module Arel
  module Predications
    def as other
      Nodes::As.new self, Nodes::SqlLiteral.new(other)
    end

    def not_eq other
      Nodes::NotEqual.new self, other
    end

    def not_eq_any others
      grouping_any :not_eq, others
    end

    def not_eq_all others
      grouping_all :not_eq, others
    end

    def eq other
      Nodes::Equality.new self, other
    end

    def eq_any others
      grouping_any :eq, others
    end

    def eq_all others
      grouping_all :eq, others
    end

    def in other
      case other
      when Arel::SelectManager
        Arel::Nodes::In.new(self, other.ast)
      when Range
        if other.exclude_end?
          left  = Nodes::GreaterThanOrEqual.new(self, other.begin)
          right = Nodes::LessThan.new(self, other.end)
          Nodes::And.new [left, right]
        else
          Nodes::Between.new(self, Nodes::And.new([other.begin, other.end]))
        end
      else
        Nodes::In.new self, other
      end
    end

    def in_any others
      grouping_any :in, others
    end

    def in_all others
      grouping_all :in, others
    end

    def not_in other
      case other
      when Arel::SelectManager
        Arel::Nodes::NotIn.new(self, other.ast)
      when Range
        if other.exclude_end?
          left  = Nodes::LessThan.new(self, other.begin)
          right = Nodes::GreaterThanOrEqual.new(self, other.end)
          Nodes::Or.new left, right
        else
          left  = Nodes::LessThan.new(self, other.begin)
          right = Nodes::GreaterThan.new(self, other.end)
          Nodes::Or.new left, right
        end
      else
        Nodes::NotIn.new self, other
      end
    end

    def not_in_any others
      grouping_any :not_in, others
    end

    def not_in_all others
      grouping_all :not_in, others
    end

    def matches other
      Nodes::Matches.new self, other
    end

    def matches_any others
      grouping_any :matches, others
    end

    def matches_all others
      grouping_all :matches, others
    end

    def does_not_match other
      Nodes::DoesNotMatch.new self, other
    end

    def does_not_match_any others
      grouping_any :does_not_match, others
    end

    def does_not_match_all others
      grouping_all :does_not_match, others
    end

    def gteq right
      Nodes::GreaterThanOrEqual.new self, right
    end

    def gteq_any others
      grouping_any :gteq, others
    end

    def gteq_all others
      grouping_all :gteq, others
    end

    def gt right
      Nodes::GreaterThan.new self, right
    end

    def gt_any others
      grouping_any :gt, others
    end

    def gt_all others
      grouping_all :gt, others
    end

    def lt right
      Nodes::LessThan.new self, right
    end

    def lt_any others
      grouping_any :lt, others
    end

    def lt_all others
      grouping_all :lt, others
    end

    def lteq right
      Nodes::LessThanOrEqual.new self, right
    end

    def lteq_any others
      grouping_any :lteq, others
    end

    def lteq_all others
      grouping_all :lteq, others
    end

    def asc
      Nodes::Ordering.new self, :asc
    end

    def desc
      Nodes::Ordering.new self, :desc
    end

    private

    def grouping_any method_id, others
      others = others.dup
      first = send method_id, others.shift

      Nodes::Grouping.new others.inject(first) { |memo,expr|
        Nodes::Or.new(memo, send(method_id, expr))
      }
    end

    def grouping_all method_id, others
      others = others.dup
      first = send method_id, others.shift

      Nodes::Grouping.new others.inject(first) { |memo,expr|
        Nodes::And.new([memo, send(method_id, expr)])
      }
    end
  end
end