anjlab/triggerable

module Triggerable
  module Conditions
    class Condition
      def self.build condition
        return Condition.new if condition.blank?
        return LambdaCondition.new(condition) if condition.is_a?(Proc)
        return MethodCondition.new(condition) if condition.is_a?(Symbol)

        key = condition.keys.first
        value = condition[key]

        if [:and, :or].include?(key)
          predicate_condition(key, value)
        else
          field_condition(key, value)
        end
      end

      def true_for?(object); true; end

      def scope; ''; end

      private

      def self.predicate_condition class_name, value
        condition_class(class_name).new(value)
      end

      def self.field_condition field, value
        if value.is_a?(Array)
          In.new(field, value)
        elsif value.is_a?(Hash)
          condition_class(value.keys.first).new(field, value.values.first)
        else
          Is.new(field, value)
        end
      end

      def self.condition_class sym
        "Triggerable::Conditions::#{sym.to_s.camelize}".constantize
      end
    end
  end
end