import bpy

def is_in_view3d_area(x,y):
    for area in bpy.context.screen.areas:
        if area.type == "VIEW_3D":
            x_in_range = x >= area.x and x <= area.x + area.width
            y_in_range = y >= area.y and y <= area.y + area.height
            return x_in_range and y_in_range
    return False

class SimpleMouseOperator(bpy.types.Operator):
    bl_idname = "wm.mouse_position"
    bl_label = "Mouse location"

    x : bpy.props.IntProperty()
    y : bpy.props.IntProperty()

    def execute(self, context):
        # rather then printing, use the report function,
        # this way the message appears in the header,
        in_range = is_in_view3d_area(self.x, self.y)
        self.report({'INFO'}, "Mouse coords are %d %d" % (self.x, self.y))
        self.report({'INFO'}, f"{in_range}")
        return {'FINISHED'}

    def invoke(self, context, event):
        self.x = event.mouse_x
        self.y = event.mouse_y
        return self.execute(context)



class MousePanel(bpy.types.Panel):
    bl_label = "Mouse"
    bl_space_type = "VIEW_3D"
    bl_region_type = "UI"

    def draw(self, context):

        layout = self.layout

        #what I want to do:
        #update this whenever the user moves the cursor outside or back inside the 3d viewport

        #if in_3dview:
            #layout.label(text = "within the 3d viewport")
        #else:
            #layout.label(text = "outside the 3d viewport")



        #this doesnt work
        if bpy.ops.wm.mouse_position():
            layout.label(text="HELLO")

bpy.utils.register_class(SimpleMouseOperator)
bpy.utils.register_class(MousePanel)