From eccdc228ecccfa33bfc32b52b7152299073b2961 Mon Sep 17 00:00:00 2001
From: Ignacio Baixas <iobaixas@gmail.com>
Date: Thu, 14 Jul 2016 17:46:17 -0400
Subject: [PATCH] feat(): adds service pattern

---
 lib/power_types.rb                  |  1 +
 lib/power_types/patterns/command.rb | 40 +++++------------------------
 lib/power_types/patterns/service.rb | 37 ++++++++++++++++++++++++++
 spec/lib/patterns/service_spec.rb   | 23 +++++++++++++++++
 4 files changed, 67 insertions(+), 34 deletions(-)
 create mode 100644 lib/power_types/patterns/service.rb
 create mode 100644 spec/lib/patterns/service_spec.rb

diff --git a/lib/power_types.rb b/lib/power_types.rb
index 2cf8652..65413d4 100644
--- a/lib/power_types.rb
+++ b/lib/power_types.rb
@@ -1,4 +1,5 @@
 require "power_types/version"
+require "power_types/patterns/service"
 require "power_types/patterns/command"
 
 module PowerTypes
diff --git a/lib/power_types/patterns/command.rb b/lib/power_types/patterns/command.rb
index 4d05dc1..e0b5dce 100644
--- a/lib/power_types/patterns/command.rb
+++ b/lib/power_types/patterns/command.rb
@@ -1,45 +1,17 @@
 module PowerTypes
   module Command
-    # rubocop:disable Metrics/MethodLength
     def self.new(*_attributes)
-      attr_names = []
-      attr_defaults = {}
-
-      _attributes.each do |att|
-        if att.is_a? Hash
-          attr_defaults.merge! att
-          attr_names += att.keys
-        else
-          attr_names << att
-        end
-      end
-
-      Class.new do
-        def self.for(kwargs = {})
-          new(kwargs).perform
-        end
-
-        def logger
-          Rails.logger
-        end
-
-        def perform
-          raise NotImplementedError, "Command must implement `perform`"
-        end
-
-        define_method(:initialize) do |kwargs = {}|
-          unless (kwargs.keys - attr_names).empty?
-            raise ArgumentError, "Unexpected arguments: #{(kwargs.keys - attr_names).join(', ')}"
+      Service.new(*_attributes).tap do |klass|
+        klass.class_eval do
+          def self.for(kwargs = {})
+            new(kwargs).perform
           end
 
-          kwargs = attr_defaults.merge kwargs
-          attr_names.map do |a|
-            raise ArgumentError, "Missing parameter: #{a}" unless kwargs.key? a
-            instance_variable_set "@#{a}", kwargs[a]
+          def perform
+            raise NotImplementedError, "Command must implement `perform`"
           end
         end
       end
     end
-    # rubocop:enable Metrics/MethodLength
   end
 end
diff --git a/lib/power_types/patterns/service.rb b/lib/power_types/patterns/service.rb
new file mode 100644
index 0000000..867b903
--- /dev/null
+++ b/lib/power_types/patterns/service.rb
@@ -0,0 +1,37 @@
+module PowerTypes
+  module Service
+    # rubocop:disable Metrics/MethodLength
+    def self.new(*_attributes)
+      attr_names = []
+      attr_defaults = {}
+
+      _attributes.each do |att|
+        if att.is_a? Hash
+          attr_defaults.merge! att
+          attr_names += att.keys
+        else
+          attr_names << att
+        end
+      end
+
+      Class.new do
+        def logger
+          Rails.logger
+        end
+
+        define_method(:initialize) do |kwargs = {}|
+          unless (kwargs.keys - attr_names).empty?
+            raise ArgumentError, "Unexpected arguments: #{(kwargs.keys - attr_names).join(', ')}"
+          end
+
+          kwargs = attr_defaults.merge kwargs
+          attr_names.map do |a|
+            raise ArgumentError, "Missing parameter: #{a}" unless kwargs.key? a
+            instance_variable_set "@#{a}", kwargs[a]
+          end
+        end
+      end
+    end
+    # rubocop:enable Metrics/MethodLength
+  end
+end
diff --git a/spec/lib/patterns/service_spec.rb b/spec/lib/patterns/service_spec.rb
new file mode 100644
index 0000000..ecae7c9
--- /dev/null
+++ b/spec/lib/patterns/service_spec.rb
@@ -0,0 +1,23 @@
+require 'spec_helper'
+
+describe PowerTypes::Service do
+  let(:service) do
+    Class.new(described_class.new(:foo, bar: nil)) do
+    end
+  end
+
+  describe "new" do
+    it "fails if argument it not declared in argument list" do
+      expect { service.new(teapot: 'bar') }.to raise_error(ArgumentError)
+    end
+
+    it "fails if required argument is not provided" do
+      expect { service.new(bar: 'bar') }.to raise_error(ArgumentError)
+    end
+
+    it { expect(service.new(foo: 'bar').instance_variable_defined?(:@foo)).to be true }
+    it { expect(service.new(foo: 'bar').instance_variable_defined?(:@bar)).to be true }
+    it { expect(service.new(foo: 'bar').instance_variable_defined?(:@fur)).to be false }
+    it { expect(service.new(foo: 'bar').instance_variable_get(:@foo)).to eq 'bar' }
+  end
+end