from zope.component import getMultiAdapter
from zope.component import queryMultiAdapter
from zope.interface import directlyProvides

from webob import Request
from webob.exc import HTTPNotFound

from repoze.bfg.interfaces import IPublishTraverserFactory
from repoze.bfg.interfaces import IViewFactory
from repoze.bfg.interfaces import IWSGIApplicationFactory

from repoze.bfg.interfaces import IRequest

_marker = ()

class Router:
    def __init__(self, root_policy):
        self.root_policy = root_policy

    def __call__(self, environ, start_response):
        request = Request(environ)
        directlyProvides(request, IRequest)
        root = self.root_policy(environ)
        path = environ.get('PATH_INFO', '/')
        traverser = getMultiAdapter((root, request), IPublishTraverserFactory)
        context, name, subpath = traverser(path)
        request.subpath = subpath
        app = queryMultiAdapter((context, request), IViewFactory, name=name,
                                default=_marker)
        if app is _marker:
            app = HTTPNotFound(request.url)
        else:
            app = getMultiAdapter((app, request), IWSGIApplicationFactory)
        return app(environ, start_response)

def make_app(root_policy,
             default_publish_traverser_factory=None,
             default_wsgi_application_factory=None
             ):
    if default_publish_traverser_factory is None:
        from repoze.bfg.traversal import NaivePublishTraverser
        default_publish_traverser_factory = NaivePublishTraverser
    if default_wsgi_application_factory is None:
        from repoze.bfg.wsgiadapter import NaiveWSGIViewAdapter
        default_wsgi_application_factory = NaiveWSGIViewAdapter
    from zope.component import getGlobalSiteManager
    gsm = getGlobalSiteManager()
    gsm.registerAdapter(default_publish_traverser_factory, (None, None),
                        IPublishTraverserFactory)
    gsm.registerAdapter(default_wsgi_application_factory, (None, None),
                        IWSGIApplicationFactory)
    return Router(root_policy)