/*
 * Copyright (C) 2012 Google Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1.  Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 * 2.  Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
 * DAMAGE.
 */

#ifndef THIRD_PARTY_BLINK_RENDERER_CORE_PAGE_POINTER_LOCK_CONTROLLER_H_
#define THIRD_PARTY_BLINK_RENDERER_CORE_PAGE_POINTER_LOCK_CONTROLLER_H_

#include <memory>

#include "cc/trees/layer_tree_host.h"
#include "third_party/blink/public/mojom/input/pointer_lock_context.mojom-blink.h"
#include "third_party/blink/public/mojom/input/pointer_lock_result.mojom-blink-forward.h"
#include "third_party/blink/renderer/bindings/core/v8/script_promise.h"
#include "third_party/blink/renderer/bindings/core/v8/script_promise_resolver.h"
#include "third_party/blink/renderer/core/core_export.h"
#include "third_party/blink/renderer/platform/heap/garbage_collected.h"
#include "third_party/blink/renderer/platform/mojo/heap_mojo_remote.h"
#include "third_party/blink/renderer/platform/wtf/text/atomic_string.h"
#include "ui/gfx/geometry/point_f.h"

namespace blink {

class Element;
class Document;
class LocalFrame;
class Page;
class PointerLockOptions;
class WebMouseEvent;

// This class handles mouse pointer lock and unlock, and dispatching mouse
// events when locked. See: https://w3c.github.io/pointerlock
class CORE_EXPORT PointerLockController final
    : public GarbageCollected<PointerLockController> {
 public:
  explicit PointerLockController(Page*);
  PointerLockController(const PointerLockController&) = delete;
  PointerLockController& operator=(const PointerLockController&) = delete;

  using ResultCallback =
      base::OnceCallback<void(mojom::blink::PointerLockResult)>;
  bool RequestPointerLock(Element* target, ResultCallback callback);

  void RequestPointerLock(ScriptPromiseResolver<IDLUndefined>* resolver,
                          Element* target,
                          const PointerLockOptions* options = nullptr);
  void ExitPointerLock();
  void ElementRemoved(Element*);
  void DocumentDetached(Document*);
  bool LockPending() const;
  bool IsPointerLocked() const;
  Element* GetElement() const;

  void DidAcquirePointerLock();
  void DidNotAcquirePointerLock();
  void DispatchLockedMouseEvent(const WebMouseEvent&,
                                const Vector<WebMouseEvent>& coalesced_events,
                                const Vector<WebMouseEvent>& predicted_events,
                                const AtomicString& event_type);

  // Fetch the locked mouse position when pointer is locked. The values are not
  // changed if pointer is not locked.
  void GetPointerLockPosition(gfx::PointF* lock_position,
                              gfx::PointF* lock_screen_position);
  void Trace(Visitor*) const;

  static Element* GetPointerLockedElement(LocalFrame* frame);

 private:
  friend class PointerLockControllerTest;

  void ClearElement();
  void EnqueueEvent(const AtomicString& type, Element*);
  void EnqueueEvent(const AtomicString& type, Document*);
  void ChangeLockRequestCallback(Element* target,
                                 ResultCallback callback,
                                 bool unadjusted_movement_requested,
                                 mojom::blink::PointerLockResult result);
  void LockRequestCallback(
      ResultCallback callback,
      bool unadjusted_movement_requested,
      mojom::blink::PointerLockResult result,
      mojo::PendingRemote<blink::mojom::blink::PointerLockContext> context);

  void ProcessResult(ResultCallback callback,
                     bool unadjusted_movement_requested,
                     mojom::blink::PointerLockResult result);

  static void ProcessResultPromise(
      ScriptPromiseResolver<IDLUndefined>* resolver,
      mojom::blink::PointerLockResult result);
  static DOMException* ConvertResultToException(
      mojom::blink::PointerLockResult result);

  Member<Page> page_;
  bool lock_pending_;
  Member<Element> element_;
  Member<Document> document_of_removed_element_while_waiting_for_unlock_;

  HeapMojoRemote<mojom::blink::PointerLockContext> mouse_lock_context_{nullptr};

  std::unique_ptr<cc::ScopedRequestHighFramerate> high_framerate_request_;

  // Store the locked position so that the event position keeps unchanged when
  // in locked states. These values only get set when entering lock states.
  gfx::PointF pointer_lock_position_;
  gfx::PointF pointer_lock_screen_position_;

  // If there are more than `kMaxLocksInWindow` lock requests within
  // `kLockRateLimitWindow`, reject all pointer lock requests until
  // `kLockRateLimitWindow` has passed since the last successful lock. These
  // values were chosen were chosen to allow common use-cases and not determined
  // through any user-study or specification. Rate limiting was added in blink
  // instead of the browser process because a pointer lock request causes a
  // roundtrip to the browser process, so a page that is spamming pointer lock
  // requests would be able to cause a large amount of unnecessary IPC traffic
  // which would bog down the browser and cause it to lag, even if the page is
  // not able to successfully acquire pointer lock.
  static constexpr size_t kMaxLocksInWindow = 4;
  static constexpr base::TimeDelta kLockRateLimitWindow = base::Seconds(2);

  // The timestamp of the most recent pointer lock request. Used for rate
  // limiting to prevent abuse where a page rapidly locks and unlocks the
  // pointer.
  base::TimeTicks last_successful_lock_timestamp_;
  uint8_t recent_lock_attempts_ = 0;

  bool current_unadjusted_movement_setting_ = false;
};

}  // namespace blink

#endif  // THIRD_PARTY_BLINK_RENDERER_CORE_PAGE_POINTER_LOCK_CONTROLLER_H_