kv.rb

Dir[File.dirname(__FILE__) + '/application/*.rb'].each { |file| require file }

class KV
  attr_reader :hash
  def initialize
    @hash = Hash.new { |h, k| h[k] = {} }
  end

  def set(key, value)
    @hash[key][Time.now.to_i] = value
  end

  def get(key, timestamp = nil)
    if timestamp.nil?
      @hash[key][latest_key(key)]
    else
      @hash[key][fuzzy_match_timestamp(key, timestamp)]
    end
  end

  private

  def latest_key(key)
    @hash[key].keys.sort.last
  end

  def fuzzy_match_timestamp(key, timestamp)
    timestamp_values = @hash[key].keys.map { |key| timestamp - key }.select { |values| values >= 0 }
    timestamp - timestamp_values.min
  end
end