module ActiveRecord
  class Base
    class << self
      def quote_bound_value_with_postgresql_arrays(value, c = connection)
        if ::PGArrays::PgArray === value
          c.quote_array_by_base_type(value, value.base_type)
        else
          quote_bound_value_without_postgresql_arrays(value, c)
        end
      end
      alias_method_chain :quote_bound_value, :postgresql_arrays
    end
  end
end

module PGArrays
  class PgArray < Array
    attr_reader :base_type
    
    def initialize(array, type=nil)
      super(array)
      @base_type = type if type
    end
    
    def base_type
      @base_type || :other
    end
  end
  
  class PgAny < PgArray; end
  class PgAll < PgArray; end
  class PgIncludes < PgArray; end
  
  if defined? CanCan::Ability
    class PgAny
      def include?(v)
        Array === v && !( v & self ).empty?
      end
    end
  
    class PgAll
      def include?(v)
        Array === v && (self - v).empty?
      end
    end

    class PgIncludes < PgArray
      def include?(v)
        Array === v && (v - self).empty?
      end
    end
  end
end

class Array
  
  def pg(type=nil)
    ::PGArrays::PgArray.new(self, type)
  end
  
  def search_any(type=nil)
    ::PGArrays::PgAny.new(self, type)
  end
  
  def search_all(type=nil)
    ::PGArrays::PgAll.new(self, type)
  end
  
  def search_subarray(type=nil)
    ::PGArrays::PgIncludes.new(self, type)
  end
end