#!/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_vlan
version_added: "2.1"
short_description: Manages VLAN resources and attributes.
description:
    - Manages VLAN configurations on NX-OS switches.
author: Jason Edelman (@jedelman8)
extends_documentation_fragment: nxos
options:
    vlan_id:
        description:
            - Single VLAN ID.
        required: false
        default: null
    vlan_range:
        description:
            - Range of VLANs such as 2-10 or 2,5,10-15, etc.
        required: false
        default: null
    name:
        description:
            - Name of VLAN.
        required: false
        default: null
    vlan_state:
        description:
            - Manage the vlan operational state of the VLAN
              (equivalent to state {active | suspend} command.
        required: false
        default: active
        choices: ['active','suspend']
    admin_state:
        description:
            - Manage the VLAN administrative state of the VLAN equivalent
              to shut/no shut in VLAN config mode.
        required: false
        default: up
        choices: ['up','down']
    mapped_vni:
        description:
            - The Virtual Network Identifier (VNI) ID that is mapped to the
              VLAN. Valid values are integer and keyword 'default'.
        required: false
        default: null
        version_added: "2.2"
    state:
        description:
            - Manage the state of the resource.
        required: false
        default: present
        choices: ['present','absent']

'''
EXAMPLES = '''
# Ensure a range of VLANs are not present on the switch
- nxos_vlan: vlan_range="2-10,20,50,55-60,100-150" host=68.170.147.165 username=cisco password=cisco state=absent transport=nxapi

# Ensure VLAN 50 exists with the name WEB and is in the shutdown state
- nxos_vlan: vlan_id=50 host=68.170.147.165 admin_state=down name=WEB transport=nxapi username=cisco password=cisco

# Ensure VLAN is NOT on the device
- nxos_vlan: vlan_id=50 host=68.170.147.165 state=absent transport=nxapi username=cisco password=cisco


'''

RETURN = '''

proposed_vlans_list:
    description: list of VLANs being proposed
    returned: always
    type: list
    sample: ["100"]
existing_vlans_list:
    description: list of existing VLANs on the switch prior to making changes
    returned: always
    type: list
    sample: ["1", "2", "3", "4", "5", "20"]
end_state_vlans_list:
    description: list of VLANs after the module is executed
    returned: always
    type: list
    sample:  ["1", "2", "3", "4", "5", "20", "100"]
proposed:
    description: k/v pairs of parameters passed into module (does not include
                 vlan_id or vlan_range)
    returned: always
    type: dict or null
    sample: {"admin_state": "down", "name": "app_vlan",
            "vlan_state": "suspend", "mapped_vni": "5000"}
existing:
    description: k/v pairs of existing vlan or null when using vlan_range
    returned: always
    type: dict
    sample: {"admin_state": "down", "name": "app_vlan",
             "vlan_id": "20", "vlan_state": "suspend", "mapped_vni": ""}
end_state:
    description: k/v pairs of the VLAN after executing module or null
                 when using vlan_range
    returned: always
    type: dict or null
    sample: {"admin_state": "down", "name": "app_vlan", "vlan_id": "20",
             "vlan_state": "suspend", "mapped_vni": "5000"}
updates:
    description: command string sent to the device
    returned: always
    type: list
    sample: ["vlan 20", "vlan 55", "vn-segment 5000"]
changed:
    description: check to see if a change was made on the device
    returned: always
    type: boolean
    sample: true

'''

import json
import collections

# 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, NetworkError


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

def vlan_range_to_list(vlans):
    result = []
    if vlans:
        for part in vlans.split(','):
            if part == 'none':
                break
            if '-' in part:
                a, b = part.split('-')
                a, b = int(a), int(b)
                result.extend(range(a, b + 1))
            else:
                a = int(part)
                result.append(a)
        return numerical_sort(result)
    return result


def numerical_sort(string_int_list):
    """Sort list of strings (VLAN IDs) that are digits in numerical order.
    """

    as_int_list = []
    as_str_list = []
    for vlan in string_int_list:
        as_int_list.append(int(vlan))
    as_int_list.sort()
    for vlan in as_int_list:
        as_str_list.append(str(vlan))
    return as_str_list


def build_commands(vlans, state):
    commands = []
    for vlan in vlans:
        if state == 'present':
            command = 'vlan {0}'.format(vlan)
            commands.append(command)
        elif state == 'absent':
            command = 'no vlan {0}'.format(vlan)
            commands.append(command)
    return commands


def get_vlan_config_commands(vlan, vid):
    """Build command list required for VLAN configuration
    """

    reverse_value_map = {
        "admin_state": {
            "down": "shutdown",
            "up": "no shutdown"
        }
    }

    if vlan.get('admin_state'):
        # apply value map when making change to the admin state
        # note: would need to be a loop or more in depth check if
        # value map has more than 1 key
        vlan = apply_value_map(reverse_value_map, vlan)

    VLAN_ARGS = {
        'name': 'name {0}',
        'vlan_state': 'state {0}',
        'admin_state': '{0}',
        'mode': 'mode {0}',
        'mapped_vni': 'vn-segment {0}'
    }

    commands = []

    for param, value in vlan.items():
        if param == 'mapped_vni' and value == 'default':
            command = 'no vn-segment'
        else:
            command = VLAN_ARGS.get(param).format(vlan.get(param))
        if command:
            commands.append(command)

    commands.insert(0, 'vlan ' + vid)
    commands.append('exit')

    return commands


def get_list_of_vlans(module):
    command = 'show vlan'
    body = execute_show_command(command, module)
    vlan_list = []
    vlan_table = body[0].get('TABLE_vlanbrief')['ROW_vlanbrief']

    if isinstance(vlan_table, list):
        for vlan in vlan_table:
            vlan_list.append(str(vlan['vlanshowbr-vlanid-utf']))
    else:
        vlan_list.append('1')

    return vlan_list


def get_vni(vlanid, module):
    command = 'show run all | section vlan.{0}'.format(vlanid)
    body = execute_show_command(command, module, command_type='cli_show_ascii')[0]
    value = ''
    if body:
        REGEX = re.compile(r'(?:vn-segment\s)(?P<value>.*)$', re.M)
        if 'vn-segment' in body:
            value = REGEX.search(body).group('value')
    return value


def get_vlan(vlanid, module):
    """Get instance of VLAN as a dictionary
    """

    command = 'show vlan id ' + vlanid

    body = execute_show_command(command, module)

    try:
        vlan_table = body[0]['TABLE_vlanbriefid']['ROW_vlanbriefid']
    except (TypeError, IndexError):
        return {}

    key_map = {
        "vlanshowbr-vlanid-utf": "vlan_id",
        "vlanshowbr-vlanname": "name",
        "vlanshowbr-vlanstate": "vlan_state",
        "vlanshowbr-shutstate": "admin_state"
    }

    vlan = apply_key_map(key_map, vlan_table)

    value_map = {
        "admin_state": {
            "shutdown": "down",
            "noshutdown": "up"
        }
    }

    vlan = apply_value_map(value_map, vlan)
    vlan['mapped_vni'] = get_vni(vlanid, module)
    return vlan


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


def apply_value_map(value_map, resource):
    for key, value in value_map.items():
        resource[key] = value[resource.get(key)]
    return resource


def execute_config_command(commands, module):
    try:
        module.configure(commands)
    except ShellError:
        clie = get_exception()
        module.fail_json(msg='Error sending CLI commands',
                         error=str(clie), commands=commands)
    except AttributeError:
        try:
            module.config.load_config(commands)
        except NetworkError:
            clie = get_exception()
            module.fail_json(msg='Error sending CLI commands',
                             error=str(clie), commands=commands)


def get_cli_body_ssh(command, response, module):
    """Get response for when transport=cli.  This is kind of a hack and mainly
    needed because these modules were originally written for NX-API.  And
    not every command supports "| json" when using cli/ssh.  As such, we assume
    if | json returns an XML string, it is a valid command, but that the
    resource doesn't exist yet.
    """
    if 'show run' in command or response[0] == '\n':
        body = response
    elif 'xml' in response[0]:
        body = []
    else:
        try:
            body = [json.loads(response[0])]
        except ValueError:
            module.fail_json(msg='Command does not support JSON output',
                             command=command)
    return body


def execute_show(cmds, module, command_type=None):
    command_type_map = {
        'cli_show': 'json',
        'cli_show_ascii': 'text'
    }

    try:
        if command_type:
            response = module.execute(cmds, command_type=command_type)
        else:
            response = module.execute(cmds)
    except ShellError:
        clie = get_exception()
        module.fail_json(msg='Error sending {0}'.format(cmds),
                         error=str(clie))
    except AttributeError:
        try:
            if command_type:
                command_type = command_type_map.get(command_type)
                module.cli.add_commands(cmds, output=command_type)
                response = module.cli.run_commands()
            else:
                module.cli.add_commands(cmds, raw=True)
                response = module.cli.run_commands()
        except NetworkError:
            clie = get_exception()
            module.fail_json(msg='Error sending {0}'.format(cmds),
                             error=str(clie))
    return response


def execute_show_command(command, module, command_type='cli_show'):
    if module.params['transport'] == 'cli':
        if 'show run' not in command:
            command += ' | json'
        cmds = [command]
        response = execute_show(cmds, module)
        body = get_cli_body_ssh(command, response, module)
    elif module.params['transport'] == 'nxapi':
        cmds = [command]
        body = execute_show(cmds, module, command_type=command_type)

    return body


def main():
    argument_spec = dict(
            vlan_id=dict(required=False, type='str'),
            vlan_range=dict(required=False),
            name=dict(required=False),
            vlan_state=dict(choices=['active', 'suspend'], required=False),
            mapped_vni=dict(required=False, type='str'),
            state=dict(choices=['present', 'absent'], default='present',
                       required=False),
            admin_state=dict(choices=['up', 'down'], required=False),
            include_defaults=dict(default=False),
            config=dict(),
            save=dict(type='bool', default=False)
    )
    module = get_network_module(argument_spec=argument_spec,
                                 mutually_exclusive=[['vlan_range', 'name'],
                                                     ['vlan_id', 'vlan_range']],
                                 supports_check_mode=True)

    vlan_range = module.params['vlan_range']
    vlan_id = module.params['vlan_id']
    name = module.params['name']
    vlan_state = module.params['vlan_state']
    admin_state = module.params['admin_state']
    mapped_vni = module.params['mapped_vni']
    state = module.params['state']

    changed = False

    if vlan_id:
        if not vlan_id.isdigit():
            module.fail_json(msg='vlan_id must be a valid VLAN ID')

    args = dict(name=name, vlan_state=vlan_state,
                admin_state=admin_state, mapped_vni=mapped_vni)

    proposed = dict((k, v) for k, v in args.items() if v is not None)

    proposed_vlans_list = numerical_sort(vlan_range_to_list(
        vlan_id or vlan_range))
    existing_vlans_list = numerical_sort(get_list_of_vlans(module))
    commands = []
    existing = None

    if vlan_range:
        if state == 'present':
            # These are all of the VLANs being proposed that don't
            # already exist on the switch
            vlans_delta = list(
                set(proposed_vlans_list).difference(existing_vlans_list))
            commands = build_commands(vlans_delta, state)
        elif state == 'absent':
            # VLANs that are common between what is being proposed and
            # what is on the switch
            vlans_common = list(
                set(proposed_vlans_list).intersection(existing_vlans_list))
            commands = build_commands(vlans_common, state)
    else:
        existing = get_vlan(vlan_id, module)
        if state == 'absent':
            if existing:
                commands = ['no vlan ' + vlan_id]
        elif state == 'present':
            if (existing.get('mapped_vni') == '0' and
                proposed.get('mapped_vni') == 'default'):
                proposed.pop('mapped_vni')
            delta = dict(set(
                proposed.items()).difference(existing.items()))
            if delta or not existing:
                commands = get_vlan_config_commands(delta, vlan_id)

    end_state = existing
    end_state_vlans_list = existing_vlans_list

    if commands:
        if existing.get('mapped_vni'):
            if (existing.get('mapped_vni') != proposed.get('mapped_vni') and
                existing.get('mapped_vni') != '0' and proposed.get('mapped_vni') != 'default'):
                commands.insert(1, 'no vn-segment')
        if module.check_mode:
            module.exit_json(changed=True,
                             commands=commands)
        else:
            execute_config_command(commands, module)
            changed = True
            end_state_vlans_list = numerical_sort(get_list_of_vlans(module))
            if vlan_id:
                end_state = get_vlan(vlan_id, module)

    results = {}
    results['proposed_vlans_list'] = proposed_vlans_list
    results['existing_vlans_list'] = existing_vlans_list
    results['proposed'] = proposed
    results['existing'] = existing
    results['end_state'] = end_state
    results['end_state_vlans_list'] = end_state_vlans_list
    results['updates'] = commands
    results['changed'] = changed

    module.exit_json(**results)


if __name__ == '__main__':
    main()
