accounting: rework Organisation_getMappingRelatedOrganisation ( WIP )

TODO:

 * [ ] file as bug
 * [ ] unify implementation with Base_getAccountingPeriodStartDateForSectionCategory
 * [ ] MR for nexedi/erp5
 * [ ] capago: stop creating accounting period for durban in `ERP5Site_openCapagoAccountingPeriod`, this was just hiding the bug

/reviewed-on https://lab.nexedi.com/nexedi/erp5-capago/merge_requests/20

bt5/erp5_accounting/SkinTemplateItem/portal_skins/erp5_accounting/Organisation_getMappingRelatedOrganisation.py

-"""Returns the main organisation for that group.
-"""
-
-if len(context.contentValues(filter=
-    dict(portal_type='Accounting Period'))) or context.getMapping():
-  return context
+"""Returns the "main organisation" for that group, from accounting point of view.
 
-def getOrganisationForSectionCategory(section):
-  mapping = section.getMappingRelatedValue(portal_type='Organisation',
-                           checked_permission='Access contents information')
-  if mapping is not None:
-    return mapping
+Other organisation from this group are considered subsidiaries and have same
+accounting periods as the main organisation. This is also used for invoice reconciliation.
 
-  organisation_list = section.getGroupRelatedValueList(portal_type='Organisation',
-                              strict_membership=1,
-                              checked_permission='Access contents information')
+XXX: the name of this script should include something "Accounting"
+TODO: unify with Base_getAccountingPeriodStartDateForSectionCategory
+"""
+portal = context.getPortalObject()
 
-  for organisation in organisation_list:
-    if organisation.getProperty('validation_state', 'unset') not in ('deleted', 'invalidated'):
-      return organisation
+def isMainOrganisation(organisation):
+  return bool(organisation.contentValues(
+    portal_type='Accounting Period',
+    checked_permission='Access contents information'))
 
+if isMainOrganisation(context):
+  return context
 
 group = context.getGroupValue()
 if group is None:
   return context
 
-group_chain = []
 while group.getPortalType() != 'Base Category':
-  group_chain.append(group)
+  section_uid_list = portal.Base_getSectionUidListForSectionCategory(
+      section_category=group.getRelativeUrl(),
+      strict_membership=True)
+  if -1 in section_uid_list:
+    section_uid_list.remove(-1) # XXX explain this
+  if section_uid_list:
+    for brain in portal.portal_catalog(uid=section_uid_list):
+      section = brain.getObject()
+      if isMainOrganisation(section):
+        return section
   group = group.getParentValue()
-
-for group in group_chain:
-  organisation = getOrganisationForSectionCategory(group)
-  if organisation is not None and (
-      len(organisation.contentValues(
-              filter=dict(portal_type='Accounting Period'))) or 
-      organisation.getMapping()):
-    return organisation
-
-return context