check rank item count

specifyweb/businessrules/rules/tree_rules.py

@@ -32,6 +32,14 @@ def cannot_delete_root_treedefitem(sender, obj):
                  "node": {
                      "id": obj.id
                  }})
+        elif is_tree_rank_empty(sender, obj):
+            raise TreeBusinessRuleException(
+                "cannot delete tree rank containing items",
+                {"tree": obj.__class__.__name__,
+                 "localizationKey": 'deletingNonEmptyTreeRank',
+                 "node": {
+                     "id": obj.id
+                 }})
         pre_tree_rank_deletion(sender, obj)
         verify_rank_parent_chain_integrity(obj, RankOperation.DELETED)
 

specifyweb/specify/tree_ranks.py

@@ -93,6 +93,32 @@
     'lithostrat': (LITHO_STRAT_RANKS, LITHO_STRAT_INCREMENT),
 }
 
+TREE_RANK_TO_ITEM_MAP = {
+    'Taxontreedefitem': 'Taxon',
+    'Geographytreedefitem': 'Geography',
+    'Storagetreedefitem': 'Storage',
+    'Geologictimeperiodtreedefitem': 'Geologictimeperiod',
+    'Lithostrattreedefitem': 'Lithostrat'
+}
+
+def get_tree_item_model(tree_rank_model_name):
+    tree_item_model_name = TREE_RANK_TO_ITEM_MAP.get(tree_rank_model_name.title(), None)
+    if not tree_item_model_name:
+        return None
+    return getattr(spmodels, tree_item_model_name, None)
+
+def tree_rank_count(tree_rank_model_name, tree_rank_id) -> int:
+    tree_item_model = get_tree_item_model(tree_rank_model_name)
+    if not tree_item_model:
+        return 0
+    return tree_item_model.objects.filter(definitionitem_id=tree_rank_id).count()
+
+def is_tree_rank_empty(tree_rank_model, tree_rank) -> bool:
+    tree_item_model = get_tree_item_model(tree_rank_model.__name__)
+    if not tree_item_model:
+        return False
+    return tree_item_model.objects.filter(definitionitem=tree_rank).count() == 0
+
 def post_tree_rank_save(tree_def_item_model, new_rank):
     tree_def = new_rank.treedef
     parent_rank = new_rank.parent

specifyweb/specify/tree_views.py

@@ -9,6 +9,7 @@
 from specifyweb.businessrules.exceptions import BusinessRuleException
 from specifyweb.permissions.permissions import PermissionTarget, \
     PermissionTargetAction, check_permission_targets
+from specifyweb.specify.tree_ranks import tree_rank_count
 from specifyweb.stored_queries import models
 from . import tree_extras
 from .api import get_object_or_404, obj_to_data, toJson
@@ -290,6 +291,14 @@ def repair_tree(request, tree):
     tree_extras.renumber_tree(table)
     tree_extras.validate_tree_numbering(table)
 
+@login_maybe_required
+@require_GET
+def tree_rank_item_count(request, tree, rankid):
+    """Returns the number of items in the tree rank with id <rank_id>."""
+    tree_rank_model_name = tree if tree.endswith('treedefitem') else tree + 'treedefitem'
+    rank = get_object_or_404(tree_rank_model_name, id=rankid)
+    count = tree_rank_count(tree, rank.id)
+    return HttpResponse(toJson(count), content_type='application/json')
 
 class TaxonMutationPT(PermissionTarget):
     resource = "/tree/edit/taxon"