#!/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/>.
#
from __future__ import absolute_import, division, print_function


__metaclass__ = type


DOCUMENTATION = """
module: nxos_vxlan_vtep
extends_documentation_fragment:
- cisco.nxos.nxos
short_description: Manages VXLAN Network Virtualization Endpoint (NVE).
description:
- Manages VXLAN Network Virtualization Endpoint (NVE) overlay interface that terminates
  VXLAN tunnels.
version_added: 1.0.0
author: Gabriele Gerbino (@GGabriele)
notes:
- Tested against NXOSv 7.3.(0)D1(1) on VIRL
- Unsupported for Cisco MDS
- The module is used to manage NVE properties, not to create NVE interfaces. Use M(cisco.nxos.nxos_interface)
  if you wish to do so.
- C(state=absent) removes the interface.
- Default, where supported, restores params default value.
options:
  interface:
    description:
    - Interface name for the VXLAN Network Virtualization Endpoint.
    required: true
    type: str
  description:
    description:
    - Description of the NVE interface.
    type: str
  host_reachability:
    description:
    - Specify mechanism for host reachability advertisement.  A Boolean value of 'true'
      indicates that BGP will be used for host reachability advertisement. A Boolean
      value of 'false' indicates that no protocol is used for host reachability advertisement.
      Other host reachability advertisement protocols (e.g. OpenFlow, controller, etc.) are not
      supported.
    type: bool
  shutdown:
    description:
    - Administratively shutdown the NVE interface.
    type: bool
  source_interface:
    description:
    - Specify the loopback interface whose IP address should be used for the NVE interface.
    type: str
  source_interface_hold_down_time:
    description:
    - Suppresses advertisement of the NVE loopback address until the overlay has converged.
    type: str
  global_mcast_group_L3:
    description:
    - Global multicast IP prefix for L3 VNIs or the keyword 'default'. This is available on
      Nexus 9000 series switches running NX-OS software release 9.2(x) or higher.
    type: str
  global_mcast_group_L2:
    description:
    - Global multicast IP prefix for L2 VNIs or the keyword 'default'. This is available on
      Nexus 9000 series switches running NX-OS software release 9.2(x) or higher.
    type: str
  global_suppress_arp:
    description:
    - Enables ARP suppression for all VNIs. This is available on NX-OS 9K series running
      9.2.x or higher.
    type: bool
  global_ingress_replication_bgp:
    description:
    - Configures ingress replication protocol as bgp for all VNIs. This is available on Nexus
      9000 series switches running NX-OS software release 9.2(x) or higher.
    type: bool
  state:
    description:
    - Determines whether the config should be present or not on the device.
    default: present
    choices:
    - present
    - absent
    type: str
  multisite_border_gateway_interface:
    description:
    - Specify the loopback interface whose IP address should be used for the NVE
      Multisite Border-gateway Interface. This is available on specific Nexus 9000
      series switches running NX-OS 7.0(3)I7(x) or higher. Specify "default" to remove
      an existing gateway config.
    type: str
    version_added: 1.1.0
"""
EXAMPLES = """
- cisco.nxos.nxos_vxlan_vtep:
    interface: nve1
    description: default
    host_reachability: true
    source_interface: Loopback0
    source_interface_hold_down_time: 30
    shutdown: default
    multisite_border_gateway_interface: Loopback0
"""

RETURN = """
commands:
    description: commands sent to the device
    returned: always
    type: list
    sample: ["interface nve1", "source-interface loopback0",
        "source-interface hold-down-time 30", "description simple description",
        "shutdown", "host-reachability protocol bgp",
        "multisite border-gateway interface loopback0"]
"""

import re

from ansible.module_utils.basic import AnsibleModule
from ansible_collections.ansible.netcommon.plugins.module_utils.network.common.config import (
    CustomNetworkConfig,
)

from ansible_collections.cisco.nxos.plugins.module_utils.network.nxos.nxos import (
    get_config,
    load_config,
    nxos_argument_spec,
    run_commands,
)


BOOL_PARAMS = [
    "shutdown",
    "host_reachability",
    "global_ingress_replication_bgp",
    "global_suppress_arp",
]
PARAM_TO_COMMAND_KEYMAP = {
    "description": "description",
    "global_suppress_arp": "global suppress-arp",
    "global_ingress_replication_bgp": "global ingress-replication protocol bgp",
    "global_mcast_group_L3": "global mcast-group L3",
    "global_mcast_group_L2": "global mcast-group L2",
    "host_reachability": "host-reachability protocol bgp",
    "interface": "interface",
    "shutdown": "shutdown",
    "source_interface": "source-interface",
    "source_interface_hold_down_time": "source-interface hold-down-time",
    "multisite_border_gateway_interface": "multisite border-gateway interface",
}
PARAM_TO_DEFAULT_KEYMAP = {
    "description": False,
    "shutdown": True,
    "source_interface_hold_down_time": "180",
}


def get_value(arg, config, module):
    if arg in BOOL_PARAMS:
        REGEX = re.compile(r"\s+{0}\s*$".format(PARAM_TO_COMMAND_KEYMAP[arg]), re.M)
        NO_SHUT_REGEX = re.compile(r"\s+no shutdown\s*$", re.M)
        value = False
        if arg == "shutdown":
            try:
                if NO_SHUT_REGEX.search(config):
                    value = False
                elif REGEX.search(config):
                    value = True
            except TypeError:
                value = False
        else:
            try:
                if REGEX.search(config):
                    value = True
            except TypeError:
                value = False
    else:
        REGEX = re.compile(
            r"(?:{0}\s)(?P<value>.*)$".format(PARAM_TO_COMMAND_KEYMAP[arg]),
            re.M,
        )
        NO_DESC_REGEX = re.compile(r"\s+{0}\s*$".format("no description"), re.M)
        SOURCE_INTF_REGEX = re.compile(
            r"(?:{0}\s)(?P<value>\S+)$".format(PARAM_TO_COMMAND_KEYMAP[arg]),
            re.M,
        )
        value = ""
        if arg == "description":
            if NO_DESC_REGEX.search(config):
                value = False
            elif PARAM_TO_COMMAND_KEYMAP[arg] in config:
                value = REGEX.search(config).group("value").strip()
        elif arg == "source_interface":
            for line in config.splitlines():
                try:
                    if PARAM_TO_COMMAND_KEYMAP[arg] in config:
                        value = SOURCE_INTF_REGEX.search(config).group("value").strip()
                        break
                except AttributeError:
                    value = ""
        elif arg == "global_mcast_group_L2":
            for line in config.splitlines():
                try:
                    if "global mcast-group" in line and "L2" in line:
                        value = line.split()[2].strip()
                        break
                except AttributeError:
                    value = ""
        elif arg == "global_mcast_group_L3":
            for line in config.splitlines():
                try:
                    if "global mcast-group" in line and "L3" in line:
                        value = line.split()[2].strip()
                        break
                except AttributeError:
                    value = ""
        elif arg == "multisite_border_gateway_interface":
            for line in config.splitlines():
                try:
                    if PARAM_TO_COMMAND_KEYMAP[arg] in config:
                        value = SOURCE_INTF_REGEX.search(config).group("value").strip()
                        break
                except AttributeError:
                    value = ""
        else:
            if PARAM_TO_COMMAND_KEYMAP[arg] in config:
                value = REGEX.search(config).group("value").strip()
    return value


def get_existing(module, args):
    existing = {}
    netcfg = CustomNetworkConfig(indent=2, contents=get_config(module, flags=["all"]))

    interface_string = "interface {0}".format(module.params["interface"].lower())
    parents = [interface_string]
    config = netcfg.get_section(parents)

    if config:
        for arg in args:
            existing[arg] = get_value(arg, config, module)

        existing["interface"] = module.params["interface"].lower()
    else:
        if interface_string in str(netcfg):
            existing["interface"] = module.params["interface"].lower()
            for arg in args:
                existing[arg] = ""
    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 fix_commands(commands, module):
    source_interface_command = ""
    no_source_interface_command = ""
    no_host_reachability_command = ""
    host_reachability_command = ""

    for command in commands:
        if "no source-interface hold-down-time" in command:
            pass
        elif "source-interface hold-down-time" in command:
            pass
        elif "no source-interface" in command:
            no_source_interface_command = command
        elif "source-interface" in command:
            source_interface_command = command
        elif "no host-reachability" in command:
            no_host_reachability_command = command
        elif "host-reachability" in command:
            host_reachability_command = command

    if host_reachability_command:
        commands.pop(commands.index(host_reachability_command))
        commands.insert(0, host_reachability_command)

    if source_interface_command:
        commands.pop(commands.index(source_interface_command))
        commands.insert(0, source_interface_command)

    if no_host_reachability_command:
        commands.pop(commands.index(no_host_reachability_command))
        commands.append(no_host_reachability_command)

    if no_source_interface_command:
        commands.pop(commands.index(no_source_interface_command))
        commands.append(no_source_interface_command)

    commands.insert(0, "terminal dont-ask")
    return commands


def gsa_tcam_check(module):
    """
    global_suppress_arp is an N9k-only command that requires TCAM resources.
    This method checks the current TCAM allocation.
    Note that changing tcam_size requires a switch reboot to take effect.
    """
    cmds = [{"command": "show hardware access-list tcam region", "output": "json"}]
    body = run_commands(module, cmds)
    if body:
        tcam_region = body[0]["TCAM_Region"]["TABLE_Sizes"]["ROW_Sizes"]
        if bool(
            [
                i
                for i in tcam_region
                if i["type"].startswith("Ingress ARP-Ether ACL") and i["tcam_size"] == "0"
            ],
        ):
            msg = (
                "'show hardware access-list tcam region' indicates 'ARP-Ether' tcam size is 0 (no allocated resources). "
                + "'global_suppress_arp' will be rejected by device."
            )
            module.fail_json(msg=msg)


def state_present(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 is True:
            commands.append(key)

        elif value is False:
            commands.append("no {0}".format(key))

        elif value == "default":
            if existing_commands.get(key):
                existing_value = existing_commands.get(key)
                if "global mcast-group" in key:
                    commands.append("no {0}".format(key))
                else:
                    commands.append("no {0} {1}".format(key, existing_value))
            else:
                if key.replace(" ", "_").replace("-", "_") in BOOL_PARAMS:
                    commands.append("no {0}".format(key.lower()))
                    module.exit_json(commands=commands)
        else:
            if "L2" in key:
                commands.append("global mcast-group " + value + " L2")
            elif "L3" in key:
                commands.append("global mcast-group " + value + " L3")
            else:
                command = "{0} {1}".format(key, value.lower())
                commands.append(command)

    if commands:
        commands = fix_commands(commands, module)
        parents = ["interface {0}".format(module.params["interface"].lower())]
        candidate.add(commands, parents=parents)
    else:
        if not existing and module.params["interface"]:
            commands = ["interface {0}".format(module.params["interface"].lower())]
            candidate.add(commands, parents=[])


def state_absent(module, existing, proposed, candidate):
    commands = ["no interface {0}".format(module.params["interface"].lower())]
    candidate.add(commands, parents=[])


def main():
    argument_spec = dict(
        interface=dict(required=True, type="str"),
        description=dict(required=False, type="str"),
        host_reachability=dict(required=False, type="bool"),
        global_ingress_replication_bgp=dict(required=False, type="bool"),
        global_suppress_arp=dict(required=False, type="bool"),
        global_mcast_group_L2=dict(required=False, type="str"),
        global_mcast_group_L3=dict(required=False, type="str"),
        shutdown=dict(required=False, type="bool"),
        source_interface=dict(required=False, type="str"),
        source_interface_hold_down_time=dict(required=False, type="str"),
        state=dict(choices=["present", "absent"], default="present", required=False),
        multisite_border_gateway_interface=dict(required=False, type="str"),
    )

    argument_spec.update(nxos_argument_spec)

    mutually_exclusive = [("global_ingress_replication_bgp", "global_mcast_group_L2")]

    module = AnsibleModule(
        argument_spec=argument_spec,
        mutually_exclusive=mutually_exclusive,
        supports_check_mode=True,
    )

    warnings = list()
    result = {"changed": False, "commands": [], "warnings": warnings}

    state = module.params["state"]

    args = PARAM_TO_COMMAND_KEYMAP.keys()

    existing = get_existing(module, args)
    proposed_args = dict((k, v) for k, v in module.params.items() if v is not None and k in args)
    proposed = {}
    for key, value in proposed_args.items():
        if key != "interface":
            if str(value).lower() == "default":
                value = PARAM_TO_DEFAULT_KEYMAP.get(key)
                if value is None:
                    if key in BOOL_PARAMS:
                        value = False
                    else:
                        value = "default"
            if str(existing.get(key)).lower() != str(value).lower():
                proposed[key] = value

    candidate = CustomNetworkConfig(indent=3)

    if proposed.get("global_suppress_arp"):
        gsa_tcam_check(module)
    if state == "present":
        if not existing:
            warnings.append(
                "The proposed NVE interface did not exist. "
                "It's recommended to use nxos_interface to create "
                "all logical interfaces.",
            )
        state_present(module, existing, proposed, candidate)
    elif state == "absent" and existing:
        state_absent(module, existing, proposed, candidate)

    if candidate:
        candidate = candidate.items_text()
        result["commands"] = candidate
        result["changed"] = True
        load_config(module, candidate)

    module.exit_json(**result)


if __name__ == "__main__":
    main()
