from zope.interface import Attribute
from zope.interface import Interface

from zope.component.interfaces import IObjectEvent

class IRequest(Interface):
    """ Request type interface attached to all request objects """

class IRouteRequest(IRequest):
    """ *internal only* interface used to mark a request when a route
    matches.  Not an API."""

class IResponseFactory(Interface):
    """ A utility which generates a response factory """
    def __call__():
        """ Return a response factory (e.g. a callable that returns an
        object implementing IResponse, e.g. ``webob.Response``; it
        should accept all the arguments that the webob.Response class
        accepts)"""

class IResponse(Interface):
    status = Attribute('WSGI status code of response')
    headerlist = Attribute('List of response headers')
    app_iter = Attribute('Iterable representing the response body')

class IView(Interface):
    def __call__(context, request):
        """ Must return an object that implements IResponse.  May
        optionally raise ``repoze.bfg.exceptions.Forbidden`` if an
        authorization failure is detected during view execution or
        ``repoze.bfg.exceptions.NotFound`` if the not found page is
        meant to be returned."""

class ISecuredView(IView):
    """ *Internal only* interface.  Not an API. """
    def __call_permissive__(context, request):
        """ Guaranteed-permissive version of __call__ """

    def __permitted__(context, request):
        """ Return True if view execution will be permitted using the
        context and request, False otherwise"""

class IMultiView(ISecuredView):
    """ *internal only*.  A multiview is a secured view that is a
    collection of other views.  Each of the views is associated with
    zero or more predicates.  Not an API."""
    def add(view, predicates, score):
        """ Add a view to the multiview. """

class IRootFactory(Interface):
    def __call__(environ):
        """ Return a root object based on the WSGI environ """

class IDefaultRootFactory(Interface):
    def __call__(environ):
        """ Return the *default* root object for an application """

class ITraverser(Interface):
    def __call__(environ):
        """ Return a dictionary with the keys ``root``, ``context``,
        ``view_name``, ``subpath``, ``traversed``, ``virtual_root``,
        and ``virtual_root_path``.  These values are typically the
        result of an object graph traversal.  ``root`` is the physical
        root object, ``context`` will be a model object, ``view_name``
        will be the view name used (a Unicode name), ``subpath`` will
        be a sequence of Unicode names that followed the view name but
        were not traversed, ``traversed`` will be a sequence of
        Unicode names that were traversed (including the virtual root
        path, if any) ``virtual_root`` will be a model object
        representing the virtual root (or the physical root if
        traversal was not performed), and ``virtual_root_path`` will
        be a sequence representing the virtual root path (a sequence
        of Unicode names) or None if traversal was not performed."""

class ITraverserFactory(Interface):
    def __call__(context):
        """ Return an object that implements ITraverser """

class IRenderer(Interface):
    def __call__(value, system):
        """ Call a the renderer implementation with the result of the
        view (``value``) passed in and return a result (a string or
        unicode object useful as a response body).  Values computed by
        the system are passed by the system in the ``system``
        parameter, which is a dictionary.  Keys in the dictionary
        include: ``view`` (the view object that returned the value),
        ``renderer_name`` (the template name or simple name of the
        renderer), ``context`` (the context object passed to the
        view), and ``request`` (the request object passed to the
        view)."""

class IRendererFactory(Interface):
    def __call__(name):
        """ Return an object that implements ``IRenderer``  """

class ITemplateRenderer(IRenderer):
    def implementation():
        """ Return the object that the underlying templating system
        uses to render the template; it is typically a callable that
        accepts arbitrary keyword arguments and returns a string or
        unicode object """

class ITemplateRendererFactory(IRendererFactory):
    def __call__(path):
        """ Return an object that implements ``ITemplateRenderer`` """

class IViewPermission(Interface):
    def __call__(context, request):
        """ Return True if the permission allows, return False if it denies. """

class IRouter(Interface):
    """WSGI application which routes requests to 'view' code based on
    a view registry."""
    registry = Attribute(
        """Component architecture registry local to this application.""")
    
class INewRequest(Interface):
    """ An event type that is emitted whenever repoze.bfg begins to
    process a new request """
    request = Attribute('The request object')
    
class INewResponse(Interface):
    """ An event type that is emitted whenever any repoze.bfg view
    returns a response."""
    response = Attribute('The response object')

class ISettings(Interface):
    """ Runtime settings utility for repoze.bfg; represents the
    deployment settings for the application"""
    
class IWSGIApplicationCreatedEvent(IObjectEvent):
    """ Event issued after the application has been created and
    configured."""
    app = Attribute(u"Published application")

# this interface, even if it becomes unused within BFG, is imported by
# other packages (such as repoze.bfg.traversalwrapper)
class ILocation(Interface):
    """Objects that have a structural location"""
    __parent__ = Attribute("The parent in the location hierarchy")
    __name__ = Attribute("The name within the parent")

class ILogger(Interface):
    """ Interface representing a PEP 282 logger """

class IRoutesMapper(Interface):
    """ Interface representing a Routes ``Mapper`` object """
    
class IForbiddenView(Interface):
    """ A utility which returns an IResponse as the result of the
    denial of a view invocation by a security policy."""
    def __call__(context, request):
        """ Return an object implementing IResponse (an object with
        the status, headerlist, and app_iter attributes) as a result
        of a view invocation denial by a security policy.
        
        Note that the ``message`` key in the WSGI environ
        (request.environ) provides information pertaining to the
        reason for the view invocation denial.  The ``context`` passed
        to the forbidden app factory will be the context found by the
        repoze.bfg router during traversal or url dispatch.  The
        ``request`` will be the request object which caused the deny."""

class INotFoundView(Interface):
    """ A utility which returns a NotFound response (an IResponse)
    when a view cannot be located for a particular URL"""
    def __call__(context, request):
        """ Return a NotFound response.  When the view is rendered,
        a``message`` key in the WSGI environ provides information
        pertaining to the reason for the notfound error."""

class IContextURL(Interface):
    """ An adapter which deals with URLs related to a context.
    """
    def virtual_root():
        """ Return the virtual root related to a request and the
        current context"""

    def __call__():
        """ Return a URL that points to the context """

class IAuthenticationPolicy(Interface):
    """ An object representing a BFG authentication policy. """
    def authenticated_userid(request):
        """ Return the authenticated userid or ``None`` if no
        authenticated userid can be found. """

    def effective_principals(request):
        """ Return a sequence representing the effective principals
        including the userid and any groups belonged to by the current
        user, including 'system' groups such as Everyone and
        Authenticated. """

    def remember(request, principal, **kw):
        """ Return a set of headers suitable for 'remembering' the
        principal named ``principal`` when set in a response.  An
        individual authentication policy and its consumers can decide
        on the composition and meaning of **kw. """
    
    def forget(request):
        """ Return a set of headers suitable for 'forgetting' the
        current user on subsequent requests. """

class IAuthorizationPolicy(Interface):
    """ A adapter on context """
    def permits(context, principals, permission):
        """ Return True if any of the principals is allowed the
        permission in the current context, else return False """
        
    def principals_allowed_by_permission(context, permission):
        """ Return a set of principal identifiers allowed by the permission """

class IPackageOverrides(Interface):
    """ Utility for pkg_resources overrides """

# VH_ROOT_KEY is an interface; its imported from other packages (e.g.
# traversalwrapper)
VH_ROOT_KEY = 'HTTP_X_VHM_ROOT'