import sys

import logging

from pyramid import security

from pyramid import tweens

from pyramid.httpexceptions import HTTPSeeOther

from pyramid import httpexceptions

from pyramid.settings import asbool

import cubicweb

import cubicweb.web

from cubicweb.web.application import CubicWebPublisher

from cubicweb.web import LogOut, PublishException

from cubicweb.pyramid.core import cw_to_pyramid

log = logging.getLogger(__name__)

class PyramidSessionHandler(object):

    """A CW Session handler that rely on the pyramid API to fetch the needed

    informations.

    It implements the :class:`cubicweb.web.application.CookieSessionHandler`

    API.

    """

    def __init__(self, appli):

        self.appli = appli

    def get_session(self, req):

        return req._request.cw_session

    def logout(self, req, goto_url):

        raise LogOut(url=goto_url)

class CubicWebPyramidHandler(object):

    """ A Pyramid request handler that rely on a cubicweb instance to do the

    whole job

    :param appli: A CubicWeb 'Application' object.

    """

    def __init__(self, appli):

        self.appli = appli

    def __call__(self, request):

        """

        Handler that mimics what CubicWebPublisher.main_handle_request and

        CubicWebPublisher.core_handle do

        """

        req = request.cw_request

        vreg = request.registry['cubicweb.registry']

        try:

            content = None

            try:

                with cw_to_pyramid(request):

                    ctrlid, rset = self.appli.url_resolver.process(req,

                                                                   req.path)

                    try:

                        controller = vreg['controllers'].select(

                            ctrlid, req, appli=self.appli)

                    except cubicweb.NoSelectableObject:

                        raise httpexceptions.HTTPUnauthorized(

                            req._('not authorized'))

                    req.update_search_state()

                    content = controller.publish(rset=rset)

                    # XXX this auto-commit should be handled by the cw_request

                    # cleanup or the pyramid transaction manager.

                    # It is kept here to have the ValidationError handling bw

                    # compatible

                    if req.cnx:

                        txuuid = req.cnx.commit()

                        # commited = True

                        if txuuid is not None:

                            req.data['last_undoable_transaction'] = txuuid

            except cubicweb.web.ValidationError as ex:

                # XXX The validation_error_handler implementation is light, we

                # should redo it better in cw_to_pyramid, so it can be properly

                # handled when raised from a cubicweb view.

                # BUT the real handling of validation errors should be done

                # earlier in the controllers, not here. In the end, the

                # ValidationError should never by handled here.

                content = self.appli.validation_error_handler(req, ex)

            except cubicweb.web.RemoteCallFailed as ex:

                # XXX The default pyramid error handler (or one that we provide

                # for this exception) should be enough

                # content = self.appli.ajax_error_handler(req, ex)

                raise

            if content is not None:

                request.response.body = content

        except LogOut as ex:

            # The actual 'logging out' logic should be in separated function

            # that is accessible by the pyramid views

            headers = security.forget(request)

            raise HTTPSeeOther(ex.url, headers=headers)

        except cubicweb.AuthenticationError:

            # Will occur upon access to req.cnx which is a

            # cubicweb.dbapi._NeedAuthAccessMock.

            if not content:

                content = vreg['views'].main_template(req, 'login')

                request.response.status_code = 403

                request.response.body = content

        except cubicweb.web.NotFound as ex:

            view = vreg['views'].select('404', req)

            content = vreg['views'].main_template(req, view=view)

            request.response.status_code = ex.status

            request.response.body = content

        finally:

            # XXX CubicWebPyramidRequest.headers_out should

            # access directly the pyramid response headers.

            request.response.headers.clear()

            for k, v in req.headers_out.getAllRawHeaders():

                for item in v:

                    request.response.headers.add(k, item)

        return request.response

    def error_handler(self, exc, request):

        req = request.cw_request

        if isinstance(exc, httpexceptions.HTTPException):

            request.response = exc

        elif isinstance(exc, PublishException) and exc.status is not None:

            request.response = httpexceptions.exception_response(exc.status)

        else:

            request.response = httpexceptions.HTTPInternalServerError()

        request.response.cache_control = 'no-cache'

        vreg = request.registry['cubicweb.registry']

        excinfo = sys.exc_info()

        req.reset_message()

        if req.ajax_request:

            content = self.appli.ajax_error_handler(req, exc)

        else:

            try:

                req.data['ex'] = exc

                req.data['excinfo'] = excinfo

                errview = vreg['views'].select('error', req)

                template = self.appli.main_template_id(req)

                content = vreg['views'].main_template(req, template, view=errview)

            except Exception:

                content = vreg['views'].main_template(req, 'error-template')

        log.exception(exc)

        request.response.body = content

        return request.response

class TweenHandler(object):

    """ A Pyramid tween handler that submit unhandled requests to a Cubicweb

    handler.

    The CubicWeb handler to use is expected to be in the pyramid registry, at

    key ``'cubicweb.handler'``.

    """

    def __init__(self, handler, registry):

        self.handler = handler

        self.cwhandler = registry['cubicweb.handler']

    def __call__(self, request):

        try:

            response = self.handler(request)

        except httpexceptions.HTTPNotFound:

            response = self.cwhandler(request)

        return response

def includeme(config):

    """ Set up a tween app that will handle the request if the main application

    raises a HTTPNotFound exception.

    This is to keep legacy compatibility for cubes that makes use of the

    cubicweb urlresolvers.

    It provides, for now, support for cubicweb controllers, but this feature

    will be reimplemented separatly in a less compatible way.

    It is automatically included by the configuration system, but can be

    disabled in the :ref:`pyramid_settings`:

    .. code-block:: ini

        cubicweb.bwcompat = no

    """

    cwconfig = config.registry['cubicweb.config']

    repository = config.registry['cubicweb.repository']

    cwappli = CubicWebPublisher(

        repository, cwconfig,

        session_handler_fact=PyramidSessionHandler)

    cwhandler = CubicWebPyramidHandler(cwappli)

    config.registry['cubicweb.appli'] = cwappli

    config.registry['cubicweb.handler'] = cwhandler

    config.add_tween(

        'cubicweb.pyramid.bwcompat.TweenHandler', under=tweens.EXCVIEW)

    if asbool(config.registry.settings.get(

            'cubicweb.bwcompat.errorhandler', True)):

        config.add_view(cwhandler.error_handler, context=Exception)

        # XXX why do i need this?

        config.add_view(cwhandler.error_handler, context=httpexceptions.HTTPForbidden)