module PhusionPassenger::DebugLogging

def self._log_device
	return @@log_device
end

def self.included(klass)
	klass.class_eval do
		private :debug
		private :trace
	end
end

def self.log_file=(filename)
	if filename && filename.empty?
		@@log_filename = nil
	else
		@@log_filename = filename
	end
	@@log_device.close if @@log_device && !@@log_device.closed?
	@@log_device = nil
end

def self.log_level=(level)
	@@log_level = level
end

def self.stderr_evaluator=(block)
	if block
		@@stderr_evaluator = block
	else
		@@stderr_evaluator = lambda { STDERR }
	end
end

def debug(message)
	trace(1, message, 1)
end

def error(message)
	trace(-1, message, 1)
end

def trace(level, message, nesting_level = 0)
	if @@log_level >= level
		if @@log_filename
			if !@@log_device || @@log_device.closed?
				@@log_device = File.open(@@log_filename, "a")
			end
			output = @@log_device
		else
			output = @@stderr_evaluator.call
		end
		location = caller[nesting_level].sub(/.*phusion_passenger\//, '')
		location.sub!(/(.*):.*/, '\1')
		now = Time.now
		time_str = now.strftime("%Y-%m-%d %H:%M:%S.")
		time_str << sprintf("%04d", now.usec / 100)
		if thread_name = Thread.current[:name]
			thread_name = "(#{thread_name})"
		end
		output.write("[ pid=#{$$} thr=0x#{Thread.current.object_id.to_s(16)}#{thread_name} file=#{location} time=#{time_str} ]: #{message}\n")
		output.flush
	end
end

def warn(message)
	trace(0, message, 1)
end