class_name GameScreen
extends Control

## T-WIN-008：游戏界面（3D 角色 + 实时评分 HUD）
## T-WIN-009：来源信息展示
## T-WIN-013：场景载入与物理落地（重力 / 风 / 碰撞 / 环境 / 机位）

const UiKit = preload("res://src/ui/ui_kit.gd")
const Scoring = preload("res://src/score/scoring.gd")
const VrmLoader = preload("res://src/model/vrm_loader.gd")
const SkeletonRetarget = preload("res://src/anim/skeleton_retarget.gd")
const SourcePanel = preload("res://src/ui/source_panel.gd")
const ScenePanel = preload("res://src/ui/scene_panel.gd")
const SceneRuntime = preload("res://src/scene/scene_runtime.gd")
const CatalogTypes = preload("res://src/net/catalog_types.gd")

enum State { IDLE, PREPARING, RUNNING, FINISHED, FAILED }

var state: State = State.IDLE
var vrm: VrmLoader.VrmModel = null
var retarget: SkeletonRetarget = null
var scene_runtime: SceneRuntime = null
var scene_warning: String = ""

var _viewport: SubViewport
var _camera: Camera3D
var _world_env: Environment
var _model_host: Node3D
var _scene_host: Node3D
var _score_label: Label
var _grade_label: Label
var _combo_label: Label
var _progress: ProgressBar
var _status_label: Label
var _hint_label: Label
var _source_panel: SourcePanel
var _scene_panel: ScenePanel
var _scene_note: Label
var _start_button: Button
var _stop_button: Button

var _motion: CatalogTypes.Motion = null
var _song: CatalogTypes.Song = null
var _model: CatalogTypes.Model = null
var _scene: CatalogTypes.Scene = null
var _good_frames: int = 0
var _total_frames: int = 0
var _elapsed: float = 0.0

var _on_exit: Callable = Callable()
var _on_finished: Callable = Callable()


func _init(on_exit: Callable = Callable(), on_finished: Callable = Callable()) -> void:
	_on_exit = on_exit
	_on_finished = on_finished


func _ready() -> void:
	set_anchors_preset(Control.PRESET_FULL_RECT)
	name = "GameScreen"

	var root := UiKit.hbox(14)
	root.set_anchors_preset(Control.PRESET_FULL_RECT)
	root.offset_left = 20
	root.offset_top = 16
	root.offset_right = -20
	root.offset_bottom = -16
	add_child(root)

	# ---- 左侧：3D 视图 ----
	var view_container := SubViewportContainer.new()
	view_container.stretch = true
	view_container.size_flags_horizontal = Control.SIZE_EXPAND_FILL
	view_container.size_flags_vertical = Control.SIZE_EXPAND_FILL

	_viewport = SubViewport.new()
	_viewport.size = Vector2i(960, 720)
	_viewport.render_target_update_mode = SubViewport.UPDATE_ALWAYS
	_viewport.transparent_bg = false
	view_container.add_child(_viewport)
	root.add_child(view_container)

	_env_setup()

	# ---- 右侧：HUD ----
	var side := UiKit.vbox(10)
	side.custom_minimum_size = Vector2(380, 0)
	root.add_child(side)

	side.add_child(UiKit.title("评分"))

	var score_card := UiKit.panel()
	var score_box := UiKit.vbox(4)
	_score_label = UiKit.label("—", 52, UiKit.COLOR_ACCENT)
	_score_label.horizontal_alignment = HORIZONTAL_ALIGNMENT_CENTER
	score_box.add_child(_score_label)
	_grade_label = UiKit.label("等待开始", UiKit.FONT_BODY, UiKit.COLOR_MUTED)
	_grade_label.horizontal_alignment = HORIZONTAL_ALIGNMENT_CENTER
	score_box.add_child(_grade_label)
	_combo_label = UiKit.label("连击 0", UiKit.FONT_SMALL, UiKit.COLOR_MUTED)
	_combo_label.horizontal_alignment = HORIZONTAL_ALIGNMENT_CENTER
	score_box.add_child(_combo_label)
	score_card.add_child(score_box)
	side.add_child(score_card)

	side.add_child(UiKit.label("动作进度", UiKit.FONT_SMALL, UiKit.COLOR_MUTED))
	_progress = UiKit.progress_bar(0.0)
	side.add_child(_progress)

	_status_label = UiKit.label("", UiKit.FONT_SMALL, UiKit.COLOR_MUTED)
	_status_label.autowrap_mode = TextServer.AUTOWRAP_WORD_SMART
	side.add_child(_status_label)

	_hint_label = UiKit.label("", UiKit.FONT_SMALL, UiKit.COLOR_MUTED)
	_hint_label.autowrap_mode = TextServer.AUTOWRAP_WORD_SMART
	side.add_child(_hint_label)

	_source_panel = SourcePanel.new("动作来源")
	side.add_child(_source_panel)

	_scene_panel = ScenePanel.new("场景参数")
	side.add_child(_scene_panel)

	_scene_note = UiKit.label("", UiKit.FONT_SMALL, UiKit.COLOR_MUTED)
	_scene_note.autowrap_mode = TextServer.AUTOWRAP_WORD_SMART
	_scene_note.visible = false
	side.add_child(_scene_note)

	side.add_child(UiKit.expander())

	var actions := UiKit.hbox(8)
	_start_button = UiKit.button("开始跟练", _on_start_pressed)
	_stop_button = UiKit.button("结束本轮", _on_stop_pressed)
	_stop_button.disabled = true
	actions.add_child(_start_button)
	actions.add_child(_stop_button)
	side.add_child(actions)
	side.add_child(UiKit.button("返回主菜单", func(): if _on_exit.is_valid(): _on_exit.call()))

	PoseReceiver.frame_received.connect(_on_frame_received)
	ScoreService.score_updated.connect(_on_score_updated)
	PoseReceiver.client_connected.connect(func(_d): _refresh_connection_hint())
	PoseReceiver.client_disconnected.connect(func(_r): _refresh_connection_hint())

	_refresh_connection_hint()


func _env_setup() -> void:
	var world := WorldEnvironment.new()
	var env := Environment.new()
	env.background_mode = Environment.BG_COLOR
	env.background_color = UiKit.COLOR_BG
	env.ambient_light_source = Environment.AMBIENT_SOURCE_COLOR
	env.ambient_light_color = Color(1, 1, 1)
	env.ambient_light_energy = 0.9
	world.environment = env
	_viewport.add_child(world)
	# 场景的环境参数（环境光 / 雾）直接写进这个 Environment，不另建 WorldEnvironment
	_world_env = env

	var light := DirectionalLight3D.new()
	light.name = "SceneSun"
	light.rotation_degrees = Vector3(-35, 40, 0)
	light.light_energy = 1.2
	_viewport.add_child(light)

	_camera = Camera3D.new()
	_camera.position = Vector3(0, 1.35, 2.4)
	_camera.rotation_degrees = Vector3(-6, 0, 0)
	_camera.fov = 40.0
	_viewport.add_child(_camera)

	_scene_host = Node3D.new()
	_scene_host.name = "SceneHost"
	_viewport.add_child(_scene_host)

	_model_host = Node3D.new()
	_model_host.name = "ModelHost"
	_viewport.add_child(_model_host)


## 设置本轮要跟练的场景、曲目与动作，并加载模型
## `scene` 可以为 null（服务端未发布场景）—— 此时用内置空场景，**不阻塞开始跟练**
func prepare(song: CatalogTypes.Song, motion: CatalogTypes.Motion, model: CatalogTypes.Model, scene: CatalogTypes.Scene = null) -> void:
	_song = song
	_motion = motion
	_model = model
	_scene = scene
	_good_frames = 0
	_total_frames = 0
	_elapsed = 0.0
	state = State.PREPARING
	_progress.value = 0.0
	_score_label.text = "—"
	_grade_label.text = "正在准备…"
	_start_button.disabled = true
	_stop_button.disabled = true

	_source_panel.show_source(motion.source if motion != null else null, motion.name if motion != null else "")
	_scene_panel.show_scene(scene)
	_set_status("正在载入场景…")

	_clear_model()
	_clear_scene()

	var scene_note: String = await _load_scene(scene)
	if scene_note != "":
		scene_warning = scene_note

	if model == null or model.file_url == "":
		_fail("目录中没有可用模型（未发布任何模型）")
		return

	_set_status("正在下载并加载模型…")
	var cached: Dictionary = await CatalogStore.ensure_model_cached(model)
	if not cached["ok"]:
		_fail("模型下载失败：%s" % str(cached["error"]))
		return

	var path := str(cached["path"])
	vrm = VrmLoader.load_from_file(path)
	if not vrm.available or vrm.skeleton == null:
		_fail("模型加载失败：%s" % (vrm.error if vrm.error != "" else "缺少骨骼"))
		return

	vrm.root.visible = true
	_model_host.add_child(vrm.root)

	# 角色落在场景出生点（无场景时即世界原点），再按相机模式取景
	_place_character_on_spawn()
	_apply_camera(0.0)

	retarget = SkeletonRetarget.new(vrm.skeleton, vrm.bones)
	retarget.capture_rest()
	if not retarget.is_bound():
		_fail("骨骼绑定失败，模型可能不受支持")
		return

	var coverage := vrm.coverage() * 100.0
	_set_status("模型就绪：%s（VRM %s，%d 骨骼，人形覆盖率 %.0f%%）｜ %s" % [
		model.name, vrm.vrm_version if vrm.vrm_version != "" else "—", vrm.bone_count, coverage,
		scene_runtime.describe() if scene_runtime != null else "无场景",
	])
	if coverage < 60.0:
		_grade_label.text = "骨骼覆盖偏低，动作可能不完整"
	_show_scene_note(scene_warning)

	state = State.IDLE
	_start_button.disabled = false
	_refresh_connection_hint()


func _show_scene_note(note: String) -> void:
	if _scene_note == null:
		return
	_scene_note.visible = note != ""
	_scene_note.text = "⚠ %s" % note if note != "" else ""
	_scene_note.add_theme_color_override("font_color", UiKit.COLOR_BAD)


# ---------------- 场景（T-WIN-013） ----------------

## 载入场景并落地物理。返回非空字符串表示需要提示的降级原因（不阻塞开始跟练）。
func _load_scene(scene: CatalogTypes.Scene) -> String:
	scene_warning = ""
	var config: CatalogTypes.SceneConfig = null
	if scene != null:
		config = scene.config

	if scene == null:
		scene_runtime = SceneRuntime.create_empty(config)
		scene_runtime.apply_environment(_world_env)
		_scene_host.add_child(scene_runtime)
		push_warning("[GameScreen] 未选择场景，使用内置空场景")
		return "未选择场景，已使用内置空场景"

	if not scene.is_usable():
		scene_runtime = SceneRuntime.create_empty(config, scene.name)
		scene_runtime.apply_environment(_world_env)
		_scene_host.add_child(scene_runtime)
		return "场景「%s」缺少 GLB 文件，已回退内置空场景" % scene.name

	var cached: Dictionary = await CatalogStore.ensure_scene_cached(scene)
	if not cached["ok"]:
		scene_runtime = SceneRuntime.create_empty(config, scene.name)
		scene_runtime.apply_environment(_world_env)
		_scene_host.add_child(scene_runtime)
		return "场景下载失败（%s），已回退内置空场景" % str(cached["error"])

	scene_runtime = SceneRuntime.load_from_file(str(cached["path"]), config, scene.name)
	scene_runtime.apply_environment(_world_env)
	_scene_host.add_child(scene_runtime)
	# 日志核对：重力 / 风 / 摩擦 / 碰撞体数量（文档 §5.6 第 3 条要求可核对）
	print("[GameScreen] %s" % scene_runtime.describe())
	if scene_runtime.warnings.size() > 0:
		push_warning("[GameScreen] 场景降级：%s" % scene_runtime.warnings_text())
		return scene_runtime.warnings_text()
	return ""


## 角色落到场景出生点（含 yaw 朝向）
func _place_character_on_spawn() -> void:
	if vrm == null or vrm.root == null:
		return
	var transform := Transform3D.IDENTITY
	if scene_runtime != null:
		transform = scene_runtime.spawn_transform(0)
	vrm.root.transform = transform


## 按场景相机配置摆机位；无场景时退回原来的"框住模型"行为
func _apply_camera(time_seconds: float) -> void:
	if vrm == null or vrm.root == null:
		return
	if scene_runtime != null:
		var target := scene_runtime.spawn_transform(0).origin
		# 以模型上半身为焦点，避免角色高出镜头
		target.y += 1.0
		scene_runtime.apply_camera(_camera, target, time_seconds)
		return
	_frame_camera_on(vrm.root)


## 让相机框住模型
func _frame_camera_on(root: Node3D) -> void:
	var aabb := _compute_aabb(root)
	if aabb.size == Vector3.ZERO:
		return
	var height := aabb.size.y
	var center := aabb.get_center()
	_camera.position = center + Vector3(0, 0, maxf(height * 1.5, 2.0))
	_camera.rotation_degrees = Vector3(0, 0, 0)
	# 略微俯视，看向模型上半身
	_camera.position.y = center.y + height * 0.15
	_camera.look_at(center + Vector3(0, height * 0.02, 0), Vector3.UP)


func _compute_aabb(node: Node) -> AABB:
	var result := AABB()
	var first := true
	if node is MeshInstance3D:
		var mesh := (node as MeshInstance3D).get_aabb()
		var world := (node as MeshInstance3D).global_transform
		# 用节点自身变换近似（骨架绑定姿态下足够用于定机位）
		result = world * mesh
		first = false
	for child in node.get_children():
		var child_aabb := _compute_aabb(child)
		if child_aabb.size == Vector3.ZERO:
			continue
		if first:
			result = child_aabb
			first = false
		else:
			result = result.merge(child_aabb)
	return result


func _on_start_pressed() -> void:
	if _motion == null:
		_fail("未选择动作")
		return
	if not PoseReceiver.is_listening():
		PoseReceiver.start()
	if PoseReceiver.connected_client_count() == 0:
		_set_status("尚未连接 Android 辅助 App，已开始计时但暂无可评分数据。")

	_set_status("正在拉取参考动作序列…")
	_start_button.disabled = true

	var fetched: Dictionary = await CatalogStore.fetch_sequence(_motion.id)
	if not fetched["ok"]:
		_fail("参考序列拉取失败：%s" % str(fetched["error"]))
		_start_button.disabled = false
		return

	var sequence = fetched["sequence"]
	ScoreService.start_session(sequence.features, _motion.id, AppConfig.score_tolerance)
	state = State.RUNNING
	_stop_button.disabled = false
	_progress.value = 0.0
	_set_status("跟练进行中：参考 %d 帧（约 %.1f 秒）" % [
		sequence.frame_count(), sequence.duration_ms() / 1000.0,
	])


func _on_stop_pressed() -> void:
	if state != State.RUNNING:
		return
	_finish_session("已手动结束")


func _finish_session(reason: String) -> void:
	var summary := ScoreService.finish()
	state = State.FINISHED
	_stop_button.disabled = true
	_start_button.disabled = false
	_set_status("本轮结束（%s）" % reason)
	if retarget != null:
		retarget.reset()
	if _on_finished.is_valid():
		_on_finished.call(summary, _motion.source if _motion != null else null, _motion.name if _motion != null else "")


func _on_frame_received(frame: Object) -> void:
	if state != State.RUNNING or retarget == null:
		return
	retarget.apply(frame, 4.0 / 3.0)
	_total_frames += 1


func _on_score_updated(result: Dictionary) -> void:
	var score := float(result.get("score", 0.0))
	_score_label.text = "%d" % int(round(score))
	_score_label.add_theme_color_override("font_color", Scoring.grade_color(score))
	_grade_label.text = "%s ｜ %s" % [Scoring.grade(score), Scoring.grade_label(score)]
	_combo_label.text = "连击 %d ｜ 最高连击 %d" % [int(result.get("combo", 0)), int(result.get("max_combo", 0))]
	_progress.value = float(result.get("progress", 0.0)) * 100.0
	if score >= Scoring.COMBO_THRESHOLD:
		_good_frames += 1

	# 参考序列走完自动结算
	if bool(result.get("progress", 0.0) >= 0.999):
		_finish_session("动作已完成")


func _refresh_connection_hint() -> void:
	var count := PoseReceiver.connected_client_count()
	if count > 0:
		_hint_label.text = "● 已连接 %d 台设备：%s" % [count, AppConfig.listen_url()]
		_hint_label.add_theme_color_override("font_color", UiKit.COLOR_GOOD)
	elif PoseReceiver.is_listening():
		_hint_label.text = "○ 等待 Android 辅助 App 连接 %s" % AppConfig.listen_url()
		_hint_label.add_theme_color_override("font_color", UiKit.COLOR_MUTED)
	else:
		_hint_label.text = "○ 接收服务未启动（将在开始跟练时自动启动 %s）" % AppConfig.listen_url()
		_hint_label.add_theme_color_override("font_color", UiKit.COLOR_MUTED)


func _set_status(text: String) -> void:
	_status_label.text = text


func _fail(message: String) -> void:
	state = State.FAILED
	_set_status(message)
	_grade_label.text = "无法开始"
	_start_button.disabled = true
	_stop_button.disabled = true
	push_warning("[GameScreen] %s" % message)


func _clear_model() -> void:
	if vrm != null:
		if vrm.root != null and is_instance_valid(vrm.root) and vrm.root.get_parent() == _model_host:
			_model_host.remove_child(vrm.root)
		vrm.dispose()
		vrm = null
	retarget = null


func _clear_scene() -> void:
	if scene_runtime != null:
		if is_instance_valid(scene_runtime) and scene_runtime.get_parent() == _scene_host:
			_scene_host.remove_child(scene_runtime)
		scene_runtime.queue_free()
		scene_runtime = null
	scene_warning = ""


## 只在跟练进行中推进相机（orbit 模式需要时间轴），其余时候不动相机
func _process(delta: float) -> void:
	if scene_runtime == null or vrm == null or _camera == null:
		return
	if scene_runtime.config == null or scene_runtime.config.camera.mode != "orbit":
		return
	_elapsed += delta
	_apply_camera(_elapsed)


func _exit_tree() -> void:
	if PoseReceiver.frame_received.is_connected(_on_frame_received):
		PoseReceiver.frame_received.disconnect(_on_frame_received)
	if ScoreService.score_updated.is_connected(_on_score_updated):
		ScoreService.score_updated.disconnect(_on_score_updated)
	_clear_model()
	_clear_scene()