#!/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 = {'status': ['preview'],
                    'supported_by': 'community',
                    'version': '1.0'}

DOCUMENTATION = '''
---
module: nxos_evpn_vni
version_added: "2.2"
short_description: Manages Cisco EVPN VXLAN Network Identifier (VNI).
description:
    - Manages Cisco Ethernet Virtual Private Network (EVPN) VXLAN Network
      Identifier (VNI) configurations of a Nexus device.
author: Gabriele Gerbino (@GGabriele)
extends_documentation_fragment: nxos
notes:
    - default, where supported, restores params default value.
    - RD override is not permitted. You should set it to the default values
      first and then reconfigure it.
    - C(route_target_both), C(route_target_import) and
      C(route_target_export valid) values are a list of extended communities,
      (i.e. ['1.2.3.4:5', '33:55']) or the keywords 'auto' or 'default'.
    - The C(route_target_both) property is discouraged due to the inconsistent
      behavior of the property across Nexus platforms and image versions.
      For this reason it is recommended to use explicit C(route_target_export)
      and C(route_target_import) properties instead of C(route_target_both).
    - RD valid values are a string in one of the route-distinguisher formats,
      the keyword 'auto', or the keyword 'default'.
options:
    vni:
        description:
            - The EVPN VXLAN Network Identifier.
        required: true
        default: null
    route_distinguisher:
        description:
            - The VPN Route Distinguisher (RD). The RD is combined with
              the IPv4 or IPv6 prefix learned by the PE router to create a
              globally unique address.
        required: true
        default: null
    route_target_both:
        description:
            - Enables/Disables route-target settings for both import and
              export target communities using a single property.
        required: false
        default: null
    route_target_import:
        description:
            - Sets the route-target 'import' extended communities.
        required: false
        default: null
    route_target_export:
        description:
            - Sets the route-target 'import' extended communities.
        required: false
        default: null
    state:
        description:
            - Determines whether the config should be present or not
              on the device.
        required: false
        default: present
        choices: ['present','absent']
'''
EXAMPLES = '''
- nxos_evpn_vni:
    vni: 6000
    route_distinguisher: "60:10"
    route_target_import:
        - "5000:10"
        - "4100:100"
    route_target_export: auto
    route_target_both: default
    username: "{{ un }}"
    password: "{{ pwd }}"
    host: "{{ inventory_hostname }}"
'''

RETURN = '''
proposed:
    description: k/v pairs of parameters passed into module
    returned: verbose mode
    type: dict
    sample: {"route_target_import": ["5000:10", "4100:100",
             "5001:10"],"vni": "6000"}
existing:
    description: k/v pairs of existing EVPN VNI configuration
    returned: verbose mode
    type: dict
    sample: {"route_distinguisher": "70:10", "route_target_both": [],
            "route_target_export": [], "route_target_import": [
            "4100:100", "5000:10"], "vni": "6000"}
end_state:
    description: k/v pairs of EVPN VNI configuration after module execution
    returned: verbose mode
    type: dict
    sample: {"route_distinguisher": "70:10", "route_target_both": [],
             "route_target_export": [], "route_target_import": [
             "4100:100", "5000:10", "5001:10"], "vni": "6000"}
updates:
    description: commands sent to the device
    returned: always
    type: list
    sample: ["evpn", "vni 6000 l2", "route-target import 5001:10"]
changed:
    description: check to see if a change was made on the device
    returned: always
    type: boolean
    sample: true
'''

# COMMON CODE FOR MIGRATION
import re

import ansible.module_utils.nxos
from ansible.module_utils.basic import get_exception
from ansible.module_utils.netcfg import NetworkConfig, ConfigLine
from ansible.module_utils.shell import ShellError
from ansible.module_utils.network import NetworkModule


def to_list(val):
     if isinstance(val, (list, tuple)):
         return list(val)
     elif val is not None:
         return [val]
     else:
         return list()


class CustomNetworkConfig(NetworkConfig):

    def expand_section(self, configobj, S=None):
        if S is None:
            S = list()
        S.append(configobj)
        for child in configobj.children:
            if child in S:
                continue
            self.expand_section(child, S)
        return S

    def get_object(self, path):
        for item in self.items:
            if item.text == path[-1]:
                parents = [p.text for p in item.parents]
                if parents == path[:-1]:
                    return item

    def to_block(self, section):
        return '\n'.join([item.raw for item in section])

    def get_section(self, path):
        try:
            section = self.get_section_objects(path)
            return self.to_block(section)
        except ValueError:
            return list()

    def get_section_objects(self, path):
        if not isinstance(path, list):
            path = [path]
        obj = self.get_object(path)
        if not obj:
            raise ValueError('path does not exist in config')
        return self.expand_section(obj)


    def add(self, lines, parents=None):
        """Adds one or lines of configuration
        """

        ancestors = list()
        offset = 0
        obj = None

        ## global config command
        if not parents:
            for line in to_list(lines):
                item = ConfigLine(line)
                item.raw = line
                if item not in self.items:
                    self.items.append(item)

        else:
            for index, p in enumerate(parents):
                try:
                    i = index + 1
                    obj = self.get_section_objects(parents[:i])[0]
                    ancestors.append(obj)

                except ValueError:
                    # add parent to config
                    offset = index * self.indent
                    obj = ConfigLine(p)
                    obj.raw = p.rjust(len(p) + offset)
                    if ancestors:
                        obj.parents = list(ancestors)
                        ancestors[-1].children.append(obj)
                    self.items.append(obj)
                    ancestors.append(obj)

            # add child objects
            for line in to_list(lines):
                # check if child already exists
                for child in ancestors[-1].children:
                    if child.text == line:
                        break
                else:
                    offset = len(parents) * self.indent
                    item = ConfigLine(line)
                    item.raw = line.rjust(len(line) + offset)
                    item.parents = ancestors
                    ancestors[-1].children.append(item)
                    self.items.append(item)


def get_network_module(**kwargs):
    try:
        return get_module(**kwargs)
    except NameError:
        return NetworkModule(**kwargs)

def get_config(module, include_defaults=False):
    config = module.params['config']
    if not config:
        try:
            config = module.get_config()
        except AttributeError:
            defaults = module.params['include_defaults']
            config = module.config.get_config(include_defaults=defaults)
    return CustomNetworkConfig(indent=2, contents=config)

def load_config(module, candidate):
    config = get_config(module)

    commands = candidate.difference(config)
    commands = [str(c).strip() for c in commands]

    save_config = module.params['save']

    result = dict(changed=False)

    if commands:
        if not module.check_mode:
            try:
                module.configure(commands)
            except AttributeError:
                module.config(commands)

            if save_config:
                try:
                    module.config.save_config()
                except AttributeError:
                    module.execute(['copy running-config startup-config'])

        result['changed'] = True
        result['updates'] = commands

    return result
# END OF COMMON CODE

PARAM_TO_COMMAND_KEYMAP = {
    'vni': 'vni',
    'route_target_both': 'route-target both',
    'route_target_import': 'route-target import',
    'route_target_export': 'route-target export',
    'route_distinguisher': 'rd'
}
WARNINGS = []

import time

def invoke(name, *args, **kwargs):
    func = globals().get(name)
    if func:
        return func(*args, **kwargs)


def get_value(arg, config, module):
    REGEX = re.compile(r'(?:{0}\s)(?P<value>.*)$'.format(PARAM_TO_COMMAND_KEYMAP[arg]), re.M)
    value = ''
    if PARAM_TO_COMMAND_KEYMAP[arg] in config:
        value = REGEX.search(config).group('value')
    return value


def get_route_target_value(arg, config, module):
    splitted_config = config.splitlines()
    value_list = []
    REGEX = re.compile(r'(?:{0}\s)(?P<value>.*)$'.format(PARAM_TO_COMMAND_KEYMAP[arg]), re.M)

    for line in splitted_config:
        value = ''
        if PARAM_TO_COMMAND_KEYMAP[arg] in line.strip():
            value = REGEX.search(line).group('value')
            value_list.append(value)
    return value_list


def get_existing(module, args):
    existing = {}
    netcfg = get_config(module)
    parents = ['evpn', 'vni {0} l2'.format(module.params['vni'])]
    config = netcfg.get_section(parents)

    if config:
        for arg in args:
            if arg != 'vni':
                if arg == 'route_distinguisher':
                    existing[arg] = get_value(arg, config, module)
                else:
                    existing[arg] = get_route_target_value(arg, config, module)

        existing_fix = dict((k, v) for k, v in existing.iteritems() if v)
        if existing_fix:
            existing['vni'] = module.params['vni']
        else:
            existing = existing_fix

    return existing


def apply_key_map(key_map, table):
    new_dict = {}
    for key, value in table.items():
        new_key = key_map.get(key)
        if new_key:
            value = table.get(key)
            if value:
                new_dict[new_key] = value
            else:
                new_dict[new_key] = value
    return new_dict


def state_present(module, existing, proposed):
    commands = list()
    parents = list()
    proposed_commands = apply_key_map(PARAM_TO_COMMAND_KEYMAP, proposed)
    existing_commands = apply_key_map(PARAM_TO_COMMAND_KEYMAP, existing)

    for key, value in proposed_commands.iteritems():
        if key.startswith('route-target'):
            if value == ['default']:
                existing_value = existing_commands.get(key)

                if existing_value:
                    for target in existing_value:
                        commands.append('no {0} {1}'.format(key, target))
            else:
                if not isinstance(value, list):
                    value = [value]
                for target in value:
                    if existing:
                        if target not in existing.get(key.replace('-', '_').replace(' ', '_')):
                            commands.append('{0} {1}'.format(key, target))
                    else:
                        commands.append('{0} {1}'.format(key, target))
        else:
            if value == 'default':
                existing_value = existing_commands.get(key)
                if existing_value:
                    commands.append('no {0} {1}'.format(key, existing_value))
            else:
                command = '{0} {1}'.format(key, value)
                commands.append(command)

    if commands:
        parents = ['evpn', 'vni {0} l2'.format(module.params['vni'])]

    return commands, parents


def state_absent(module, existing, proposed):
    commands = ['no vni {0} l2'.format(module.params['vni'])]
    parents = ['evpn']
    return commands, parents


def execute_config(module, candidate):
    result = {}
    try:
        response = load_config(module, candidate)
        result.update(response)
    except ShellError:
        exc = get_exception()
        module.fail_json(msg=str(exc))
    return result


def main():
    argument_spec = dict(
            vni=dict(required=True, type='str'),
            route_distinguisher=dict(required=False, type='str'),
            route_target_both=dict(required=False, type='list'),
            route_target_import=dict(required=False, type='list'),
            route_target_export=dict(required=False, type='list'),
            state=dict(choices=['present', 'absent'], default='present',
                       required=False),
            include_defaults=dict(default=True),
            config=dict(),
            save=dict(type='bool', default=False)
    )
    module = get_network_module(argument_spec=argument_spec,
                        supports_check_mode=True)

    state = module.params['state']
    args =  [
            'vni',
            'route_distinguisher',
            'route_target_both',
            'route_target_import',
            'route_target_export'
        ]

    existing = invoke('get_existing', module, args)
    end_state = existing
    proposed_args = dict((k, v) for k, v in module.params.iteritems()
                    if v is not None and k in args)

    proposed = {}
    for key, value in proposed_args.iteritems():
        if key != 'vni':
            if value == 'true':
                value = True
            elif value == 'false':
                value = False
            if existing.get(key) or (not existing.get(key) and value):
                proposed[key] = value
    result = {}
    if state == 'present' or (state == 'absent' and existing):
        candidate = CustomNetworkConfig(indent=3)
        commands, parents = invoke('state_%s' % state, module, existing,
                                                proposed)
        if commands:
            if (existing.get('route_distinguisher') and
                    proposed.get('route_distinguisher')):
                if (existing['route_distinguisher'] != proposed[
                    'route_distinguisher'] and
                    proposed['route_distinguisher'] != 'default'):
                    WARNINGS.append('EVPN RD {0} was automatically removed. '
                                         'It is highly recommended to use a task '
                                         '(with default as value) to explicitly '
                                         'unconfigure it.'.format(
                                            existing['route_distinguisher']))
                    remove_commands = ['no rd {0}'.format(
                                            existing['route_distinguisher'])]

                    candidate.add(remove_commands, parents=parents)
                    result = execute_config(module, candidate)
                    time.sleep(30)

            candidate = CustomNetworkConfig(indent=3)
            candidate.add(commands, parents=parents)
            result = execute_config(module, candidate)
    else:
        result['updates'] = []

    result['connected'] = module.connected
    if module._verbosity > 0:
        end_state = invoke('get_existing', module, args)
        result['end_state'] = end_state
        result['existing'] = existing
        result['proposed'] = proposed_args

    if WARNINGS:
        result['warnings'] = WARNINGS

    module.exit_json(**result)


if __name__ == '__main__':
    main()