#
# (c) 2015 Peter Sprygada, <psprygada@ansible.com>
#
# 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/>.
#

import re

from ansible.module_utils.basic import AnsibleModule, env_fallback, get_exception
from ansible.module_utils.shell import Shell, ShellError, Command, HAS_PARAMIKO
from ansible.module_utils.netcfg import parse

NET_PASSWD_RE = re.compile(r"[\r\n]?password: $", re.I)

NET_COMMON_ARGS = dict(
    host=dict(required=True),
    port=dict(default=22, type='int'),
    username=dict(fallback=(env_fallback, ['ANSIBLE_NET_USERNAME'])),
    password=dict(no_log=True, fallback=(env_fallback, ['ANSIBLE_NET_PASSWORD'])),
    ssh_keyfile=dict(fallback=(env_fallback, ['ANSIBLE_NET_SSH_KEYFILE']), type='path'),
    authorize=dict(default=False, fallback=(env_fallback, ['ANSIBLE_NET_AUTHORIZE']), type='bool'),
    auth_pass=dict(no_log=True, fallback=(env_fallback, ['ANSIBLE_NET_AUTH_PASS'])),
    provider=dict(),
    timeout=dict(default=10, type='int')
)

CLI_PROMPTS_RE = [
    re.compile(r"[\r\n]?[\w+\-\.:\/\[\]]+(?:\([^\)]+\)){,3}(?:>|#) ?$"),
    re.compile(r"\[\w+\@[\w\-\.]+(?: [^\]])\] ?[>#\$] ?$")
]

CLI_ERRORS_RE = [
    re.compile(r"% ?Error"),
    re.compile(r"% ?Bad secret"),
    re.compile(r"invalid input", re.I),
    re.compile(r"(?:incomplete|ambiguous) command", re.I),
    re.compile(r"connection timed out", re.I),
    re.compile(r"[^\r\n]+ not found", re.I),
    re.compile(r"'[^']' +returned error code: ?\d+"),
]


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


class Cli(object):

    def __init__(self, module):
        self.module = module
        self.shell = None

    def connect(self, **kwargs):
        host = self.module.params['host']
        port = self.module.params['port'] or 22

        username = self.module.params['username']
        password = self.module.params['password']
        key_filename = self.module.params['ssh_keyfile']
        timeout = self.module.params['timeout']

        allow_agent = (key_filename is not None) or (key_filename is None and password is None)

        try:
            self.shell = Shell(kickstart=False, prompts_re=CLI_PROMPTS_RE,
                    errors_re=CLI_ERRORS_RE)
            self.shell.open(host, port=port, username=username,
                    password=password, key_filename=key_filename,
                    allow_agent=allow_agent, timeout=timeout)
        except ShellError:
            e = get_exception()
            msg = 'failed to connect to %s:%s - %s' % (host, port, str(e))
            self.module.fail_json(msg=msg)

    def authorize(self):
        passwd = self.module.params['auth_pass']
        self.send(Command('enable', prompt=NET_PASSWD_RE, response=passwd))

    def send(self, commands):
        try:
            return self.shell.send(commands)
        except ShellError:
            e = get_exception()
            self.module.fail_json(msg=e.message, commands=commands)


class NetworkModule(AnsibleModule):

    def __init__(self, *args, **kwargs):
        super(NetworkModule, self).__init__(*args, **kwargs)
        self.connection = None
        self._config = None
        self._connected = False

    @property
    def connected(self):
        return self._connected

    @property
    def config(self):
        if not self._config:
            self._config = self.get_config()
        return self._config

    def _load_params(self):
        super(NetworkModule, self)._load_params()
        provider = self.params.get('provider') or dict()
        for key, value in provider.items():
            if key in NET_COMMON_ARGS:
                if self.params.get(key) is None and value is not None:
                    self.params[key] = value

    def connect(self):
        self.connection = Cli(self)

        self.connection.connect()
        self.connection.send('terminal length 0')

        if self.params['authorize']:
            self.connection.authorize()

        self._connected = True

    def configure(self, commands):
        commands = to_list(commands)
        commands.insert(0, 'configure terminal')
        responses = self.execute(commands)
        responses.pop(0)
        return responses

    def execute(self, commands, **kwargs):
        if not self.connected:
            self.connect()
        return self.connection.send(commands, **kwargs)

    def disconnect(self):
        self.connection.close()
        self._connected = False

    def parse_config(self, cfg):
        return parse(cfg, indent=1)

    def get_config(self):
        cmd = 'show running-config'
        if self.params.get('include_defaults'):
            cmd += ' all'
        return self.execute(cmd)[0]


def get_module(**kwargs):
    """Return instance of NetworkModule
    """
    argument_spec = NET_COMMON_ARGS.copy()
    if kwargs.get('argument_spec'):
        argument_spec.update(kwargs['argument_spec'])
    kwargs['argument_spec'] = argument_spec

    module = NetworkModule(**kwargs)

    if not HAS_PARAMIKO:
        module.fail_json(msg='paramiko is required but does not appear to be installed')

    return module