extends ItemList
class_name TouchItemList

const POINTER_VELOCITY_DECAYING_FACTOR: float = 2.5

var is_pointer_dragging		:= false
var pointer_drag_velocity	:= 0.0

onready var sensor			:= get_node("sensor") as PointerInputSensor
onready var v_scroll_bar	:= get_v_scroll() as ScrollBar


func _ready():
	sensor.connect("on_press", self, "pointer_input_on_press_handler")
	sensor.connect("on_drag", self, "pointer_input_on_drag_handler")
	sensor.connect("on_end_drag", self, "pointer_input_on_end_drag_handler")
	sensor.connect("on_click", self, "pointer_input_on_click_handler")
	sensor.connect("on_scroll", self, "pointer_input_on_scroll_handler")


func _process(delta: float):
	# Apply drag movement inertia.
	if is_pointer_dragging == false && abs(pointer_drag_velocity) > 0.5:
		pointer_drag_velocity *= clamp((1.0 - POINTER_VELOCITY_DECAYING_FACTOR * delta), 0.0, 1.0)
		v_scroll_bar.value -= pointer_drag_velocity * delta


func pointer_input_on_press_handler(pointer: PointerInputSensor.PointerInputData):
	is_pointer_dragging = true


func pointer_input_on_drag_handler(pointer: PointerInputSensor.PointerInputData):
	is_pointer_dragging = true
	pointer_drag_velocity = pointer.velocity.y
	v_scroll_bar.value -= pointer.relative_position.y


func pointer_input_on_end_drag_handler(pointer: PointerInputSensor.PointerInputData):
	is_pointer_dragging = false


func pointer_input_on_click_handler(pointer: PointerInputSensor.PointerInputData):
	var target := self
	var position := target.get_global_mouse_position() - target.rect_global_position
	
	var event_touch := InputEventScreenTouch.new()
	event_touch.index = 0
	event_touch.position = position
	
	var event_mouse := InputEventMouseButton.new()
	event_mouse.button_index = BUTTON_LEFT
	event_mouse.button_mask = BUTTON_MASK_LEFT
	event_mouse.position = position
	
	event_mouse.pressed = true
	event_touch.pressed = true
	target._gui_input(event_mouse)
	target._gui_input(event_touch)
	
	target.grab_focus()
	
	event_mouse.pressed = false
	event_touch.pressed = false
	target._gui_input(event_mouse)
	target._gui_input(event_touch)


func pointer_input_on_scroll_handler(pointer: PointerInputSensor.PointerInputData):
	var target := self
	target._gui_input(pointer.event)