lib/grumlin/repository.rb in grumlin-0.16.1 vs lib/grumlin/repository.rb in grumlin-0.17.0

@@ -1,9 +1,16 @@
 # frozen_string_literal: true
 
 module Grumlin
   module Repository
+    RETURN_MODES = {
+      list: :toList,
+      none: :iterate,
+      single: :next,
+      traversal: :nil
+    }.freeze
+
     module InstanceMethods
       def __
         TraversalStart.new(self.class.shortcuts)
       end
 
@@ -16,8 +23,56 @@
       base.extend(Grumlin::Shortcuts)
       base.include(Grumlin::Expressions)
       base.include(InstanceMethods)
 
       base.shortcuts_from(Grumlin::Shortcuts::Properties)
+    end
+
+    def query(name, return_mode: :list, postprocess_with: nil, &query_block) # rubocop:disable Metrics/AbcSize, Metrics/CyclomaticComplexity, Metrics/PerceivedComplexity
+      return_mode = validate_return_mode!(return_mode)
+      postprocess_with = validate_postprocess_with!(postprocess_with)
+
+      define_method name do |*args, query_params: {}, **params, &block|
+        t = instance_exec(*args, **params, &query_block)
+        return t if self.class.empty_result?(t)
+
+        unless t.is_a?(Grumlin::Action)
+          raise WrongQueryResult,
+                "queries must return #{Grumlin::Action}, nil or an empty collection. Given: #{t.class}"
+        end
+
+        return block.call(t) unless block.nil?
+
+        return t.profile.next if query_params[:profile] == true
+
+        return_mode = self.class.validate_return_mode!(query_params[:return_mode] || return_mode)
+
+        return t if return_mode == :traversal
+
+        t.public_send(RETURN_MODES[return_mode]).tap do |result|
+          return postprocess_with.call(result) if postprocess_with.respond_to?(:call)
+          return send(postprocess_with, result) unless postprocess_with.nil?
+        end
+      end
+    end
+
+    def validate_return_mode!(return_mode)
+      return return_mode if RETURN_MODES.key?(return_mode)
+
+      raise ArgumentError, "unsupported return mode #{return_mode}. Supported modes: #{RETURN_MODES.keys}"
+    end
+
+    def validate_postprocess_with!(postprocess_with)
+      if postprocess_with.nil? || postprocess_with.is_a?(Symbol) ||
+         postprocess_with.is_a?(String) || postprocess_with.respond_to?(:call)
+        return postprocess_with
+      end
+
+      raise ArgumentError,
+            "postprocess_with must be a String, Symbol or a callable object, given: #{postprocess_with.class}"
+    end
+
+    def empty_result?(result)
+      result.nil? || (result.respond_to?(:empty?) && result.empty?)
     end
   end
 end