lib/rasti/db/relations/graph_builder.rb in rasti-db-1.0.0 vs lib/rasti/db/relations/graph_builder.rb in rasti-db-1.1.0

@@ -5,24 +5,53 @@
         class << self
 
           def graph_to(rows, relations, collection_class, db, schema=nil)
             return if rows.empty?
 
-            parse(relations).each do |relation, nested_relations|
-              raise "Undefined relation #{relation} for #{collection_class}" unless collection_class.relations.key? relation
-              collection_class.relations[relation].graph_to rows, db, schema, nested_relations
+            parse(relations).each do |relation_name, nested_relations|
+              relation = get_relation collection_class, relation_name
+              relation.graph_to rows, db, schema, nested_relations
             end
           end
 
+          def joins_to(dataset, relations, collection_class, schema=nil)
+            ds = recusrive_joins dataset, recursive_parse(relations), collection_class, schema
+            qualified_collection_name = schema ? Sequel[schema][collection_class.collection_name] : Sequel[collection_class.collection_name]
+            ds.distinct.select_all(qualified_collection_name)
+          end
+
           private
 
+          def get_relation(collection_class, relation_name)
+            raise "Undefined relation #{relation_name} for #{collection_class}" unless collection_class.relations.key? relation_name
+            collection_class.relations[relation_name]
+          end
+
           def parse(relations)
             relations.each_with_object({}) do |relation, hash|
               tail = relation.to_s.split '.'
               head = tail.shift.to_sym
               hash[head] ||= []
               hash[head] << tail.join('.') unless tail.empty?
             end
+          end
+
+          def recursive_parse(relations)
+            parse(relations).each_with_object({}) do |(key, value), hash|
+              hash[key] = recursive_parse value
+            end
+          end
+
+          def recusrive_joins(dataset, joins, collection_class, schema, prefix=nil)
+            joins.each do |relation_name, nested_joins|
+              relation = get_relation collection_class, relation_name
+
+              dataset = relation.join_to dataset, schema, prefix
+
+              dataset = recusrive_joins dataset, nested_joins, relation.target_collection_class, schema, relation.join_relation_name(prefix) unless nested_joins.empty?
+            end
+
+            dataset
           end
 
         end
       end
     end
\ No newline at end of file