// Copyright 2020 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef CONTENT_PUBLIC_BROWSER_BROWSER_XR_RUNTIME_H_
#define CONTENT_PUBLIC_BROWSER_BROWSER_XR_RUNTIME_H_

#include "base/observer_list_types.h"
#include "content/common/content_export.h"
#include "device/vr/public/mojom/vr_service.mojom.h"

namespace content {

class WebContents;

// This interface allows observing the state of the XR service for a particular
// runtime.  In particular, observers may currently know when the browser
// considers a WebContents presenting to an immersive headset.  Implementers of
// this interface will be called on the main browser thread.  Currently this is
// used on Windows to drive overlays.
class CONTENT_EXPORT BrowserXRRuntime {
 public:
  class Observer : public base::CheckedObserver {
   public:
    // Called when a page starts or ends an immersive WebXR session. When a
    // session was started, |web_contents| will be non-null. There can only be
    // at most one active immersive session for the XRRuntime. When there is no
    // active immersive session, this method will be called with |web_contents|
    // set to null.
    virtual void WebXRWebContentsChanged(WebContents* web_contents) {}

    // Called when the currently active immersive WebXR session has its frames
    // [un/]throttled by the compositor.
    virtual void WebXRFramesThrottledChanged(bool throttled) {}

    // Called when the observed runtime's camera in use state changes for the
    // currently active immersive WebXR session. When |in_use| is true,
    // |web_contents| will not be null.
    virtual void WebXRCameraInUseChanged(WebContents* web_contents,
                                         bool in_use) {}

    virtual void SetDefaultXrViews(
        const std::vector<device::mojom::XRViewPtr>& views) {}
  };

  virtual void AddObserver(Observer* observer) = 0;
  virtual void RemoveObserver(Observer* observer) = 0;
};

}  // namespace content

#endif  // CONTENT_PUBLIC_BROWSER_BROWSER_XR_RUNTIME_H_