from zope.component import queryUtility, getUtility
from zope.annotation.interfaces import IAnnotations

from Acquisition import aq_base

from plone.contentrules.engine.interfaces import IRuleStorage
from plone.contentrules.engine.interfaces import IRuleAssignmentManager

from plone.contentrules.rule.rule import Rule as BaseRule

from OFS.SimpleItem import SimpleItem
from BTrees.OOBTree import OOSet
from Products.CMFCore.interfaces import ISiteRoot

ANNOTATION_KEY = "plone.app.contentrules.ruleassignments"


class Rule(SimpleItem, BaseRule):
    """A Zope 2 version of a rule, subject to acqusition, but otherwise
    identical.
    """

    __name__ = u""

    @property
    def id(self):
        return '++rule++%s' % self.__name__


def get_assignments(rule):
    annotations = IAnnotations(rule)
    # do not use setdefault here as it'll write to the database on read
    return annotations.get(ANNOTATION_KEY, OOSet())


def insert_assignment(rule, path):
    annotations = IAnnotations(rule)
    if ANNOTATION_KEY not in annotations:
        annotations[ANNOTATION_KEY] = OOSet()
    annotations[ANNOTATION_KEY].insert(path)


# Events that keep track of rule-to-assignment mappings
def rule_removed(rule, event):

    storage = queryUtility(IRuleStorage)
    rule_name = rule.__name__

    if storage is None:
        return

    portal = getUtility(ISiteRoot)
    for path in get_assignments(rule):
        container = portal.unrestrictedTraverse(path)
        if container is not None:
            assignable = IRuleAssignmentManager(container, None)
            if assignable is not None and rule_name in assignable:
                del assignable[rule_name]


def container_moved(container, event):

    if event.oldParent is None or event.newParent is None or \
            event.oldName is None:
        return

    assignable = IRuleAssignmentManager(container, None)
    storage = queryUtility(IRuleStorage)

    if assignable is None or storage is None:
        return

    old_path = "%s/%s" % ('/'.join(event.oldParent.getPhysicalPath()),
                          event.oldName, )
    new_path = '/'.join(container.getPhysicalPath())

    if aq_base(event.object) is not aq_base(container):
        new_path_of_moved = '/'.join(event.object.getPhysicalPath())
        old_path = old_path + new_path[len(new_path_of_moved):]

    for rule_name in assignable.keys():
        rule = storage.get(rule_name, None)
        if rule is not None:
            assignments = get_assignments(rule)
            if old_path in assignments:
                assignments.remove(old_path)
                assignments.insert(new_path)


def container_removed(container, event):

    assignable = IRuleAssignmentManager(container, None)
    storage = queryUtility(IRuleStorage)

    if assignable is None or storage is None:
        return

    path = '/'.join(container.getPhysicalPath())
    for rule_name in assignable.keys():
        rule = storage.get(rule_name, None)
        if rule is not None:
            assignments = get_assignments(rule)
            if path in assignments:
                assignments.remove(path)