRF definitions on
    Cisco IOS devices.  It allows playbooks to manage individual or
    the entire VRF collection.  It also supports purging VRF definitions from
    the configuration that are not explicitly defined.
extends_documentation_fragment: ios
options:
  vrfs:
    description:
      - The set of VRF definition objects to be configured on the remote
        IOS device.  Ths list entries can either be the VRF name or a hash
        of VRF definitions and attributes.  This argument is mutually
        exclusive with the C(name) argument.
  name:
    description:
      - The name of the VRF definition to be managed on the remote IOS
        device.  The VRF definition name is an ASCII string name used
        to uniquely identify the VRF.  This argument is mutually exclusive
        with the C(vrfs) argument
  description:
    description:
      - Provides a short description of the VRF definition in the
        current active configuration.  The VRF definition value accepts
        alphanumeric characters used to provide additional information
        about the VRF.
  rd:
    description:
      - The router-distinguisher value uniquely identifies the VRF to
        routing processes on the remote IOS system.  The RD value takes
        the form of C(A:B) where C(A) and C(B) are both numeric values.
  interfaces:
    description:
      - Identifies the set of interfaces that
        should be configured in the VRF.  Interfaces must be routed
        interfaces in order to be placed into a VRF.
  purge:
    description:
      - Instructs the module to consider the
        VRF definition absolute.  It will remove any previously configured
        VRFs on the device.
    default: false
  state:
    description:
      - Configures the state of the VRF definition
        as it relates to the device operational configuration.  When set
        to I(present), the VRF should be configured in the device active
        configuration and when set to I(absent) the VRF should not be
        in the device active configuration
    default: present
    choices: ['present', 'absent']
"""

EXAMPLES = """
- name: configure a vrf named management
  ios_vrf:
    name: management
    description: oob mgmt vrf
    interfaces:
      - Management1

- name: remove a vrf named test
  ios_vrf:
    name: test
    state: absent

- name: configure set of VRFs and purge any others
  ios_vrf:
    vrfs:
      - red
      - blue
      - green
    purge: yes
"""

RETURN = """
commands:
  description: The list of configuration mode commands to send to the device
  returned: always
  type: list
  sample:
    - vrf definition ansible
    - description management vrf
    - rd: 1:100
start:
  description: The time the job started
  returned: always
  type: str
  sample: "2016-11-16 10:38:15.126146"
end:
  description: The time the job ended
  returned: always
  type: str
  sample: "2016-11-16 10:38:25.595612"
delta:
  description: The time elapsed to perform all operations
  returned: always
  type: str
  sample: "0:00:10.469466"
"""
import re

from functools import partial

from ansible.module_utils.basic import AnsibleModule
from ansible.module_utils.ios import load_config, get_config
from ansible.module_utils.ios import ios_argument_spec, check_args
from ansible.module_utils.netcfg import NetworkConfig
from ansible.module_utils.six import iteritems


def add_command_to_vrf(name, cmd, commands):
    if 'vrf definition %s' % name not in commands:
        commands.append('vrf definition %s' % name)
    commands.append(cmd)

def map_obj_to_commands(updates, module):
    commands = list()
    state = module.params['state'] # FIXME NOT USED

    for update in updates:
        want, have = update

        needs_update = lambda x: want.get(x) and (want.get(x) != have.get(x))

        if want['state'] == 'absent':
            commands.append('no vrf definition %s' % want['name'])
            continue

        if not have.get('state'):
            commands.append('vrf definition %s' % want['name'])

        if needs_update('description'):
            cmd = 'description %s' % want['description']
            add_command_to_vrf(want['name'], cmd, commands)

        if needs_update('rd'):
            cmd = 'rd %s' % want['rd']
            add_command_to_vrf(want['name'], cmd, commands)

        if want['interfaces'] is not None:
            # handle the deletes
            for intf in set(have.get('interfaces', [])).difference(want['interfaces']):
                commands.extend(['interface %s' % intf,
                                 'no vrf forwarding %s' % want['name']])

            # handle the adds
            for intf in set(want['interfaces']).difference(have.get('interfaces', [])):
                cfg = get_config(module)
                configobj = NetworkConfig(indent=1, contents=cfg)
                children = configobj['interface %s' % intf].children
                intf_config = '\n'.join(children)

                commands.extend(['interface %s' % intf,
                                 'vrf forwarding %s' % want['name']])

                match = re.search('ip address .+', intf_config, re.M)
                if match:
                    commands.append(match.group())

    return commands

def parse_description(configobj, name):
    cfg = configobj['vrf definition %s' % name]
    cfg = '\n'.join(cfg.children)
    match = re.search(r'description (.+)$', cfg, re.M)
    if match:
        return match.group(1)

def parse_rd(configobj, name):
    cfg = configobj['vrf definition %s' % name]
    cfg = '\n'.join(cfg.children)
    match = re.search(r'rd (.+)$', cfg, re.M)
    if match:
        return match.group(1)

def parse_interfaces(configobj, name):
    vrf_cfg = 'vrf forwarding %s' % name
    interfaces = list()

    for intf in re.findall('^interface .+', str(configobj), re.M):
        if vrf_cfg in '\n'.join(configobj[intf].children):
            interfaces.append(intf.split(' ')[1])
    return interfaces

def map_config_to_obj(module):
    config = get_config(module)
    configobj = NetworkConfig(indent=1, contents=config)

    match = re.findall(r'^vrf definition (\S+)', config, re.M)
    if not match:
        return list()

    instances = list()

    for item in set(match):
        obj = {
            'name': item,
            'state': 'present',
            'description': parse_description(configobj, item),
            'rd': parse_rd(configobj, item),
            'interfaces': parse_interfaces(configobj, item)
        }
        instances.append(obj)
    return instances


def get_param_value(key, item, module):
    # if key doesn't exist in the item, get it from module.params
    if not item.get(key):
        value = module.params[key]

    # if key does exist, do a type check on it to validate it
    else:
        value_type = module.argument_spec[key].get('type', 'str')
        type_checker = module._CHECK_ARGUMENT_TYPES_DISPATCHER[value_type]
        type_checker(item[key])
        value = item[key]

    # validate the param value (if validator func exists)
    validator = globals().get('validate_%s' % key)
    if validator:
        validator(value, module)

    return value

def map_params_to_obj(module):
    vrfs = module.params.get('vrfs')
    if not vrfs:
        if not module.params['name'] and module.params['purge']:
            return list()
        elif not module.params['name']:
            module.fail_json(msg='name is required')
        collection = [{'name': module.params['name']}]
    else:
        collection = list()
        for item in vrfs:
            if not isinstance(item, dict):
                collection.append({'name': item})
            elif 'name' not in item:
                module.fail_json(msg='name is required')
            else:
                collection.append(item)

    objects = list()

    for item in collection:
        get_value = partial(get_param_value, item=item, module=module)
        item['description'] = get_value('description')
        item['rd'] = get_value('rd')
        item['interfaces'] = get_value('interfaces')
        item['state'] = get_value('state')
        objects.append(item)

    return objects

def update_objects(want, have):
    updates = list()
    for entry in want:
        item = next((i for i in have if i['name'] == entry['name']), None)
        if all((item is None, entry['state'] == 'present')):
            updates.append((entry, {}))
        else:
            for key, value in iteritems(entry):
                if value:
                    if isinstance(value, list):
                        if sorted(value) != sorted(item[key]):
                            if (entry, item) not in updates:
                                updates.append((entry, item))
                    elif value != item[key]:
                        if (entry, item) not in updates:
                            updates.append((entry, item))
    return updates

def main():
    """ main entry point for module execution
    """
    argument_spec = dict(
        vrfs=dict(type='list'),
        name=dict(),

        description=dict(),
        rd=dict(),

        interfaces=dict(type='list'),

        purge=dict(type='bool', default=False),
        state=dict(default='present', choices=['present', 'absent'])
    )

    argument_spec.update(ios_argument_spec)

    mutually_exclusive = [('name', 'vrfs')]

    module = AnsibleModule(argument_spec=argument_spec,
                           mutually_exclusive=mutually_exclusive,
                           supports_check_mode=True)

    result = {'changed': False}

    warnings = list()
    check_args(module, warnings)
    result['warnings'] = warnings

    want = map_params_to_obj(module)
    have = map_config_to_obj(module)

    commands = map_obj_to_commands(update_objects(want, have), module)

    if module.params['purge']:
        want_vrfs = [x['name'] for x in want]
        have_vrfs = [x['name'] for x in have]
        for item in set(have_vrfs).difference(want_vrfs):
            cmd = 'no vrf definition %s' % item
            if cmd not in commands:
                commands.append(cmd)

    result['commands'] = commands

    if commands:
        if not module.check_mode:
            load_config(module, commands)
        result['changed'] = True

    module.exit_json(**result)

if __name__ == '__main__':
    main()