"""WSGI request adapter for cubicweb

NOTE: each docstring tagged with ``COME FROM DJANGO`` means that

the code has been taken (or adapted) from Djanco source code :

  http://www.djangoproject.com/

:organization: Logilab

:copyright: 2008-2009 LOGILAB S.A. (Paris, FRANCE), license is LGPL v2.

:contact: http://www.logilab.fr/ -- mailto:contact@logilab.fr

:license: GNU Lesser General Public License, v2.1 - http://www.gnu.org/licenses

"""

__docformat__ = "restructuredtext en"

from StringIO import StringIO

from urllib import quote

from logilab.common.decorators import cached

from cubicweb.web.request import CubicWebRequestBase

from cubicweb.wsgi import (pformat, qs2dict, safe_copyfileobj, parse_file_upload,

                        normalize_header)

class CubicWebWsgiRequest(CubicWebRequestBase):

    """most of this code COMES FROM DJANO

    """

    def __init__(self, environ, vreg, base_url=None):

        self.environ = environ

        self.path = environ['PATH_INFO']

        self.method = environ['REQUEST_METHOD'].upper()

        self._headers = dict([(normalize_header(k[5:]), v) for k, v in self.environ.items()

                              if k.startswith('HTTP_')])

        https = environ.get("HTTPS") in ('yes', 'on', '1')

        post, files = self.get_posted_data()

        super(CubicWebWsgiRequest, self).__init__(vreg, https, post)

        if files is not None:

            for fdef in files.itervalues():

                fdef[0] = unicode(fdef[0], self.encoding)

            self.form.update(files)

        # prepare output headers

        self.headers_out = {}

    def __repr__(self):

        # Since this is called as part of error handling, we need to be very

        # robust against potentially malformed input.

        form = pformat(self.form)

        meta = pformat(self.environ)

        return '<CubicWebWsgiRequest\FORM:%s,\nMETA:%s>' % \

            (form, meta)

    ## cubicweb request interface ################################################

    def base_url(self):

        return self._base_url

    def http_method(self):

        """returns 'POST', 'GET', 'HEAD', etc."""

        return self.method

    def relative_path(self, includeparams=True):

        """return the normalized path of the request (ie at least relative

        so that the returned path may be used to compare to generated urls

        :param includeparams:

           boolean indicating if GET form parameters should be kept in the path

        """

        path = self.environ['PATH_INFO']

        path = path[1:] # remove leading '/'

        if includeparams:

            qs = self.environ.get('QUERY_STRING')

            if qs:

                return '%s?%s' % (path, qs)

        return path

    def get_header(self, header, default=None):

        """return the value associated with the given input HTTP header,

        raise KeyError if the header is not set

        """

        return self._headers.get(normalize_header(header), default)

    def set_header(self, header, value, raw=True):

        """set an output HTTP header"""

        assert raw, "don't know anything about non-raw headers for wsgi requests"

        self.headers_out[header] = value

    def add_header(self, header, value):

        """add an output HTTP header"""

        self.headers_out[header] = value

    def remove_header(self, header):

        """remove an output HTTP header"""

        self.headers_out.pop(header, None)

    def header_if_modified_since(self):

        """If the HTTP header If-modified-since is set, return the equivalent

        mx date time value (GMT), else return None

        """

        return None

    ## wsgi request helpers ###################################################

        """

        environ = self.environ

        url = environ['wsgi.url_scheme'] + '://'

        if environ.get('HTTP_HOST'):

            url += environ['HTTP_HOST']

        else:

            url += environ['SERVER_NAME']

            if environ['wsgi.url_scheme'] == 'https':

                if environ['SERVER_PORT'] != '443':

                    url += ':' + environ['SERVER_PORT']

            else:

                if environ['SERVER_PORT'] != '80':

                    url += ':' + environ['SERVER_PORT']

        url += quote(environ.get('SCRIPT_NAME') or '/')

        return url

    def get_full_path(self):

        return '%s%s' % (self.path, self.environ.get('QUERY_STRING', '') and ('?' + self.environ.get('QUERY_STRING', '')) or '')

    def is_secure(self):

        return 'wsgi.url_scheme' in self.environ \

            and self.environ['wsgi.url_scheme'] == 'https'

    def get_posted_data(self):

        files = None

        if self.method == 'POST':

            if self.environ.get('CONTENT_TYPE', '').startswith('multipart'):

                header_dict = dict((normalize_header(k[5:]), v)

                                   for k, v in self.environ.items()

                                   if k.startswith('HTTP_'))

                header_dict['Content-Type'] = self.environ.get('CONTENT_TYPE', '')

                post, files = parse_file_upload(header_dict, self.raw_post_data)

            else:

                post = qs2dict(self.raw_post_data)

        else:

            # The WSGI spec says 'QUERY_STRING' may be absent.

            post = qs2dict(self.environ.get('QUERY_STRING', ''))

        return post, files

    @property

    @cached

    def raw_post_data(self):

        buf = StringIO()

        try:

            # CONTENT_LENGTH might be absent if POST doesn't have content at all (lighttpd)

            content_length = int(self.environ.get('CONTENT_LENGTH', 0))

        except ValueError: # if CONTENT_LENGTH was empty string or not an integer

            content_length = 0

        if content_length > 0:

            safe_copyfileobj(self.environ['wsgi.input'], buf,

                    size=content_length)

        postdata = buf.getvalue()

        buf.close()

        return postdata

    def _validate_cache(self):

        """raise a `DirectResponse` exception if a cached page along the way

        exists and is still usable

        """

        # XXX

#         if self.get_header('Cache-Control') in ('max-age=0', 'no-cache'):

#             # Expires header seems to be required by IE7

#             self.add_header('Expires', 'Sat, 01 Jan 2000 00:00:00 GMT')

#             return

#         try:

#             http.checkPreconditions(self._twreq, _PreResponse(self))

#         except http.HTTPError, ex:

#             self.info('valid http cache, no actual rendering')

#             raise DirectResponse(ex.response)

        # Expires header seems to be required by IE7

        self.add_header('Expires', 'Sat, 01 Jan 2000 00:00:00 GMT')