CLOSER-Cohorts/archivist

# frozen_string_literal: true

# The CodeList is based on the CodeList model from DDI3.X
#
# A CodeList has a label and typically pulls together multiple {Code Codes} to
# create either a {QuestionGrid} axis or a {ResponseDomain}.
#
# Please visit http://www.ddialliance.org/Specification/DDI-Lifecycle/3.2/XMLSchema/FieldLevelDocumentation/schemas/logicalproduct_xsd/elements/CodeList.html
#
# === Properties
# * Label
class CodeList < ApplicationRecord
  # This model is exportable as DDI
  include Exportable

  # This model can be tracked using an Identifier
  include Identifiable

  # Used to create CLOSER UserID and URNs
  URN_TYPE = 'cl'

  # XML tag name
  TYPE = 'CodeList'

  validates :label, uniqueness: {scope: :instrument_id}

  # Before creating a new model in the database, check whether this would be a duplicate
  before_create :no_duplicates

  # All categories must belong to an instrument
  belongs_to :instrument

  # Each CodeList can have multiple {Code Codes}
  has_many :codes, -> { includes(:category).order('"order" ASC') }, dependent: :destroy, inverse_of: :code_list

  # Each CodeList can have multiple {Category Categories} through a {Code} as a
  # many-to-many relationship
  has_many :categories, through: :codes

  # Every {QuestionGrid} where this CodeList was used as a horizontal axis
  #
  # Horizontal axis is considered to be rank 2 in DDI
  has_many :qgrids_via_h, class_name: 'QuestionGrid', foreign_key: 'horizontal_code_list_id', dependent: :destroy

  # Every {QuestionGrid} where this CodeList was used as a vertical axis
  #
  # Vertical axis is considered to be rank 1 in DDI
  has_many :qgrids_via_v, class_name: 'QuestionGrid', foreign_key: 'vertical_code_list_id', dependent: :destroy

  # Each CodeList can optionally be represented as a {ResponseDomainCode}
  has_one :response_domain_code, dependent: :destroy, inverse_of: :code_list

  # Because of Foreign key constraints we need to ensure that all ResponseDomainCodes
  # are removed even if they've been created in error.
  has_many :response_domain_codes, dependent: :destroy

  # Accept nested attributes for Codes so that we can manage associated
  # Codes from within a CodeList form.
  accepts_nested_attributes_for :codes, :response_domain_code, allow_destroy: true

  validates :label, presence: true, uniqueness: {scope: :instrument_id}

  # Returns all the {QuestionGrid QuestionGrids} that this CodeList has been
  # used as an axis in
  #
  # @return [Array]
  def question_grids
    self.qgrids_via_h.to_a + self.qgrids_via_v.to_a
  end

  # Gets the associatedd {ResponseDomainCode}
  #
  # Returns nil if CodeList is not also a {ResponseDomain}
  #
  # @return [ResponseDomainCode]
  def response_domain
    self.response_domain_code
  end

  # Sets wheather CodeList should be a {ResponseDomainCode}
  #
  # @param [Object] be_code_answer True/False whether CodeList should be used as a {ResponseDomain}
  def response_domain=(be_code_answer)
    if be_code_answer && response_domain.nil?
      self.response_domain_code = ResponseDomainCode.new instrument_id: self.instrument_id
    end

    unless be_code_answer || response_domain.nil?
      self.response_domain_code.delete
    end
  end

  # Returns an array of all objects that use this CodeList
  #
  # @return [Array]
  def used_by
    if self.response_domain.nil?
      self.question_grids
    else
      self.response_domain.questions + self.question_grids
    end
  end

  private # Private methods

  # Checks whether the CodeList label is already in use
  #
  # If the label is already in use then '_dup' is added and the process
  # is repeated until the CodeList can be created.
  def no_duplicates
    until self.instrument.code_lists.find_by_label(self.label).nil?
      self.label += '_dup'
    end
  end
end