extends Control

# ============================================================================
# SettingsSlider.gd - 设置面板自绘滑条
# ============================================================================
# 使用白色圆形滑块和柔和轨道，贴近概念图里的轻量滑条样式。
# ============================================================================

signal value_changed(value: float)

const TRACK_COLOR: Color = Color(0.842, 0.894, 0.936, 0.95)
const FILL_COLOR: Color = Color(0.258824, 0.627451, 0.913725, 1.0)
const KNOB_COLOR: Color = Color(1.0, 1.0, 1.0, 1.0)
const KNOB_SHADOW_COLOR: Color = Color(0.125, 0.282, 0.408, 0.16)

var value: float = 1.0
var _dragging: bool = false

func _ready() -> void:
	custom_minimum_size = Vector2(360, 34)
	mouse_filter = Control.MOUSE_FILTER_STOP
	mouse_default_cursor_shape = Control.CURSOR_POINTING_HAND

func set_value(newValue: float, emitSignal: bool = false) -> void:
	var clamped: float = clampf(newValue, 0.0, 1.0)
	if abs(value - clamped) < 0.001:
		return
	value = clamped
	queue_redraw()
	if emitSignal:
		value_changed.emit(value)

func _gui_input(event: InputEvent) -> void:
	if event is InputEventMouseButton:
		var mouseEvent := event as InputEventMouseButton
		if mouseEvent.button_index != MOUSE_BUTTON_LEFT:
			return
		_dragging = mouseEvent.pressed
		if _dragging:
			_update_from_x(mouseEvent.position.x)
			accept_event()
		return

	if event is InputEventMouseMotion and _dragging:
		var motionEvent := event as InputEventMouseMotion
		_update_from_x(motionEvent.position.x)
		accept_event()

func _draw() -> void:
	var trackHeight: float = 8.0
	var knobRadius: float = 12.0
	var left: float = knobRadius + 1.0
	var right: float = size.x - knobRadius - 1.0
	var centerY: float = size.y * 0.5
	var width: float = max(1.0, right - left)
	var knobX: float = left + width * value

	var trackRect: Rect2 = Rect2(Vector2(left, centerY - trackHeight * 0.5), Vector2(width, trackHeight))
	draw_style_box(_round_box(TRACK_COLOR, int(trackHeight * 0.5)), trackRect)

	var fillRect: Rect2 = Rect2(trackRect.position, Vector2(max(trackHeight, knobX - left), trackHeight))
	draw_style_box(_round_box(FILL_COLOR, int(trackHeight * 0.5)), fillRect)

	var knobCenter: Vector2 = Vector2(knobX, centerY)
	draw_circle(knobCenter + Vector2(0, 1.4), knobRadius + 1.0, KNOB_SHADOW_COLOR)
	draw_circle(knobCenter, knobRadius, KNOB_COLOR)
	draw_arc(knobCenter, knobRadius, 0.0, TAU, 32, Color(0.790, 0.848, 0.902, 0.75), 1.0, true)

func _update_from_x(x: float) -> void:
	var knobRadius: float = 12.0
	var left: float = knobRadius + 1.0
	var right: float = size.x - knobRadius - 1.0
	var width: float = max(1.0, right - left)
	set_value((x - left) / width, true)

func _round_box(color: Color, radius: int) -> StyleBoxFlat:
	var style := StyleBoxFlat.new()
	style.bg_color = color
	style.corner_radius_top_left = radius
	style.corner_radius_top_right = radius
	style.corner_radius_bottom_left = radius
	style.corner_radius_bottom_right = radius
	return style