from pyramid.httpexceptions import HTTPNotFound

from cubicweb import rdf

def negociate_mime_type(request, possible_mimetypes):

    accepted_headers_by_weight = sorted(

        request.accept.parsed or [], key=lambda h: h[1], reverse=True

    )

    mime_type_negociated = None

    for parsed_header in accepted_headers_by_weight:

        accepted_mime_type = parsed_header[0]

        if accepted_mime_type in possible_mimetypes:

            mime_type_negociated = accepted_mime_type

            break

    return mime_type_negociated

def rdf_context_from_eid(request):

    mime_type = negociate_mime_type(request, rdf.RDF_MIMETYPE_TO_FORMAT)

    if mime_type is None:

        raise HTTPNotFound()

    entity = request.cw_request.entity_from_eid(request.matchdict['eid'])

    return RDFResource(entity, mime_type)

class RDFResource:

    def __init__(self, entity, mime_type):

        self.entity = entity

        self.mime_type = mime_type