extends Node


var port_range_start: int = 5000
var port_range_end: int   = 5010
var threads: Dictionary   = Dictionary() 


func _wait_for_child(id: String, port: String, mode: String) -> void:
	if port == "-1":
		call_deferred("_child_finished", id, -1)
		return

	var output    := []
	var exit_code := OS.execute(
		"./game.sh",
		[
			"--headless", "--", "server_" + port, "game", mode
		],
		output,
		true
	)

	call_deferred("_child_finished", id, exit_code)

func _child_finished(id: String, exit_code: int) -> void:
	var thread: Thread = threads.get(id)
	if not thread: return

	push_warning("Game Server [ %s ] Exited: %d" % [id, exit_code])

	thread.wait_to_finish()
	threads.erase(id)

func is_port_free(port: int) -> bool:
	var server := TCPServer.new()
	var state  := server.listen(port)

	match state:
		OK:
			server.stop()
			return true
		_:
			return false

func find_free_port(start_port: int = 1024, end_port: int = 65535) -> int:
	for port in range(start_port, end_port + 1):
		if is_port_free(port):
			return port

	return -1

func launch_game_server(mode: String) -> String:
	var thread    := Thread.new()
	var thread_id := str( thread.get_instance_id() )
	var port      := str(
		find_free_port(
			port_range_start,
			port_range_end
		)
	)

	thread.start(
		_wait_for_child.bind(
			thread_id,
			port,
			mode
		)
	)

	threads.set(thread_id, thread)
	return port