move acts_as_list to backlogs_list which wraps acts_as_list (scoped to :project) and also has a custom move_after method. Impediment and Story include backlogs_list

* move_after method silently updates position on elements without a position

app/models/impediment.rb

@@ -1,7 +1,10 @@
+require_dependency 'backlogs_list'
+
 class Impediment < Task
   unloadable
 
-  acts_as_list :scope => :project
+  include Backlogs::List
+  acts_as_backlogs_list(Setting.plugin_redmine_backlogs[:task_tracker])
 
   after_save :update_blocks_list
 
@@ -40,38 +43,6 @@ class Impediment < Task
     @blocks_ids_list ||= relations_from.select{ |rel| rel.relation_type == IssueRelation::TYPE_BLOCKS }.collect(&:issue_to_id)
   end
 
-  def move_after(prev_id)
-    #our super's, move after is using awesome_nested_set which is inapproriate for impediments.
-    #Impediments always have a parent_id of nil, it is their defining criteria.
-    #Therefore we use the acts_as_list method
-    #TODO: create a module to be included by story and impediment, for now this code is just copy&paste
-
-    # remove so the potential 'prev' has a correct position
-    remove_from_list
-
-    begin
-      prev = self.class.find(prev_id)
-    rescue ActiveRecord::RecordNotFound
-      prev = nil
-    end
-
-    # if it's the first story, move it to the 1st position
-    if prev.blank?
-      insert_at
-      move_to_top
-
-    # if its predecessor has no position (shouldn't happen), make it
-    # the last story
-    elsif !prev.in_list?
-      insert_at
-      move_to_bottom
-
-    # there's a valid predecessor
-    else
-      insert_at(prev.position + 1)
-    end
-  end
-
   private
 
   def update_blocks_list

app/models/story.rb

@@ -1,7 +1,10 @@
+require_dependency 'backlogs_list'
+
 class Story < Issue
     unloadable
 
-    acts_as_list :scope => :project
+    include Backlogs::List
+    acts_as_backlogs_list(Setting.plugin_redmine_backlogs[:story_trackers])
 
     def self.condition(project_id, sprint_id, extras=[])
       if sprint_id.nil?
@@ -95,33 +98,6 @@ class Story < Issue
       end
     end
 
-    def move_after(prev_id)
-      # remove so the potential 'prev' has a correct position
-      remove_from_list
-
-      begin
-        prev = self.class.find(prev_id)
-      rescue ActiveRecord::RecordNotFound
-        prev = nil
-      end
-
-      # if it's the first story, move it to the 1st position
-      if prev.blank?
-        insert_at
-        move_to_top
-
-      # if its predecessor has no position (shouldn't happen), make it
-      # the last story
-      elsif !prev.in_list?
-        insert_at
-        move_to_bottom
-
-      # there's a valid predecessor
-      else
-        insert_at(prev.position + 1)
-      end
-    end
-
     def set_points(p)
         self.init_journal(User.current)
 

lib/backlogs_list.rb

@@ -0,0 +1,68 @@
+module Backlogs
+  module List
+    unloadable
+
+    def self.included(base)
+      base.send(:include, InstanceMethods)
+      base.send(:extend, ClassMethods)
+    end
+
+    module ClassMethods
+      def acts_as_backlogs_list(trackers)
+        self.class_eval do
+          acts_as_list :scope => :project #TODO: consider changing the scope to project, version and tracker
+          @trackers = trackers
+        end
+      end
+    end
+
+    module InstanceMethods
+      def move_after(prev_id)
+        # remove so the potential 'prev' has a correct position
+        remove_from_list
+
+        begin
+          prev = self.class.find(prev_id)
+        rescue ActiveRecord::RecordNotFound
+          prev = nil
+        end
+
+        # if it's the first story, move it to the 1st position
+        if prev.blank?
+          insert_at
+          move_to_top
+
+        # if its predecessor has no position, create an order on position silently.
+        # This can happen when sorting inside a version for the first time after backlogs was activated
+        # and there have already been items inside the version at the time of backlogs activation
+        elsif !prev.in_list?
+          prev_pos = set_default_prev_positions_silently(prev)
+          insert_at(prev_pos += 1)
+
+        # there's a valid predecessor
+        else
+          insert_at(prev.position + 1)
+        end
+      end
+
+      private
+      def set_default_prev_positions_silently(prev)
+        stories = self.class.find(:all, :conditions => {:fixed_version_id => self.fixed_version_id, :tracker_id => @trackers})
+
+        self.class.record_timestamps = false #temporarily turn off column updates
+
+        highest_pos = stories.sort_by{|s| s.position ? s.position : 0}.collect(&:position).last
+        highest_pos = 0 if highest_pos.nil?
+
+        stories.sort_by { |s| s.id }.each do |story|
+          next if story.in_list? || story.id > prev.id || self.id == story.id
+          story.insert_at(highest_pos += 1)
+        end
+
+        self.class.record_timestamps = true #turning updates back on
+
+        highest_pos
+      end
+    end
+  end
+end