import cPickle
import os
from os.path import realpath
import time
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.path import package_path

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 """
    pass

def view(_context,
         permission=None,
         for_=None,
         view=None,
         name="",
         request_type=None,
         cacheable=True,
         ):

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

    # adapts() decorations may be used against either functions or
    # class instances
    if isinstance(view, types.FunctionType):
        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

    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),
            )

    cacheable = cacheable or Uncacheable

    _context.action(
        discriminator = ('view', for_, name, request_type, IView, cacheable),
        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 = GlobalObject(
        title=u"""The request type 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 pickle_name(name, package):
    path = package_path(package)
    basename = os.path.join(path, name)
    return os.path.join(path, basename + '.cache')

def zcml_configure(name, package, load=cPickle.load):
    """ Execute pickled zcml actions or fall back to parsing from file
    """
    pckname = pickle_name(name, package)

    if not (os.path.isfile(pckname) or os.path.islink(pckname)):
        return file_configure(name, package)

    try:
        vers, ptime, actions = load(open(pckname, 'rb'))
    except (IOError, cPickle.UnpicklingError, EOFError, TypeError, ValueError,
            AttributeError, NameError, ImportError):
        return file_configure(name, package)

    if vers != PVERSION:
        return file_configure(name, package)

    try:
        ptime = int(ptime)
    except:
        return file_configure(name, package)

    if not hasattr(actions, '__iter__'):
        return file_configure(name, package)

    files = set()
    for action in actions:
        try:
            fileset = action[4]
            files.update(fileset)
        except (TypeError, IndexError):
            return file_configure(name, package)

    for file in files:
        if not(os.path.isfile(file) or os.path.islink(file)):
            return file_configure(name, package)

        mtime = os.stat(realpath(file)).st_mtime
        
        if  mtime >= ptime:
            return file_configure(name, package)

    context = zope.configuration.config.ConfigurationMachine()
    xmlconfig.registerCommonDirectives(context)
    context.actions = actions
    context.cached_execution = True
    context.execute_actions()
    return True

def remove(name, os=os): # os parameterized for unit tests
    try:
        os.remove(name)
        return True
    except:
        pass
    return False

def file_configure(name, package, dump=cPickle.dump):
    context = zope.configuration.config.ConfigurationMachine()
    xmlconfig.registerCommonDirectives(context)
    context.package = package

    xmlconfig.include(context, name, package)
    context.execute_actions(clear=False)

    actions = context.actions
    pckname = pickle_name(name, package)

    for action in actions:
        
        discriminator = action[0]
        if discriminator and Uncacheable in discriminator:
            remove(pckname)
            return False

    try:
        data = (PVERSION, time.time(), actions)
        dump(data, open(pckname, 'wb'), -1)
    except (OSError, IOError, TypeError, cPickle.PickleError):
        remove(pckname)

    return False

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']
            # we dont technically need to pass "Uncacheable" here; any
            # view function decorated with an __is_bfg_view__ attr via
            # repoze.bfg.view.bfg_view is unpickleable; but the
            # uncacheable bit helps pickling fail more quickly
            # (pickling is never attempted)
            view(context, permission=permission, for_=for_,
                 view=obj, name=name, request_type=request_type,
                 cacheable=Uncacheable)
            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)
    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 = {}
    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
    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)

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