savonarola/pulse_meter_core

module PulseMeter
  module Sensor
    module Timelined
      # Calculates n'th percentile in interval
      class MultiPercentile < ZSetBased
        attr_reader :p_value

        def initialize(name, options)
          @p_value = assert_array!(options, :p, [])
          @p_value.each {|p| assert_ranged_float!({:percentile => p}, :percentile, 0, 1)}
          super(name, options)
        end

        def calculate(key, count)
          count = 
          @p_value.each_with_object({}) { |p, acc|
            position = p > 0 ? (p * count).round - 1 : 0
            el = redis.zrange(key, position, position)[0]
            acc[p] = redis.zscore(key, el)
          }.to_json
        end

        private
        
        def deflate(value)
          hash = JSON.parse(value)
          hash.each {|p, v| hash[p] = v.to_f}
          hash
        end

      end
    end
  end
end