# bgm_test —— §9.1 地图 BGM 选曲 + §9.2 前后台音量存/恢复的 headless 自检。
#   godot --headless --path project --script bgm_test.gd
# exit 0 = pass。
extends SceneTree

const BgmDirector = preload("res://bgm_director.gd")
const Audio = preload("res://audio.gd")
const AppLifecycle = preload("res://app_lifecycle.gd")
const MusicInfo = preload("res://musicinfo.gd")

const DEFAULT_VOL := 1.0 / 5.0 * 0.1   # 0.02

# 假 M2Client：只发 §9.1 关心的两个信号。
class FakeClient extends Node:
	signal bgm_changed(name: String, volume: float)
	signal world_reset()

# 假 Audio：记录 play_bgm / stop_bgm 调用与音量，够 director 断言用。
class FakeAudio extends Node:
	var master_bgm := 0.6
	var master_sfx := 0.9
	var _bgm_name := ""
	var played: Array[String] = []
	var stopped := 0
	func play_bgm(name: String, _fade := 1.2) -> void:
		if name == _bgm_name:
			return
		_bgm_name = name
		played.append(name)
	func stop_bgm(_fade := 1.0) -> void:
		_bgm_name = ""
		stopped += 1
	func set_music_volume(v: float) -> void:
		master_bgm = clampf(v, 0.0, 1.0)

var _fail := 0
func _ck(c: bool, m: String) -> void:
	if not c:
		_fail += 1
		printerr("FAIL: " + m)

func _init() -> void:
	_test_select_server_volume()
	_test_select_default_volume()
	_test_select_empty_falls_back()
	_test_world_reset_reruns()
	_test_musicinfo_lastplay_roundtrip()
	_test_background_save_restore()
	if _fail == 0:
		print("PASS: bgm_test (§9.1 map BGM select + §9.2 volume save/restore)")
		quit(0)
	else:
		printerr("%d check(s) failed" % _fail)
		quit(1)

func _mk_director() -> Array:
	var client := FakeClient.new()
	var audio := FakeAudio.new()
	var bd := BgmDirector.new()
	get_root().add_child(client)
	get_root().add_child(audio)
	get_root().add_child(bd)
	bd.bind(client, audio)
	return [client, audio, bd]

# §9.1：服务端给了名字 + 音量 -> 用服务端音量并播放该曲。
func _test_select_server_volume() -> void:
	var t := _mk_director()
	var client: FakeClient = t[0]
	var audio: FakeAudio = t[1]
	client.bgm_changed.emit("pvp_bgm.mp3", 0.5)
	_ck(audio.played == ["pvp_bgm.mp3"], "server name played, got %s" % [audio.played])
	_ck(is_equal_approx(audio.master_bgm, 0.5), "server volume applied, got %f" % audio.master_bgm)
	_ck(audio.stopped == 0, "no stop_bgm on server-provided track")
	t[0].free(); t[1].free(); t[2].free()

# §9.1：服务端给了名字但音量 <0（GC_MAIN_CHARACTER3_BGM，未收 BGM4）-> 默认 0.02。
func _test_select_default_volume() -> void:
	var t := _mk_director()
	var client: FakeClient = t[0]
	var audio: FakeAudio = t[1]
	client.bgm_changed.emit("field_a.mp3", -1.0)
	_ck(audio.played == ["field_a.mp3"], "name played on unspecified volume, got %s" % [audio.played])
	_ck(is_equal_approx(audio.master_bgm, DEFAULT_VOL), "default 0.02 applied, got %f" % audio.master_bgm)
	t[0].free(); t[1].free(); t[2].free()

# §9.1：服务端名为空 -> 回落 musicInfo.fieldMusic（METIN2THEMA = "M2BG.mp3"）。
func _test_select_empty_falls_back() -> void:
	var t := _mk_director()
	var client: FakeClient = t[0]
	var audio: FakeAudio = t[1]
	client.bgm_changed.emit("", -1.0)
	_ck(audio.played == [String(MusicInfo.fieldMusic)],
		"empty name falls back to fieldMusic, got %s" % [audio.played])
	_ck(String(MusicInfo.fieldMusic) == "M2BG.mp3", "METIN2THEMA constant is M2BG.mp3")
	_ck(is_equal_approx(audio.master_bgm, DEFAULT_VOL), "default 0.02 on fallback, got %f" % audio.master_bgm)
	t[0].free(); t[1].free(); t[2].free()

# §9.1 / §1.3：换图（world_reset）重跑选曲逻辑。
func _test_world_reset_reruns() -> void:
	var t := _mk_director()
	var client: FakeClient = t[0]
	var audio: FakeAudio = t[1]
	var bd: BgmDirector = t[2]
	_ck(client.world_reset.is_connected(bd._on_world_reset), "director connected to world_reset")
	client.bgm_changed.emit("map_a.mp3", 0.4)
	# warp：world_reset 先到（旧曲目仍在 store 里），随后新图的 BGM 包。
	client.world_reset.emit()
	_ck(audio.played == ["map_a.mp3"], "world_reset keeps current track, got %s" % [audio.played])
	client.bgm_changed.emit("map_b.mp3", 0.2)
	_ck(audio.played == ["map_a.mp3", "map_b.mp3"], "new map BGM played, got %s" % [audio.played])
	_ck(is_equal_approx(audio.master_bgm, 0.2), "new map volume applied, got %f" % audio.master_bgm)
	t[0].free(); t[1].free(); t[2].free()

# §9.1：musicInfo.SaveLastPlayFieldMusic / LoadLastPlayFieldMusic 往返。
func _test_musicinfo_lastplay_roundtrip() -> void:
	MusicInfo.save_last_play_field_music("last_field.mp3")
	_ck(MusicInfo.load_last_play_field_music() == "last_field.mp3",
		"lastplay.inf roundtrip, got %s" % MusicInfo.load_last_play_field_music())

# §9.2：后台保存音量 + 静音，前台恢复；_bgm_name 不变，同一首继续播。
func _test_background_save_restore() -> void:
	var client := FakeClient.new()
	var audio := Audio.new()
	var life := AppLifecycle.new()
	get_root().add_child(audio)
	audio.setup("res://__no_assets__")   # 无资源，play_bgm 只置名不出声
	get_root().add_child(life)
	life.pause_tree_on_background = false   # 别把测试树暂停了
	life.background_max_fps = 0
	life.bind(null, audio)

	audio.master_bgm = 0.6
	audio.master_sfx = 0.9
	# 模拟「某首战场曲目正在播放」（headless 无资源，不实际解码）。
	audio._bgm_name = "M2BG.mp3"
	var name_before := audio._bgm_name
	_ck(name_before == "M2BG.mp3", "bgm name set before background, got %s" % name_before)

	life._enter_background()
	_ck(is_equal_approx(audio.master_bgm, 0.0), "music muted in background, got %f" % audio.master_bgm)
	_ck(audio._volume_saved, "save_volume ran (backup taken)")
	_ck(is_equal_approx(audio._backup_music_volume, 0.6), "backup music volume, got %f" % audio._backup_music_volume)
	_ck(is_equal_approx(audio._backup_sound_volume, 0.9), "backup sound volume, got %f" % audio._backup_sound_volume)
	_ck(audio._bgm_name == name_before, "_bgm_name unchanged in background, got %s" % audio._bgm_name)

	life._exit_background()
	_ck(is_equal_approx(audio.master_bgm, 0.6), "music volume restored, got %f" % audio.master_bgm)
	_ck(is_equal_approx(audio.master_sfx, 0.9), "sound volume restored, got %f" % audio.master_sfx)
	_ck(audio._bgm_name == name_before, "_bgm_name still unchanged after restore, got %s" % audio._bgm_name)
	_ck(not audio._volume_saved, "backup flag cleared after restore")

	client.free(); life.free(); audio.free()