from zope.component.event import dispatch

from zope.interface import implements
from zope.interface import providedBy

from repoze.bfg.interfaces import IForbiddenView
from repoze.bfg.interfaces import ILogger
from repoze.bfg.interfaces import INotFoundView
from repoze.bfg.interfaces import IRootFactory
from repoze.bfg.interfaces import IRouter
from repoze.bfg.interfaces import ISettings
from repoze.bfg.interfaces import ITraverserFactory
from repoze.bfg.interfaces import IView

from repoze.bfg.configuration import make_registry
from repoze.bfg.configuration import DefaultRootFactory
from repoze.bfg.events import NewRequest
from repoze.bfg.events import NewResponse
from repoze.bfg.events import WSGIApplicationCreatedEvent
from repoze.bfg.exceptions import Forbidden
from repoze.bfg.exceptions import NotFound
from repoze.bfg.request import request_factory
from repoze.bfg.threadlocal import manager
from repoze.bfg.traversal import ModelGraphTraverser
from repoze.bfg.traversal import _traverse
from repoze.bfg.view import default_forbidden_view
from repoze.bfg.view import default_notfound_view

_marker = object()

class Router(object):
    """ The main repoze.bfg WSGI application. """
    implements(IRouter)

    debug_notfound = False
    threadlocal_manager = manager

    def __init__(self, registry):
        q = registry.queryUtility
        self.logger = q(ILogger, 'repoze.bfg.debug')
        self.notfound_view = q(INotFoundView, default=default_notfound_view)
        self.forbidden_view = q(IForbiddenView, default=default_forbidden_view)
        self.root_factory = q(IRootFactory, default=DefaultRootFactory)
        self.root_policy = self.root_factory # b/w compat
        self.registry = registry
        settings = registry.queryUtility(ISettings)
        if settings is not None:
            self.debug_notfound = settings['debug_notfound']
        self.traverser_warned = {}

    def __call__(self, environ, start_response):
        """
        Accept ``environ`` and ``start_response``; route requests to
        ``repoze.bfg`` views based on registrations within the
        application registry; call ``start_response`` and return an
        iterable.
        """
        registry = self.registry
        logger = self.logger
        manager = self.threadlocal_manager
        threadlocals = {'registry':registry, 'request':None}
        manager.push(threadlocals)
 
        try:
            root = self.root_factory(environ)
            request = request_factory(environ)

            # webob.Request's __setattr__ (as of 0.9.5 and lower) is a
            # bottleneck; since we're sure we're using a
            # webob.Request, we can go around its back and set stuff
            # into the environ directly
            attrs = environ.setdefault('webob.adhoc_attrs', {})
            attrs['registry'] = registry

            threadlocals['request'] = request
            registry.has_listeners and registry.notify(NewRequest(request))
            traverser = registry.queryAdapter(root, ITraverserFactory)
            if traverser is None:
                traverser = ModelGraphTraverser(root)
            tdict = _traverse(root, environ, traverser=traverser)
            context, view_name, subpath, traversed, vroot, vroot_path = (
                tdict['context'], tdict['view_name'], tdict['subpath'],
                tdict['traversed'], tdict['virtual_root'],
                tdict['virtual_root_path'])
            attrs.update(tdict)

            provides = map(providedBy, (context, request))
            view_callable = registry.adapters.lookup(
                provides, IView, name=view_name, default=None)

            if view_callable is None:
                if self.debug_notfound:
                    msg = (
                        'debug_notfound of url %s; path_info: %r, context: %r, '
                        'view_name: %r, subpath: %r, traversed: %r, '
                        'root: %r, vroot: %r,  vroot_path: %r' % (
                        request.url, request.path_info, context, view_name,
                        subpath, traversed, root, vroot, vroot_path)
                        )
                    logger and logger.debug(msg)
                else:
                    msg = request.path_info
                environ['repoze.bfg.message'] = msg
                response = self.notfound_view(context, request)
            else:
                try:
                    response = view_callable(context, request)
                except Forbidden, why:
                    msg = why[0]
                    environ = getattr(request, 'environ', {})
                    environ['repoze.bfg.message'] = msg
                    response = self.forbidden_view(context, request)
                except NotFound, why:
                    msg = why[0]
                    environ = getattr(request, 'environ', {})
                    environ['repoze.bfg.message'] = msg
                    response = self.notfound_view(context, request)

            registry.has_listeners and registry.notify(NewResponse(response))

            try:
                start_response(response.status, response.headerlist)
                return response.app_iter
            except AttributeError:
                raise ValueError(
                    'Non-response object returned from view named %s '
                    '(and no renderer): %r' % (view_name, response))

        finally:
            manager.pop()

# make_registry kw arg for unit testing only
def make_app(root_factory, package=None, filename='configure.zcml',
             authentication_policy=None, authorization_policy=None,
             options=None, manager=manager, make_registry=make_registry):
    """ Return a Router object, representing a fully configured
    ``repoze.bfg`` WSGI application.

    ``root_factory`` must be a callable that accepts a WSGI
    environment and returns a traversal root object.  The traversal
    root returned by the root factory is the *default* traversal root;
    it can be overridden on a per-view basis.  ``root_factory`` may be
    ``None``, in which case a 'default default' traversal root is
    used.

    ``package`` is a Python module representing the application's
    package.  It is optional, defaulting to ``None``.  ``package`` may
    be ``None``.  If ``package`` is ``None``, the ``filename`` passed
    or the value in the ``options`` dictionary named
    ``configure_zcml`` must be a) absolute pathname to a ZCML file
    that represents the application's configuration *or* b) a
    'specification' in the form
    ``dotted_package_name:relative/file/path.zcml``.

    ``filename`` is the filesystem path to a ZCML file (optionally
    relative to the package path) that should be parsed to create the
    application registry.  It defaults to ``configure.zcml``.  It can
    also be a 'specification' in the form
    ``dotted_package_name:relatve/file/path.zcml``. Note that if any
    value for ``configure_zcml`` is passed within the ``options``
    dictionary, the value passed as ``filename`` will be ignored,
    replaced with the ``configure_zcml`` value.

    ``options``, if used, should be a dictionary containing runtime
    options (e.g. the key/value pairs in an app section of a
    PasteDeploy file), with each key representing the option and the
    key's value representing the specific option value,
    e.g. ``{'reload_templates':True}``"""
    registry = make_registry(root_factory, package, filename,
                             authentication_policy, authorization_policy,
                             options)
    app = Router(registry)
    # We push the registry on to the stack here in case any ZCA API is
    # used in listeners subscribed to the WSGIApplicationCreatedEvent
    # we send.
    manager.push({'registry':registry, 'request':None})
    try:
        # use dispatch here instead of registry.notify to make unit
        # tests possible
        dispatch(WSGIApplicationCreatedEvent(app))
    finally:
        manager.pop()
    return app