module RailsCacheIt
  module RelationExtension
    extend ActiveSupport::Concern

    included do
      alias_method_chain :to_a, :cache_it
    end

    def to_a_with_cache_it
      options = @_cache_it_options
      if options
        cache_name = to_sql
        blk =  options.delete :blk
        if blk && (RailsCacheIt.cache_it[cache_name] != (new_result = blk.call))
          RailsCacheIt.cache_it[cache_name] = new_result
          Rails.cache.delete cache_name
        end
        Rails.cache.fetch(cache_name, options) do
          self.to_a_without_cache_it
        end
      else
        self.to_a_without_cache_it
      end
    end

    def cache_it options = RailsCacheIt.default_options.dup, &blk
      options[:blk] = blk if blk
      @_cache_it_options = options
      self
    end
  end
end