#!/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/>.
#

DOCUMENTATION = '''
---
module: nxos_overlay_global
version_added: "2.2"
short_description: Configures anycast gateway MAC of the switch.
description:
    - Configures anycast gateway MAC of the switch.
author: Gabriele Gerbino (@GGabriele)
extends_documentation_fragment: nxos
notes:
    - Default restores params default value
    - Supported MAC address format are "E.E.E", "EE-EE-EE-EE-EE-EE",
      "EE:EE:EE:EE:EE:EE" and "EEEE.EEEE.EEEE"
options:
    anycast_gateway_mac:
        description:
            - Anycast gateway mac of the switch.
        required: true
        default: null
'''

EXAMPLES = '''
- nxos_overlay_global:
    anycast_gateway_mac: "b.b.b"
    username: "{{ un }}"
    password: "{{ pwd }}"
    host: "{{ inventory_hostname }}"
'''

RETURN = '''
proposed:
    description: k/v pairs of parameters passed into module
    returned: verbose mode
    type: dict
    sample: {"asn": "65535", "router_id": "1.1.1.1", "vrf": "test"}
existing:
    description: k/v pairs of existing BGP configuration
    returned: verbose mode
    type: dict
    sample: {"asn": "65535", "bestpath_always_compare_med": false,
            "bestpath_aspath_multipath_relax": false,
            "bestpath_compare_neighborid": false,
            "bestpath_compare_routerid": false,
            "bestpath_cost_community_ignore": false,
            "bestpath_med_confed": false,
            "bestpath_med_missing_as_worst": false,
            "bestpath_med_non_deterministic": false, "cluster_id": "",
            "confederation_id": "", "confederation_peers": "",
            "graceful_restart": true, "graceful_restart_helper": false,
            "graceful_restart_timers_restart": "120",
            "graceful_restart_timers_stalepath_time": "300", "local_as": "",
            "log_neighbor_changes": false, "maxas_limit": "",
            "neighbor_down_fib_accelerate": false, "reconnect_interval": "60",
            "router_id": "11.11.11.11", "suppress_fib_pending": false,
            "timer_bestpath_limit": "", "timer_bgp_hold": "180",
            "timer_bgp_keepalive": "60", "vrf": "test"}
end_state:
    description: k/v pairs of BGP configuration after module execution
    returned: verbose mode
    type: dict
    sample: {"asn": "65535", "bestpath_always_compare_med": false,
            "bestpath_aspath_multipath_relax": false,
            "bestpath_compare_neighborid": false,
            "bestpath_compare_routerid": false,
            "bestpath_cost_community_ignore": false,
            "bestpath_med_confed": false,
            "bestpath_med_missing_as_worst": false,
            "bestpath_med_non_deterministic": false, "cluster_id": "",
            "confederation_id": "", "confederation_peers": "",
            "graceful_restart": true, "graceful_restart_helper": false,
            "graceful_restart_timers_restart": "120",
            "graceful_restart_timers_stalepath_time": "300", "local_as": "",
            "log_neighbor_changes": false, "maxas_limit": "",
            "neighbor_down_fib_accelerate": false, "reconnect_interval": "60",
            "router_id": "1.1.1.1",  "suppress_fib_pending": false,
            "timer_bestpath_limit": "", "timer_bgp_hold": "180",
            "timer_bgp_keepalive": "60", "vrf": "test"}
updates:
    description: commands sent to the device
    returned: always
    type: list
    sample: ["router bgp 65535", "vrf test", "router-id 1.1.1.1"]
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

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

try:
    from ansible.module_utils.nxos import get_module
except ImportError:
    from ansible.module_utils.nxos 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 = {
    'anycast_gateway_mac': 'fabric forwarding anycast-gateway-mac',
}


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_existing(module, args):
    existing = {}
    config = str(get_config(module))

    for arg in args:
        existing[arg] = get_value(arg, config, module)
    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 get_commands(module, existing, proposed, candidate):
    commands = 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.items():
        if value == 'default':
            existing_value = existing_commands.get(key)
            if existing_value:
                commands.append('no {0} {1}'.format(key, existing_value))
        else:
            if 'anycast-gateway-mac' in key:
                value = normalize_mac(value, module)
            command = '{0} {1}'.format(key, value)
            commands.append(command)

    if commands:
        candidate.add(commands, parents=[])


def normalize_mac(proposed_mac, module):
    try:
        if '-' in proposed_mac:
            splitted_mac = proposed_mac.split('-')
            if len(splitted_mac) != 6:
                raise ValueError

            for octect in splitted_mac:
                if len(octect) != 2:
                    raise ValueError

        elif '.' in proposed_mac:
            splitted_mac = []
            splitted_dot_mac = proposed_mac.split('.')
            if len(splitted_dot_mac) != 3:
                raise ValueError

            for octect in splitted_dot_mac:
                if len(octect) > 4:
                    raise ValueError
                else:
                    octect_len = len(octect)
                    padding = 4 - octect_len
                    splitted_mac.append(octect.zfill(padding+1))

        elif ':' in proposed_mac:
            splitted_mac = proposed_mac.split(':')
            if len(splitted_mac) != 6:
                raise ValueError

            for octect in splitted_mac:
                if len(octect) != 2:
                    raise ValueError
        else:
            raise ValueError
    except ValueError:
        module.fail_json(msg='Invalid MAC address format',
                             proposed_mac=proposed_mac)

    joined_mac = ''.join(splitted_mac)
    mac = [joined_mac[i:i+4] for i in range(0, len(joined_mac), 4)]
    return '.'.join(mac).upper()


def main():
    argument_spec = dict(
            anycast_gateway_mac=dict(required=True, type='str'),
            m_facts=dict(required=False, default=False, type='bool'),
            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)

    args =  [
            'anycast_gateway_mac'
        ]

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

    result = {}
    candidate = CustomNetworkConfig(indent=3)
    invoke('get_commands', module, existing, proposed, candidate)

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

    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

    module.exit_json(**result)


if __name__ == '__main__':
    main()
