# frozen_string_literal: true

class SentrySmartSampler
  class RateLimit
    KEY_PREFIX = "sentry_smart_sampler"
    private_constant :KEY_PREFIX

    attr_reader :key, :threshold, :interval, :increment, :cache
    private     :key, :threshold, :interval, :increment, :cache

    def initialize(key:, threshold:, interval:, increment: 1, cache: SentrySmartSampler.configuration.cache_storage)
      @key = key
      @threshold = threshold
      @interval = interval
      @increment = increment
      @cache = cache
    end

    def throttled?
      count >= threshold
    end

    def count
      cache.read(storage_key, raw: true).to_i
    end

    def remaining
      threshold - count
    end

    def clear!
      cache.delete(storage_key)
    end

    def increase
      cache.increment(storage_key, increment) || increment
    end

    def storage_key
      "#{KEY_PREFIX}/#{normalized_key}"
    end

    # let's say that the interval is 1.hour
    # the current time is 15:05
    # window is going to keep the same value until another interval time starts
    # a new window is going to be start at 16:00
    def window
      Time.current.to_i / interval
    end

    private

    def normalized_key
      Digest::MD5.hexdigest([key, window].flatten.join("/"))
    end
  end
end