refactoring: extracts method get_collection_info from get_collection

preparation for use in controller.py

ckanext/odsh/collection/helpers.py

@@ -10,14 +10,18 @@ from profilehooks import timecall, profile
 def get_collection(dataset_dict):
     collection_id = get_collection_id(dataset_dict)
     if collection_id:
+        return get_collection_info(collection_id, dataset_dict)
+    
+    return None
+    
+
+def get_collection_info(collection_id, dataset_dict=None):
     collection_dict = get_package_dict(collection_id)
     dataset_names = get_dataset_names(collection_dict)
     datasets_in_collection = get_datasets_from_solr(dataset_names)
-        collection_info = gather_collection_info(collection_dict, dataset_dict, datasets_in_collection)
+    collection_info = gather_collection_info(collection_dict, datasets_in_collection, dataset_dict)
     return collection_info
 
-    return None
-
 
 @timecall(immediate=True)
 def get_collection_id(dataset_dict):
@@ -67,23 +71,9 @@ def get_datasets_from_solr(dataset_names):
     return datasets_found
 
 
-def gather_collection_info(collection_dict, dataset_dict, datasets_in_collection):
+def gather_collection_info(collection_dict, datasets_in_collection, dataset_dict=None):
     url_from_id = lambda id: helpers.url_for(controller='package', action='read', id=id)
 
-    name_current_dataset = dataset_dict.get('name')
-    dataset_names = [d.get('name') for d in datasets_in_collection]
-    
-    def get_predecessor():
-        id_current = dataset_names.index(name_current_dataset)
-        if id_current > 0:
-            return dataset_names[id_current - 1]
-        return None
-    
-    def get_successor():
-        id_current = dataset_names.index(name_current_dataset)
-        if id_current < len(dataset_names) - 1:
-            return dataset_names[id_current + 1]
-        return None
 
     name_first_dataset = datasets_in_collection[0].get('name')
     url_first_dataset = url_from_id(name_first_dataset)
@@ -98,11 +88,29 @@ def gather_collection_info(collection_dict, dataset_dict, datasets_in_collection
         id=name_collection
     )
 
+    if dataset_dict:
+        name_current_dataset = dataset_dict.get('name')
+        dataset_names = [d.get('name') for d in datasets_in_collection]
+        
+        def get_predecessor():
+            id_current = dataset_names.index(name_current_dataset)
+            if id_current and id_current > 0:
+                return dataset_names[id_current - 1]
+            return None
+        
+        def get_successor():
+            id_current = dataset_names.index(name_current_dataset)
+            if id_current and id_current < len(dataset_names) - 1:
+                return dataset_names[id_current + 1]
+            return None
+        
         name_predecessor = get_predecessor()
         url_predecessor = url_from_id(name_predecessor) if name_predecessor else None
         
         name_successor = get_successor()
         url_successor = url_from_id(name_successor) if name_successor else None
+    else:
+        url_predecessor = url_successor = None
     
     return {
         'title': collection_dict.get('title'),