class IO::Event::Debug::Selector

def self.wrap(selector, env = ENV)
	log = nil
	
	if log_path = env["IO_EVENT_DEBUG_SELECTOR_LOG"]
		log = File.open(log_path, "w")
	end
	
	return self.new(selector, log: log)
end

def close
	log("Closing selector")
	
	if @selector.nil?
		Kernel::raise "Selector already closed!"
	end
	
	@selector.close
	@selector = nil
end

def idle_duration
	@selector.idle_duration
end

def initialize(selector, log: nil)
	@selector = selector
	
	@readable = {}
	@writable = {}
	@priority = {}
	
	unless Fiber.current == selector.loop
		Kernel::raise "Selector must be initialized on event loop fiber!"
	end
	
	@log = log
end

def io_read(fiber, io, buffer, length, offset = 0)
	log("Reading from IO #{io.inspect} with buffer #{buffer}; length #{length} offset #{offset}")
	@selector.io_read(fiber, io, buffer, length, offset)
end

def io_wait(fiber, io, events)
	log("Waiting for IO #{io.inspect} for events #{events.inspect}")
	@selector.io_wait(fiber, io, events)
end

def io_write(fiber, io, buffer, length, offset = 0)
	log("Writing to IO #{io.inspect} with buffer #{buffer}; length #{length} offset #{offset}")
	@selector.io_write(fiber, io, buffer, length, offset)
end

def log(message)
	return unless @log
	
	Fiber.blocking do
		@log.puts("T+%10.1f; %s" % [now, message])
	end
end

def now
	Process.clock_gettime(Process::CLOCK_MONOTONIC)
end

def process_wait(*arguments)
	log("Waiting for process with #{arguments.inspect}")
	@selector.process_wait(*arguments)
end

def push(fiber)
	log("Pushing fiber #{fiber.inspect} to ready list")
	@selector.push(fiber)
end

def raise(fiber, *arguments)
	log("Raising exception on fiber #{fiber.inspect} with #{arguments.inspect}")
	@selector.raise(fiber, *arguments)
end

def ready?
	@selector.ready?
end

def respond_to?(name, include_private = false)
	@selector.respond_to?(name, include_private)
end

def resume(*arguments)
	log("Resuming fiber with #{arguments.inspect}")
	@selector.resume(*arguments)
end

def select(duration = nil)
	log("Selecting for #{duration.inspect}")
	unless Fiber.current == @selector.loop
		Kernel::raise "Selector must be run on event loop fiber!"
	end
	
	@selector.select(duration)
end

def transfer
	log("Transfering to event loop")
	@selector.transfer
end

def wakeup
	@selector.wakeup
end

def yield
	log("Yielding to event loop")
	@selector.yield
end