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

      delegate :cast_value, :to => :first_attribute

      attr_reader :predicate

      class << self
        def extract(context, key, values)
          attributes, predicate = extract_attributes_and_predicate(key)
          if attributes.size > 0
            combinator = key.match(/_(or|and)_/) ? $1 : nil
            condition = self.new(context)
            condition.build(
              :a => attributes,
              :p => predicate.name,
              :m => combinator,
              :v => [values]
            )
            predicate.validate(condition.values) ? condition : nil
          end
        end

        private

        def extract_attributes_and_predicate(key)
          str = key.dup
          name = Predicate.detect_and_strip_from_string!(str)
          predicate = Predicate.named(name)
          raise ArgumentError, "No valid predicate for #{key}" unless predicate
          attributes = str.split(/_and_|_or_/)
          [attributes, predicate]
        end
      end

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

      def valid_arity?
        values.size <= 1 || predicate.compound || %w(in not_in).include?(predicate.name)
      end

      def first_attribute
        attributes.first
      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.compound ? values.map {|v| cast_value(v)} : cast_value(values.first)
      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=(predicate)
        @predicate = predicate
        predicate
      end

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

      def arel_predicate
        predicates = attributes.map do |attr|
          attr.attr.send(predicate.arel_predicate, 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 ? predicate.validator.call(v.value) : v.present?}
      end

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

      def formatted_values_for_attribute(attr)
        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
      end

      private

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

    end
  end
end