camera rotate with limitation around x and y axis by using touch

hello there i have recently developed an app for both mac and pc, and now i am trying to modify the same app for mobile usage.

my question is this: by using a transform variable i set an object to be in the middle right in front of the camera. there are no limits for x rotation, but a 85 degree limitation for the y axis for the camera. therefore my camera orbits x by 360 and 85 degrees on y from the facing side of the object, so i can not see the bottom of the object which is what i intend to do with touch as well. the whole code is shown below:

 var target : Transform;
 var edgeBorder = 0.1;
 var horizontalSpeed = 360.0;
 var verticalSpeed = 120.0;
 var maxVertical = 85.0;
 var minVertical = 0;
 
 private var x = 0.0;
 private var y = 0.0;
 private var distance = 0.0;
 
 function Start()
 {
     y = transform.eulerAngles.x;
     x = transform.eulerAngles.y;
     distance = (transform.position - target.position).magnitude;
 }
 
 function LateUpdate()
 {
     var dt = Time.deltaTime;
     x += Input.GetAxis("Horizontal") * horizontalSpeed * dt;
     y -= Input.GetAxis("Vertical") * verticalSpeed * dt;
     
     y = ClampAngle(y, minVertical, maxVertical);
      
     var rotation = Quaternion.Euler(y, x, 0);
     var position = rotation * Vector3(0.0, 0.0, -distance) + target.position;
     
     transform.rotation = rotation;
     transform.position = position;
 }
 
 static function ClampAngle (angle : float, min : float, max : float) {
     if (angle < -360)
         angle += 360;
     if (angle > 360)
         angle -= 360;
     return Mathf.Clamp (angle, min, max);
 }

how is it possible to use or edit this to something similar by using touch for mobile? thanks a bunch in advance...