namespace com.keyman.osk {
  /**
   * Implementations of this interface allow individual types of gestures to
   * specify any additional user interaction and functionality (which may
   * include UI elements) appropriate for obtaining a key event that may be
   * produced by the modeled gesture type.  These should only be instantiated
   * once the associated `PendingLongpress` is no longer 'pending' - once it
   * has become clear that the input touch-event sequence could only correspond
   * to the modeled gesture.
   * 
   * For example, when a longpress gesture completes - and hence, the user has
   * kept their finger stationary on the same key for a long enough period -
   * we display a popup view presenting subkeys corresponding to the gesture's
   * underlying element.  This popup view accepts touch input and completes only
   * upon release of the ongoing touch sequence.
   * 
   * Gestures are events that occur over intervals of time, and since some of them
   * will require time and user interaction after becoming 'realized', these cases
   * will be inherently async.  The simplest way to model this is with `Promise`s.
   * 
   * If appropriate for the modeled gesture type, an implementation may supply an
   * instantly-resolving `Promise`.  This may be appropriate for modeling "flick"
   * or "swipe" gestures in the future, which may require no additional input once
   * such a gesture is fully realized.
   */
  export interface RealizedGesture {
    readonly baseKey: KeyElement;
    readonly promise: Promise<text.KeyEvent>;

    clear(): void;
    isVisible(): boolean;
    updateTouch(input: InputEventCoordinate): void;
  }
}