# All Rights Reserved.
#
#    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

import six


def safe_decode(text, incoming=None, errors="strict"):
    """Decodes incoming string using `incoming` if they're not already unicode.

    :param text: text/bytes string to decode
    :param incoming: Text's current encoding
    :param errors: Errors handling policy. See here for valid
        values http://docs.python.org/2/library/codecs.html
    :returns: text or a unicode `incoming` encoded representation of it.
    :raises TypeError: If text is not an instance of str
    """
    if not isinstance(text, (six.string_types, six.binary_type)):
        raise TypeError("%s can't be decoded" % type(text))

    if isinstance(text, six.text_type):
        return text

    if not incoming:
        incoming = (sys.stdin.encoding or
                    sys.getdefaultencoding())

    try:
        return text.decode(incoming, errors)
    except UnicodeDecodeError:
        # Note(flaper87) If we get here, it means that
        # sys.stdin.encoding / sys.getdefaultencoding
        # didn't return a suitable encoding to decode
        # text. This happens mostly when global LANG
        # var is not set correctly and there's no
        # default encoding. In this case, most likely
        # python will use ASCII or ANSI encoders as
        # default encodings but they won't be capable
        # of decoding non-ASCII characters.
        #
        # Also, UTF-8 is being used since it's an ASCII
        # extension.
        return text.decode("utf-8", errors)


def safe_encode(text, incoming=None, encoding="utf-8", errors="strict"):
    """Encodes incoming text/bytes string using `encoding`.

    If incoming is not specified, text is expected to be encoded with
    current python's default encoding. (`sys.getdefaultencoding`)

    :param text: Incoming text/bytes string
    :param incoming: Text's current encoding
    :param encoding: Expected encoding for text (Default UTF-8)
    :param errors: Errors handling policy. See here for valid
        values http://docs.python.org/2/library/codecs.html
    :returns: text or a bytestring `encoding` encoded representation of it.
    :raises TypeError: If text is not an instance of str
        See also to_utf8() function which is simpler and don't depend on
        the locale encoding.
    """
    if not isinstance(text, (six.string_types, six.binary_type)):
        raise TypeError("%s can't be encoded" % type(text))

    if not incoming:
        incoming = (sys.stdin.encoding or
                    sys.getdefaultencoding())

    # Avoid case issues in comparisons
    if hasattr(incoming, "lower"):
        incoming = incoming.lower()
    if hasattr(encoding, "lower"):
        encoding = encoding.lower()

    if isinstance(text, six.text_type):
        return text.encode(encoding, errors)
    elif text and encoding != incoming:
        # Decode text before encoding it with `encoding`
        text = safe_decode(text, incoming, errors)
        return text.encode(encoding, errors)
    else:
        return text
