piotrmurach/finite_machine

# frozen_string_literal: true

module FiniteMachine
  # A generic interface for executing strings, symbol methods or procs.
  class Callable

    attr_reader :object

    # Initialize a Callable
    #
    # @param [Symbol, String, Proc] object
    #   the callable object
    #
    # @api public
    def initialize(object)
      @object = object
    end

    # Invert callable
    #
    # @api public
    def invert
      ->(*args, &block) { !call(*args, &block) }
    end

    # Execute action
    #
    # @param [Object] target
    #
    # @api public
    def call(target, *args, &block)
      case object
      when Symbol
        target.public_send(object.to_sym, *args, &block)
      when String
        string = args.empty? ? "-> { #{object} }" : "-> { #{object}(*#{args}) }"
        value  = eval(string)
        target.instance_exec(&value)
      when ::Proc
        object.arity.zero? ? object.call : object.call(target, *args)
      else
        raise ArgumentError, "Unknown callable #{object}"
      end
    end
  end # Callable
end # FiniteMachine