scinote-web/app/models/repository_row_connection.rb

# frozen_string_literal: true

class RepositoryRowConnection < ApplicationRecord
  belongs_to :parent,
             class_name: 'RepositoryRow',
             inverse_of: :child_connections,
             counter_cache: :child_connections_count
  belongs_to :child,
             class_name: 'RepositoryRow',
             inverse_of: :parent_connections,
             counter_cache: :parent_connections_count
  belongs_to :created_by, class_name: 'User'
  belongs_to :last_modified_by, class_name: 'User'

  validates :parent_id, uniqueness: { scope: :child_id }
  validate :prevent_self_connections, :prevent_reciprocal_connections

  private

  def prevent_self_connections
    errors.add(:base, 'A repository_row cannot have a connection with itself') if parent_id == child_id
  end

  def prevent_reciprocal_connections
    if parent_id && child_id && RepositoryRowConnection.exists?(parent_id: child_id, child_id: parent_id)
      errors.add(:base, 'Reciprocal connections are not allowed')
    end
  end
end