# 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) 2018,  NetApp Ansible Team <ng-ansibleteam@netapp.com>
# All rights reserved.
#
# 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
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''' Support class for NetApp ansible modules '''

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


def cmp(a, b):
    """
    Python 3 does not have a cmp function, this will do the cmp.
    :param a: first object to check
    :param b: second object to check
    :return:
    """
    # convert to lower case for string comparison.
    if a is None:
        return -1
    if type(a) is str and type(b) is str:
        a = a.lower()
        b = b.lower()
    # if list has string element, convert string to lower case.
    if type(a) is list and type(b) is list:
        a = [x.lower() if type(x) is str else x for x in a]
        b = [x.lower() if type(x) is str else x for x in b]
        a.sort()
        b.sort()
    return (a > b) - (a < b)


class NetAppModule(object):
    '''
    Common class for NetApp modules
    set of support functions to derive actions based
    on the current state of the system, and a desired state
    '''

    def __init__(self):
        self.log = list()
        self.changed = False
        self.parameters = {'name': 'not intialized'}
        # self.debug = list()

    def set_parameters(self, ansible_params):
        self.parameters = dict()
        for param in ansible_params:
            if ansible_params[param] is not None:
                self.parameters[param] = ansible_params[param]
        return self.parameters

    def get_cd_action(self, current, desired):
        ''' takes a desired state and a current state, and return an action:
            create, delete, None
            eg:
            is_present = 'absent'
            some_object = self.get_object(source)
            if some_object is not None:
                is_present = 'present'
            action = cd_action(current=is_present, desired = self.desired.state())
        '''
        if 'state' in desired:
            desired_state = desired['state']
        else:
            desired_state = 'present'

        if current is None and desired_state == 'absent':
            return None
        if current is not None and desired_state == 'present':
            return None
        # change in state
        self.changed = True
        if current is not None:
            return 'delete'
        return 'create'

    def compare_and_update_values(self, current, desired, keys_to_compare):
        updated_values = dict()
        is_changed = False
        for key in keys_to_compare:
            if key in current:
                if key in desired and desired[key] is not None:
                    if current[key] != desired[key]:
                        updated_values[key] = desired[key]
                        is_changed = True
                    else:
                        updated_values[key] = current[key]
                else:
                    updated_values[key] = current[key]

        return updated_values, is_changed

    @staticmethod
    def check_keys(current, desired):
        ''' TODO: raise an error if keys do not match
            with the exception of:
            new_name, state in desired
        '''
        pass

    @staticmethod
    def compare_lists(current, desired, get_list_diff):
        ''' compares two lists and return a list of elements that are either the desired elements or elements that are
            modified from the current state depending on the get_list_diff flag
            :param: current: current item attribute in ONTAP
            :param: desired: attributes from playbook
            :param: get_list_diff: specifies whether to have a diff of desired list w.r.t current list for an attribute
            :return: list of attributes to be modified
            :rtype: list
        '''
        desired_diff_list = [item for item in desired if item not in current]  # get what in desired and not in current
        current_diff_list = [item for item in current if item not in desired]  # get what in current but not in desired

        if desired_diff_list or current_diff_list:
            # there are changes
            if get_list_diff:
                return desired_diff_list
            else:
                return desired
        else:
            return []

    def get_modified_attributes(self, current, desired, get_list_diff=False, additional_keys=False):
        ''' takes two dicts of attributes and return a dict of attributes that are
            not in the current state
            It is expected that all attributes of interest are listed in current and
            desired.
            The same assumption holds true for any nested directory.
            TODO: This is actually not true for the ElementSW 'attributes' directory.
                  Practically it means you cannot add or remove a key in a modify.
            :param: current: current attributes in ONTAP
            :param: desired: attributes from playbook
            :param: get_list_diff: specifies whether to have a diff of desired list w.r.t current list for an attribute
            :return: dict of attributes to be modified
            :rtype: dict

            NOTE: depending on the attribute, the caller may need to do a modify or a
            different operation (eg move volume if the modified attribute is an
            aggregate name)
        '''
        # uncomment these 2 lines if needed
        # self.log.append('current: %s' % repr(current))
        # self.log.append('desired: %s' % repr(desired))
        # if the object does not exist,  we can't modify it
        modified = dict()
        if current is None:
            return modified

        # error out if keys do not match
        self.check_keys(current, desired)

        # collect changed attributes
        for key, value in current.items():
            if key in desired and desired[key] is not None:
                if type(value) is list:
                    modified_list = self.compare_lists(value, desired[key], get_list_diff)  # get modified list from current and desired
                    if modified_list:
                        modified[key] = modified_list
                elif type(value) is dict:
                    modified_dict = self.get_modified_attributes(value, desired[key], get_list_diff, additional_keys=True)
                    if modified_dict:
                        modified[key] = modified_dict
                elif cmp(value, desired[key]) != 0:
                    modified[key] = desired[key]
        if additional_keys:
            for key, value in desired.items():
                if key not in current:
                    modified[key] = desired[key]
        if modified:
            self.changed = True
        # Uncomment this line if needed
        # self.log.append('modified: %s' % repr(modified))
        return modified

    def is_rename_action(self, source, target):
        ''' takes a source and target object, and returns True
            if a rename is required
            eg:
            source = self.get_object(source_name)
            target = self.get_object(target_name)
            action = is_rename_action(source, target)
            :return: None for error, True for rename action, False otherwise
        '''
        if source is None and target is None:
            # error, do nothing
            # cannot rename an non existent resource
            # alternatively we could create B
            return None
        if source is not None and target is not None:
            # error, do nothing
            # idempotency (or) new_name_is_already_in_use
            # alternatively we could delete B and rename A to B
            return False
        if source is None and target is not None:
            # do nothing, maybe the rename was already done
            return False
        # source is not None and target is None:
        # rename is in order
        self.changed = True
        return True