module Surveyor
  module Models
    module ValidationMethods
      def self.included(base)
        # Associations
        base.send :belongs_to, :answer
        base.send :has_many, :validation_conditions, :dependent => :destroy

        # Scopes

        # Validations
        base.send :validates_presence_of, :rule
        base.send :validates_format_of, :rule, :with => /^(?:and|or|\)|\(|[A-Z]|\s)+$/
        # this causes issues with building and saving
        # base.send :validates_numericality_of, :answer_id
      end

      # Instance Methods
      def is_valid?(response_set)
        ch = conditions_hash(response_set)
        rgx = Regexp.new(self.validation_conditions.map{|vc| ["a","o"].include?(vc.rule_key) ? "#{vc.rule_key}(?!nd|r)" : vc.rule_key}.join("|")) # exclude and, or
        # logger.debug "v: #{self.inspect}"
        # logger.debug "rule: #{self.rule.inspect}"
        # logger.debug "rexp: #{rgx.inspect}"
        # logger.debug "keyp: #{ch.inspect}"
        # logger.debug "subd: #{self.rule.gsub(rgx){|m| ch[m.to_sym]}}"
        eval(self.rule.gsub(rgx){|m| ch[m.to_sym]})
      end

      # A hash of the conditions (keyed by rule_key) and their evaluation (boolean) in the context of response_set
      def conditions_hash(response_set)
        hash = {}
        response = response_set.responses.detect{|r| r.answer_id.to_i == self.answer_id.to_i}
        # logger.debug "r: #{response.inspect}"
        self.validation_conditions.each{|vc| hash.merge!(vc.to_hash(response))}
        return hash
      end
    end
  end
end