Extract behavior from Todo.from_rich_message

`Todo.from_rich_message` was partially tested from the MessageGateway,
but it is mostly untested and does not belong in Todo due to it's unique
nature. Extract it entirely from `Todo` into it's own dedicated object
for unit testing.

app/models/message_gateway.rb

@@ -23,7 +23,8 @@ class MessageGateway < ActionMailer::Base
       end
     end
 
-    todo = Todo.from_rich_message(user, context.id, description, notes)
+    todo_builder = TodoFromRichMessage.new(user, context.id, description, notes)
+    todo = todo_builder.construct
     todo.save!
     Rails.logger.info "Saved email as todo for user #{user.login} in context #{context.name}"
   end

app/models/todo.rb

@@ -381,48 +381,6 @@ class Todo < ActiveRecord::Base
     end
   end
 
-  # Rich Todo API
-  def self.from_rich_message(user, default_context_id, description, notes)
-    fields = description.match(/([^>@]*)@?([^>]*)>?(.*)/)
-    description = fields[1].strip
-    context = fields[2].strip
-    project = fields[3].strip
-
-    context = nil if context == ""
-    project = nil if project == ""
-
-    context_id = default_context_id
-    unless(context.nil?)
-      found_context = user.contexts.active.where("name like ?", "%#{context}%").first
-      found_context = user.contexts.where("name like ?", "%#{context}%").first if !found_context
-      context_id = found_context.id if found_context
-    end
-
-    unless user.contexts.exists? context_id
-      raise(CannotAccessContext, "Cannot access a context that does not belong to this user.")
-    end
-
-    project_id = nil
-    unless(project.blank?)
-      if(project[0..3].downcase == "new:")
-        found_project = user.projects.build
-        found_project.name = project[4..255+4].strip
-        found_project.save!
-      else
-        found_project = user.projects.active.find_by_namepart(project)
-        found_project = user.projects.find_by_namepart(project) if found_project.nil?
-      end
-      project_id = found_project.id unless found_project.nil?
-    end
-
-    todo = user.todos.build
-    todo.description = description
-    todo.raw_notes = notes
-    todo.context_id = context_id
-    todo.project_id = project_id unless project_id.nil?
-    return todo
-  end
-
   def render_note
     unless self.notes.nil?
       self.rendered_notes = Tracks::Utils.render_text(self.notes)

app/models/todo_from_rich_message.rb

@@ -0,0 +1,78 @@
+class TodoFromRichMessage
+
+  class RichMessageExtractor
+
+    RICH_MESSAGE_FIELDS_REGEX = /([^>@]*)@?([^>]*)>?(.*)/
+
+    def initialize(message)
+      @message = message
+    end
+
+    def description
+      fields[1].strip
+    end
+
+    def context
+      fields[2].strip
+    end
+
+    def project
+      stripped = fields[3].strip
+      stripped.blank? ? nil : stripped
+    end
+
+    private
+
+      def fields
+        @message.match(RICH_MESSAGE_FIELDS_REGEX)
+      end
+
+  end
+
+  attr_reader :user, :default_context_id, :description, :notes
+
+  def initialize(user, default_context_id, description, notes)
+    @user = user
+    @default_context_id = default_context_id
+    @description = description
+    @notes = notes
+  end
+
+  def construct
+    extractor   = RichMessageExtractor.new(description)
+    description = extractor.description
+    context     = extractor.context
+    project     = extractor.project
+
+    context_id = default_context_id
+    unless context.blank?
+      found_context = user.contexts.active.where("name like ?", "%#{context}%").first
+      found_context = user.contexts.where("name like ?", "%#{context}%").first if !found_context
+      context_id = found_context.id if found_context
+    end
+
+    unless user.context_ids.include? context_id
+      raise(CannotAccessContext, "Cannot access a context that does not belong to this user.")
+    end
+
+    project_id = nil
+    unless project.blank?
+      if project[0..3].downcase == "new:"
+        found_project = user.projects.build
+        found_project.name = project[4..259].strip
+        found_project.save!
+      else
+        found_project = user.projects.active.find_by_namepart(project)
+        found_project = user.projects.find_by_namepart(project) if found_project.nil?
+      end
+      project_id = found_project.id unless found_project.nil?
+    end
+
+    todo = user.todos.build
+    todo.description = description
+    todo.raw_notes = notes
+    todo.context_id = context_id
+    todo.project_id = project_id unless project_id.nil?
+    todo
+  end
+end

test/models/todo_from_rich_message_test.rb

@@ -0,0 +1,21 @@
+require File.expand_path(File.dirname(__FILE__) + '/../test_helper')
+
+class TodoFromRichMessageTest < ActiveSupport::TestCase
+
+  def setup
+    @completed = Todo.find(8)
+  end
+
+  def test_from_rich_message_adds_to_default_context
+    user = @completed.user
+    default_context_id = @completed.context_id
+    builder = TodoFromRichMessage.new(user, default_context_id, "new todo", "notes")
+    new_todo = builder.construct
+
+    assert_not_nil new_todo
+    assert_equal "new todo", new_todo.description
+    assert_equal "notes", new_todo.notes
+    assert_equal default_context_id, new_todo.context_id
+  end
+
+end

test/models/todo_test.rb

@@ -477,15 +477,4 @@ class TodoTest < ActiveSupport::TestCase
     assert_equal "<p><strong>test</strong></p>", todo.rendered_notes
   end
 
-  def test_from_rich_message_adds_to_default_context
-    user = @completed.user
-    default_context_id = @completed.context_id
-    new_todo = Todo::from_rich_message(user, default_context_id, "new todo", "notes")
-
-    assert_not_nil new_todo
-    assert_equal "new todo", new_todo.description
-    assert_equal "notes", new_todo.notes
-    assert_equal default_context_id, new_todo.context_id
-  end
-  
 end