"""The edit controller, handling form submitting.

:organization: Logilab

:copyright: 2001-2009 LOGILAB S.A. (Paris, FRANCE), license is LGPL v2.

:contact: http://www.logilab.fr/ -- mailto:contact@logilab.fr

:license: GNU Lesser General Public License, v2.1 - http://www.gnu.org/licenses

"""

__docformat__ = "restructuredtext en"

from decimal import Decimal

from rql.utils import rqlvar_maker

from cubicweb import Binary, ValidationError, typed_eid

from cubicweb.web import INTERNAL_FIELD_VALUE, RequestError, NothingToEdit, ProcessFormError

from cubicweb.web.controller import parse_relations_descr

from cubicweb.web.views.basecontrollers import ViewController

class ToDoLater(Exception):

    """exception used in the edit controller to indicate that a relation

    can't be handled right now and have to be handled later

    """

class RqlQuery(object):

    def __init__(self):

        self.edited = []

        self.restrictions = []

        self.kwargs = {}

    def insert_query(self, etype):

        if self.edited:

            rql = 'INSERT %s X: %s' % (etype, ','.join(self.edited))

        else:

            rql = 'INSERT %s X' % etype

        if self.restrictions:

            rql += ' WHERE %s' % ','.join(self.restrictions)

        return rql

    def update_query(self, eid):

        varmaker = rqlvar_maker()

        var = varmaker.next()

        while var in self.kwargs:

            var = varmaker.next()

        rql = 'SET %s WHERE X eid %%(%s)s' % (','.join(self.edited), var)

        if self.restrictions:

            rql += ', %s' % ','.join(self.restrictions)

        self.kwargs[var] = eid

        return rql

class EditController(ViewController):

    __regid__ = 'edit'

    def publish(self, rset=None):

        """edit / create / copy / delete entity / relations"""

        for key in self._cw.form:

            # There should be 0 or 1 action

            if key.startswith('__action_'):

                cbname = key[1:]

                try:

                    callback = getattr(self, cbname)

                except AttributeError:

                    raise RequestError(self._cw._('invalid action %r' % key))

                else:

                    return callback()

        self._default_publish()

        self.reset()

    def _default_publish(self):

        req = self._cw

        self.errors = []

        self.relations_rql = []

        # no specific action, generic edition

        self._to_create = req.data['eidmap'] = {}

        self._pending_relations = []

        todelete = self._cw.get_pending_deletes()

        toinsert = self._cw.get_pending_inserts()

        try:

            methodname = req.form.pop('__method', None)

            for eid in req.edited_eids():

                # __type and eid

                formparams = req.extract_entity_params(eid, minparams=2)

                if methodname is not None:

                    entity = req.entity_from_eid(eid)

                    method = getattr(entity, methodname)

                    method(formparams)

                eid = self.edit_entity(formparams)

        except (RequestError, NothingToEdit):

            if '__linkto' in req.form and 'eid' in req.form:

                self.execute_linkto()

            elif not ('__delete' in req.form or '__insert' in req.form or todelete or toinsert):

                raise ValidationError(None, {None: req._('nothing to edit')})

        for querydef in self.relations_rql:

            self._cw.execute(*querydef)

        # handle relations in newly created entities

        # XXX find a way to merge _pending_relations and relations_rql

        if self._pending_relations:

            for form, field, entity in self._pending_relations:

                for querydef in self.handle_relation(form, field, entity, True):

                    self._cw.execute(*querydef)

        # XXX this processes *all* pending operations of *all* entities

        if req.form.has_key('__delete'):

            todelete += req.list_form_param('__delete', req.form, pop=True)

        if todelete:

            self.delete_relations(parse_relations_descr(todelete))

        if req.form.has_key('__insert'):

            toinsert = req.list_form_param('__insert', req.form, pop=True)

        if toinsert:

            self.insert_relations(parse_relations_descr(toinsert))

        self._cw.remove_pending_operations()

    def _insert_entity(self, etype, eid, rqlquery):

        rql = rqlquery.insert_query(etype)

        try:

            # get the new entity (in some cases, the type might have

            # changed as for the File --> Image mutation)

            entity = self._cw.execute(rql, rqlquery.kwargs).get_entity(0, 0)

            neweid = entity.eid

        except ValidationError, ex:

            self._to_create[eid] = ex.entity

            if self._cw.json_request: # XXX (syt) why?

                ex.entity = eid

            raise

        self._to_create[eid] = neweid

        return neweid

    def _update_entity(self, eid, rqlquery):

        rql = rqlquery.update_query(eid)

        self._cw.execute(rql, rqlquery.kwargs)

    def edit_entity(self, formparams, multiple=False):

        """edit / create / copy an entity and return its eid"""

        etype = formparams['__type']

        entity = self._cw.vreg['etypes'].etype_class(etype)(self._cw)

        entity.eid = formparams['eid']

        eid = self._get_eid(entity.eid)

        is_main_entity = self._cw.form.get('__maineid') == formparams['eid']

        # let a chance to do some entity specific stuff.tn

        entity.pre_web_edit()

        # create a rql query from parameters

        rqlquery = RqlQuery()

        # process inlined relations at the same time as attributes

        # this will generate less rql queries and might be useful in

        # a few dark corners

        formid = self._cw.form.get('__form_id', 'edition')

        form = self._cw.vreg['forms'].select(formid, self._cw, entity=entity)

        for field in form.fields:

            if form.form_field_modified(field):

                self.handle_formfield(form, field, entity, rqlquery)

        if eid is None: # creation or copy

            entity.eid = self._insert_entity(etype, formparams['eid'], rqlquery)

        elif rqlquery.edited: # edition of an existant entity

            self._update_entity(eid, rqlquery)

        if is_main_entity:

            self.notify_edited(entity)

        if formparams.has_key('__delete'):

            todelete = self._cw.list_form_param('__delete', formparams, pop=True)

            self.delete_relations(parse_relations_descr(todelete))

        if formparams.has_key('__cloned_eid'):

            entity.copy_relations(formparams['__cloned_eid'])

        if formparams.has_key('__insert'):

            toinsert = self._cw.list_form_param('__insert', formparams, pop=True)

            self.insert_relations(parse_relations_descr(toinsert))

        if is_main_entity: # only execute linkto for the main entity

            self.execute_linkto(eid)

        return eid

    def handle_formfield(self, form, field, entity, rqlquery):

        eschema = entity.e_schema

        try:

            for attr, value in field.process_posted(form):

                if not (

                    (field.role == 'subject' and eschema.has_subject_relation(field.name))

                    or

                    (field.role == 'object' and eschema.has_object_relation(field.name))):

                    continue

                rschema = self._cw.schema.rschema(field.name)

                if rschema.is_final():

                    rqlquery.kwargs[attr] = value

                    rqlquery.edited.append('X %s %%(%s)s' % (attr, attr))

                elif rschema.inlined:

                    self.handle_inlined_relation(form, field, entity, rqlquery)

                else:

                    self.relations_rql += self.handle_relation(

                        form, field, entity)

        except ProcessFormError, exc:

            self.errors.append((field, exc))

    def _action_apply(self):

        self._default_publish()

        self.reset()

    def _action_cancel(self):

        errorurl = self._cw.form.get('__errorurl')

        if errorurl:

            self._cw.cancel_edition(errorurl)

        self._cw.message = self._cw._('edit canceled')

        return self.reset()

    def _action_delete(self):

        self.delete_entities(self._cw.edited_eids(withtype=True))

        return self.reset()

    def _relation_values(self, form, field, entity, late=False):

        """handle edition for the (rschema, x) relation of the given entity

        """

        values = set()

        for eid in field.process_form_value(form):

            if not eid: # AutoCompletionWidget

                continue

            typed_eid = self._get_eid(eid)

            if typed_eid is None:

                if late:

                    # eid is still None while it's already a late call

                    # this mean that the associated entity has not been created

                    raise Exception("eid %s is still not created" % eid)

                self._pending_relations.append( (form, field, entity) )

                return None

            values.add(typed_eid)

        return values

    def handle_inlined_relation(self, form, field, entity, rqlquery):

        """handle edition for the (rschema, x) relation of the given entity

        """

        origvalues = set(row[0] for row in entity.related(field.name, field.role))

        values  = self._relation_values(form, field, entity)

        if values is None or values == origvalues:

            return # not edited / not modified / to do later

        attr = field.name

        if values:

            rqlquery.kwargs[attr] = iter(values).next()

            rqlquery.edition.append('X %s %s' % (attr, attr.upper()))

            rqlquery.restrictions.append('%s eid %%(%s)s' % (attr.upper(), attr))

        elif entity.has_eid():

            self.relations_rql += self.handle_relation(form, field, entity)

    def handle_relation(self, form, field, entity, late=False):

        """handle edition for the (rschema, x) relation of the given entity

        """

        origvalues = set(row[0] for row in entity.related(field.name, field.role))

        values  = self._relation_values(form, field, entity, late)

        if values is None or values == origvalues:

            return # not edited / not modified / to do later

        etype = entity.e_schema

        rschema = self._cw.schema.rschema(field.name)

        if field.role == 'subject':

            desttype = rschema.objects(etype)[0]

            card = rschema.rproperty(etype, desttype, 'cardinality')[0]

            subjvar, objvar = 'X', 'Y'

        else:

            desttype = rschema.subjects(etype)[0]

            card = rschema.rproperty(desttype, etype, 'cardinality')[1]

            subjvar, objvar = 'Y', 'X'

        eid = entity.eid

        if field.role == 'object' or not rschema.inlined or not values:

            # this is not an inlined relation or no values specified,

            # explicty remove relations

            rql = 'DELETE %s %s %s WHERE X eid %%(x)s, Y eid %%(y)s' % (

                subjvar, rschema, objvar)

            for reid in origvalues.difference(values):

                yield (rql, {'x': eid, 'y': reid}, ('x', 'y'))

        seteids = values.difference(origvalues)

        if seteids:

            rql = 'SET %s %s %s WHERE X eid %%(x)s, Y eid %%(y)s' % (

                subjvar, rschema, objvar)

            for reid in seteids:

                yield (rql, {'x': eid, 'y': reid}, ('x', 'y'))

    def _get_eid(self, eid):

        # should be either an int (existant entity) or a variable (to be

        # created entity)

        assert eid or eid == 0, repr(eid) # 0 is a valid eid

        try:

            return typed_eid(eid)

        except ValueError:

            try:

                return self._to_create[eid]

            except KeyError:

                self._to_create[eid] = None

                return None

    def _linked_eids(self, eids, late=False):

        """return a list of eids if they are all known, else raise ToDoLater

        """