class ElasticAPM::Metrics::Metric

def collect
  @mutex.synchronize do
    collected = @value
    return nil if collected.is_a?(Float) && !collected.finite?
    @value = initial_value if reset_on_collect?
    return nil if reset_on_collect? && collected == 0
    collected
  end
end

def initialize(
  key,
  initial_value: nil,
  tags: nil,
  reset_on_collect: false
)
  @key = key
  @initial_value = initial_value
  @value = initial_value
  @tags = tags
  @reset_on_collect = reset_on_collect
  @mutex = Mutex.new
end

def reset!
  self.value = initial_value
end

def reset_on_collect?
  @reset_on_collect
end

def tags?
  !!tags&.any?
end

def value=(value)
  @mutex.synchronize { @value = value }
end