# Copyright 2014-2015 MongoDB, Inc.
#
# 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.

"""Tools for specifying BSON codec options."""

import datetime

from collections import MutableMapping, namedtuple

from bson.py3compat import string_type
from bson.binary import (ALL_UUID_REPRESENTATIONS,
                         PYTHON_LEGACY,
                         UUID_REPRESENTATION_NAMES)

_RAW_BSON_DOCUMENT_MARKER = 101


def _raw_document_class(document_class):
    """Determine if a document_class is a RawBSONDocument class."""
    marker = getattr(document_class, '_type_marker', None)
    return marker == _RAW_BSON_DOCUMENT_MARKER


_options_base = namedtuple(
    'CodecOptions',
    ('document_class', 'tz_aware', 'uuid_representation',
     'unicode_decode_error_handler', 'tzinfo'))


class CodecOptions(_options_base):
    """Encapsulates BSON options used in CRUD operations.

    :Parameters:
      - `document_class`: BSON documents returned in queries will be decoded
        to an instance of this class. Must be a subclass of
        :class:`~collections.MutableMapping`. Defaults to :class:`dict`.
      - `tz_aware`: If ``True``, BSON datetimes will be decoded to timezone
        aware instances of :class:`~datetime.datetime`. Otherwise they will be
        naive. Defaults to ``False``.
      - `uuid_representation`: The BSON representation to use when encoding
        and decoding instances of :class:`~uuid.UUID`. Defaults to
        :data:`~bson.binary.PYTHON_LEGACY`.
      - `unicode_decode_error_handler`: The error handler to use when decoding
        an invalid BSON string. Valid options include 'strict', 'replace', and
        'ignore'. Defaults to 'strict'.
      - `tzinfo`: A :class:`~datetime.tzinfo` subclass that specifies the
        timezone to/from which :class:`~datetime.datetime` objects should be
        encoded/decoded.

    .. warning:: Care must be taken when changing
       `unicode_decode_error_handler` from its default value ('strict').
       The 'replace' and 'ignore' modes should not be used when documents
       retrieved from the server will be modified in the client application
       and stored back to the server.
    """

    def __new__(cls, document_class=dict,
                tz_aware=False, uuid_representation=PYTHON_LEGACY,
                unicode_decode_error_handler="strict",
                tzinfo=None):
        if not (issubclass(document_class, MutableMapping) or
                _raw_document_class(document_class)):
            raise TypeError("document_class must be dict, bson.son.SON, "
                            "bson.raw_bson.RawBSONDocument, or a "
                            "sublass of collections.MutableMapping")
        if not isinstance(tz_aware, bool):
            raise TypeError("tz_aware must be True or False")
        if uuid_representation not in ALL_UUID_REPRESENTATIONS:
            raise ValueError("uuid_representation must be a value "
                             "from bson.binary.ALL_UUID_REPRESENTATIONS")
        if not isinstance(unicode_decode_error_handler, (string_type, None)):
            raise ValueError("unicode_decode_error_handler must be a string "
                             "or None")
        if tzinfo is not None:
            if not isinstance(tzinfo, datetime.tzinfo):
                raise TypeError(
                    "tzinfo must be an instance of datetime.tzinfo")
            if not tz_aware:
                raise ValueError(
                    "cannot specify tzinfo without also setting tz_aware=True")

        return tuple.__new__(
            cls, (document_class, tz_aware, uuid_representation,
                  unicode_decode_error_handler, tzinfo))

    def _arguments_repr(self):
        """Representation of the arguments used to create this object."""
        document_class_repr = (
            'dict' if self.document_class is dict
            else repr(self.document_class))

        uuid_rep_repr = UUID_REPRESENTATION_NAMES.get(self.uuid_representation,
                                                      self.uuid_representation)

        return ('document_class=%s, tz_aware=%r, uuid_representation='
                '%s, unicode_decode_error_handler=%r, tzinfo=%r' %
                (document_class_repr, self.tz_aware, uuid_rep_repr,
                 self.unicode_decode_error_handler, self.tzinfo))

    def __repr__(self):
        return '%s(%s)' % (self.__class__.__name__, self._arguments_repr())


DEFAULT_CODEC_OPTIONS = CodecOptions()


def _parse_codec_options(options):
    """Parse BSON codec options."""
    return CodecOptions(
        document_class=options.get(
            'document_class', DEFAULT_CODEC_OPTIONS.document_class),
        tz_aware=options.get(
            'tz_aware', DEFAULT_CODEC_OPTIONS.tz_aware),
        uuid_representation=options.get(
            'uuidrepresentation', DEFAULT_CODEC_OPTIONS.uuid_representation),
        unicode_decode_error_handler=options.get(
            'unicode_decode_error_handler',
            DEFAULT_CODEC_OPTIONS.unicode_decode_error_handler),
        tzinfo=options.get('tzinfo', DEFAULT_CODEC_OPTIONS.tzinfo))
