# -*- coding: utf-8 -*-

"""
requests.utils
~~~~~~~~~~~~~~

This module provides utility functions that are used within Requests
that are also useful for external consumption.

"""

import cgi
import codecs
# import cookielib
from http import cookiejar as cookielib
import os
import random
import re
import zlib
import urllib.request, urllib.parse, urllib.error


from urllib.parse import quote, unquote

# from urllib2 import parse_http_list as _parse_list_header
from urllib.request import parse_http_list as _parse_list_header

from http.cookies import SimpleCookie

def dict_from_string(s):
    """Returns a MultiDict with Cookies."""

    cookies = dict()

    c = SimpleCookie()
    c.load(s)

    for k,v in list(c.items()):
        cookies.update({k: v.value})

    return cookies

def guess_filename(obj):
    """Tries to guess the filename of the given object."""
    name = getattr(obj, 'name', None)
    if name and name[0] != '<' and name[-1] != '>':
        return name

# From mitsuhiko/werkzeug (used with permission).
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


# From mitsuhiko/werkzeug (used with permission).
def parse_dict_header(value):
    """Parse lists of key, value pairs as described by RFC 2068 Section 2 and
    convert them into a python dict:

    >>> d = parse_dict_header('foo="is a fish", bar="as well"')
    >>> type(d) is dict
    True
    >>> sorted(d.items())
    [('bar', 'as well'), ('foo', 'is a fish')]

    If there is no value for a key it will be `None`:

    >>> parse_dict_header('key_without_value')
    {'key_without_value': None}

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

    :param value: a string with a dict header.
    :return: :class:`dict`
    """
    result = {}
    for item in _parse_list_header(value):
        if '=' not in item:
            result[item] = None
            continue
        name, value = item.split('=', 1)
        if value[:1] == value[-1:] == '"':
            value = unquote_header_value(value[1:-1])
        result[name] = value
    return result


# From mitsuhiko/werkzeug (used with permission).
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.

    :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 header_expand(headers):
    """Returns an HTTP Header value string from a dictionary.

    Example expansion::

        {'text/x-dvi': {'q': '.8', 'mxb': '100000', 'mxt': '5.0'}, 'text/x-c': {}}
        # Accept: text/x-dvi; q=.8; mxb=100000; mxt=5.0, text/x-c

        (('text/x-dvi', {'q': '.8', 'mxb': '100000', 'mxt': '5.0'}), ('text/x-c', {}))
        # Accept: text/x-dvi; q=.8; mxb=100000; mxt=5.0, text/x-c
    """

    collector = []

    if isinstance(headers, dict):
        headers = list(headers.items())

    elif isinstance(headers, str):
        return headers

    for i, (value, params) in enumerate(headers):

        _params = []

        for (p_k, p_v) in list(params.items()):

            _params.append('%s=%s' % (p_k, p_v))

        collector.append(value)
        collector.append('; ')

        if len(params):

            collector.append('; '.join(_params))

            if not len(headers) == i+1:
                collector.append(', ')


    # Remove trailing separators.
    if collector[-1] in (', ', '; '):
        del collector[-1]

    return ''.join(collector)



def randombytes(n):
    """Return n random bytes."""
    L = [chr(random.randrange(0, 256)).encode('utf-8') for i in range(n)]
    return b"".join(L)


def dict_from_cookiejar(cj):
    """Returns a key/value dictionary from a CookieJar.

    :param cj: CookieJar object to extract cookies from.
    """

    cookie_dict = {}

    for _, cookies in list(cj._cookies.items()):
        for _, cookies in list(cookies.items()):
            for cookie in list(cookies.values()):
                # print cookie
                cookie_dict[cookie.name] = cookie.value

    return cookie_dict


def cookiejar_from_dict(cookie_dict):
    """Returns a CookieJar from a key/value dictionary.

    :param cookie_dict: Dict of key/values to insert into CookieJar.
    """

    # return cookiejar if one was passed in
    if isinstance(cookie_dict, cookielib.CookieJar):
        return cookie_dict

    # create cookiejar
    cj = cookielib.CookieJar()

    cj = add_dict_to_cookiejar(cj, cookie_dict)

    return cj


def add_dict_to_cookiejar(cj, cookie_dict):
    """Returns a CookieJar from a key/value dictionary.

    :param cj: CookieJar to insert cookies into.
    :param cookie_dict: Dict of key/values to insert into CookieJar.
    """

    for k, v in list(cookie_dict.items()):

        cookie = cookielib.Cookie(
            version=0,
            name=k,
            value=v,
            port=None,
            port_specified=False,
            domain='',
            domain_specified=False,
            domain_initial_dot=False,
            path='/',
            path_specified=True,
            secure=False,
            expires=None,
            discard=True,
            comment=None,
            comment_url=None,
            rest={'HttpOnly': None},
            rfc2109=False
        )

        # add cookie to cookiejar
        cj.set_cookie(cookie)

    return cj


def get_encodings_from_content(content):
    """Returns encodings from given content string.

    :param content: bytestring to extract encodings from.
    """

    charset_re = re.compile(r'<meta.*?charset=["\']*(.+?)["\'>]', flags=re.I)

    return charset_re.findall(content)


def get_encoding_from_headers(headers):
    """Returns encodings from given HTTP Header Dict.

    :param headers: dictionary to extract encoding from.
    """

    content_type = headers.get('content-type')

    if not content_type:
        return None

    content_type, params = cgi.parse_header(content_type)

    if 'charset' in params:
        return params['charset'].strip("'\"")

    if 'text' in content_type:
        return 'ISO-8859-1'


def unicode_from_html(content):
    """Attempts to decode an HTML string into unicode.
    If unsuccessful, the original content is returned.
    """

    encodings = get_encodings_from_content(content)

    for encoding in encodings:

        try:
            return str(content, encoding)
        except (UnicodeError, TypeError):
            pass

        return content


def stream_decode_response_unicode(iterator, r):
    """Stream decodes a iterator."""

    if r.encoding is None:
        for item in iterator:
            yield item
        return

    decoder = codecs.getincrementaldecoder(r.encoding)(errors='replace')
    for chunk in iterator:
        rv = decoder.decode(chunk)
        if rv:
            yield rv
    rv = decoder.decode('', final=True)
    if rv:
        yield rv


def get_unicode_from_response(r):
    """Returns the requested content back in unicode.

    :param r: Response object to get unicode content from.

    Tried:

    1. charset from content-type

    2. every encodings from ``<meta ... charset=XXX>``

    3. fall back and replace all unicode characters

    """

    tried_encodings = []

    # Try charset from content-type
    encoding = get_encoding_from_headers(r.headers)

    if encoding:
        try:
            return str(r.content, encoding)
        except UnicodeError:
            tried_encodings.append(encoding)

    # Fall back:
    try:
        return str(r.content, encoding, errors='replace')
    except TypeError:
        return r.content


def decode_gzip(content):
    """Return gzip-decoded string.

    :param content: bytestring to gzip-decode.
    """

    return zlib.decompress(content, 16 + zlib.MAX_WBITS)


def stream_decompress(iterator, mode='gzip'):
    """
    Stream decodes an iterator over compressed data

    :param iterator: An iterator over compressed data
    :param mode: 'gzip' or 'deflate'
    :return: An iterator over decompressed data
    """

    if mode not in ['gzip', 'deflate']:
        raise ValueError('stream_decompress mode must be gzip or deflate')

    zlib_mode = 16 + zlib.MAX_WBITS if mode == 'gzip' else -zlib.MAX_WBITS
    dec = zlib.decompressobj(zlib_mode)
    try:
        for chunk in iterator:
            rv = dec.decompress(chunk)
            if rv:
                yield rv
    except zlib.error:
        # If there was an error decompressing, just return the raw chunk
        yield chunk
        # Continue to return the rest of the raw data
        for chunk in iterator:
            yield chunk
    else:
        # Make sure everything has been returned from the decompression object
        buf = dec.decompress('')
        rv = buf + dec.flush()
        if rv:
            yield rv


def requote_path(path):
    """Re-quote the given URL path component.

    This function passes the given path through an unquote/quote cycle to
    ensure that it is fully and consistently quoted.
    """
    parts = path.split(b"/")
    parts = (quote(unquote(part), safe=b"") for part in parts)
    return b"/".join(parts)