#
# This code is part of Ansible, but is an independent component.
#
# This particular file snippet, and this file snippet only, is BSD licensed.
# Modules you write using this snippet, which is embedded dynamically by Ansible
# still belong to the author of the module, and may assign their own license
# to the complete work.
#
# Copyright: (c) 2017, Red Hat Inc.
#
# Redistribution and use in source and binary forms, with or without modification,
# are permitted provided that the following conditions are met:
#
#    * Redistributions of source code must retain the above copyright
#      notice, this list of conditions and the following disclaimer.
#    * Redistributions in binary form must reproduce the above copyright notice,
#      this list of conditions and the following disclaimer in the documentation
#      and/or other materials provided with the distribution.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
# WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
# IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
# INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
# PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
# USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.


import collections
import json
import re
import sys
from copy import deepcopy

from ansible.module_utils._text import to_text
from ansible.module_utils.basic import env_fallback
from ansible.module_utils.network.common.utils import to_list, ComplexList
from ansible.module_utils.connection import Connection, ConnectionError
from ansible.module_utils.common._collections_compat import Mapping
from ansible.module_utils.network.common.config import NetworkConfig, dumps
from ansible.module_utils.network.common.config import CustomNetworkConfig
from ansible.module_utils.six import iteritems, string_types, PY2, PY3
from ansible.module_utils.urls import fetch_url

try:
    import yaml
    HAS_YAML = True
except ImportError:
    HAS_YAML = False

try:
    if sys.version_info[:2] < (2, 7):
        from ordereddict import OrderedDict
    else:
        from collections import OrderedDict
    HAS_ORDEREDDICT = True
except ImportError:
    HAS_ORDEREDDICT = False

_DEVICE_CONNECTION = None

nxos_provider_spec = {
    'host': dict(type='str'),
    'port': dict(type='int'),

    'username': dict(type='str', fallback=(env_fallback, ['ANSIBLE_NET_USERNAME'])),
    'password': dict(type='str', no_log=True, fallback=(env_fallback, ['ANSIBLE_NET_PASSWORD'])),
    'ssh_keyfile': dict(type='str', fallback=(env_fallback, ['ANSIBLE_NET_SSH_KEYFILE'])),

    'authorize': dict(type='bool', fallback=(env_fallback, ['ANSIBLE_NET_AUTHORIZE'])),
    'auth_pass': dict(type='str', no_log=True, fallback=(env_fallback, ['ANSIBLE_NET_AUTH_PASS'])),

    'use_ssl': dict(type='bool'),
    'use_proxy': dict(type='bool', default=True),
    'validate_certs': dict(type='bool'),

    'timeout': dict(type='int'),

    'transport': dict(type='str', default='cli', choices=['cli', 'nxapi'])
}
nxos_argument_spec = {
    'provider': dict(type='dict', options=nxos_provider_spec),
}
nxos_top_spec = {
    'host': dict(type='str', removed_in_version=2.9),
    'port': dict(type='int', removed_in_version=2.9),

    'username': dict(type='str', removed_in_version=2.9),
    'password': dict(type='str', no_log=True, removed_in_version=2.9),
    'ssh_keyfile': dict(type='str', removed_in_version=2.9),

    'authorize': dict(type='bool', fallback=(env_fallback, ['ANSIBLE_NET_AUTHORIZE'])),
    'auth_pass': dict(type='str', no_log=True, removed_in_version=2.9),

    'use_ssl': dict(type='bool', removed_in_version=2.9),
    'validate_certs': dict(type='bool', removed_in_version=2.9),
    'timeout': dict(type='int', removed_in_version=2.9),

    'transport': dict(type='str', choices=['cli', 'nxapi'], removed_in_version=2.9)
}
nxos_argument_spec.update(nxos_top_spec)


def get_provider_argspec():
    return nxos_provider_spec


def check_args(module, warnings):
    pass


def load_params(module):
    provider = module.params.get('provider') or dict()
    for key, value in iteritems(provider):
        if key in nxos_provider_spec:
            if module.params.get(key) is None and value is not None:
                module.params[key] = value


def get_connection(module):
    global _DEVICE_CONNECTION
    if not _DEVICE_CONNECTION:
        load_params(module)
        if is_local_nxapi(module):
            conn = LocalNxapi(module)
        else:
            connection_proxy = Connection(module._socket_path)
            cap = json.loads(connection_proxy.get_capabilities())
            if cap['network_api'] == 'cliconf':
                conn = Cli(module)
            elif cap['network_api'] == 'nxapi':
                conn = HttpApi(module)
        _DEVICE_CONNECTION = conn
    return _DEVICE_CONNECTION


class Cli:

    def __init__(self, module):
        self._module = module
        self._device_configs = {}
        self._connection = None

    def _get_connection(self):
        if self._connection:
            return self._connection
        self._connection = Connection(self._module._socket_path)

        return self._connection

    def get_config(self, flags=None):
        """Retrieves the current config from the device or cache
        """
        flags = [] if flags is None else flags

        cmd = 'show running-config '
        cmd += ' '.join(flags)
        cmd = cmd.strip()

        try:
            return self._device_configs[cmd]
        except KeyError:
            connection = self._get_connection()
            try:
                out = connection.get_config(flags=flags)
            except ConnectionError as exc:
                self._module.fail_json(msg=to_text(exc, errors='surrogate_then_replace'))

            cfg = to_text(out, errors='surrogate_then_replace').strip() + '\n'
            self._device_configs[cmd] = cfg
            return cfg

    def run_commands(self, commands, check_rc=True):
        """Run list of commands on remote device and return results
        """
        connection = self._get_connection()

        try:
            out = connection.run_commands(commands, check_rc)
            if check_rc == 'retry_json':
                capabilities = self.get_capabilities()
                network_api = capabilities.get('network_api')

                if network_api == 'cliconf' and out:
                    for index, resp in enumerate(out):
                        if ('Invalid command at' in resp or 'Ambiguous command at' in resp) and 'json' in resp:
                            if commands[index]['output'] == 'json':
                                commands[index]['output'] = 'text'
                                out = connection.run_commands(commands, check_rc)
            return out
        except ConnectionError as exc:
            self._module.fail_json(msg=to_text(exc))

    def load_config(self, config, return_error=False, opts=None, replace=None):
        """Sends configuration commands to the remote device
        """
        if opts is None:
            opts = {}

        connection = self._get_connection()
        responses = []
        try:
            resp = connection.edit_config(config, replace=replace)
            if isinstance(resp, Mapping):
                resp = resp['response']
        except ConnectionError as e:
            code = getattr(e, 'code', 1)
            message = getattr(e, 'err', e)
            err = to_text(message, errors='surrogate_then_replace')
            if opts.get('ignore_timeout') and code:
                responses.append(err)
                return responses
            elif code and 'no graceful-restart' in err:
                if 'ISSU/HA will be affected if Graceful Restart is disabled' in err:
                    msg = ['']
                    responses.extend(msg)
                    return responses
                else:
                    self._module.fail_json(msg=err)
            elif code:
                self._module.fail_json(msg=err)

        responses.extend(resp)
        return responses

    def get_diff(self, candidate=None, running=None, diff_match='line', diff_ignore_lines=None, path=None, diff_replace='line'):
        conn = self._get_connection()
        try:
            response = conn.get_diff(candidate=candidate, running=running, diff_match=diff_match, diff_ignore_lines=diff_ignore_lines, path=path,
                                     diff_replace=diff_replace)
        except ConnectionError as exc:
            self._module.fail_json(msg=to_text(exc, errors='surrogate_then_replace'))
        return response

    def get_capabilities(self):
        """Returns platform info of the remove device
        """
        if hasattr(self._module, '_capabilities'):
            return self._module._capabilities

        connection = self._get_connection()
        try:
            capabilities = connection.get_capabilities()
        except ConnectionError as exc:
            self._module.fail_json(msg=to_text(exc, errors='surrogate_then_replace'))
        self._module._capabilities = json.loads(capabilities)
        return self._module._capabilities

    def read_module_context(self, module_key):
        connection = self._get_connection()
        try:
            module_context = connection.read_module_context(module_key)
        except ConnectionError as exc:
            self._module.fail_json(msg=to_text(exc, errors='surrogate_then_replace'))

        return module_context

    def save_module_context(self, module_key, module_context):
        connection = self._get_connection()
        try:
            connection.save_module_context(module_key, module_context)
        except ConnectionError as exc:
            self._module.fail_json(msg=to_text(exc, errors='surrogate_then_replace'))

        return None


class LocalNxapi:

    OUTPUT_TO_COMMAND_TYPE = {
        'text': 'cli_show_ascii',
        'json': 'cli_show',
        'bash': 'bash',
        'config': 'cli_conf'
    }

    def __init__(self, module):
        self._module = module
        self._nxapi_auth = None
        self._device_configs = {}
        self._module_context = {}

        self._module.params['url_username'] = self._module.params['username']
        self._module.params['url_password'] = self._module.params['password']

        host = self._module.params['host']
        port = self._module.params['port']

        if self._module.params['use_ssl']:
            proto = 'https'
            port = port or 443
        else:
            proto = 'http'
            port = port or 80

        self._url = '%s://%s:%s/ins' % (proto, host, port)

    def _error(self, msg, **kwargs):
        self._nxapi_auth = None
        if 'url' not in kwargs:
            kwargs['url'] = self._url
        self._module.fail_json(msg=msg, **kwargs)

    def _request_builder(self, commands, output, version='1.0', chunk='0', sid=None):
        """Encodes a NXAPI JSON request message
        """
        try:
            command_type = self.OUTPUT_TO_COMMAND_TYPE[output]
        except KeyError:
            msg = 'invalid format, received %s, expected one of %s' % \
                (output, ','.join(self.OUTPUT_TO_COMMAND_TYPE.keys()))
            self._error(msg=msg)

        if isinstance(commands, (list, set, tuple)):
            commands = ' ;'.join(commands)

        # Order should not matter but some versions of NX-OS software fail
        # to process the payload properly if 'input' gets serialized before
        # 'type' and the payload of 'input' contains the word 'type'.
        msg = collections.OrderedDict()
        msg['version'] = version
        msg['type'] = command_type
        msg['chunk'] = chunk
        msg['sid'] = sid
        msg['input'] = commands
        msg['output_format'] = 'json'

        return dict(ins_api=msg)

    def send_request(self, commands, output='text', check_status=True,
                     return_error=False, opts=None):
        # only 10 show commands can be encoded in each request
        # messages sent to the remote device
        if opts is None:
            opts = {}
        if output != 'config':
            commands = collections.deque(to_list(commands))
            stack = list()
            requests = list()

            while commands:
                stack.append(commands.popleft())
                if len(stack) == 10:
                    body = self._request_builder(stack, output)
                    data = self._module.jsonify(body)
                    requests.append(data)
                    stack = list()

            if stack:
                body = self._request_builder(stack, output)
                data = self._module.jsonify(body)
                requests.append(data)

        else:
            body = self._request_builder(commands, 'config')
            requests = [self._module.jsonify(body)]

        headers = {'Content-Type': 'application/json'}
        result = list()
        timeout = self._module.params['timeout']
        use_proxy = self._module.params['provider']['use_proxy']

        for req in requests:
            if self._nxapi_auth:
                headers['Cookie'] = self._nxapi_auth

            response, headers = fetch_url(
                self._module, self._url, data=req, headers=headers,
                timeout=timeout, method='POST', use_proxy=use_proxy
            )
            self._nxapi_auth = headers.get('set-cookie')

            if opts.get('ignore_timeout') and re.search(r'(-1|5\d\d)', str(headers['status'])):
                result.append(headers['status'])
                return result
            elif headers['status'] != 200:
                self._error(**headers)

            try:
                response = self._module.from_json(response.read())
            except ValueError:
                self._module.fail_json(msg='unable to parse response')

            if response['ins_api'].get('outputs'):
                output = response['ins_api']['outputs']['output']
                for item in to_list(output):
                    if check_status is True and item['code'] != '200':
                        if return_error:
                            result.append(item)
                        else:
                            self._error(output=output, **item)
                    elif 'body' in item:
                        result.append(item['body'])
                    # else:
                        # error in command but since check_status is disabled
                        # silently drop it.
                        # result.append(item['msg'])

            return result

    def get_config(self, flags=None):
        """Retrieves the current config from the device or cache
        """
        flags = [] if flags is None else flags

        cmd = 'show running-config '
        cmd += ' '.join(flags)
        cmd = cmd.strip()

        try:
            return self._device_configs[cmd]
        except KeyError:
            out = self.send_request(cmd)
            cfg = str(out[0]).strip()
            self._device_configs[cmd] = cfg
            return cfg

    def run_commands(self, commands, check_rc=True):
        """Run list of commands on remote device and return results
        """
        output = None
        queue = list()
        responses = list()

        def _send(commands, output):
            return self.send_request(commands, output, check_status=check_rc)

        for item in to_list(commands):
            if is_json(item['command']):
                item['command'] = str(item['command']).rsplit('|', 1)[0]
                item['output'] = 'json'

            if all((output == 'json', item['output'] == 'text')) or all((output == 'text', item['output'] == 'json')):
                responses.extend(_send(queue, output))
                queue = list()

            output = item['output'] or 'json'
            queue.append(item['command'])

        if queue:
            responses.extend(_send(queue, output))

        return responses

    def load_config(self, commands, return_error=False, opts=None, replace=None):
        """Sends the ordered set of commands to the device
        """

        if opts is None:
            opts = {}

        responses = []

        if replace:
            device_info = self.get_device_info()
            if '9K' not in device_info.get('network_os_platform', ''):
                self._module.fail_json(msg='replace is supported only on Nexus 9K devices')
            commands = 'config replace {0}'.format(replace)

        commands = to_list(commands)
        try:
            resp = self.send_request(commands, output='config', check_status=True,
                                     return_error=return_error, opts=opts)
        except ValueError as exc:
            code = getattr(exc, 'code', 1)
            message = getattr(exc, 'err', exc)
            err = to_text(message, errors='surrogate_then_replace')
            if opts.get('ignore_timeout') and code:
                responses.append(code)
                return responses
            elif code and 'no graceful-restart' in err:
                if 'ISSU/HA will be affected if Graceful Restart is disabled' in err:
                    msg = ['']
                    responses.extend(msg)
                    return responses
                else:
                    self._module.fail_json(msg=err)
            elif code:
                self._module.fail_json(msg=err)

        if return_error:
            return resp
        else:
            return responses.extend(resp)

    def get_diff(self, candidate=None, running=None, diff_match='line', diff_ignore_lines=None, path=None, diff_replace='line'):
        diff = {}

        # prepare candidate configuration
        candidate_obj = NetworkConfig(indent=2)
        candidate_obj.load(candidate)

        if running and diff_match != 'none' and diff_replace != 'config':
            # running configuration
            running_obj = NetworkConfig(indent=2, contents=running, ignore_lines=diff_ignore_lines)
            configdiffobjs = candidate_obj.difference(running_obj, path=path, match=diff_match, replace=diff_replace)

        else:
            configdiffobjs = candidate_obj.items

        diff['config_diff'] = dumps(configdiffobjs, 'commands') if configdiffobjs else ''
        return diff

    def get_device_info(self):
        device_info = {}

        device_info['network_os'] = 'nxos'
        reply = self.run_commands({'command': 'show version', 'output': 'json'})
        data = reply[0]

        platform_reply = self.run_commands({'command': 'show inventory', 'output': 'json'})
        platform_info = platform_reply[0]

        device_info['network_os_version'] = data.get('sys_ver_str') or data.get('kickstart_ver_str')
        device_info['network_os_model'] = data['chassis_id']
        device_info['network_os_hostname'] = data['host_name']
        device_info['network_os_image'] = data.get('isan_file_name') or data.get('kick_file_name')

        if platform_info:
            inventory_table = platform_info['TABLE_inv']['ROW_inv']
            for info in inventory_table:
                if 'Chassis' in info['name']:
                    device_info['network_os_platform'] = info['productid']

        return device_info

    def get_capabilities(self):
        result = {}
        result['device_info'] = self.get_device_info()
        result['network_api'] = 'nxapi'
        return result

    def read_module_context(self, module_key):
        if self._module_context.get(module_key):
            return self._module_context[module_key]

        return None

    def save_module_context(self, module_key, module_context):
        self._module_context[module_key] = module_context

        return None


class HttpApi:
    def __init__(self, module):
        self._module = module
        self._device_configs = {}
        self._module_context = {}
        self._connection_obj = None

    @property
    def _connection(self):
        if not self._connection_obj:
            self._connection_obj = Connection(self._module._socket_path)

        return self._connection_obj

    def run_commands(self, commands, check_rc=True):
        """Runs list of commands on remote device and returns results
        """
        try:
            out = self._connection.send_request(commands)
        except ConnectionError as exc:
            if check_rc is True:
                raise
            out = to_text(exc)

        out = to_list(out)
        if not out[0]:
            return out

        for index, response in enumerate(out):
            if response[0] == '{':
                out[index] = json.loads(response)

        return out

    def get_config(self, flags=None):
        """Retrieves the current config from the device or cache
        """
        flags = [] if flags is None else flags

        cmd = 'show running-config '
        cmd += ' '.join(flags)
        cmd = cmd.strip()

        try:
            return self._device_configs[cmd]
        except KeyError:
            try:
                out = self._connection.send_request(cmd)
            except ConnectionError as exc:
                self._module.fail_json(msg=to_text(exc, errors='surrogate_then_replace'))

            cfg = to_text(out).strip()
            self._device_configs[cmd] = cfg
            return cfg

    def get_diff(self, candidate=None, running=None, diff_match='line', diff_ignore_lines=None, path=None, diff_replace='line'):
        diff = {}

        # prepare candidate configuration
        candidate_obj = NetworkConfig(indent=2)
        candidate_obj.load(candidate)

        if running and diff_match != 'none' and diff_replace != 'config':
            # running configuration
            running_obj = NetworkConfig(indent=2, contents=running, ignore_lines=diff_ignore_lines)
            configdiffobjs = candidate_obj.difference(running_obj, path=path, match=diff_match, replace=diff_replace)

        else:
            configdiffobjs = candidate_obj.items

        diff['config_diff'] = dumps(configdiffobjs, 'commands') if configdiffobjs else ''
        return diff

    def load_config(self, commands, return_error=False, opts=None, replace=None):
        """Sends the ordered set of commands to the device
        """
        if opts is None:
            opts = {}

        responses = []
        try:
            resp = self.edit_config(commands, replace=replace)
        except ConnectionError as exc:
            code = getattr(exc, 'code', 1)
            message = getattr(exc, 'err', exc)
            err = to_text(message, errors='surrogate_then_replace')
            if opts.get('ignore_timeout') and code:
                responses.append(code)
                return responses
            elif code and 'no graceful-restart' in err:
                if 'ISSU/HA will be affected if Graceful Restart is disabled' in err:
                    msg = ['']
                    responses.extend(msg)
                    return responses
                else:
                    self._module.fail_json(msg=err)
            elif code:
                self._module.fail_json(msg=err)

        responses.extend(resp)
        return responses

    def edit_config(self, candidate=None, commit=True, replace=None, comment=None):
        resp = list()

        self.check_edit_config_capability(candidate, commit, replace, comment)

        if replace:
            candidate = 'config replace {0}'.format(replace)

        responses = self._connection.send_request(candidate, output='config')
        for response in to_list(responses):
            if response != '{}':
                resp.append(response)
        if not resp:
            resp = ['']

        return resp

    def get_capabilities(self):
        """Returns platform info of the remove device
        """
        try:
            capabilities = self._connection.get_capabilities()
        except ConnectionError as exc:
            self._module.fail_json(msg=to_text(exc, errors='surrogate_then_replace'))

        return json.loads(capabilities)

    def check_edit_config_capability(self, candidate=None, commit=True, replace=None, comment=None):
        operations = self._connection.get_device_operations()

        if not candidate and not replace:
            raise ValueError("must provide a candidate or replace to load configuration")

        if commit not in (True, False):
            raise ValueError("'commit' must be a bool, got %s" % commit)

        if replace and not operations.get('supports_replace'):
            raise ValueError("configuration replace is not supported")

        if comment and not operations.get('supports_commit_comment', False):
            raise ValueError("commit comment is not supported")

    def read_module_context(self, module_key):
        try:
            module_context = self._connection.read_module_context(module_key)
        except ConnectionError as exc:
            self._module.fail_json(msg=to_text(exc, errors='surrogate_then_replace'))

        return module_context

    def save_module_context(self, module_key, module_context):
        try:
            self._connection.save_module_context(module_key, module_context)
        except ConnectionError as exc:
            self._module.fail_json(msg=to_text(exc, errors='surrogate_then_replace'))

        return None


class NxosCmdRef:
    """NXOS Command Reference utilities.
    The NxosCmdRef class takes a yaml-formatted string of nxos module commands
    and converts it into dict-formatted database of getters/setters/defaults
    and associated common and platform-specific values. The utility methods
    add additional data such as existing states, playbook states, and proposed cli.
    The utilities also abstract away platform differences such as different
    defaults and different command syntax.

    Callers must provide a yaml formatted string that defines each command and
    its properties; e.g. BFD global:
    ---
    _template: # _template holds common settings for all commands
      # Enable feature bfd if disabled
      feature: bfd
      # Common getter syntax for BFD commands
      get_command: show run bfd all | incl '^(no )*bfd'

    interval:
      kind: dict
      getval: bfd interval (?P<tx>\\d+) min_rx (?P<min_rx>\\d+) multiplier (?P<multiplier>\\d+)
      setval: bfd interval {tx} min_rx {min_rx} multiplier {multiplier}
      default:
        tx: 50
        min_rx: 50
        multiplier: 3
      N3K:
        # Platform overrides
        default:
          tx: 250
          min_rx: 250
          multiplier: 3
    """

    def __init__(self, module, cmd_ref_str, ref_only=False):
        """Initialize cmd_ref from yaml data."""

        self._module = module
        self._check_imports()
        self._yaml_load(cmd_ref_str)
        self.cache_existing = None
        self.present_states = ['present', 'merged', 'replaced']
        self.absent_states = ['absent', 'deleted']
        ref = self._ref

        # Create a list of supported commands based on ref keys
        ref['commands'] = sorted([k for k in ref if not k.startswith('_')])
        ref['_proposed'] = []
        ref['_context'] = []
        ref['_resource_key'] = None

        if not ref_only:
            ref['_state'] = module.params.get('state', 'present')
            self.feature_enable()
            self.get_platform_defaults()
            self.normalize_defaults()

    def __getitem__(self, key=None):
        if key is None:
            return self._ref
        return self._ref[key]

    def _check_imports(self):
        module = self._module
        msg = nxosCmdRef_import_check()
        if msg:
            module.fail_json(msg=msg)

    def _yaml_load(self, cmd_ref_str):
        if PY2:
            self._ref = yaml.load(cmd_ref_str)
        elif PY3:
            self._ref = yaml.load(cmd_ref_str, Loader=yaml.FullLoader)

    def feature_enable(self):
        """Add 'feature <foo>' to _proposed if ref includes a 'feature' key. """
        ref = self._ref
        feature = ref['_template'].get('feature')
        if feature:
            show_cmd = "show run | incl 'feature {0}'".format(feature)
            output = self.execute_show_command(show_cmd, 'text')
            if not output or 'CLI command error' in output:
                msg = "** 'feature {0}' is not enabled. Module will auto-enable feature {0} ** ".format(feature)
                self._module.warn(msg)
                ref['_proposed'].append('feature {0}'.format(feature))
                ref['_cli_is_feature_disabled'] = ref['_proposed']

    def get_platform_shortname(self):
        """Query device for platform type, normalize to a shortname/nickname.
        Returns platform shortname (e.g. 'N3K-3058P' returns 'N3K') or None.
        """
        # TBD: add this method logic to get_capabilities() after those methods
        #      are made consistent across transports
        platform_info = self.execute_show_command('show inventory', 'json')
        if not platform_info or not isinstance(platform_info, dict):
            return None
        inventory_table = platform_info['TABLE_inv']['ROW_inv']
        for info in inventory_table:
            if 'Chassis' in info['name']:
                network_os_platform = info['productid']
                break
        else:
            return None

        # Supported Platforms: N3K,N5K,N6K,N7K,N9K,N3K-F,N9K-F
        m = re.match('(?P<short>N[35679][K57])-(?P<N35>C35)*', network_os_platform)
        if not m:
            return None
        shortname = m.group('short')

        # Normalize
        if m.groupdict().get('N35'):
            shortname = 'N35'
        elif re.match('N77', shortname):
            shortname = 'N7K'
        elif re.match(r'N3K|N9K', shortname):
            for info in inventory_table:
                if '-R' in info['productid']:
                    # Fretta Platform
                    shortname += '-F'
                    break
        return shortname

    def get_platform_defaults(self):
        """Update ref with platform specific defaults"""
        plat = self.get_platform_shortname()
        if not plat:
            return

        ref = self._ref
        ref['_platform_shortname'] = plat
        # Remove excluded commands (no platform support for command)
        for k in ref['commands']:
            if plat in ref[k].get('_exclude', ''):
                ref['commands'].remove(k)

        # Update platform-specific settings for each item in ref
        plat_spec_cmds = [k for k in ref['commands'] if plat in ref[k]]
        for k in plat_spec_cmds:
            for plat_key in ref[k][plat]:
                ref[k][plat_key] = ref[k][plat][plat_key]

    def normalize_defaults(self):
        """Update ref defaults with normalized data"""
        ref = self._ref
        for k in ref['commands']:
            if 'default' in ref[k] and ref[k]['default']:
                kind = ref[k]['kind']
                if 'int' == kind:
                    ref[k]['default'] = int(ref[k]['default'])
                elif 'list' == kind:
                    ref[k]['default'] = [str(i) for i in ref[k]['default']]
                elif 'dict' == kind:
                    for key, v in ref[k]['default'].items():
                        if v:
                            v = str(v)
                        ref[k]['default'][key] = v

    def execute_show_command(self, command, format):
        """Generic show command helper.
        Warning: 'CLI command error' exceptions are caught, must be handled by caller.
        Return device output as a newline-separated string or None.
        """
        cmds = [{
            'command': command,
            'output': format,
        }]
        output = None
        try:
            output = run_commands(self._module, cmds)
            if output:
                output = output[0]
        except ConnectionError as exc:
            if 'CLI command error' in repr(exc):
                # CLI may be feature disabled
                output = repr(exc)
            else:
                raise
        return output

    def pattern_match_existing(self, output, k):
        """Pattern matching helper for `get_existing`.
        `k` is the command name string. Use the pattern from cmd_ref to
        find a matching string in the output.
        Return regex match object or None.
        """
        ref = self._ref
        pattern = re.compile(ref[k]['getval'])
        multiple = 'multiple' in ref[k].keys()
        match_lines = [re.search(pattern, line) for line in output]
        if 'dict' == ref[k]['kind']:
            match = [m for m in match_lines if m]
            if not match:
                return None
            if len(match) > 1 and not multiple:
                raise ValueError("get_existing: multiple matches found for property {0}".format(k))
        else:
            match = [m.groups() for m in match_lines if m]
            if not match:
                return None
            if len(match) > 1 and not multiple:
                raise ValueError("get_existing: multiple matches found for property {0}".format(k))
            for item in match:
                index = match.index(item)
                match[index] = list(item)  # tuple to list

                # Handle config strings that nvgen with the 'no' prefix.
                # Example match behavior:
                # When pattern is: '(no )*foo *(\S+)*$' AND
                #  When output is: 'no foo'  -> match: ['no ', None]
                #  When output is: 'foo 50'  -> match: [None, '50']
                if None is match[index][0]:
                    match[index].pop(0)
                elif 'no' in match[index][0]:
                    match[index].pop(0)
                    if not match:
                        return None

        return match

    def set_context(self, context=None):
        """Update ref with command context.
        """
        if context is None:
            context = []
        ref = self._ref
        # Process any additional context that this propoerty might require.
        # 1) Global context from NxosCmdRef _template.
        # 2) Context passed in using context arg.
        ref['_context'] = ref['_template'].get('context', [])
        for cmd in context:
            ref['_context'].append(cmd)
        # Last key in context is the resource key
        ref['_resource_key'] = context[-1] if context else ref['_resource_key']

    def get_existing(self, cache_output=None):
        """Update ref with existing command states from the device.
        Store these states in each command's 'existing' key.
        """
        ref = self._ref
        if ref.get('_cli_is_feature_disabled'):
            # Add context to proposed if state is present
            if ref['_state'] in self.present_states:
                [ref['_proposed'].append(ctx) for ctx in ref['_context']]
            return

        show_cmd = ref['_template']['get_command']
        if cache_output:
            output = cache_output
        else:
            output = self.execute_show_command(show_cmd, 'text') or []
            self.cache_existing = output

        # Add additional command context if needed.
        if ref['_context']:
            output = CustomNetworkConfig(indent=2, contents=output)
            output = output.get_section(ref['_context'])

        if not output:
            # Add context to proposed if state is present
            if ref['_state'] in self.present_states:
                [ref['_proposed'].append(ctx) for ctx in ref['_context']]
            return

        # We need to remove the last item in context for state absent case.
        if ref['_state'] in self.absent_states and ref['_context']:
            if ref['_resource_key'] and ref['_resource_key'] == ref['_context'][-1]:
                if ref['_context'][-1] in output:
                    ref['_context'][-1] = 'no ' + ref['_context'][-1]
                else:
                    del ref['_context'][-1]
                return

        # Walk each cmd in ref, use cmd pattern to discover existing cmds
        output = output.split('\n')
        for k in ref['commands']:
            match = self.pattern_match_existing(output, k)
            if not match:
                continue
            ref[k]['existing'] = {}
            for item in match:
                index = match.index(item)
                kind = ref[k]['kind']
                if 'int' == kind:
                    ref[k]['existing'][index] = int(item[0])
                elif 'list' == kind:
                    ref[k]['existing'][index] = [str(i) for i in item[0]]
                elif 'dict' == kind:
                    # The getval pattern should contain regex named group keys that
                    # match up with the setval named placeholder keys; e.g.
                    #   getval: my-cmd (?P<foo>\d+) bar (?P<baz>\d+)
                    #   setval: my-cmd {foo} bar {baz}
                    ref[k]['existing'][index] = {}
                    for key in item.groupdict().keys():
                        ref[k]['existing'][index][key] = str(item.group(key))
                elif 'str' == kind:
                    ref[k]['existing'][index] = item[0]
                else:
                    raise ValueError("get_existing: unknown 'kind' value specified for key '{0}'".format(k))

    def get_playvals(self):
        """Update ref with values from the playbook.
        Store these values in each command's 'playval' key.
        """
        ref = self._ref
        module = self._module
        params = {}
        if module.params.get('config'):
            # Resource module builder packs playvals under 'config' key
            param_data = module.params.get('config')
            params['global'] = param_data
            for key in param_data.keys():
                if isinstance(param_data[key], list):
                    params[key] = param_data[key]
        else:
            params['global'] = module.params
        for k in ref.keys():
            for level in params.keys():
                if isinstance(params[level], dict):
                    params[level] = [params[level]]
                for item in params[level]:
                    if k in item and item[k] is not None:
                        if not ref[k].get('playval'):
                            ref[k]['playval'] = {}
                        playval = item[k]
                        index = params[level].index(item)
                        # Normalize each value
                        if 'int' == ref[k]['kind']:
                            playval = int(playval)
                        elif 'list' == ref[k]['kind']:
                            playval = [str(i) for i in playval]
                        elif 'dict' == ref[k]['kind']:
                            for key, v in playval.items():
                                playval[key] = str(v)
                        ref[k]['playval'][index] = playval

    def build_cmd_set(self, playval, existing, k):
        """Helper function to create list of commands to configure device
        Return a list of commands
        """
        ref = self._ref
        proposed = ref['_proposed']
        cmd = None
        kind = ref[k]['kind']
        if 'int' == kind:
            cmd = ref[k]['setval'].format(playval)
        elif 'list' == kind:
            cmd = ref[k]['setval'].format(*(playval))
        elif 'dict' == kind:
            # The setval pattern should contain placeholder keys that
            # match up with the getval regex named group keys; e.g.
            #   getval: my-cmd (?P<foo>\d+) bar (?P<baz>\d+)
            #   setval: my-cmd {foo} bar {baz}
            cmd = ref[k]['setval'].format(**playval)
        elif 'str' == kind:
            if 'deleted' in playval:
                if existing:
                    cmd = 'no ' + ref[k]['setval'].format(existing)
            else:
                cmd = ref[k]['setval'].format(playval)
        else:
            raise ValueError("get_proposed: unknown 'kind' value specified for key '{0}'".format(k))
        if cmd:
            if ref['_state'] in self.absent_states and not re.search(r'^no', cmd):
                cmd = 'no ' + cmd
            # Commands may require parent commands for proper context.
            # Global _template context is replaced by parameter context
            [proposed.append(ctx) for ctx in ref['_context']]
            [proposed.append(ctx) for ctx in ref[k].get('context', [])]
            proposed.append(cmd)

    def get_proposed(self):
        """Compare playbook values against existing states and create a list
        of proposed commands.
        Return a list of raw cli command strings.
        """
        ref = self._ref
        # '_proposed' may be empty list or contain initializations; e.g. ['feature foo']
        proposed = ref['_proposed']

        if ref['_context'] and ref['_context'][-1].startswith('no'):
            [proposed.append(ctx) for ctx in ref['_context']]
            return proposed

        # Create a list of commands that have playbook values
        play_keys = [k for k in ref['commands'] if 'playval' in ref[k]]

        def compare(playval, existing):
            if ref['_state'] in self.present_states:
                if existing is None:
                    return False
                elif playval == existing:
                    return True
                elif isinstance(existing, dict) and playval in existing.values():
                    return True

            if ref['_state'] in self.absent_states:
                if isinstance(existing, dict) and all(x is None for x in existing.values()):
                    existing = None
                if existing is None or playval not in existing.values():
                    return True
            return False

        # Compare against current state
        for k in play_keys:
            playval = ref[k]['playval']
            # Create playval copy to avoid RuntimeError
            #   dictionary changed size during iteration error
            playval_copy = deepcopy(playval)
            existing = ref[k].get('existing', ref[k]['default'])
            multiple = 'multiple' in ref[k].keys()

            # Multiple Instances:
            if isinstance(existing, dict) and multiple:
                item_found = False

                for ekey, evalue in existing.items():
                    if isinstance(evalue, dict):
                        # Remove values set to string 'None' from dvalue
                        evalue = dict((k, v) for k, v in evalue.items() if v != 'None')
                    for pkey, pvalue in playval.items():
                        if compare(pvalue, evalue):
                            if playval_copy.get(pkey):
                                del playval_copy[pkey]
                if not playval_copy:
                    continue
            # Single Instance:
            else:
                for pkey, pval in playval.items():
                    if compare(pval, existing):
                        if playval_copy.get(pkey):
                            del playval_copy[pkey]
                if not playval_copy:
                    continue

            playval = playval_copy
            # Multiple Instances:
            if isinstance(existing, dict):
                for dkey, dvalue in existing.items():
                    for pval in playval.values():
                        self.build_cmd_set(pval, dvalue, k)
            # Single Instance:
            else:
                for pval in playval.values():
                    self.build_cmd_set(pval, existing, k)

        # Remove any duplicate commands before returning.
        # pylint: disable=unnecessary-lambda
        cmds = sorted(set(proposed), key=lambda x: proposed.index(x))
        return cmds


def nxosCmdRef_import_check():
    """Return import error messages or empty string"""
    msg = ''
    if PY2:
        if not HAS_ORDEREDDICT and sys.version_info[:2] < (2, 7):
            msg += "Mandatory python library 'ordereddict' is not present, try 'pip install ordereddict'\n"
        if not HAS_YAML:
            msg += "Mandatory python library 'yaml' is not present, try 'pip install yaml'\n"
    elif PY3:
        if not HAS_YAML:
            msg += "Mandatory python library 'PyYAML' is not present, try 'pip install PyYAML'\n"
    return msg


def is_json(cmd):
    return to_text(cmd).endswith('| json')


def is_text(cmd):
    return not is_json(cmd)


def is_local_nxapi(module):
    transport = module.params.get('transport')
    provider = module.params.get('provider')
    provider_transport = provider['transport'] if provider else None
    return 'nxapi' in (transport, provider_transport)


def to_command(module, commands):
    if is_local_nxapi(module):
        default_output = 'json'
    else:
        default_output = 'text'

    transform = ComplexList(dict(
        command=dict(key=True),
        output=dict(default=default_output),
        prompt=dict(type='list'),
        answer=dict(type='list'),
        newline=dict(type='bool', default=True),
        sendonly=dict(type='bool', default=False),
        check_all=dict(type='bool', default=False),
    ), module)

    commands = transform(to_list(commands))

    for item in commands:
        if is_json(item['command']):
            item['output'] = 'json'

    return commands


def get_config(module, flags=None):
    flags = [] if flags is None else flags

    conn = get_connection(module)
    return conn.get_config(flags=flags)


def run_commands(module, commands, check_rc=True):
    conn = get_connection(module)
    return conn.run_commands(to_command(module, commands), check_rc)


def load_config(module, config, return_error=False, opts=None, replace=None):
    conn = get_connection(module)
    return conn.load_config(config, return_error, opts, replace=replace)


def get_capabilities(module):
    conn = get_connection(module)
    return conn.get_capabilities()


def get_diff(self, candidate=None, running=None, diff_match='line', diff_ignore_lines=None, path=None, diff_replace='line'):
    conn = self.get_connection()
    return conn.get_diff(candidate=candidate, running=running, diff_match=diff_match, diff_ignore_lines=diff_ignore_lines, path=path, diff_replace=diff_replace)


def normalize_interface(name):
    """Return the normalized interface name
    """
    if not name:
        return

    def _get_number(name):
        digits = ''
        for char in name:
            if char.isdigit() or char in '/.':
                digits += char
        return digits

    if name.lower().startswith('et'):
        if_type = 'Ethernet'
    elif name.lower().startswith('vl'):
        if_type = 'Vlan'
    elif name.lower().startswith('lo'):
        if_type = 'loopback'
    elif name.lower().startswith('po'):
        if_type = 'port-channel'
    elif name.lower().startswith('nv'):
        if_type = 'nve'
    else:
        if_type = None

    number_list = name.split(' ')
    if len(number_list) == 2:
        number = number_list[-1].strip()
    else:
        number = _get_number(name)

    if if_type:
        proper_interface = if_type + number
    else:
        proper_interface = name

    return proper_interface


def get_interface_type(interface):
    """Gets the type of interface
    """
    if interface.upper().startswith('ET'):
        return 'ethernet'
    elif interface.upper().startswith('VL'):
        return 'svi'
    elif interface.upper().startswith('LO'):
        return 'loopback'
    elif interface.upper().startswith('MG'):
        return 'management'
    elif interface.upper().startswith('MA'):
        return 'management'
    elif interface.upper().startswith('PO'):
        return 'portchannel'
    elif interface.upper().startswith('NV'):
        return 'nve'
    else:
        return 'unknown'


def read_module_context(module):
    conn = get_connection(module)
    return conn.read_module_context(module._name)


def save_module_context(module, module_context):
    conn = get_connection(module)
    return conn.save_module_context(module._name, module_context)
