module Evvnt
  # Internal: Methods for defining API actions for each resource Class.
  #
  module Actions
    ##
    # The first record from the API index actions
    #
    # Returns {Evvnt::Base} subclass
    def first
      defined_actions.include?(:index) ? all.first : method_missing(:first)
    end

    ##
    # The last record from the API index actions
    #
    # Returns {Evvnt::Base} subclass
    def last
      defined_actions.include?(:index) ? all.first : method_missing(:last)
    end

    private

    ##
    # A list of the API actions defined on this class
    #
    # Returns Array
    def defined_actions
      @defined_actions ||= []
    end

    ##
    # Define an action for this class to map on to the Evvnt API for this class's
    # resource.
    #
    # action - A Symbol or String representing the action name. Should be one of the
    #          template actions if block is not provided.
    # block  - A Proc to be used as the action method definition when custom behaviour
    #          is required.
    #
    # Examples
    #
    #   class Package < Evvnt::Base
    #     # Define using the template `all` method
    #     define_action :all
    #     define_action :mine do
    #       # define the custom behaviour here
    #     end
    #   end
    #
    # Returns Symbol
    def define_action(action, &block)
      action = action.to_sym
      defined_actions << action unless defined_actions.include?(action)
      if action.in?(Evvnt::ClassTemplateMethods.instance_methods)
        define_class_action(action, &block)
      end
      if action.in?(Evvnt::InstanceTemplateMethods.instance_methods)
        define_instance_action(action, &block)
      end
      action
    end

    # Define a class-level action on the current class. See {define_action}.
    def define_class_action(action, &block)
      body = block_given? ? block : ClassTemplateMethods.instance_method(action)
      define_singleton_method(action, body)
      singleton_class.send(:alias_method, :all, :index) if action == :index
      singleton_class.send(:alias_method, :find, :show) if action == :show
    end

    # Define an instance-level action on the current class. See {define_action}.
    def define_instance_action(action, &block)
      body = block_given? ? block : InstanceTemplateMethods.instance_method(action)
      define_method(action, body)
    end
  end
end