#  Copyright 2008-2015 Nokia Networks
#  Copyright 2016-     Robot Framework Foundation
#
#  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 os
import sys

from .encodingsniffer import get_console_encoding, get_system_encoding
from .compat import isatty
from .platform import JYTHON, IRONPYTHON, PY3, PY_VERSION
from .robottypes import is_unicode
from .unic import unic


CONSOLE_ENCODING = get_console_encoding()
SYSTEM_ENCODING = get_system_encoding()
PYTHONIOENCODING = os.getenv('PYTHONIOENCODING')


def console_decode(string, encoding=CONSOLE_ENCODING, force=False):
    """Decodes bytes from console encoding to Unicode.

    By default uses the system console encoding, but that can be configured
    using the `encoding` argument. In addition to the normal encodings,
    it is possible to use case-insensitive values `CONSOLE` and `SYSTEM` to
    use the system console and system encoding, respectively.

    By default returns Unicode strings as-is. The `force` argument can be used
    on IronPython where all strings are `unicode` and caller knows decoding
    is needed.
    """
    if is_unicode(string) and not (IRONPYTHON and force):
        return string
    encoding = {'CONSOLE': CONSOLE_ENCODING,
                'SYSTEM': SYSTEM_ENCODING}.get(encoding.upper(), encoding)
    try:
        return string.decode(encoding)
    except UnicodeError:
        return unic(string)


def console_encode(string, errors='replace', stream=sys.__stdout__):
    """Encodes Unicode to bytes in console or system encoding.

    Determines the encoding to use based on the given stream and system
    configuration. On Python 3 and IronPython returns Unicode, otherwise
    returns bytes.
    """
    encoding = _get_console_encoding(stream)
    if PY3 and encoding != 'UTF-8':
        return string.encode(encoding, errors).decode(encoding)
    if PY3 or IRONPYTHON:
        return string
    return string.encode(encoding, errors)


def _get_console_encoding(stream):
    encoding = getattr(stream, 'encoding', None)
    if isatty(stream):
        return encoding or CONSOLE_ENCODING
    if PYTHONIOENCODING:
        return PYTHONIOENCODING
    # Jython and IronPython have wrong encoding if outputs are redirected.
    if encoding and not (JYTHON or IRONPYTHON):
        return encoding
    return SYSTEM_ENCODING


# These interpreters handle communication with system APIs using Unicode.
if PY3 or IRONPYTHON or (JYTHON and PY_VERSION < (2, 7, 1)):

    def system_decode(string):
        return string if is_unicode(string) else unic(string)

    def system_encode(string, errors='replace'):
        return string if is_unicode(string) else unic(string)

else:

    # Jython 2.7.1+ uses UTF-8 with cli args etc. regardless the actual system
    # encoding. Cannot set the "real" SYSTEM_ENCODING to that value because
    # we use it also for other purposes.
    _SYSTEM_ENCODING = SYSTEM_ENCODING if not JYTHON else 'UTF-8'

    def system_decode(string):
        """Decodes bytes from system (e.g. cli args or env vars) to Unicode.

        Depending on the usage, at least cli args may already be Unicode.
        """
        if is_unicode(string):
            return string
        try:
            return string.decode(_SYSTEM_ENCODING)
        except UnicodeError:
            return unic(string)

    def system_encode(string, errors='replace'):
        """Encodes Unicode to system encoding (e.g. cli args and env vars).

        Non-Unicode values are first converted to Unicode.
        """
        if not is_unicode(string):
            string = unic(string)
        return string.encode(_SYSTEM_ENCODING, errors)