from cubicweb import typed_eid, uilib

from cubicweb.schema import display_name

from cubicweb.web import formwidgets as fw, formfields as ff

from cubicweb.web.views import baseviews, linksearch_select_url

def relation_id(eid, rtype, role, reid):

    """return an identifier for a relation between two entities"""

    if role == 'subject':

        return u'%s:%s:%s' % (eid, rtype, reid)

    return u'%s:%s:%s' % (reid, rtype, eid)

def toggleable_relation_link(eid, nodeid, label='x'):

    """return javascript snippet to delete/undelete a relation between two

    entities

    """

    js = u"javascript: togglePendingDelete('%s', %s);" % (

        nodeid, xml_escape(dumps(eid)))

    return u'[<a class="handle" href="%s" id="handle%s">%s</a>]' % (

        js, nodeid, label)

def get_pending_inserts(req, eid=None):

    """shortcut to access req's pending_insert entry

    This is where are stored relations being added while editing

    an entity. This used to be stored in a temporary cookie.

    """

    pending = req.get_session_data('pending_insert') or ()

    return ['%s:%s:%s' % (subj, rel, obj) for subj, rel, obj in pending

            if eid is None or eid in (subj, obj)]

def get_pending_deletes(req, eid=None):

    """shortcut to access req's pending_delete entry

    This is where are stored relations being removed while editing

    an entity. This used to be stored in a temporary cookie.

    """

    pending = req.get_session_data('pending_delete') or ()

    return ['%s:%s:%s' % (subj, rel, obj) for subj, rel, obj in pending

            if eid is None or eid in (subj, obj)]

def parse_relations_descr(rdescr):

    """parse a string describing some relations, in the form

    subjeids:rtype:objeids

    where subjeids and objeids are eids separeted by a underscore

    return an iterator on (subject eid, relation type, object eid) found

    """

    for rstr in rdescr:

        subjs, rtype, objs = rstr.split(':')

        for subj in subjs.split('_'):

            for obj in objs.split('_'):

                yield typed_eid(subj), rtype, typed_eid(obj)

def delete_relations(req, rdefs):

    """delete relations from the repository"""

    # FIXME convert to using the syntax subject:relation:eids

    execute = req.execute

    for subj, rtype, obj in parse_relations_descr(rdefs):

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

        execute(rql, {'x': subj, 'y': obj}, ('x', 'y'))

    req.set_message(req._('relations deleted'))

def insert_relations(req, rdefs):

    """insert relations into the repository"""

    execute = req.execute

    for subj, rtype, obj in parse_relations_descr(rdefs):

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

        execute(rql, {'x': subj, 'y': obj}, ('x', 'y'))

class GenericRelationsWidget(fw.FieldWidget):

    def render(self, form, field, renderer):

        stream = []

        w = stream.append

        req = form._cw

        _ = req._

        __ = _

        label = u'%s :' % __('This %s' % form.edited_entity.e_schema).capitalize()

        eid = form.edited_entity.eid

        w(u'<fieldset class="subentity">')

        w(u'<legend class="iformTitle">%s</legend>' % label)

        w(u'<table id="relatedEntities">')

        for rschema, role, related in field.relations_table(form):

            # already linked entities

            if related:

                w(u'<tr><th class="labelCol">%s</th>' % rschema.display_name(req, role))

                w(u'<td>')

                w(u'<ul>')

                for viewparams in related:

                    w(u'<li class="invisible">%s<div id="span%s" class="%s">%s</div></li>'

                      % (viewparams[1], viewparams[0], viewparams[2], viewparams[3]))

                if not form.force_display and form.maxrelitems < len(related):

                    link = (u'<span class="invisible">'

                            '[<a href="javascript: window.location.href+=\'&amp;__force_display=1\'">%s</a>]'

                            '</span>' % self._cw._('view all'))

                    w(u'<li class="invisible">%s</li>' % link)

                w(u'</ul>')

                w(u'</td>')

                w(u'</tr>')

        pendings = list(field.restore_pending_inserts(form))

        if not pendings:

            w(u'<tr><th>&#160;</th><td>&#160;</td></tr>')

        else:

            for row in pendings:

                # soon to be linked to entities

                w(u'<tr id="tr%s">' % row[1])

                w(u'<th>%s</th>' % row[3])

                w(u'<td>')

                w(u'<a class="handle" title="%s" href="%s">[x]</a>' %

                  (_('cancel this insert'), row[2]))

                w(u'<a id="a%s" class="editionPending" href="%s">%s</a>'

                  % (row[1], row[4], xml_escape(row[5])))

                w(u'</td>')

                w(u'</tr>')

        w(u'<tr id="relationSelectorRow_%s" class="separator">' % eid)

        w(u'<th class="labelCol">')

        w(u'<select id="relationSelector_%s" tabindex="%s" '

          'onchange="javascript:showMatchingSelect(this.options[this.selectedIndex].value,%s);">'

          % (eid, req.next_tabindex(), xml_escape(dumps(eid))))

        w(u'<option value="">%s</option>' % _('select a relation'))

        for i18nrtype, rschema, role in field.relations:

            # more entities to link to

            w(u'<option value="%s_%s">%s</option>' % (rschema, role, i18nrtype))

        w(u'</select>')

        w(u'</th>')

        w(u'<td id="unrelatedDivs_%s"></td>' % eid)

        w(u'</tr>')

        w(u'</table>')

        w(u'</fieldset>')

        return '\n'.join(stream)

class GenericRelationsField(ff.Field):

    widget = GenericRelationsWidget

    def __init__(self, relations, name='_cw_generic_field', **kwargs):

        assert relations

        kwargs['eidparam'] = True

        super(GenericRelationsField, self).__init__(name, **kwargs)

        self.relations = relations

        self.label = None

    def process_posted(self, form):

        todelete = get_pending_deletes(form._cw)

        if todelete:

            delete_relations(form._cw, todelete)

        toinsert = get_pending_inserts(form._cw)

        if toinsert:

            insert_relations(form._cw, toinsert)

        return ()

    def relations_table(self, form):

        """yiels 3-tuples (rtype, role, 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 = form.edited_entity

        pending_deletes = get_pending_deletes(form._cw, entity.eid)

        for label, rschema, role in self.relations:

            related = []

            if entity.has_eid():

                rset = entity.related(rschema, role, limit=form.related_limit)

                if rschema.has_perm(form._cw, 'delete'):

                    toggleable_rel_link_func = toggleable_relation_link

                else:

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

                for row in xrange(rset.rowcount):

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

                                         rset[row][0])

                    if nodeid in pending_deletes:

                        status, label = u'pendingDelete', '+'

                    else:

                        status, label = u'', 'x'

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

                    eview = form._cw.view('oneline', rset, row=row)

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

            yield (rschema, role, related)

    def restore_pending_inserts(self, form):

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

        'search for <some entity type>'

        """

        entity = form.edited_entity

        pending_inserts = set(get_pending_inserts(form._cw, form.edited_entity.eid))

        for pendingid in pending_inserts:

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

            if typed_eid(eidfrom) == entity.eid: # subject

                label = display_name(form._cw, rtype, 'subject',

                                     entity.__regid__)

                reid = eidto

            else:

                label = display_name(form._cw, rtype, 'object',

                                     entity.__regid__)

                reid = eidfrom

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

                     % (pendingid, entity.eid)

            rset = form._cw.eid_rset(reid)

            eview = form._cw.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(form._cw, 'Basket'))

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

        etypes = uilib.cut(etypes, self._cw.property_value('navigation.short-line-size'))

        pending_inserts = get_pending_inserts(self._cw, entity.eid)

                if eview: # skip blank value

                    options.append('<option class="separator">-- %s --</option>'

                                   % xml_escape(eview))