Implemented asiniy#18

.gitignore

@@ -5,3 +5,5 @@ erl_crash.dump
 *.ez
 .idea
 *.iml
+*.gv
+*.png

graphviz_example.exs

@@ -0,0 +1,10 @@
+
+# Generate and write Grpahviz file.
+IO.puts "ESM Config:"
+dot = Dummy.User.esm_config(:rules)
+  |> IO.inspect
+  |> EctoStateMachine.config_to_dot
+File.write!("dummy_user_rules.gv", dot)
+
+# Running dot to create PND
+System.cmd("dot", ["-Tpng", "dummy_user_rules.gv", "-o", "dummy_user_rules.png"])

lib/ecto_state_machine.ex

@@ -4,7 +4,9 @@ defmodule EctoStateMachine do
     states = Keyword.get(opts, :states)
     events = Keyword.get(opts, :events)
       |> Enum.map(fn(event) ->
-        Keyword.put_new(event, :callback, quote do: fn(model) -> model end)
+        event
+          |> Keyword.put(:is_custom_callback, Keyword.has_key?(event, :callback))
+          |> Keyword.put_new(:callback, quote do: fn(model) -> model end)
       end)
       |> Enum.map(fn(event) ->
         Keyword.update!(event, :callback, &Macro.escape/1)
@@ -43,6 +45,50 @@ defmodule EctoStateMachine do
             )
         end
       end
+
+      @doc "Returning the config from EctoStateMachine for given column atom."
+      def esm_config(unquote(column)) do
+        %{
+          module: __MODULE__,
+          column: unquote(column),
+          states: unquote(states),
+          events: unquote(events) |> Enum.map(&Enum.into(&1, %{})),
+        }
+      end
     end
   end
+
+  @doc """
+    Creating a GraphViz definition from a config given by esm_config.
+  """
+  def config_to_dot(%{module: module, column: column, states: states, events: events}) when states != [] do
+
+    transition_strings = events
+      |> Enum.flat_map(fn(%{from: states_from, name: transition_name, to: state_to, is_custom_callback: custom_callback}) ->
+        states_from
+          |> Enum.map(fn(state_from) ->
+            {transition_name, state_from, state_to, custom_callback}
+          end)
+      end)
+      |> Enum.map(fn({transition_name, state_from, state_to, custom_callback}) ->
+        case custom_callback do
+          true -> "#{state_from} -> #{state_to}  [style=\"bold\", label=< <B>#{transition_name}</B> >]"
+          false -> "#{state_from} -> #{state_to}  [label=<#{transition_name}>]"
+        end
+      end)
+
+    "digraph G {
+      // initial node
+      \"\" [shape=none];
+      \"\" -> \"#{states |> List.first}\";
+
+      // Transitions.
+      #{transition_strings |> Enum.join(" ; ")}
+
+      // title
+      labelloc=\"t\";
+      label=\"#{module} #{column}\";
+    }"
+  end
+
 end

test/ecto_state_machine_test.exs

@@ -93,4 +93,25 @@ defmodule EctoStateMachineTest do
       assert Dummy.User.can_make_admin?(context[:admin])            == false
     end
   end
+
+  describe "esm_config" do
+    it "can get config for :rules" do
+      assert match? %{
+        module: Dummy.User,
+        column: :rules,
+        events: [
+          %{from: [:unconfirmed], name: :confirm, to: :confirmed, callback: _, is_custom_callback: true},
+          %{from: [:confirmed, :admin], name: :block, to: :blocked, callback: _, is_custom_callback: false},
+          %{from: [:confirmed], name: :make_admin, to: :admin, callback: _, is_custom_callback: false},
+        ],
+        states: [:unconfirmed, :confirmed, :blocked, :admin]
+      }, Dummy.User.esm_config(:rules)
+    end
+  end
+
+  describe "config_to_dot" do
+    it "can convert config to dot" do
+      assert "digraph G {\n      // initial node\n      \"\" [shape=none];\n      \"\" -> \"unconfirmed\";\n\n      // Transitions.\n      unconfirmed -> confirmed  [style=\"bold\", label=< <B>confirm</B> >] ; confirmed -> blocked  [label=<block>] ; admin -> blocked  [label=<block>] ; confirmed -> admin  [label=<make_admin>]\n\n      // title\n      labelloc=\"t\";\n      label=\"Elixir.Dummy.User rules\";\n    }" == Dummy.User.esm_config(:rules) |> EctoStateMachine.config_to_dot
+    end
+  end
 end