"""The automatic entity form.

: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"

_ = unicode

from logilab.common.decorators import iclassmethod, cached

from cubicweb import typed_eid

from cubicweb.web import stdmsgs, uicfg

from cubicweb.web import form, formwidgets as fwdgs

from cubicweb.web.formfields import guess_field

from cubicweb.web.views import forms, editforms

class AutomaticEntityForm(forms.EntityFieldsForm):

    """base automatic form to edit any entity.

    Designed to be fully generated from schema but highly configurable through:

    * rtags (rcategories, rfields, rwidgets, inlined, rpermissions)

    * various standard form parameters

    XXX s/rtags/uicfg/ ?

    You can also easily customise it by adding/removing fields in

    AutomaticEntityForm instances.

    """

    id = 'edition'

    cwtarget = 'eformframe'

    cssclass = 'entityForm'

    copy_nav_params = True

    form_buttons = [fwdgs.SubmitButton(),

                    fwdgs.Button(stdmsgs.BUTTON_APPLY, cwaction='apply'),

                    fwdgs.Button(stdmsgs.BUTTON_CANCEL, cwaction='cancel')]

    attrcategories = ('primary', 'secondary')

    # class attributes below are actually stored in the uicfg module since we

    # don't want them to be reloaded

    rcategories = uicfg.autoform_section

    rfields = uicfg.autoform_field

    rfields_kwargs = uicfg.autoform_field_kwargs

    rinlined = uicfg.autoform_is_inlined

    rpermissions_overrides = uicfg.autoform_permissions_overrides

    # class methods mapping schema relations to fields in the form ############

    @classmethod

    def erelations_by_category(cls, entity, categories=None, permission=None,

                               rtags=None, strict=False):

        """return a list of (relation schema, target schemas, role) matching

        categories and permission

        `strict`:

          bool telling if having local role is enough (strict = False) or not

        """

        if categories is not None:

            if not isinstance(categories, (list, tuple, set, frozenset)):

                categories = (categories,)

            if not isinstance(categories, (set, frozenset)):

                categories = frozenset(categories)

        eschema  = entity.e_schema

        if rtags is None:

            rtags = cls.rcategories

        permsoverrides = cls.rpermissions_overrides

        if entity.has_eid():

            eid = entity.eid

        else:

            eid = None

            strict = False

        for rschema, targetschemas, role in eschema.relation_definitions(True):

            # check category first, potentially lower cost than checking

            # permission which may imply rql queries

            if categories is not None:

                targetschemas = [tschema for tschema in targetschemas

                                 if rtags.etype_get(eschema, rschema, role, tschema) in categories]

                if not targetschemas:

                    continue

            if permission is not None:

                # tag allowing to hijack the permission machinery when

                # permission is not verifiable until the entity is actually

                # created...

                if eid is None and '%s_on_new' % permission in permsoverrides.etype_get(eschema, rschema, role):

                    yield (rschema, targetschemas, role)

                    continue

                    if not rschema.has_perm(entity.req, permission, eid):

                        continue

                elif role == 'subject':

                    if not ((not strict and rschema.has_local_role(permission)) or

                            rschema.has_perm(entity.req, permission, fromeid=eid)):

                        continue

                    # on relation with cardinality 1 or ?, we need delete perm as well

                    # if the relation is already set

                    if (permission == 'add'

                        and rschema.cardinality(eschema, targetschemas[0], role) in '1?'

                        and eid and entity.related(rschema.type, role)

                        and not rschema.has_perm(entity.req, 'delete', fromeid=eid,

                                                 toeid=entity.related(rschema.type, role)[0][0])):

                        continue

                elif role == 'object':

                    if not ((not strict and rschema.has_local_role(permission)) or

                            rschema.has_perm(entity.req, permission, toeid=eid)):

                        continue

                    # on relation with cardinality 1 or ?, we need delete perm as well

                    # if the relation is already set

                    if (permission == 'add'

                        and rschema.cardinality(targetschemas[0], eschema, role) in '1?'

                        and eid and entity.related(rschema.type, role)

                        and not rschema.has_perm(entity.req, 'delete', toeid=eid,

                                                 fromeid=entity.related(rschema.type, role)[0][0])):

                        continue

            yield (rschema, targetschemas, role)

    @classmethod

    def esrelations_by_category(cls, entity, categories=None, permission=None,

                                strict=False):

        """filter out result of relations_by_category(categories, permission) by

        removing final relations

        return a sorted list of (relation's label, relation'schema, role)

        """

        result = []

        for rschema, ttypes, role in cls.erelations_by_category(

            entity, categories, permission, strict=strict):

                continue

            result.append((rschema.display_name(entity.req, role), rschema, role))

        return sorted(result)

    @iclassmethod

    def field_by_name(cls_or_self, name, role='subject', eschema=None):

        """return field with the given name and role. If field is not explicitly

        defined for the form but `eclass` is specified, guess_field will be

        called.

        """

        try:

            return super(AutomaticEntityForm, cls_or_self).field_by_name(name, role)

        except form.FieldNotFound:

            if eschema is None or not name in cls_or_self.schema:

                raise

            rschema = cls_or_self.schema.rschema(name)

            # XXX use a sample target type. Document this.

            tschemas = rschema.targets(eschema, role)

            fieldcls = cls_or_self.rfields.etype_get(eschema, rschema, role,

                                                     tschemas[0])

            kwargs = cls_or_self.rfields_kwargs.etype_get(eschema, rschema,

                                                          role, tschemas[0])

            if kwargs is None:

                kwargs = {}

            if fieldcls:

                if not isinstance(fieldcls, type):

                    return fieldcls # already and instance

                return fieldcls(name=name, role=role, eidparam=True, **kwargs)

            field = guess_field(eschema, rschema, role, eidparam=True, **kwargs)

            if field is None:

                raise

            return field

    # base automatic entity form methods #######################################

    def __init__(self, *args, **kwargs):

        super(AutomaticEntityForm, self).__init__(*args, **kwargs)

        entity = self.edited_entity

        if entity.has_eid():

            entity.complete()

        for rschema, role in self.editable_attributes():

            try:

                self.field_by_name(rschema.type, role)

                continue # explicitly specified

            except form.FieldNotFound:

                # has to be guessed

                try:

                    field = self.field_by_name(rschema.type, role,

                                               eschema=entity.e_schema)

                    self.fields.append(field)

                except form.FieldNotFound:

                    # meta attribute such as <attr>_format

                    continue

        self.maxrelitems = self.req.property_value('navigation.related-limit')

        self.force_display = bool(self.req.form.get('__force_display'))

    @property

    def related_limit(self):

        if self.force_display:

            return None

        return self.maxrelitems + 1

    @property

    def form_needs_multipart(self):

        """true if the form needs enctype=multipart/form-data"""

        return self._subform_needs_multipart()

    def build_context(self, rendervalues=None):

        super(AutomaticEntityForm, self).build_context(rendervalues)

        for form in self.inlined_forms():

            form.build_context(rendervalues)

    def _subform_needs_multipart(self, _tested=None):

        if _tested is None:

            _tested = set()

        if super(AutomaticEntityForm, self).form_needs_multipart:

            return True

        # take a look at inlined forms to check (recursively) if they

        # need multipart handling.

        # XXX: this is very suboptimal because inlined forms will be

        #      selected / instantiated twice : here and during form rendering.

        #      Potential solutions:

        #       -> use subforms for inlined forms to get easiser access

        #       -> use a simple onload js function to check if there is

        #          a input type=file in the form

        #       -> generate the <form> node when the content is rendered

        #          and we know the correct enctype (formrenderer's w attribute

        #          is not a StringIO)

        for formview in self.inlined_form_views():

            if formview.form:

                if hasattr(formview.form, '_subform_needs_multipart'):

                    needs_multipart = formview.form._subform_needs_multipart(_tested)

                else:

                    needs_multipart = formview.form.form_needs_multipart

                if needs_multipart:

                    return True

        return False

    def action(self):

        """return the form's action attribute. Default to validateform if not

        explicitly overriden.

        """

        try:

            return self._action

        except AttributeError:

            return self.build_url('validateform')

    def set_action(self, value):

        """override default action"""

        self._action = value

    action = property(action, set_action)

    # methods mapping edited entity relations to fields in the form ############

    def relations_by_category(self, categories=None, permission=None):

        """return a list of (relation schema, target schemas, role) matching

        given category(ies) and permission

        """

        return self.erelations_by_category(self.edited_entity, categories,

                                           permission)

    def inlined_relations(self):

        """return a list of (relation schema, target schemas, role) matching

        given category(ies) and permission

        """

        # we'll need an initialized varmaker if there are some inlined relation

        self.initialize_varmaker()

        return self.erelations_by_category(self.edited_entity, True, 'add',

                                           self.rinlined)

    def srelations_by_category(self, categories=None, permission=None,

                               strict=False):

        """filter out result of relations_by_category(categories, permission) by

        removing final relations

        return a sorted list of (relation's label, relation'schema, role)

        """

        return self.esrelations_by_category(self.edited_entity, categories,

                                           permission, strict=strict)

    def editable_attributes(self):

        """return a list of (relation schema, role) to edit for the entity"""

        return [(rschema, role) for rschema, _, role in self.relations_by_category(

                self.attrcategories, 'add') if rschema != 'eid']

    # generic relations modifier ###############################################

    def relations_table(self):

        """yiels 3-tuples (rtype, target, related_list)

        where <related_list> itself a list of :

          - node_id (will be the entity element's DOM id)

          - appropriate javascript's togglePendingDelete() function call

          - status 'pendingdelete' or ''

          - oneline view of related entity

        """

        entity = self.edited_entity

        pending_deletes = self.req.get_pending_deletes(entity.eid)

        for label, rschema, role in self.srelations_by_category('generic', 'add',

                                                                strict=True):

            relatedrset = entity.related(rschema, role, limit=self.related_limit)

            if rschema.has_perm(self.req, 'delete'):

                toggleable_rel_link_func = editforms.toggleable_relation_link

            else:

                toggleable_rel_link_func = lambda x, y, z: u''

            related = []

            for row in xrange(relatedrset.rowcount):

                nodeid = editforms.relation_id(entity.eid, rschema, role,

                                               relatedrset[row][0])

                if nodeid in pending_deletes:

                    status = u'pendingDelete'

                    label = '+'

                else:

                    status = u''

                    label = 'x'

                dellink = toggleable_rel_link_func(entity.eid, nodeid, label)

                eview = self.view('oneline', relatedrset, row=row)

                related.append((nodeid, dellink, status, eview))

            yield (rschema, role, related)

    def restore_pending_inserts(self, cell=False):

        """used to restore edition page as it was before clicking on

        'search for <some entity type>'

        """

        eid = self.edited_entity.eid

        cell = cell and "div_insert_" or "tr"

        pending_inserts = set(self.req.get_pending_inserts(eid))

        for pendingid in pending_inserts:

            eidfrom, rtype, eidto = pendingid.split(':')

            if typed_eid(eidfrom) == eid: # subject

                label = display_name(self.req, rtype, 'subject')

                reid = eidto

            else:

                label = display_name(self.req, rtype, 'object')

                reid = eidfrom

            jscall = "javascript: cancelPendingInsert('%s', '%s', null, %s);" \

                     % (pendingid, cell, eid)

            rset = self.req.eid_rset(reid)

            eview = self.view('text', rset, row=0)

            # XXX find a clean way to handle baskets

            if rset.description[0][0] == 'Basket':

                eview = '%s (%s)' % (eview, display_name(self.req, 'Basket'))

            yield rtype, pendingid, jscall, label, reid, eview

    # inlined forms support ####################################################

    @cached

    def inlined_form_views(self):

        """compute and return list of inlined form views (hosting the inlined form object)

        """

        allformviews = []

        entity = self.edited_entity

        for rschema, ttypes, role in self.inlined_relations():

            # show inline forms only if there's one possible target type

            # for rschema

            if len(ttypes) != 1:

                self.warning('entity related by the %s relation should have '

                             'inlined form but there is multiple target types, '

                             'dunno what to do', rschema)

                continue

            ttype = ttypes[0].type

            if self.should_inline_relation_form(rschema, ttype, role):

                formviews = list(self.inline_edition_form_view(rschema, ttype, role))

                if role == 'subject':

                    card = rschema.rproperty(entity.e_schema, ttype, 'cardinality')[0]

                else:

                    card = rschema.rproperty(ttype, entity.e_schema, 'cardinality')[1]

                # there is no related entity and we need at least one: we need to

                # display one explicit inline-creation view

                if self.should_display_inline_creation_form(rschema, formviews, card):

                    formviews += self.inline_creation_form_view(rschema, ttype, role)

                # we can create more than one related entity, we thus display a link

                # to add new related entities

                if self.should_display_add_new_relation_link(rschema, formviews, card):

                    addnewlink = self.vreg['views'].select(

                        'inline-addnew-link', self.req,

                        etype=ttype, rtype=rschema, role=role,

                        peid=self.edited_entity.eid, pform=self, card=card)

                    formviews.append(addnewlink)

                allformviews += formviews

        return allformviews

    def inlined_forms(self):

        for formview in self.inlined_form_views():

            if formview.form: # may be None for the addnew_link artefact form

                yield formview.form

    def should_inline_relation_form(self, rschema, targettype, role):

        """return true if the given relation with entity has role and a

        targettype target should be inlined

        """

        return True