supporting instance level inspection for states (including permissible state, see issue #54)

CHANGELOG.md

@@ -2,7 +2,7 @@
 
 ## Unreleased
 
- * supporting instance level inspection for states
+ * supporting instance level inspection for states (including permissible state, see issue #54)
  * added autocreation of constants for each state ([@jherdman](https://github.com/jherdman))
 
 ## 3.0.16

README.md

@@ -304,7 +304,7 @@ class AddJobState < ActiveRecord::Migration
 end
 ```
 
-## Inspection ##
+## <a id="inspection">Inspection
 
 AASM supports a couple of methods to find out which states or events are provided or permissible.
 
@@ -316,6 +316,12 @@ job = Job.new
 job.states
 => [:sleeping, :running, :cleaning]
 
+job.states(:permissible => true)
+=> [:running]
+job.run
+job.states(:permissible => true)
+=> [:cleaning, :sleeping]
+
 job.events
 => [:run, :clean, :sleep]
 ```

lib/aasm/instance_base.rb

@@ -30,8 +30,15 @@ module AASM
       AASM::Localizer.new.human_state_name(@instance.class, current_state)
     end
 
-    def states
-      @instance.class.aasm.states
+    def states(options={})
+      if options[:permissible]
+        # ugliness level 1000
+        transitions = @instance.class.aasm.events.values.map {|e| e.transitions_from_state(current_state) }
+        tos = transitions.map {|t| t[0] ? t[0].to : nil}.flatten.compact.map(&:to_sym).uniq
+        @instance.class.aasm.states.select {|s| tos.include?(s.name.to_sym)}
+      else
+        @instance.class.aasm.states
+      end
     end
 
     # QUESTION: shouldn't events and permissible_events be the same thing?

spec/models/foo.rb

@@ -5,11 +5,11 @@ class Foo
     state :closed, :enter => :enter
 
     event :close, :success => :success_callback do
-      transitions :to => :closed, :from => [:open]
+      transitions :from => [:open], :to => [:closed]
     end
 
     event :null do
-      transitions :to => :closed, :from => [:open], :guard => :always_false
+      transitions :from => [:open], :to => :closed, :guard => :always_false
     end
   end
 

spec/unit/inspection_spec.rb

@@ -28,15 +28,37 @@ describe 'inspection for common cases' do
   end
 
   context "instance level inspection" do
+    let(:foo) { Foo.new }
+    let(:two) { FooTwo.new }
+
     it "delivers all states" do
-      foo = Foo.new
       states = foo.aasm.states
       states.should include(:open)
       states.should include(:closed)
+
+      states = foo.aasm.states(:permissible => true)
+      states.should include(:closed)
+      states.should_not include(:open)
+
+      foo.close
+      foo.aasm.states(:permissible => true).should be_empty
+    end
+
+    it "delivers all states for subclasses" do
+      states = two.aasm.states
+      states.should include(:open)
+      states.should include(:closed)
+      states.should include(:foo)
+
+      states = two.aasm.states(:permissible => true)
+      states.should include(:closed)
+      states.should_not include(:open)
+
+      two.close
+      two.aasm.states(:permissible => true).should be_empty
     end
 
     it "delivers all events" do
-      foo = Foo.new
       events = foo.aasm.events
       events.should include(:close)
       events.should include(:null)