# frozen_string_literal: true

module IIIFManifest
  ##
  # Handles configuration for the IIIFManifest gem
  #
  # @see IIIFManifest.config
  class Configuration
    DEFAULT_MANIFEST_PROPERTY_TO_RECORD_METHOD_NAME_MAP = {
      summary: :description, # for V3 manifests
      description: :description, # for V2 manifests
      label: :to_s,
      rights: :rights_statement,
      homepage: :homepage
    }.freeze

    ##
    # @!attribute [w] manifest_property_to_record_method_name_map
    #   @param value [Hash<Symbol, Symbol>]
    #   @return [Hash<Symbol, Symbol>]
    attr_writer :manifest_property_to_record_method_name_map
    # Used to map a record's public method to a manifest property.
    # @see manifest_value_for
    # @see DEFAULT_MANIFEST_PROPERTY_TO_RECORD_METHOD_NAME_MAP DEFAULT_MANIFEST_PROPERTY_TO_RECORD_METHOD_NAME_MAP
    #   are the default values
    # @return [Hash<Symbol, Symbol>]
    def manifest_property_to_record_method_name_map
      # the constant is frozen but we need to be able to configure something unfrozen
      @manifest_property_to_record_method_name_map ||= DEFAULT_MANIFEST_PROPERTY_TO_RECORD_METHOD_NAME_MAP.dup
    end

    ##
    # @param value [Integer]
    attr_writer :max_edge_for_thumbnail
    # Used to set max edge length for thumbnail generation.
    # @return [Integer]
    def max_edge_for_thumbnail
      return @max_edge_for_thumbnail unless @max_edge_for_thumbnail.nil?
      @max_edge_for_thumbnail = 200
    end

    attr_writer :manifest_thumbnail
    # Used to configure whether or not to show the manifest thumbnail property.
    # @return [Boolean]
    def manifest_thumbnail
      return @manifest_thumbnail unless @manifest_thumbnail.nil?
      @manifest_thumbnail = true
    end

    ##
    # @api private
    # @param record [Object] has the value for the :property we want to set
    # @param property [Symbol] IIIF manifest property
    # @return [NilClass] the record does not have a value for the given property
    # @return [#to_s] the record has a value that is "present"
    def manifest_value_for(record, property:)
      method_name = map_property_to_method_name(property: property)
      return nil unless record.respond_to?(method_name)
      record.public_send(method_name)
    end

    private

    def map_property_to_method_name(property:)
      manifest_property_to_record_method_name_map.fetch(property)
    end
  end
end