Add rake task for fixing invalid canvas positions

lib/tasks/my_modules.rake

@@ -0,0 +1,40 @@
+# frozen_string_literal: true
+
+# On production around 2k records for repair, for production DB it tooked cca 1 min
+
+# rubocop:disable Metrics/BlockLength
+namespace :my_modules do
+  desc 'Find new positions on canvas for already taken coordiantes'
+  task fix_positions: :environment do
+    query = MyModule.select('COUNT(*) as duplicates', :x, :y, :experiment_id)
+                    .where(archived: false)
+                    .group(:x, :y, :experiment_id)
+                    .having('COUNT(*)>1')
+
+    Rails.logger.info '*********************************************************************************'
+    Rails.logger.info "You have to relocate #{query.sum { |a| a.duplicates - 1 }} tasks"
+    Rails.logger.info '*********************************************************************************'
+
+    query.each do |row|
+      tasks_to_update = MyModule.where(experiment_id: row.experiment, x: row.x, y: row.y, archived: false)
+                                .order(created_at: :asc)
+                                .offset(1)
+
+      tasks_to_update.find_each do |task|
+        coordinates = task.get_new_position
+        task.attributes = coordinates
+        begin
+          task.save!
+          Rails.logger.info "Relocated task with ID #{task.id}"
+        rescue ActiveRecord::RecordInvalid => e
+          Rails.logger.error "Unable to save task with ID #{task.id}: #{e.message}"
+        end
+      end
+    end
+
+    Rails.logger.info '*********************************************************************************'
+    Rails.logger.info "You have #{query.reload.sum { |a| a.duplicates - 1 }} tasks on invalid positions"
+    Rails.logger.info '*********************************************************************************'
+  end
+end
+# rubocop:enable Metrics/BlockLength

spec/lib/tasks/my_modules_spec.rb

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+# frozen_string_literal: true
+
+require 'rails_helper'
+
+describe 'my_modules:fix_positions' do
+  include_context 'rake'
+
+  before(:all) do
+    experiment = create :experiment
+
+    100.times do
+      create :my_module, experiment: experiment
+    end
+
+    # set 30 tasks same position
+    my_modules_with_same_position = MyModule.limit(10)
+    my_modules_with_same_position.update_all(x: 0, y: 0)
+
+    # 1 module should be invalid
+    my_modules_with_same_position.second.update_column(:name, 'a')
+
+    my_modules_with_same_position.third.update_column(:archived, true)
+  end
+  context 'when record is valid except position' do
+    it 'changes position for my_module' do
+      expect { subject.invoke }.to(change { MyModule.find(5).y })
+    end
+  end
+
+  context 'when record is invalid' do
+    it 'remains error on position' do
+      subject.invoke
+      my_module = MyModule.find_by(name: 'a')
+      my_module.valid?
+
+      expect(my_module.errors.messages[:position])
+        .to(eq ['and Y position has already been taken by another task in the experiment.'])
+    end
+  end
+end