module Authlogic
  module Session
    # Between these callbacks and the configuration, this is the contract between me and
    # you to safely modify Authlogic's behavior. I will do everything I can to make sure
    # these do not change.
    #
    # Check out the sub modules of Authlogic::Session. They are very concise, clear, and
    # to the point. More importantly they use the same API that you would use to extend
    # Authlogic. That being said, they are great examples of how to extend Authlogic and
    # add / modify behavior to Authlogic. These modules could easily be pulled out into
    # their own plugin and become an "add on" without any change.
    #
    # Now to the point of this module. Just like in ActiveRecord you have before_save,
    # before_validation, etc. You have similar callbacks with Authlogic, see the METHODS
    # constant below. The order of execution is as follows:
    #
    #   before_persisting
    #   persist
    #   after_persisting
    #   [save record if record.changed?]
    #
    #   before_validation
    #   before_validation_on_create
    #   before_validation_on_update
    #   validate
    #   after_validation_on_update
    #   after_validation_on_create
    #   after_validation
    #   [save record if record.changed?]
    #
    #   before_save
    #   before_create
    #   before_update
    #   after_update
    #   after_create
    #   after_save
    #   [save record if record.changed?]
    #
    #   before_destroy
    #   [save record if record.changed?]
    #   destroy
    #   after_destroy
    #
    # Notice the "save record if changed?" lines above. This helps with performance. If
    # you need to make changes to the associated record, there is no need to save the
    # record, Authlogic will do it for you. This allows multiple modules to modify the
    # record and execute as few queries as possible.
    #
    # **WARNING**: unlike ActiveRecord, these callbacks must be set up on the class level:
    #
    #   class UserSession < Authlogic::Session::Base
    #     before_validation :my_method
    #     validate :another_method
    #     # ..etc
    #   end
    #
    # You can NOT define a "before_validation" method, this is bad practice and does not
    # allow Authlogic to extend properly with multiple extensions. Please ONLY use the
    # method above.
    module Callbacks
      METHODS = %w[
        before_persisting
        persist
        after_persisting
        before_validation
        before_validation_on_create
        before_validation_on_update
        validate
        after_validation_on_update
        after_validation_on_create
        after_validation
        before_save
        before_create
        before_update
        after_update
        after_create
        after_save
        before_destroy
        after_destroy
      ].freeze

      class << self
        def included(base) #:nodoc:
          base.send :include, ActiveSupport::Callbacks
          define_session_callbacks(base)
          define_session_callback_installation_methods(base)
        end

        private

        # Defines the "callback installation methods". Other modules will use
        # these class methods to install their callbacks. Examples:
        #
        # ```
        # # session/timeout.rb, in `included`
        # before_persisting :reset_stale_state
        #
        # # session/password.rb, in `included`
        # validate :validate_by_password, if: :authenticating_with_password?
        # ```
        def define_session_callback_installation_methods(base)
          METHODS.each do |method|
            base.class_eval <<-EOS, __FILE__, __LINE__ + 1
              def self.#{method}(*filter_list, &block)
                set_callback(:#{method}, *filter_list, &block)
              end
            EOS
          end
        end

        # Defines session life cycle events that support callbacks.
        def define_session_callbacks(base)
          if Gem::Version.new(ActiveSupport::VERSION::STRING) >= Gem::Version.new("5")
            base.define_callbacks(
              *METHODS,
              terminator: ->(_target, result_lambda) { result_lambda.call == false }
            )
            base.define_callbacks(
              "persist",
              terminator: ->(_target, result_lambda) { result_lambda.call == true }
            )
          else
            base.define_callbacks(
              *METHODS,
              terminator: ->(_target, result) { result == false }
            )
            base.define_callbacks(
              "persist",
              terminator: ->(_target, result) { result == true }
            )
          end
        end
      end

      METHODS.each do |method|
        class_eval <<-EOS, __FILE__, __LINE__ + 1
            def #{method}
              run_callbacks(:#{method})
            end
          EOS
      end

      def save_record(alternate_record = nil)
        r = alternate_record || record
        r.save_without_session_maintenance(validate: false) if r && r.changed? && !r.readonly?
      end
    end
  end
end