# -*- coding: utf-8 -*-
"""
    werkzeug.http
    ~~~~~~~~~~~~~

    Werkzeug comes with a bunch of utilities that help Werkzeug to deal with
    HTTP data.  Most of the classes and functions provided by this module are
    used by the wrappers, but they are useful on their own, too, especially if
    the response and request objects are not used.

    This covers some of the more HTTP centric features of WSGI, some other
    utilities such as cookie handling are documented in the `werkzeug.utils`
    module.


    :copyright: (c) 2013 by the Werkzeug Team, see AUTHORS for more details.
    :license: BSD, see LICENSE for more details.
"""
import re
from time import time, gmtime
try:
    from email.utils import parsedate_tz
except ImportError: # pragma: no cover
    from email.Utils import parsedate_tz
try:
    from urllib2 import parse_http_list as _parse_list_header
except ImportError: # pragma: no cover
    from urllib.request import parse_http_list as _parse_list_header
from datetime import datetime, timedelta
from hashlib import md5
import base64

from werkzeug._internal import _cookie_quote, _make_cookie_domain, \
     _cookie_parse_impl
from werkzeug._compat import to_unicode, iteritems, text_type, \
     string_types, try_coerce_native, to_bytes, PY2, \
     integer_types


# incorrect
_cookie_charset = 'latin1'
_accept_re = re.compile(r'([^\s;,]+)(?:[^,]*?;\s*q=(\d*(?:\.\d+)?))?')
_token_chars = frozenset("!#$%&'*+-.0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ"
                         '^_`abcdefghijklmnopqrstuvwxyz|~')
_etag_re = re.compile(r'([Ww]/)?(?:"(.*?)"|(.*?))(?:\s*,\s*|$)')
_unsafe_header_chars = set('()<>@,;:\"/[]?={} \t')
_quoted_string_re = r'"[^"\\]*(?:\\.[^"\\]*)*"'
_option_header_piece_re = re.compile(r';\s*(%s|[^\s;=]+)\s*(?:=\s*(%s|[^;]+))?\s*' %
    (_quoted_string_re, _quoted_string_re))

_entity_headers = frozenset([
    'allow', 'content-encoding', 'content-language', 'content-length',
    'content-location', 'content-md5', 'content-range', 'content-type',
    'expires', 'last-modified'
])
_hop_by_hop_headers = frozenset([
    'connection', 'keep-alive', 'proxy-get_token',
    'proxy-authorization', 'te', 'trailer', 'transfer-encoding',
    'upgrade'
])


HTTP_STATUS_CODES = {
    100:    'Continue',
    101:    'Switching Protocols',
    102:    'Processing',
    200:    'OK',
    201:    'Created',
    202:    'Accepted',
    203:    'Non Authoritative Information',
    204:    'No Content',
    205:    'Reset Content',
    206:    'Partial Content',
    207:    'Multi Status',
    226:    'IM Used',              # see RFC 3229
    300:    'Multiple Choices',
    301:    'Moved Permanently',
    302:    'Found',
    303:    'See Other',
    304:    'Not Modified',
    305:    'Use Proxy',
    307:    'Temporary Redirect',
    400:    'Bad Request',
    401:    'Unauthorized',
    402:    'Payment Required',     # unused
    403:    'Forbidden',
    404:    'Not Found',
    405:    'Method Not Allowed',
    406:    'Not Acceptable',
    407:    'Proxy Authentication Required',
    408:    'Request Timeout',
    409:    'Conflict',
    410:    'Gone',
    411:    'Length Required',
    412:    'Precondition Failed',
    413:    'Request Entity Too Large',
    414:    'Request URI Too Long',
    415:    'Unsupported Media Type',
    416:    'Requested Range Not Satisfiable',
    417:    'Expectation Failed',
    418:    'I\'m a teapot',        # see RFC 2324
    422:    'Unprocessable Entity',
    423:    'Locked',
    424:    'Failed Dependency',
    426:    'Upgrade Required',
    428:    'Precondition Required', # see RFC 6585
    429:    'Too Many Requests',
    431:    'Request Header Fields Too Large',
    449:    'Retry With',           # proprietary MS extension
    500:    'Internal Server Error',
    501:    'Not Implemented',
    502:    'Bad Gateway',
    503:    'Service Unavailable',
    504:    'Gateway Timeout',
    505:    'HTTP Version Not Supported',
    507:    'Insufficient Storage',
    510:    'Not Extended'
}


def wsgi_to_bytes(data):
    """coerce wsgi unicode represented bytes to real ones

    """
    if isinstance(data, bytes):
        return data
    return data.encode('latin1') #XXX: utf8 fallback?


def bytes_to_wsgi(data):
    assert isinstance(data, bytes), 'data must be bytes'
    if isinstance(data, str):
        return data
    else:
        return data.decode('latin1')


def quote_header_value(value, extra_chars='', allow_token=True):
    """Quote a header value if necessary.

    .. versionadded:: 0.5

    :param value: the value to quote.
    :param extra_chars: a list of extra characters to skip quoting.
    :param allow_token: if this is enabled token values are returned
                        unchanged.
    """
    if isinstance(value, bytes):
        value = bytes_to_wsgi(value)
    value = str(value)
    if allow_token:
        token_chars = _token_chars | set(extra_chars)
        if set(value).issubset(token_chars):
            return value
    return '"%s"' % value.replace('\\', '\\\\').replace('"', '\\"')


def unquote_header_value(value, is_filename=False):
    r"""Unquotes a header value.  (Reversal of :func:`quote_header_value`).
    This does not use the real unquoting but what browsers are actually
    using for quoting.

    .. versionadded:: 0.5

    :param value: the header value to unquote.
    """
    if value and value[0] == value[-1] == '"':
        # this is not the real unquoting, but fixing this so that the
        # RFC is met will result in bugs with internet explorer and
        # probably some other browsers as well.  IE for example is
        # uploading files with "C:\foo\bar.txt" as filename
        value = value[1:-1]

        # if this is a filename and the starting characters look like
        # a UNC path, then just return the value without quotes.  Using the
        # replace sequence below on a UNC path has the effect of turning
        # the leading double slash into a single slash and then
        # _fix_ie_filename() doesn't work correctly.  See #458.
        if not is_filename or value[:2] != '\\\\':
            return value.replace('\\\\', '\\').replace('\\"', '"')
    return value


def dump_options_header(header, options):
    """The reverse function to :func:`parse_options_header`.

    :param header: the header to dump
    :param options: a dict of options to append.
    """
    segments = []
    if header is not None:
        segments.append(header)
    for key, value in iteritems(options):
        if value is None:
            segments.append(key)
        else:
            segments.append('%s=%s' % (key, quote_header_value(value)))
    return '; '.join(segments)


def dump_header(iterable, allow_token=True):
    """Dump an HTTP header again.  This is the reversal of
    :func:`parse_list_header`, :func:`parse_set_header` and
    :func:`parse_dict_header`.  This also quotes strings that include an
    equals sign unless you pass it as dict of key, value pairs.

    >>> dump_header({'foo': 'bar baz'})
    'foo="bar baz"'
    >>> dump_header(('foo', 'bar baz'))
    'foo, "bar baz"'

    :param iterable: the iterable or dict of values to quote.
    :param allow_token: if set to `False` tokens as values are disallowed.
                        See :func:`quote_header_value` for more details.
    """
    if isinstance(iterable, dict):
        items = []
        for key, value in iteritems(iterable):
            if value is None:
                items.append(key)
            else:
                items.append('%s=%s' % (
                    key,
                    quote_header_value(value, allow_token=allow_token)
                ))
    else:
        items = [quote_header_value(x, allow_token=allow_token)
                 for x in iterable]
    return ', '.join(items)


def parse_list_header(value):
    """Parse lists as described by RFC 2068 Section 2.

    In particular, parse comma-separated lists where the elements of
    the list may include quoted-strings.  A quoted-string could
    contain a comma.  A non-quoted string could have quotes in the
    middle.  Quotes are removed automatically after parsing.

    It basically works like :func:`parse_set_header` just that items
    may appear multiple times and case sensitivity is preserved.

    The return value is a standard :class:`list`:

    >>> parse_list_header('token, "quoted value"')
    ['token', 'quoted value']

    To create a header from the :class:`list` again, use the
    :func:`dump_header` function.

    :param value: a string with a list header.
    :return: :class:`list`
    """
    result = []
    for item in _parse_list_header(value):
        if item[:1] == item[-1:] == '"':
            item = unquote_header_value(item[1:-1])
        result.append(item)
    return result


def parse_dict_header(value, cls=dict):
    """Parse lists of key, value pairs as described by RFC 2068 Section 2 and