from future import absolute_import
import email.utils
import mimetypes

from .packages import six

def guess_content_type(filename, default='application/octet-stream'):
"""
Guess the "Content-Type" of a file.

:param filename:
    The filename to guess the "Content-Type" of using :mod:`mimetypes`.
:param default:
    If no "Content-Type" can be guessed, default to `default`.
"""
if filename:
    return mimetypes.guess_type(filename)[0] or default
return default

def format_header_param(name, value):
"""
Helper function to format and quote a single header parameter.

Particularly useful for header parameters which might contain
non-ASCII values, like file names. This follows RFC 2231, as
suggested by RFC 2388 Section 4.4.

:param name:
    The name of the parameter, a string expected to be ASCII only.
:param value:
    The value of the parameter, provided as a unicode string.
"""
if not any(ch in value for ch in '"\\\r\n'):
    result = '%s="%s"' % (name, value)
    try:
        result.encode('ascii')
    except (UnicodeEncodeError, UnicodeDecodeError):
        pass
    else:
        return result
if not six.PY3 and isinstance(value, six.text_type):  # Python 2:
    value = value.encode('utf-8')
value = email.utils.encode_rfc2231(value, 'utf-8')
# value = '%s*=%s' % (name, value)
value = '%s="%s"' % (name, value.encode('utf-8'))
return value

class RequestField(object):
"""
A data container for request body parameters.

:param name:
    The name of this request field.
:param data:
    The data/value body.
:param filename:
    An optional filename of the request field.
:param headers:
    An optional dict-like object of headers to initially use for the field.
"""
def __init__(self, name, data, filename=None, headers=None):
    self._name = name
    self._filename = filename
    self.data = data
    self.headers = {}
    if headers:
        self.headers = dict(headers)

@classmethod
def from_tuples(cls, fieldname, value):
    """
    A :class:`~urllib3.fields.RequestField` factory from old-style tuple parameters.

    Supports constructing :class:`~urllib3.fields.RequestField` from
    parameter of key/value strings AND key/filetuple. A filetuple is a
    (filename, data, MIME type) tuple where the MIME type is optional.
    For example::

        'foo': 'bar',
        'fakefile': ('foofile.txt', 'contents of foofile'),
        'realfile': ('barfile.txt', open('realfile').read()),
        'typedfile': ('bazfile.bin', open('bazfile').read(), 'image/jpeg'),
        'nonamefile': 'contents of nonamefile field',

    Field names and filenames must be unicode.
    """
    if isinstance(value, tuple):
        if len(value) == 3:
            filename, data, content_type = value
        else:
            filename, data = value
            content_type = guess_content_type(filename)
    else:
        filename = None
        content_type = None
        data = value

    request_param = cls(fieldname, data, filename=filename)
    request_param.make_multipart(content_type=content_type)

    return request_param

def _render_part(self, name, value):
    """
    Overridable helper function to format a single header parameter.

    :param name:
        The name of the parameter, a string expected to be ASCII only.
    :param value:
        The value of the parameter, provided as a unicode string.
    """
    return format_header_param(name, value)

def _render_parts(self, header_parts):
    """
    Helper function to format and quote a single header.

    Useful for single headers that are composed of multiple items. E.g.,
    'Content-Disposition' fields.

    :param header_parts:
        A sequence of (k, v) typles or a :class:`dict` of (k, v) to format
        as `k1="v1"; k2="v2"; ...`.
    """
    parts = []
    iterable = header_parts
    if isinstance(header_parts, dict):
        iterable = header_parts.items()

    for name, value in iterable:
        if value:
            parts.append(self._render_part(name, value))

    return '; '.join(parts)

def render_headers(self):
    """
    Renders the headers for this request field.
    """
    lines = []

    sort_keys = ['Content-Disposition', 'Content-Type', 'Content-Location']
    for sort_key in sort_keys:
        if self.headers.get(sort_key, False):
            lines.append('%s: %s' % (sort_key, self.headers[sort_key]))

    for header_name, header_value in self.headers.items():
        if header_name not in sort_keys:
            if header_value:
                lines.append('%s: %s' % (header_name, header_value))

    lines.append('\r\n')
    return '\r\n'.join(lines)

def make_multipart(self, content_disposition=None, content_type=None,
                   content_location=None):
    """
    Makes this request field into a multipart request field.

    This method overrides "Content-Disposition", "Content-Type" and
    "Content-Location" headers to the request parameter.

    :param content_type:
        The 'Content-Type' of the request body.
    :param content_location:
        The 'Content-Location' of the request body.

    """
    self.headers['Content-Disposition'] = content_disposition or 'form-data'
    self.headers['Content-Disposition'] += '; '.join([
        '', self._render_parts(
            (('name', self._name), ('filename', self._filename))
        )
    ])
    self.headers['Content-Type'] = content_type
    self.headers['Content-Location'] = content_location