class JSONAPI::RelationshipsController

def active_storage_writable?(association)
  self.class.respond_to?(:active_storage_attachment?) &&
    active_storage_attachment?(@relationship_name, @resource.class) &&
    association.nil?
end

def destroy
  authorize_resource_action!(@resource, action: :update, context: { relationship: @relationship_name })
  relationship_data = parse_relationship_data
  return head :no_content if relationship_data.nil?
  remove_relationship(relationship_data)
  finalize_relationship_removal(relationship_data)
rescue ArgumentError => e
  render_invalid_relationship_error(e)
rescue JSONAPI::Errors::ParameterNotAllowed => e
  render_parameter_not_allowed_error(e)
end

def ensure_relationship_writable!(association)
  return if active_storage_writable?(association)
  relationship_def = find_relationship_definition
  readonly = relationship_def && (relationship_def[:options] || {})[:readonly] == true
  JSONAPI::RelationshipGuard.ensure_writable!(association, @relationship_name, readonly:)
end

def find_relationship_definition
  RelationshipHelpers.find_relationship_definition(@resource_class, @relationship_name)
end

def parse_relationship_data
  raw_data = params[:data]
  return nil if raw_data.nil?
  return [] if raw_data.is_a?(Array) && raw_data.empty?
  return raw_data.map { |item| ParamHelpers.deep_symbolize_params(item) } if raw_data.is_a?(Array)
  ParamHelpers.deep_symbolize_params(raw_data)
end

def polymorphic_association?
  RelationshipHelpers.polymorphic_association?(@resource_class, @relationship_name)
end

def set_relationship_name
  @relationship_name = params[:relationship_name].to_sym
end

def show
  authorize_resource_action!(@resource, action: :show, context: { relationship: @relationship_name })
  render json: build_show_response, status: :ok
end

def update
  authorize_resource_action!(@resource, action: :update, context: { relationship: @relationship_name })
  relationship_data = parse_relationship_data
  update_relationship(relationship_data)
  save_and_render_relationship(relationship_data)
rescue ArgumentError => e
  render_invalid_relationship_error(e)
rescue JSONAPI::Errors::ParameterNotAllowed => e
  render_parameter_not_allowed_error(e)
end

def validate_relationship_exists
  return if find_relationship_definition
  render_jsonapi_error(
    status: 404,
    title: "Relationship Not Found",
    detail: "Relationship '#{@relationship_name}' not found on #{@resource_name}",
  )
end