# Copyright 2013 Dean Gardiner <gardiner91@gmail.com>
#
# 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.

import sys


PY2 = sys.version_info[0] == 2
PY3 = sys.version_info[0] == 3


def is_list_type(obj, element_type):
    if not type(obj) is list:
        return False

    if len(obj) < 1:
        raise ValueError("Unable to determine list element type from empty list")

    return type(obj[0]) is element_type


def clean_dict(target, remove=None):
    """Recursively remove items matching a value 'remove' from the dictionary

    :type target: dict
    """
    if type(target) is not dict:
        raise ValueError("Target is required to be a dict")

    remove_keys = []
    for key in target.keys():
        if type(target[key]) is not dict:
            if target[key] == remove:
                remove_keys.append(key)
        else:
            clean_dict(target[key], remove)

    for key in remove_keys:
        target.pop(key)

    return target


def update_dict(a, b):
    for key, value in b.items():
        if key not in a:
            a[key] = value
        elif isinstance(a[key], dict) and isinstance(value, dict):
            update_dict(a[key], value)
        elif isinstance(a[key], list):
            a[key].append(value)
        else:
            a[key] = [a[key], value]


def xrange_six(start, stop=None, step=None):
    if stop is not None and step is not None:
        if PY3:
            return range(start, stop, step)
        else:
            return xrange(start, stop, step)
    else:
        if PY3:
            return range(start)
        else:
            return xrange(start)


def delta_seconds(td):
    return (td.microseconds + (td.seconds + td.days * 24 * 3600) * 1e6) / 1e6