class Disyuntor

# File lib/disyuntor.rb, line 6
def initialize(threshold:, timeout:)
  @threshold = threshold
  @timeout   = timeout

  on_circuit_open { fail CircuitOpenError }

  close!
end

# File lib/disyuntor.rb, line 28
def closed?
  state == :closed
end

# File lib/disyuntor.rb, line 23
def on_circuit_open(&block)
  raise ArgumentError, "Must pass a block" unless block_given?
  @on_circuit_open = block
end

# File lib/disyuntor.rb, line 32
def open?
  not (closed? or timed_out?)
end

# File lib/disyuntor.rb, line 15
def try(&block)
  if closed? or timed_out?
    circuit_closed(&block)
  else
    circuit_open
  end
end

# File lib/disyuntor.rb, line 63
def circuit_closed(&block)
  ret = block.call
rescue
  open! if increment_failures! >= threshold
  raise
else
  close!
  ret
end

# File lib/disyuntor.rb, line 73
def circuit_open
  @on_circuit_open.call(self)
end

# File lib/disyuntor.rb, line 40
def close!
  @opened_at = nil
  @failures  = 0
  @state     = :closed
end

# File lib/disyuntor.rb, line 59
def increment_failures!
  @failures += 1
end

# File lib/disyuntor.rb, line 55
def next_timeout_at
  opened_at + timeout
end

# File lib/disyuntor.rb, line 46
def open!
  @opened_at = Time.now.to_i
  @state     = :open
end

# File lib/disyuntor.rb, line 51
def timed_out?
  Time.now.to_i > next_timeout_at
end