#!/usr/bin/env ruby

# Run an agent.  Any agent.

require 'envied'
require 'logger'

envied_config = (ENVied.config || ENVied::Configuration.new).tap do |cfg|
	cfg.enable_defaults!
	cfg.variable :AMQP_URL, :string, :default => "amqp://localhost"
	cfg.variable :BROWN_LOG_LEVEL, :string, :default => "info"
end

ENVied.require(:default, :config => envied_config)

ARGV.each { |f| require f }

agent_classes = ObjectSpace.each_object(Class).select do |k|
	k != Brown::Agent and k.ancestors.include?(Brown::Agent)
end

Brown::Agent.logger = Logger.new($stderr)
Brown::Agent.logger.level = Logger.const_get(ENVied.BROWN_LOG_LEVEL.upcase.to_sym)
Brown::Agent.logger.formatter = proc { |s,dt,n,msg| "#{$$}-#{Thread.current.object_id} [#{s[0]}] #{msg}\n" }

agents = []

def stop_agents(agents)
	agents.each do |th|
		Brown::Agent.logger.debug { "Stopping agent #{th[:agent_class].inspect} (thread #{th.inspect})" }
		th[:agent_class] && th[:agent_class].stop
	end
end

Signal.trap("INT") do
	$stderr.puts "Received SIGINT; stopping agents and exiting"
	stop_agents(agents)
end
Signal.trap("TERM") do
	$stderr.puts "Received SIGTERM; stopping agents and exiting"
	stop_agents(agents)
end
Signal.trap("HUP", "IGNORE")
Signal.trap("USR1") do
	Brown::Agent.more_log_detail
	$stderr.puts "Log level now #{Logger::SEV_LABEL[Brown::Agent.logger.level]}"
end
Signal.trap("USR2") do
	Brown::Agent.less_log_detail
	$stderr.puts "Log level now #{Logger::SEV_LABEL[Brown::Agent.logger.level]}"
end

Brown::Agent.logger.info { "Brown starting up..." }

agent_classes.each do |klass|
	th = Thread.new(klass) do |klass|
		Thread.current[:agent_class] = klass
		klass.run
	end

	agents << th

	Brown::Agent.logger.info { "Started agent #{klass}" }
	Brown::Agent.logger.debug { "Agent thread is #{th.inspect}" }
end

loop do
	if agents.empty?
		break
	end

	sleep 0.5

	agents.each do |th|
		Brown::Agent.logger.debug { "Examining agent thread #{th.inspect}" }
		begin
			if th.join(0.5)
				Brown::Agent.logger.info { "Agent #{th[:agent_class]} exited cleanly; not restarting" }
				agents.delete(th)
			end
		rescue Exception => ex
			Brown::Agent.logger.fatal { "Agent #{th[:agent_class]} crashed: #{ex.message} (#{ex.class})" }
			Brown::Agent.logger.info { ex.backtrace.map { |l| "  #{l}" }.join("\n") }

			Brown::Agent.logger.info { "Re-starting #{klass} agent" }

			klass = th[:agent_class]
			agents.delete(th)

			agents << Thread.new(klass) do |klass|
				Thread.current[:agent_class] = klass
				klass.run
			end
		end

	end
end

Brown::Agent.logger.info { "Brown exiting" }