# code stolen from "six"

import sys
import types
from cgi import parse_header

# True if we are running on Python 3.
PY3 = sys.version_info[0] == 3
PY2 = sys.version_info[0] == 2

if PY3:
    string_types = str,
    integer_types = int,
    class_types = type,
    text_type = str
    long = int
else:
    string_types = basestring,
    integer_types = (int, long)
    class_types = (type, types.ClassType)
    text_type = unicode
    long = long

# TODO check if errors is ever used

def text_(s, encoding='latin-1', errors='strict'):
    if isinstance(s, bytes):
        return s.decode(encoding, errors)
    return s

def bytes_(s, encoding='latin-1', errors='strict'):
    if isinstance(s, text_type):
        return s.encode(encoding, errors)
    return s

if PY3:
    def native_(s, encoding='latin-1', errors='strict'):
        if isinstance(s, text_type):
            return s
        return str(s, encoding, errors)
else:
    def native_(s, encoding='latin-1', errors='strict'):
        if isinstance(s, text_type):
            return s.encode(encoding, errors)
        return str(s)

try:
    from queue import Queue, Empty
except ImportError:
    from Queue import Queue, Empty

try:
    from collections.abc import MutableMapping
    from collections.abc import Iterable
except ImportError:
    from collections import MutableMapping
    from collections import Iterable

if PY3:
    from urllib import parse
    urlparse = parse
    from urllib.parse import quote as url_quote
    from urllib.parse import urlencode as url_encode, quote_plus
    from urllib.request import urlopen as url_open
else:
    import urlparse
    from urllib import quote_plus
    from urllib import quote as url_quote
    from urllib import unquote as url_unquote
    from urllib import urlencode as url_encode
    from urllib2 import urlopen as url_open

if PY3: # pragma: no cover
    def reraise(exc_info):
        etype, exc, tb = exc_info
        if exc.__traceback__ is not tb:
            raise exc.with_traceback(tb)
        raise exc
else:
    exec("def reraise(exc): raise exc[0], exc[1], exc[2]")


if PY3:
    def iteritems_(d):
        return d.items()
    def itervalues_(d):
        return d.values()
else:
    def iteritems_(d):
        return d.iteritems()
    def itervalues_(d):
        return d.itervalues()


if PY3: # pragma: no cover
    def unquote(string):
        if not string:
            return b''
        res = string.split(b'%')
        if len(res) != 1:
            string = res[0]
            for item in res[1:]:
                try:
                    string += bytes([int(item[:2], 16)]) + item[2:]
                except ValueError:
                    string += b'%' + item
        return string

    def url_unquote(s):
        return unquote(s.encode('ascii')).decode('latin-1')

    def parse_qsl_text(qs, encoding='utf-8'):
        qs = qs.encode('latin-1')
        qs = qs.replace(b'+', b' ')
        pairs = [s2 for s1 in qs.split(b'&') for s2 in s1.split(b';') if s2]
        for name_value in pairs:
            nv = name_value.split(b'=', 1)
            if len(nv) != 2:
                nv.append('')
            name = unquote(nv[0])
            value = unquote(nv[1])
            yield (name.decode(encoding), value.decode(encoding))

else:
    from urlparse import parse_qsl

    def parse_qsl_text(qs, encoding='utf-8'):
        qsl = parse_qsl(
            qs,
            keep_blank_values=True,
            strict_parsing=False
        )
        for (x, y) in qsl:
            yield (x.decode(encoding), y.decode(encoding))


if PY3:
    from html import escape
else:
    from cgi import escape


if PY3:
    import cgi
    import tempfile
    from cgi import FieldStorage as _cgi_FieldStorage

    # Various different FieldStorage work-arounds required on Python 3.x
    class cgi_FieldStorage(_cgi_FieldStorage): # pragma: no cover

        # Work around https://bugs.python.org/issue27777
        def make_file(self):
            if self._binary_file or self.length >= 0:
                return tempfile.TemporaryFile("wb+")
            else:
                return tempfile.TemporaryFile(
                    "w+",
                    encoding=self.encoding, newline='\n'
                )

        # Work around http://bugs.python.org/issue23801
        # This is taken exactly from Python 3.5's cgi.py module
        def read_multi(self, environ, keep_blank_values, strict_parsing):
            """Internal: read a part that is itself multipart."""
            ib = self.innerboundary
            if not cgi.valid_boundary(ib):
                raise ValueError(
                    'Invalid boundary in multipart form: %r' % (ib,))
            self.list = []
            if self.qs_on_post:
                query = cgi.urllib.parse.parse_qsl(
                    self.qs_on_post, self.keep_blank_values,
                    self.strict_parsing,
                    encoding=self.encoding, errors=self.errors)
                for key, value in query:
                    self.list.append(cgi.MiniFieldStorage(key, value))

            klass = self.FieldStorageClass or self.__class__
            first_line = self.fp.readline()  # bytes
            if not isinstance(first_line, bytes):
                raise ValueError("%s should return bytes, got %s"
                                 % (self.fp, type(first_line).__name__))
            self.bytes_read += len(first_line)

            # Ensure that we consume the file until we've hit our innerboundary
            while (first_line.strip() != (b"--" + self.innerboundary) and
                    first_line):
                first_line = self.fp.readline()
                self.bytes_read += len(first_line)

            while True:
                parser = cgi.FeedParser()
                hdr_text = b""
                while True:
                    data = self.fp.readline()
                    hdr_text += data
                    if not data.strip():
                        break
                if not hdr_text:
                    break
                # parser takes strings, not bytes
                self.bytes_read += len(hdr_text)
                parser.feed(hdr_text.decode(self.encoding, self.errors))
                headers = parser.close()
                # Some clients add Content-Length for part headers, ignore them
                if 'content-length' in headers:
                    filename = None
                    if 'content-disposition' in self.headers:
                        cdisp, pdict = parse_header(self.headers['content-disposition'])
                        if 'filename' in pdict:
                            filename = pdict['filename']
                    if filename is None:
                        del headers['content-length']
                part = klass(self.fp, headers, ib, environ, keep_blank_values,
                             strict_parsing, self.limit-self.bytes_read,
                             self.encoding, self.errors)
                self.bytes_read += part.bytes_read
                self.list.append(part)
                if part.done or self.bytes_read >= self.length > 0:
                    break
            self.skip_lines()
else:
    from cgi import FieldStorage as cgi_FieldStorage