SpeciesFileGroup/taxonworks

# An OriginRelationship asserts that one object is derived_from another.
#
# The old object is the source_of or origin_of the new object.
# The new object originates_from the old_object.
#
# Currently these combinations are planned (* not implemented):
#
# old_object / new_object
#
# * field_observation / collection_object
# collection_object / collection_object
# collection_object / extract
# * collection_object / part_of (anatomy)
# * part_of / part_of
# * part_of / extract
# extract / extract
# extract / sequence
# sequence / sequence
#
# @!attribute old_object_id
#   @return [Integer]
#     id of the old (original) object
#
# @!attribute old_object_type
#   @return [Integer]
#     type of the old (original) object
#
# @!attribute new_object_id
#   @return [Integer]
#     id of the new (original) object
#
# @!attribute new_object_type
#   @return [Integer]
#     type of the new (original) object
#
# @!attribute position
#   @return [Integer]
#     order relative to old object
#
# @!attribute project_id
#   @return [Integer]
#     the project ID
#
class OriginRelationship < ApplicationRecord
  include Housekeeping
  include Shared::IsData
  include Shared::PolymorphicAnnotator

  polymorphic_annotates('old_object', presence_validate: false)
  polymorphic_annotates('new_object', presence_validate: false)

  acts_as_list scope: [:project_id, :old_object_id, :old_object_type]

  belongs_to :old_object, polymorphic: true
  belongs_to :new_object, polymorphic: true

  # The two validations, and the inclusion of the Shared::OriginRelationship code
  # ensure that new/old objects are indeed ones that are allowed (otherwise we will get Raises, which means the UI is messed up)
  validates_presence_of :new_object
  validates_presence_of :old_object

  validate :old_object_responds
  validate :new_object_responds
  validate :pairing_is_allowed, unless: -> {!errors.empty?}

  validate :not_a_clone

  private

  def old_object_responds
    errors.add(:old_object, "#{old_object.class.name} is not a legal part of an origin relationship") if !(old_object.class < Shared::OriginRelationship)
  end

  def new_object_responds
    errors.add(:new_object, "#{new_object.class.name} is not a legal part of an origin relationship") if !(new_object.class < Shared::OriginRelationship)
  end

  def pairing_is_allowed
    errors.add(:old_object, "#{old_object_type} is not a valid origin relationship old object of a #{old_object.class.name}") if !new_object.valid_old_object_classes.include?(old_object.class.name)
    errors.add(:new_object, "#{new_object_type} is not a valid origin relationship new object of a #{new_object.class.name}") if !old_object.valid_new_object_classes.include?(new_object.class.name)
  end

  def not_a_clone
    if (old_object == new_object) || ((old_object_type == new_object_type) && (old_object_id == new_object_id))
      errors.add(:old_object, 'objects can not be cloned (related to each other)')
    end
  end

end