extends Node2D

# ============================================================================
# 探针 P3 —— NoiseTexture2D / FastNoiseLite 平铺语义（架构 §11 P3）
# 依据：管线报告 §6.3；作用于 §5.2 纸纹 pass（双尺度 noise 有序抖动的 tileable 前提）
# 实测手册：docs/engineering/2026-10-19-f-w1-probe-p3-manual.md
# 结论回填：docs/engineering/probes/P3-result.md
#
# 验证：seamless = true 是否真正可平铺
#   - 屏上：左右两个 2×2 tile 网格（红线 = tile 边界 @256px）肉直视读接缝
#   - 按 S：生成边界差图 PNG（user://p3_diff_*.png）+ 控制台统计
#     * wrap_* = |左边缘-右边缘| / |上边缘-下边缘|（平铺接缝强度）
#     * grad_mean = 相邻像素平均差（自然梯度基线）
#     * seamless 若有效：wrap ≈ grad（同数量级）；若无效：wrap >> grad
#
# 知识缺口：FastNoiseLite/NoiseTexture2D 属性名（seamless / seamless_blend_ratio /
#   TYPE_SIMPLEX / FRACTAL_FBM）为 4.x 稳定名；4.7.2 若报错按实际属性名修正并记录。
# ============================================================================

const NOISE_SIZE := 256 # 每 tile 256×256；面板 512×512 = 2×2 平铺
const PANEL_SIZE := 512

var _textures: Array = []


func _ready() -> void:
	_textures = [_make_texture(true), _make_texture(false)]
	var positions := [Vector2(96, 160), Vector2(672, 160)]
	var titles := ["seamless = true", "seamless = false"]
	for i in _textures.size():
		var tr := TextureRect.new()
		tr.name = "Panel%d" % i
		tr.texture = _textures[i]
		tr.position = positions[i]
		tr.size = Vector2(PANEL_SIZE, PANEL_SIZE)
		tr.stretch_mode = TextureRect.STRETCH_TILE
		tr.mouse_filter = Control.MOUSE_FILTER_IGNORE
		add_child(tr)
		var overlay := SeamOverlay.new()
		overlay.position = positions[i]
		add_child(overlay)
		var t := Label.new()
		t.name = "PanelTitle%d" % i
		t.text = "%s（红线 = tile 边界；面板内 2×2 平铺）" % titles[i]
		t.position = Vector2(int(positions[i].x), 128)
		t.add_theme_color_override("font_color", Color.WHITE)
		add_child(t)
	var hud := Label.new()
	hud.name = "HUDHelp"
	hud.text = "探针 P3 | 对比两侧红线处接缝（错位/亮度跳变=异常）| S 生成检查图到 user:// 并打印统计 | Esc 退出"
	hud.position = Vector2(96, 648)
	hud.add_theme_color_override("font_color", Color.WHITE)
	add_child(hud)
	_print_environment()


func _make_texture(seamless: bool) -> NoiseTexture2D:
	var fnl := FastNoiseLite.new()
	fnl.seed = 20261019
	fnl.noise_type = FastNoiseLite.TYPE_SIMPLEX
	fnl.frequency = 0.02
	fnl.fractal_type = FastNoiseLite.FRACTAL_FBM
	fnl.fractal_octaves = 3
	fnl.fractal_lacunarity = 2.0
	fnl.fractal_gain = 0.5
	var nt := NoiseTexture2D.new()
	nt.width = NOISE_SIZE
	nt.height = NOISE_SIZE
	nt.noise = fnl
	nt.seamless = seamless
	nt.seamless_blend_ratio = 0.25
	nt.generate_mipmaps = false
	return nt


func _input(event: InputEvent) -> void:
	var key_event := event as InputEventKey
	if key_event != null and key_event.pressed and not key_event.echo:
		match key_event.keycode:
			KEY_S:
				_generate_check_images()
			KEY_ESCAPE:
				get_tree().quit()


func _generate_check_images() -> void:
	var names := ["seamless", "periodic"]
	print("=== P3 检查图与统计 ===")
	for i in _textures.size():
		var nt: NoiseTexture2D = _textures[i]
		var img := nt.get_image()
		if img == null:
			push_warning("P3: NoiseTexture2D.get_image() 返回 null（%s）。回退：系统截图（Win+Shift+S）+ 肉眼判读。" % names[i])
			continue
		var w := img.get_width()
		var h := img.get_height()
		# 边界差图（×8 放大）：wrap 接缝越亮 = 平铺越不连续
		var strip_v := Image.create(w, h, false, Image.FORMAT_RGBA8)
		var strip_h := Image.create(w, h, false, Image.FORMAT_RGBA8)
		for y in h:
			var dv := _amp(absf(img.get_pixel(0, y).r - img.get_pixel(w - 1, y).r))
			for x in w:
				strip_v.set_pixel(x, y, Color(dv, dv, dv, 1.0))
		for x in w:
			var dh := _amp(absf(img.get_pixel(x, 0).r - img.get_pixel(x, h - 1).r))
			for y in h:
				strip_h.set_pixel(x, y, Color(dh, dh, dh, 1.0))
		strip_v.save_png("user://p3_diff_v_%s.png" % names[i])
		strip_h.save_png("user://p3_diff_h_%s.png" % names[i])
		var stats := _edge_stats(img)
		print("%s: wrap_v mean=%.5f max=%.5f | wrap_h mean=%.5f max=%.5f | grad_mean=%.5f → wrap/grad v=%.2fx h=%.2fx" % [
			names[i], stats.wrap_v_mean, stats.wrap_v_max, stats.wrap_h_mean, stats.wrap_h_max, stats.grad_mean,
			stats.wrap_v_mean / maxf(stats.grad_mean, 1e-9), stats.wrap_h_mean / maxf(stats.grad_mean, 1e-9)])
	print("PNG 位置：%APPDATA%/Godot/app_userdata/<项目名>/p3_diff_*.png")
	print("判读：seamless 行 wrap/grad ≈ 1-3x = 可用；periodic 行 wrap/grad ≫ 1 = 对照组生效（说明指标有效）")


func _amp(d: float) -> float:
	return clampf(d * 8.0, 0.0, 1.0)


func _edge_stats(img: Image) -> Dictionary:
	var w := img.get_width()
	var h := img.get_height()
	var wrap_v := 0.0
	var wrap_v_max := 0.0
	for y in h:
		var d := absf(img.get_pixel(0, y).r - img.get_pixel(w - 1, y).r)
		wrap_v += d
		wrap_v_max = maxf(wrap_v_max, d)
	var wrap_h := 0.0
	var wrap_h_max := 0.0
	for x in w:
		var d := absf(img.get_pixel(x, 0).r - img.get_pixel(x, h - 1).r)
		wrap_h += d
		wrap_h_max = maxf(wrap_h_max, d)
	var grad := 0.0
	for y in h:
		for x in w - 1:
			grad += absf(img.get_pixel(x, y).r - img.get_pixel(x + 1, y).r)
	return {
		"wrap_v_mean": wrap_v / h,
		"wrap_v_max": wrap_v_max,
		"wrap_h_mean": wrap_h / w,
		"wrap_h_max": wrap_h_max,
		"grad_mean": grad / float((w - 1) * h),
	}


func _print_environment() -> void:
	var v := Engine.get_version_info()
	print("=== P3 probe 环境 ===")
	print("godot: %d.%d.%d %s" % [int(v.major), int(v.minor), int(v.patch), str(v.status)])
	print("rendering_method: ", ProjectSettings.get_setting("rendering/renderer/rendering_method"))
	print("adapter: ", RenderingServer.get_video_adapter_name())
	print("noise: FastNoiseLite simplex fbm oct3 f0.02 | tile 256×256 | blend_ratio 0.25")


class SeamOverlay extends Node2D:
	const TILE := 256
	const PANEL := 512

	func _draw() -> void:
		var c := Color(1.0, 0.2, 0.2, 0.6)
		draw_line(Vector2(TILE, 0), Vector2(TILE, PANEL), c, 1.0)
		draw_line(Vector2(0, TILE), Vector2(PANEL, TILE), c, 1.0)
		draw_rect(Rect2(Vector2.ZERO, Vector2(PANEL, PANEL)), c, false, 1.0)