# Stats that are associated with each instrumented method. 
class ProfileIt::MetricStats
  attr_accessor :call_count
  attr_accessor :min_call_time
  attr_accessor :max_call_time
  attr_accessor :total_call_time
  attr_accessor :total_exclusive_time
  attr_accessor :sum_of_squares
  
  def initialize(scoped = false)
    @scoped = scoped
    self.call_count = 0
    self.total_call_time = 0.0
    self.total_exclusive_time = 0.0
    self.min_call_time = 0.0
    self.max_call_time = 0.0
    self.sum_of_squares = 0.0
  end
  
  def update!(call_time,exclusive_time)
    # If this metric is scoped inside another, use exclusive time for min/max and sum_of_squares. Non-scoped metrics
    # (like controller actions) track the total call time.
    t = (@scoped ? exclusive_time : call_time)
    self.min_call_time = t if self.call_count == 0 or t < min_call_time
    self.max_call_time = t if self.call_count == 0 or t > max_call_time   
    self.call_count +=1
    self.total_call_time += call_time
    self.total_exclusive_time += exclusive_time
    self.sum_of_squares += (t * t)
    self
  end
  
  # combines data from another MetricStats object
  def combine!(other)
    self.call_count += other.call_count
    self.total_call_time += other.total_call_time
    self.total_exclusive_time += other.total_exclusive_time
    self.min_call_time = other.min_call_time if self.min_call_time.zero? or other.min_call_time < self.min_call_time
    self.max_call_time = other.max_call_time if other.max_call_time > self.max_call_time
    self.sum_of_squares += other.sum_of_squares
    self
  end
  
  # THIS ISN'T USED ANYMORE. STILL A CONFLICT ISSUE?
  # To avoid conflicts with different JSON libaries handle JSON ourselves. 
  # Time-based metrics are converted to milliseconds from seconds.
  def to_json(*a)
    %Q[{"total_exclusive_time":#{total_exclusive_time*1000},"min_call_time":#{min_call_time*1000},"call_count":#{call_count},"sum_of_squares":#{sum_of_squares*1000},"total_call_time":#{total_call_time*1000},"max_call_time":#{max_call_time*1000}}]
  end
end # class MetricStats