from plone.contentrules.rule.interfaces import IExecutable, IRuleElementData
import transaction
from zope.interface import implements, Interface
from zope.component import adapts

from Acquisition import aq_inner, aq_parent
from OFS.SimpleItem import SimpleItem
from Products.CMFPlone import utils
from Products.statusmessages.interfaces import IStatusMessage
from ZODB.POSException import ConflictError

from plone.app.contentrules import PloneMessageFactory as _
from plone.app.contentrules.browser.formhelper import NullAddForm


class IDeleteAction(Interface):
    """Interface for the configurable aspects of a delete action.
    """


class DeleteAction(SimpleItem):
    """The actual persistent implementation of the action element.
    """
    implements(IDeleteAction, IRuleElementData)

    element = 'plone.actions.Delete'
    summary = _(u"Delete object")


class DeleteActionExecutor(object):
    """The executor for this action.
    """
    implements(IExecutable)
    adapts(Interface, IDeleteAction, Interface)

    def __init__(self, context, element, event):
        self.context = context
        self.element = element
        self.event = event

    def __call__(self):
        obj = self.event.object
        parent = aq_parent(aq_inner(obj))

        transaction.savepoint()

        try:
            parent.manage_delObjects(obj.getId())
        except ConflictError, e:
            raise e
        except Exception, e:
            self.error(obj, str(e))
            return False

        return True

    def error(self, obj, error):
        request = getattr(self.context, 'REQUEST', None)
        if request is not None:
            title = utils.pretty_title_or_id(obj, obj)
            message = _(u"Unable to remove ${name} as part of content rule 'delete' action: ${error}",
                          mapping={'name': title, 'error': error})
            IStatusMessage(request).addStatusMessage(message, type="error")


class DeleteAddForm(NullAddForm):
    """A degenerate "add form"" for delete actions.
    """

    def create(self):
        return DeleteAction()