module Waves

  module Layers

    class FileCache < Waves::Cache

      def initialize(dir)
        @directory = dir
        super
      end

      def store(key, value, ttl = {})
        super(key, value, ttl)

        key_file = @directory / key

        file = File.new(key_file,'w') unless File.exists?(key_file)
        Marshal.dump(@cache[key], file)
        file.close
      end

      def delete(*keys)
        keys.each {|key| File.delete(@directory / key) }
        super keys
      end

      def clear
        @cache.each_key {|key| File.delete(@directory / key) }
        super
      end

      def fetch(key)
        raise "No cache found for #{key}" unless File.exists?(@directory / key)
        @cache[key] = Marshal.load(@directory / key)

        if (@cache[key][:expires] > Time.now) or (@cache[key][:expires].nil?)
          @cache[key][:value]
        else
          @cache[key][:value]
          delete(key)
        end
      end

    end

  end

end