# Copyright (c) 2018 Cisco and/or its affiliates.
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at:
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

"""Segment Routing over IPv6 dataplane utilities library."""

from resources.libraries.python.VatExecutor import VatTerminal
from resources.libraries.python.topology import Topology


# SRv6 LocalSID supported functions.
# Endpoint function
SRV6BEHAVIOUR_END = 'end'
# Endpoint function with Layer-3 cross-connect
SRV6BEHAVIOUR_END_X = 'end.x'
# Endpoint with decapsulation and Layer-2 cross-connect
SRV6BEHAVIOUR_END_DX2 = 'end.dx2'
# Endpoint with decapsulation and IPv4 cross-connect
SRV6BEHAVIOUR_END_DX4 = 'end.dx4'
# Endpoint with decapsulation and IPv4 table lookup
SRV6BEHAVIOUR_END_DT4 = 'end.dt4'
# Endpoint with decapsulation and IPv6 cross-connect
SRV6BEHAVIOUR_END_DX6 = 'end.dx6'
# Endpoint with decapsulation and IPv6 table lookup
SRV6BEHAVIOUR_END_DT6 = 'end.dt6'
# Endpoint to SR-unaware appliance via static proxy
SRV6BEHAVIOUR_END_AS = 'end.as'
# Endpoint to SR-unaware appliance via dynamic proxy
SRV6BEHAVIOUR_END_AD = 'end.ad'
# Endpoint to SR-unaware appliance via masquerading
SRV6BEHAVIOUR_END_AM = 'end.am'


class SRv6(object):
    """SRv6 class."""

    def __init__(self):
        pass

    @staticmethod
    def configure_sr_localsid(node, local_sid, behavior, interface=None,
                              next_hop=None, fib_table=None, out_if=None,
                              in_if=None, src_addr=None, sid_list=None):
        """Create SRv6 LocalSID and binds it to a particular behaviour on
        the given node.

        :param node: Given node to create localSID on.
        :param local_sid: LocalSID IPv6 address.
        :param behavior: SRv6 LocalSID function.
        :param interface: Interface name (Optional, required for
            L2/L3 xconnects).
        :param next_hop: Next hop IPv4/IPv6 address (Optional, required for L3
            xconnects).
        :param fib_table: FIB table for IPv4/IPv6 lookup (Optional, required for
            L3 routing).
        :param out_if: Interface name of local interface for sending traffic
            towards the Service Function (Optional, required for SRv6 endpoint
            to SR-unaware appliance).
        :param in_if: Interface name of local interface receiving the traffic
            coming back from the Service Function (Optional, required for SRv6
            endpoint to SR-unaware appliance).
        :param src_addr: Source address on the packets coming back on in_if
            interface (Optional, required for SRv6 endpoint to SR-unaware
            appliance via static proxy).
        :param sid_list: SID list (Optional, required for SRv6 endpoint to
            SR-unaware appliance via static proxy).
        :type node: dict
        :type local_sid: str
        :type behavior: str
        :type interface: str
        :type next_hop: int
        :type fib_table: str
        :type out_if: str
        :type in_if: str
        :type src_addr: str
        :type sid_list: list
        :raises ValueError: If unsupported SRv6 LocalSID function used or
            required parameter is missing.
        """
        if behavior == SRV6BEHAVIOUR_END:
            params = ''
        elif behavior in [SRV6BEHAVIOUR_END_X, SRV6BEHAVIOUR_END_DX4,
                          SRV6BEHAVIOUR_END_DX6]:
            if interface is None or next_hop is None:
                raise ValueError('Required parameter(s) missing.\ninterface:{0}'
                                 '\nnext_hop:{1}'.format(interface, next_hop))
            interface_name = Topology.get_interface_name(node, interface)
            params = '{0} {1}'.format(interface_name, next_hop)
        elif behavior == SRV6BEHAVIOUR_END_DX2:
            if interface is None:
                raise ValueError('Required parameter missing.\ninterface:{0}'.
                                 format(interface))
            params = '{0}'.format(interface)
        elif behavior in [SRV6BEHAVIOUR_END_DT4, SRV6BEHAVIOUR_END_DT6]:
            if fib_table is None:
                raise ValueError('Required parameter missing.\nfib_table: {0}'.
                                 format(fib_table))
            params = '{0}'.format(fib_table)
        elif behavior == SRV6BEHAVIOUR_END_AS:
            if next_hop is None or out_if is None or in_if is None or \
                            src_addr is None or sid_list is None:
                raise ValueError('Required parameter(s) missing.\nnext_hop:{0}'
                                 '\nout_if:{1}\nin_if:{2}\nsrc_addr:{3}\n'
                                 'sid_list:{4}'.format(next_hop, out_if, in_if,
                                                       src_addr, sid_list))
            sid_conf = 'next ' + ' next '.join(sid_list)
            params = 'nh {0} oif {1} iif {2} src {3} {4}'.\
                format(next_hop, out_if, in_if, src_addr, sid_conf)
        elif behavior in [SRV6BEHAVIOUR_END_AD, SRV6BEHAVIOUR_END_AM]:
            if next_hop is None or out_if is None or in_if is None:
                raise ValueError('Required parameter(s) missing.\nnext_hop:{0}'
                                 '\nout_if:{1}\nin_if:{2}'.
                                 format(next_hop, out_if, in_if))
            params = 'nh {0} oif {1} iif {2}'.format(next_hop, out_if, in_if)
        else:
            raise ValueError('Unsupported SRv6 LocalSID function: {0}'.
                             format(behavior))

        with VatTerminal(node, json_param=False) as vat:
            vat.vat_terminal_exec_cmd_from_template(
                'srv6/sr_localsid_add.vat', local_sid=local_sid,
                behavior=behavior, params=params)

        if "exec error: Misc" in vat.vat_stdout:
            raise RuntimeError('Create SRv6 LocalSID {0} failed on node {1}'.
                               format(local_sid, node['host']))

    @staticmethod
    def delete_sr_localsid(node, local_sid):
        """Delete SRv6 LocalSID on the given node.

        :param node: Given node to delete localSID on.
        :param local_sid: LocalSID IPv6 address.
        :type node: dict
        :type local_sid: str
        """
        with VatTerminal(node, json_param=False) as vat:
            vat.vat_terminal_exec_cmd_from_template(
                'srv6/sr_localsid_del.vat', local_sid=local_sid)

        if "exec error: Misc" in vat.vat_stdout:
            raise RuntimeError('Delete SRv6 LocalSID {0} failed on node {1}'.
                               format(local_sid, node['host']))

    @staticmethod
    def show_sr_localsids(node):
        """Show SRv6 LocalSIDs on the given node.

        :param node: Given node to show localSIDs on.
        :type node: dict
        """
        with VatTerminal(node, json_param=False) as vat:
            vat.vat_terminal_exec_cmd_from_template(
                'srv6/sr_localsids_show.vat')

    @staticmethod
    def configure_sr_policy(node, bsid, sid_list, mode='encap'):
        """Create SRv6 policy on the given node.

        :param node: Given node to create SRv6 policy on.
        :param bsid: BindingSID - local SID IPv6 address.
        :param sid_list: SID list.
        :param mode: Encapsulation / insertion mode.
        :type node: dict
        :type bsid: str
        :type sid_list: list
        :type mode: str
        """
        sid_conf = 'next ' + ' next '.join(sid_list)

        with VatTerminal(node, json_param=False) as vat:
            vat.vat_terminal_exec_cmd_from_template(
                'srv6/sr_policy_add.vat', bsid=bsid,
                sid_conf=sid_conf, mode=mode)

        if "exec error: Misc" in vat.vat_stdout:
            raise RuntimeError('Create SRv6 policy for BindingSID {0} failed on'
                               ' node {1}'.format(bsid, node['host']))

    @staticmethod
    def delete_sr_policy(node, bsid):
        """Delete SRv6 policy on the given node.

        :param node: Given node to delete SRv6 policy on.
        :param bsid: BindingSID IPv6 address.
        :type node: dict
        :type bsid: str
        """
        with VatTerminal(node, json_param=False) as vat:
            vat.vat_terminal_exec_cmd_from_template(
                'srv6/sr_policy_del.vat', bsid=bsid)

        if "exec error: Misc" in vat.vat_stdout:
            raise RuntimeError('Delete SRv6 policy for BindingSID {0} failed on'
                               ' node {1}'.format(bsid, node['host']))

    @staticmethod
    def show_sr_policies(node):
        """Show SRv6 policies on the given node.

        :param node: Given node to show SRv6 policies on.
        :type node: dict
        """
        with VatTerminal(node, json_param=False) as vat:
            vat.vat_terminal_exec_cmd_from_template(
                'srv6/sr_policies_show.vat')

    @staticmethod
    def configure_sr_steer(node, mode, bsid, interface=None, ip_addr=None,
                           prefix=None):
        """Create SRv6 steering policy on the given node.

        :param node: Given node to create steering policy on.
        :param mode: Mode of operation - L2 or L3.
        :param bsid: BindingSID - local SID IPv6 address.
        :param interface: Interface name (Optional, required in case of
            L2 mode).
        :param ip_addr: IPv4/IPv6 address (Optional, required in case of L3
            mode).
        :param prefix: IP address prefix (Optional, required in case of L3
            mode).
        :type node: dict
        :type mode: str
        :type bsid: str
        :type interface: str
        :type ip_addr: str
        :type prefix: int
        :raises ValueError: If unsupported mode used or required parameter
            is missing.
        """
        if mode.lower() == 'l2':
            if interface is None:
                raise ValueError('Required data missing.\ninterface:{0}\n'.
                                 format(interface))
            interface_name = Topology.get_interface_name(node, interface)
            params = 'l2 {0}'.format(interface_name)
        elif mode.lower() == 'l3':
            if ip_addr is None or prefix is None:
                raise ValueError('Required data missing.\nIP address:{0}\n'
                                 'mask:{1}'.format(ip_addr, prefix))
            params = 'l3 {0}/{1}'.format(ip_addr, prefix)
        else:
            raise ValueError('Unsupported mode: {0}'.format(mode))

        with VatTerminal(node, json_param=False) as vat:
            vat.vat_terminal_exec_cmd_from_template(
                'srv6/sr_steer_add_del.vat', params=params, bsid=bsid)

        sr_steer_errors = ("exec error: Misc",
                           "sr steer: No SR policy specified")
        for err in sr_steer_errors:
            if err in vat.vat_stdout:
                raise RuntimeError('Create SRv6 steering policy for BindingSID'
                                   ' {0} failed on node {1}'.
                                   format(bsid, node['host']))

    @staticmethod
    def delete_sr_steer(node, mode, bsid, interface=None, ip_addr=None,
                        mask=None):
        """Delete SRv6 steering policy on the given node.

        :param node: Given node to delete steering policy on.
        :param mode: Mode of operation - L2 or L3.
        :param bsid: BindingSID - local SID IPv6 address.
        :param interface: Interface name (Optional, required in case of
            L2 mode).
        :param ip_addr: IPv4/IPv6 address (Optional, required in case of L3
            mode).
        :param mask: IP address mask (Optional, required in case of L3 mode).
        :type node: dict
        :type mode: str
        :type bsid: str
        :type interface: str
        :type ip_addr: int
        :type mask: int
        :raises ValueError: If unsupported mode used or required parameter
            is missing.
        """
        params = 'del'
        if mode == 'l2':
            if interface is None:
                raise ValueError('Required data missing.\ninterface:{0}\n'.
                                 format(interface))
            interface_name = Topology.get_interface_name(node, interface)
            params += 'l2 {0}'.format(interface_name)
        elif mode == 'l3':
            if ip_addr is None or mask is None:
                raise ValueError('Required data missing.\nIP address:{0}\n'
                                 'mask:{1}'.format(ip_addr, mask))
            params += '{0}/{1}'.format(ip_addr, mask)
        else:
            raise ValueError('Unsupported mode: {0}'.format(mode))

        with VatTerminal(node, json_param=False) as vat:
            vat.vat_terminal_exec_cmd_from_template(
                'srv6/sr_steer_add_del.vat', params=params, bsid=bsid)

        if "exec error: Misc" in vat.vat_stdout:
            raise RuntimeError('Delete SRv6 policy for bsid {0} failed on node'
                               ' {1}'.format(bsid, node['host']))

    @staticmethod
    def show_sr_steering_policies(node):
        """Show SRv6 steering policies on the given node.

        :param node: Given node to show SRv6 steering policies on.
        :type node: dict
        """
        with VatTerminal(node, json_param=False) as vat:
            vat.vat_terminal_exec_cmd_from_template(
                'srv6/sr_steer_policies_show.vat')

    @staticmethod
    def set_sr_encaps_source_address(node, ip6_addr):
        """Set SRv6 encapsulation source address on the given node.

        :param node: Given node to set SRv6 encapsulation source address on.
        :param ip6_addr: Local SID IPv6 address.
        :type node: dict
        :type ip6_addr: str
        """
        with VatTerminal(node, json_param=False) as vat:
            vat.vat_terminal_exec_cmd_from_template(
                'srv6/sr_set_encaps_source.vat', ip6_addr=ip6_addr)