/**
 * Which surfaces a fullscreen toggle has to move.
 *
 * `requestFullscreen()` only ever fullscreens the *document*. That was
 * sufficient while every renderer lived inside it: the HTML5 `<video>` element
 * is part of the document, so WebKit scaled it to the screen and the OS
 * window's real size never mattered.
 *
 * A native video surface is drawn *behind* the webview at **window** size, so a
 * document-only fullscreen leaves the picture exactly where it was while the
 * page around it goes fullscreen. On WebKitGTK the observed result is a
 * maximised window with decorations still taking a strip of the screen — the
 * video renders correctly, at the wrong size, which reads as "fullscreen is
 * broken" rather than as a windowing problem.
 *
 * Android already needed its own answer here for the system bars (DR-157); this
 * is the desktop equivalent of the same rule: whoever actually owns the pixels
 * has to be the thing that goes fullscreen.
 *
 * TRACES: UR-066 | DR-240 | UT-219
 */
export interface FullscreenPlan {
  /** Ask the document to go fullscreen (harmless everywhere, needed for CSS). */
  document: boolean;
  /** Resize the OS window itself. Required when a native surface owns the picture. */
  osWindow: boolean;
}

/**
 * @param rendersNatively true when a native surface (mpv/ExoPlayer) draws the
 *        picture rather than an in-document `<video>` element.
 */
export function planFullscreen(rendersNatively: boolean): FullscreenPlan {
  return { document: true, osWindow: rendersNatively };
}