activerecord-hackery--ransack/lib/ransack/nodes/condition.rb

module Ransack
  module Nodes
    class Condition < Node
      i18n_word :attribute, :predicate, :combinator, :value
      i18n_alias :a => :attribute, :p => :predicate,
                 :m => :combinator, :v => :value

      attr_accessor :predicate

      class << self
        def extract(context, key, values)
          attributes, predicate = extract_attributes_and_predicate(key)
          if attributes.size > 0 && predicate
            combinator = key.match(/_(or|and)_/) ? $1 : nil
            condition = self.new(context)
            condition.build(
              :a => attributes,
              :p => predicate.name,
              :m => combinator,
              :v => predicate.wants_array ? Array(values) : [values]
            )
            # TODO: Figure out what to do with multiple types of attributes,
            # if anything. Tempted to go with "garbage in, garbage out" here.
            if predicate.validate(condition.values, condition.default_type)
              condition
            else
              nil
            end
          end
        end

        private

        def extract_attributes_and_predicate(key)
          str = key.dup
          name = Predicate.detect_and_strip_from_string!(str)
          predicate = Predicate.named(name)
          attributes = str.split(/_and_|_or_/)
          [attributes, predicate]
        end
      end

      def valid?
        attributes.detect(&:valid?) && predicate && valid_arity? &&
          predicate.validate(values, default_type) && valid_combinator?
      end

      def valid_arity?
        values.size <= 1 || predicate.wants_array
      end

      def attributes
        @attributes ||= []
      end
      alias :a :attributes

      def attributes=(args)
        case args
        when Array
          args.each do |attr|
            attr = Attribute.new(@context, attr)
            self.attributes << attr if attr.valid?
          end
        when Hash
          args.each do |index, attrs|
            attr = Attribute.new(@context, attrs[:name])
            self.attributes << attr if attr.valid?
          end
        else
          raise ArgumentError,
            "Invalid argument (#{args.class}) supplied to attributes="
        end
      end
      alias :a= :attributes=

      def values
        @values ||= []
      end
      alias :v :values

      def values=(args)
        case args
        when Array
          args.each do |val|
            val = Value.new(@context, val)
            self.values << val
          end
        when Hash
          args.each do |index, attrs|
            val = Value.new(@context, attrs[:value])
            self.values << val
          end
        else
          raise ArgumentError,
            "Invalid argument (#{args.class}) supplied to values="
        end
      end
      alias :v= :values=

      def combinator
        @attributes.size > 1 ? @combinator : nil
      end

      def combinator=(val)
        @combinator = ['and', 'or'].detect { |v| v == val.to_s } || nil
      end
      alias :m= :combinator=
      alias :m :combinator

      def build_attribute(name = nil)
        Attribute.new(@context, name).tap do |attribute|
          self.attributes << attribute
        end
      end

      def build_value(val = nil)
        Value.new(@context, val).tap do |value|
          self.values << value
        end
      end

      def value
        predicate.wants_array ?
          values.map { |v| v.cast(default_type) } :
          values.first.cast(default_type)
      end

      def build(params)
        params.with_indifferent_access.each do |key, value|
          if key.match(/^(a|v|p|m)$/)
            self.send("#{key}=", value)
          end
        end

        self
      end

      def persisted?
        false
      end

      def key
        @key ||= attributes.map(&:name).join("_#{combinator}_") +
          "_#{predicate.name}"
      end

      def eql?(other)
        self.class == other.class &&
        self.attributes == other.attributes &&
        self.predicate == other.predicate &&
        self.values == other.values &&
        self.combinator == other.combinator
      end
      alias :== :eql?

      def hash
        [attributes, predicate, values, combinator].hash
      end

      def predicate_name=(name)
        self.predicate = Predicate.named(name)
      end
      alias :p= :predicate_name=

      def predicate_name
        predicate.name if predicate
      end
      alias :p :predicate_name

      def arel_predicate
        predicates = attributes.map do |attr|
          attr.attr.send(
            arel_predicate_for_attribute(attr),
            formatted_values_for_attribute(attr)
          )
        end

        if predicates.size > 1
          case combinator
          when 'and'
            Arel::Nodes::Grouping.new(Arel::Nodes::And.new(predicates))
          when 'or'
            predicates.inject(&:or)
          end
        else
          predicates.first
        end
      end

      def validated_values
        values.select { |v| predicate.validator.call(v.value) }
      end

      def casted_values_for_attribute(attr)
        validated_values.map { |v| v.cast(predicate.type || attr.type) }
      end

      def formatted_values_for_attribute(attr)
        formatted = casted_values_for_attribute(attr).map do |val|
          val = attr.ransacker.formatter.call(val) if
            attr.ransacker && attr.ransacker.formatter
          val = predicate.format(val)
          val
        end
        predicate.wants_array ? formatted : formatted.first
      end

      def arel_predicate_for_attribute(attr)
        if predicate.arel_predicate === Proc
          values = casted_values_for_attribute(attr)
          predicate.arel_predicate.call(
            predicate.wants_array ? values : values.first
            )
        else
          predicate.arel_predicate
        end
      end


      def default_type
        predicate.type || (attributes.first && attributes.first.type)
      end

      def inspect
        data = [
          ['attributes', a.try(:map, &:name)],
          ['predicate', p],
          ['combinator', m],
          ['values', v.try(:map, &:value)]
        ]
        .reject { |e| e[1].blank? }
        .map { |v| "#{v[0]}: #{v[1]}" }
        .join(', ')
        "Condition <#{data}>"
      end

      private

      def valid_combinator?
        attributes.size < 2 ||
        ['and', 'or'].include?(combinator)
      end

    end
  end
end