import inspect
import types

from zope.configuration import xmlconfig

from zope.component import adaptedBy
from zope.component import getSiteManager
from zope.component import queryUtility

import zope.configuration.config

from zope.configuration.exceptions import ConfigurationError
from zope.configuration.fields import GlobalObject
from zope.configuration.fields import Tokens

from zope.interface import Interface
from zope.interface import implements

from zope.schema import Bool
from zope.schema import TextLine

from repoze.bfg.interfaces import IRequest
from repoze.bfg.interfaces import IRoutesMapper
from repoze.bfg.interfaces import IRoutesContext
from repoze.bfg.interfaces import IViewPermission
from repoze.bfg.interfaces import IView

from repoze.bfg.request import HTTP_METHOD_INTERFACES

from repoze.bfg.security import ViewPermissionFactory

import martian

def handler(methodName, *args, **kwargs):
    method = getattr(getSiteManager(), methodName)
    method(*args, **kwargs)

class Uncacheable(object):
    """ Include in discriminators of actions which are not cacheable;
    this class only exists for backwards compatibility (<0.8.1)"""

def view(
    _context,
    permission=None,
    for_=None,
    view=None,
    name="",
    request_type=None,
    cacheable=True, # not used, here for b/w compat < 0.8
    ):

    if not view:
        raise ConfigurationError('"view" attribute was not specified')

    # adapts() decorations may be used against either functions or
    # class instances
    if inspect.isfunction(view):
        adapted_by = adaptedBy(view)
    else:
        adapted_by = adaptedBy(type(view))

    if adapted_by is not None:
        try:
            if for_ is None:
                for_, _ = adapted_by
            if request_type is None:
                _, request_type = adapted_by
        except ValueError:
            # the component adaptation annotation does not conform to
            # the view specification; we ignore it.
            pass

    if request_type is None:
        request_type = IRequest

    elif isinstance(request_type, basestring):
        if request_type in HTTP_METHOD_INTERFACES:
            request_type = HTTP_METHOD_INTERFACES[request_type]
        else:
            request_type = _context.resolve(request_type)

    if inspect.isclass(view):
        # If the object we've located is a class, turn it into a
        # function that operates like a Zope view (when it's invoked,
        # construct an instance using 'context' and 'request' as
        # position arguments, then immediately invoke the __call__
        # method of the instance with no arguments; __call__ should
        # return an IResponse).
        _view = view
        def _bfg_class_view(context, request):
            inst = _view(context, request)
            return inst()
        _bfg_class_view.__module__ = view.__module__
        _bfg_class_view.__name__ = view.__name__
        _bfg_class_view.__doc__ = view.__doc__
        view = _bfg_class_view

    if permission:
        pfactory = ViewPermissionFactory(permission)
        _context.action(
            discriminator = ('permission', for_, name, request_type,
                             IViewPermission),
            callable = handler,
            args = ('registerAdapter',
                    pfactory, (for_, request_type), IViewPermission, name,
                    _context.info),
            )

    _context.action(
        discriminator = ('view', for_, name, request_type, IView),
        callable = handler,
        args = ('registerAdapter',
                view, (for_, request_type), IView, name,
                _context.info),
        )

class IViewDirective(Interface):
    for_ = GlobalObject(
        title=u"The interface or class this view is for.",
        required=False
        )

    permission = TextLine(
        title=u"Permission",
        description=u"The permission needed to use the view.",
        required=False
        )

    view = GlobalObject(
        title=u"",
        description=u"The view function",
        required=False,
        )

    name = TextLine(
        title=u"The name of the view",
        description=u"""
        The name shows up in URLs/paths. For example 'foo' or
        'foo.html'.""",
        required=False,
        )

    request_type = TextLine(
        title=u"The request type string or dotted name interface for the view",
        description=(u"The view will be called if the interface represented by "
                     u"'request_type' is implemented by the request.  The "
                     u"default request type is repoze.bfg.interfaces.IRequest"),
        required=False
        )

PVERSION = 1

def zcml_configure(name, package):
    context = zope.configuration.config.ConfigurationMachine()
    xmlconfig.registerCommonDirectives(context)
    context.package = package
    xmlconfig.include(context, name, package)
    context.execute_actions(clear=False)
    return context.actions

file_configure = zcml_configure # backwards compat (>0.8.1)

def exclude(name):
    if name.startswith('.'):
        return True
    return False

def scan(_context, package, martian=martian):
    # martian overrideable only for unit tests
    module_grokker = martian.ModuleGrokker()
    module_grokker.register(BFGViewFunctionGrokker())
    martian.grok_dotted_name(package.__name__, grokker=module_grokker,
                             context=_context, exclude_filter=exclude)

class IScanDirective(Interface):
    package = GlobalObject(
        title=u"The package we'd like to scan.",
        required=True,
        )

class BFGViewFunctionGrokker(martian.InstanceGrokker):
    martian.component(types.FunctionType)

    def grok(self, name, obj, **kw):
        if hasattr(obj, '__is_bfg_view__'):
            permission = obj.__permission__
            for_ = obj.__for__
            name = obj.__view_name__
            request_type = obj.__request_type__
            context = kw['context']
            view(context, permission=permission, for_=for_,
                 view=obj, name=name, request_type=request_type)
            return True
        return False

class IRouteRequirementDirective(Interface):
    """ The interface for the ``requirement`` route subdirective """
    attr = TextLine(title=u'attr', required=True)
    expr = TextLine(title=u'expression', required=True)

def route_requirement(context, attr, expr):
    route = context.context
    if attr in route.requirements:
        raise ValueError('Duplicate requirement', attr)
    route.requirements[attr] = expr

class IRouteDirective(Interface):
    """ The interface for the ``route`` ZCML directive
    """
    name = TextLine(title=u'name', required=True)
    path = TextLine(title=u'path', required=True)
    view = GlobalObject(title=u'view', required=True)
    permission = TextLine(title=u'permission', required=False)
    factory = GlobalObject(title=u'context factory', required=False)
    minimize = Bool(title=u'minimize', required=False)
    encoding = TextLine(title=u'encoding', required=False)
    static = Bool(title=u'static', required=False)
    filter = GlobalObject(title=u'filter', required=False)
    absolute = Bool(title=u'absolute', required=False)
    member_name = TextLine(title=u'member_name', required=False)
    collection_name = TextLine(title=u'collection_name', required=False)
    request_type = TextLine(title=u'request_type', required=False)
    condition_method = TextLine(title=u'condition_method', required=False)
    condition_subdomain = TextLine(title=u'condition_subdomain', required=False)
    condition_function = GlobalObject(title=u'condition_function',
                                      required=False)
    parent_member_name = TextLine(title=u'parent member_name', required=False)
    parent_collection_name = TextLine(title=u'parent collection_name',
                                      required=False)
    explicit = Bool(title=u'explicit', required=False)
    subdomains = Tokens(title=u'subdomains', required=False,
                        value_type=TextLine())

def connect_route(directive):
    mapper = queryUtility(IRoutesMapper)
    if mapper is None:
        return
    args = [directive.name, directive.path]
    kw = dict(requirements=directive.requirements)
    if directive.minimize:
        kw['_minimize'] = True
    if directive.explicit:
        kw['_explicit'] = True
    if directive.encoding:
        kw['_encoding'] = directive.encoding
    if directive.static:
        kw['_static'] = True
    if directive.filter:
        kw['_filter'] = directive.filter
    if directive.absolute:
        kw['_absolute'] = True
    if directive.member_name:
        kw['_member_name'] = directive.member_name
    if directive.collection_name:
        kw['_collection_name'] = directive.collection_name
    if directive.parent_member_name and directive.parent_collection_name:
            kw['_parent_resource'] = {
                'member_name':directive.parent_member_name,
                'collection_name':directive.parent_collection_name,
                }
    conditions = {}

    # request_type and condition_method are aliases; condition_method
    # "wins"
    if directive.request_type:
        conditions['method'] = directive.request_type
    if directive.condition_method:
        conditions['method'] = directive.condition_method
    if directive.condition_subdomain:
        conditions['sub_domain'] = directive.condition_subdomain
    if directive.condition_function:
        conditions['function'] = directive.condition_function
    if directive.subdomains:
        conditions['sub_domain'] = directive.subdomains
    if conditions:
        kw['conditions'] = conditions

    if directive.factory:
        kw['_factory'] = directive.factory

    return mapper.connect(*args, **kw)

class Route(zope.configuration.config.GroupingContextDecorator):
    """ Handle ``route`` ZCML directives
    """
    view = None
    permission = None
    factory = None
    minimize = True
    encoding = None
    static = False
    filter = None
    absolute = False
    member_name = None
    collection_name = None
    condition_method = None
    request_type = None
    condition_subdomain = None
    condition_function = None
    parent_member_name = None
    parent_collection_name = None
    subdomains = None
    explicit = False

    implements(zope.configuration.config.IConfigurationContext,
               IRouteDirective)

    def __init__(self, context, path, name, view, **kw):
        self.validate(**kw)
        self.requirements = {} # mutated by subdirectives
        self.context = context
        self.path = path
        self.name = name
        self.view = view
        self.__dict__.update(**kw)

    def validate(self, **kw):
        parent_member_name = kw.get('parent_member_name')
        parent_collection_name = kw.get('parent_collection_name')
        if parent_member_name or parent_collection_name:
            if not (parent_member_name and parent_collection_name):
                raise ConfigurationError(
                    'parent_member_name and parent_collection_name must be '
                    'specified together')

    def after(self):
        view(self.context, self.permission, IRoutesContext, self.view,
             self.name, None)

        method = self.condition_method or self.request_type

        self.context.action(
            discriminator = ('route', self.path, repr(self.requirements),
                             method, self.condition_subdomain,
                             self.condition_function, self.subdomains),
            callable = connect_route,
            args = (self,),
            )