Add history copying data migration

db/data/20200325084431_copy_old_history.rb

@@ -0,0 +1,73 @@
+class CopyOldHistory < ActiveRecord::Migration[5.1]
+  def up
+    models = %w[contact domain]
+    models.each do |model|
+      copy_history(model)
+    end
+  end
+
+  def down
+    # raise ActiveRecord::IrreversibleMigration
+  end
+
+  def copy_history(model)
+    old_history = "#{model.capitalize}Version".constantize.all
+    count, current = old_history.count, 1
+    puts "Proceeding #{count} entries of #{model.capitalize}Version"
+
+    new_history_class = "Audit::#{model.capitalize}".constantize
+
+    old_history.each do |old_history_entry|
+      puts "Proceeding #{current} #{model.capitalize}Version of #{count}"
+      process_old_history(new_history_class: new_history_class,
+                          old_history_entry: old_history_entry)
+      current += 1
+    end
+  end
+
+  private
+
+  def process_old_history(new_history_class:, old_history_entry:)
+    old_value = old_history_entry.object || {}
+    new_value = generate_new_value(old_history_entry&.object_changes) || {}
+    new_value['children'] = old_history_entry&.children
+    object_id = old_history_entry.item_id
+    action = generate_action(old_history_entry.event)
+    recorded_at = old_history_entry.created_at
+
+    attrs = { object_id: object_id, action: action, recorded_at: recorded_at, old_value: old_value,
+              new_value: new_value }
+
+    already_exist = new_history_class.find_by(recorded_at: recorded_at,
+                                              object_id: object_id).present?
+
+    if already_exist
+      puts "Already exists #{new_history_class} with object_id: #{object_id} "\
+           "and recorded_at: #{recorded_at}"
+    else
+      new_history_class.create(attrs) unless already_exist
+    end
+  end
+
+  def generate_new_value(object_changes)
+    hash = {}
+    return unless object_changes
+
+    object_changes.each do |key, value|
+      hash[key] = value[1]
+    end
+    hash
+  end
+
+  def generate_action(event)
+    case event
+    when 'create'
+      'INSERT'
+    when 'update'
+      'UPDATE'
+    else
+      'DELETE'
+    end
+  end
+
+end

db/data_schema.rb

@@ -1,2 +1,2 @@
 # encoding: UTF-8
-DataMigrate::Data.define(version: 20150707103801)
+DataMigrate::Data.define(version: 20200325084431)