extends SceneTree

# Headless test: run with
#   godot --headless -s res://tests/test_music_theme.gd
# Forgejo #148: the main theme plays all the time.
#
# "All the time" is the requirement, so what is checked is CONTINUITY rather
# than "a sound was started once": the same player has to survive the main
# menu becoming the game, the game becoming a planet surface, and the
# surface becoming the game again - and there must never be two of it,
# because a second copy is the theme playing over itself.
#
# Covers:
#   A. loading a scene starts the theme
#   B. it is parented to the tree root, not to the scene - the thing that
#      makes it survive change_scene_to_file at all
#   C. the stream loops, so "all the time" outlasts one play-through of it
#   D. it keeps playing while a dialog has the game stopped (#128)
#   E. swapping scenes neither restarts it nor stacks a second one up

var game_state: Node
var scene: Node
var player: AudioStreamPlayer
var stage: int = 0
var elapsed: float = 0.0


func _initialize() -> void:
	# GameState is an autoload: a bare GameState.<instance member> does not
	# compile in a SceneTree script, so the node is fetched by name instead.
	game_state = root.get_node("GameState")
	game_state.reset_new_game()
	game_state.intro_active = false
	game_state.reset_quests()


func _fail(message: String) -> bool:
	print("TEST_MUSIC_THEME: FAIL (%s)" % message)
	quit(1)
	return true


func _players() -> Array:
	var found: Array = []
	for node in root.get_children():
		if node is AudioStreamPlayer:
			found.append(node)
	return found


func _load(path: String) -> void:
	scene = load(path).instantiate()
	root.add_child(scene)
	current_scene = scene


func _process(delta: float) -> bool:
	elapsed += delta
	match stage:
		0:
			if not _players().is_empty():
				return _fail("something was already playing before any scene loaded")
			_load("res://world/Main.tscn")
			elapsed = 0.0
			stage = 1
			return false
		1:
			# The player is added deferred, so it arrives a frame later.
			if elapsed < 0.4:
				return false
			# --- A and B. it exists, at the root ---------------------
			var players: Array = _players()
			if players.size() != 1:
				return _fail("%d music players at the root, expected 1" % players.size())
			player = players[0]
			if player.get_parent() != root:
				return _fail("the music player hangs off %s - it would die with the scene" \
					% player.get_parent())
			if not player.playing:
				return _fail("the theme is not playing")
			if player.stream == null:
				return _fail("the music player has no stream on it")
			print("theme playing from %s, parented to the tree root" % player.stream.resource_path)

			# --- C. and it comes round again -------------------------
			if not ("loop" in player.stream) or not player.stream.loop:
				return _fail("the theme does not loop - it would fall silent after one play")
			if player.stream.get_length() < 10.0:
				return _fail("the theme is %.1fs long - that is not a main theme" \
					% player.stream.get_length())
			print("%.0fs of theme, looping" % player.stream.get_length())

			# --- D. and a dialog does not stop it --------------------
			var narration: Control = scene.get_node("UI/NarrationBanner")
			narration.say("Stopping everything else.", "TEST")
			if not paused:
				return _fail("the dialog did not stop the game, so this proves nothing")
			if not player.can_process():
				return _fail("the music stops whenever a dialog is up")
			print("a dialog stops the game and the music keeps playing")
			while narration.dismiss():
				pass

			elapsed = 0.0
			stage = 2
			return false
		2:
			if elapsed < 0.3:
				return false
			# --- E. through a scene change ---------------------------
			game_state.planet_name = "Music Test"
			game_state.planet_id = "music:test"
			game_state.planet_definition_id = "rocky"
			scene.free()
			_load("res://surface/PlanetSurface.tscn")
			elapsed = 0.0
			stage = 3
			return false
		3:
			if elapsed < 0.4:
				return false
			var players2: Array = _players()
			if players2.size() != 1:
				return _fail("%d music players after a scene change - the theme is playing over itself" \
					% players2.size())
			if players2[0] != player:
				return _fail("the scene change replaced the music player, restarting the theme")
			if not player.playing:
				return _fail("the theme stopped when the scene changed")
			print("scene changed to a planet surface: same player, still playing")

			scene.free()
			_load("res://world/Main.tscn")
			elapsed = 0.0
			stage = 4
			return false
		4:
			if elapsed < 0.4:
				return false
			if _players().size() != 1 or _players()[0] != player:
				return _fail("coming back from a surface left %d players" % _players().size())
			if not player.playing:
				return _fail("the theme stopped on the way back from a surface")
			print("and back again: still one player, still the same one")

			print("TEST_MUSIC_THEME: PASS")
			quit(0)
			return true
	return false