# -*- coding: utf-8 -*-
# Copyright 2019 Red Hat
# GNU General Public License v3.0+
# (see COPYING or https://www.gnu.org/licenses/gpl-3.0.txt)
"""
The eos_interfaces class
It is in this file where the current configuration (as dict)
is compared to the provided configuration (as dict) and the command set
necessary to bring the current configuration to it's desired end-state is
created
"""

from __future__ import (absolute_import, division, print_function)
__metaclass__ = type

from ansible.module_utils.network.common.cfg.base import ConfigBase
from ansible.module_utils.network.common.utils import to_list, dict_diff, param_list_to_dict
from ansible.module_utils.network.eos.facts.facts import Facts
from ansible.module_utils.network.eos.utils.utils import normalize_interface


class Interfaces(ConfigBase):
    """
    The eos_interfaces class
    """

    gather_subset = [
        '!all',
        '!min',
    ]

    gather_network_resources = [
        'interfaces',
    ]

    def get_interfaces_facts(self):
        """ Get the 'facts' (the current configuration)

        :rtype: A dictionary
        :returns: The current configuration as a dictionary
        """
        facts, _warnings = Facts(self._module).get_facts(self.gather_subset, self.gather_network_resources)
        interfaces_facts = facts['ansible_network_resources'].get('interfaces')
        if not interfaces_facts:
            return []
        return interfaces_facts

    def execute_module(self):
        """ Execute the module

        :rtype: A dictionary
        :returns: The result from module execution
        """
        result = {'changed': False}
        commands = list()
        warnings = list()

        existing_interfaces_facts = self.get_interfaces_facts()
        commands.extend(self.set_config(existing_interfaces_facts))
        if commands:
            if not self._module.check_mode:
                self._connection.edit_config(commands)
            result['changed'] = True
        result['commands'] = commands

        changed_interfaces_facts = self.get_interfaces_facts()

        result['before'] = existing_interfaces_facts
        if result['changed']:
            result['after'] = changed_interfaces_facts

        result['warnings'] = warnings
        return result

    def set_config(self, existing_interfaces_facts):
        """ Collect the configuration from the args passed to the module,
            collect the current configuration (as a dict from facts)

        :rtype: A list
        :returns: the commands necessary to migrate the current configuration
                  to the desired configuration
        """
        want = self._module.params['config']
        have = existing_interfaces_facts
        resp = self.set_state(want, have)
        return to_list(resp)

    def set_state(self, want, have):
        """ Select the appropriate function based on the state provided

        :param want: the desired configuration as a dictionary
        :param have: the current configuration as a dictionary
        :rtype: A list
        :returns: the commands necessary to migrate the current configuration
                  to the desired configuration
        """
        state = self._module.params['state']
        want = param_list_to_dict(want)
        have = param_list_to_dict(have)
        if state == 'overridden':
            commands = self._state_overridden(want, have)
        elif state == 'deleted':
            commands = self._state_deleted(want, have)
        elif state == 'merged':
            commands = self._state_merged(want, have)
        elif state == 'replaced':
            commands = self._state_replaced(want, have)
        return commands

    @staticmethod
    def _state_replaced(want, have):
        """ The command generator when state is replaced

        :rtype: A list
        :returns: the commands necessary to migrate the current configuration
                  to the desired configuration
        """
        commands = []
        for key, desired in want.items():
            interface_name = normalize_interface(key)
            if interface_name in have:
                extant = have[interface_name]
            else:
                extant = dict()

            add_config = dict_diff(extant, desired)
            del_config = dict_diff(desired, extant)

            commands.extend(generate_commands(key, add_config, del_config))

        return commands

    @staticmethod
    def _state_overridden(want, have):
        """ The command generator when state is overridden

        :rtype: A list
        :returns: the commands necessary to migrate the current configuration
                  to the desired configuration
        """
        commands = []
        for key, extant in have.items():
            if key in want:
                desired = want[key]
            else:
                desired = dict()

            add_config = dict_diff(extant, desired)
            del_config = dict_diff(desired, extant)

            commands.extend(generate_commands(key, add_config, del_config))

        return commands

    @staticmethod
    def _state_merged(want, have):
        """ The command generator when state is merged

        :rtype: A list
        :returns: the commands necessary to merge the provided into
                  the current configuration
        """
        commands = []
        for key, desired in want.items():
            interface_name = normalize_interface(key)
            if interface_name in have:
                extant = have[interface_name]
            else:
                extant = dict()

            add_config = dict_diff(extant, desired)

            commands.extend(generate_commands(key, add_config, {}))

        return commands

    @staticmethod
    def _state_deleted(want, have):
        """ The command generator when state is deleted

        :rtype: A list
        :returns: the commands necessary to remove the current configuration
                  of the provided objects
        """
        commands = []
        for key in want:
            desired = dict()
            if key in have:
                extant = have[key]
            else:
                continue

            del_config = dict_diff(desired, extant)

            commands.extend(generate_commands(key, {}, del_config))

        return commands


def generate_commands(interface, to_set, to_remove):
    commands = []
    for key, value in to_set.items():
        if value is None:
            continue

        if key == "enabled":
            commands.append('{0}shutdown'.format('no ' if value else ''))
        elif key == "speed":
            if value == "auto":
                commands.append("{0} {1}".format(key, value))
            else:
                commands.append('speed {0}{1}'.format(value, to_set['duplex']))
        elif key == "duplex":
            # duplex is handled with speed
            continue
        else:
            commands.append("{0} {1}".format(key, value))

        # Don't try to also remove the same key, if present in to_remove
        to_remove.pop(key, None)

    for key in to_remove.keys():
        if key == "enabled":
            commands.append('no shutdown')
        elif key == "speed":
            commands.append("speed auto")
        elif key == "duplex":
            # duplex is handled with speed
            continue
        else:
            commands.append("no {0}".format(key))

    if commands:
        commands.insert(0, "interface {0}".format(interface))

    return commands
