/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */

/* vim: set ts=8 sts=2 et sw=2 tw=80: */

/* This Source Code Form is subject to the terms of the Mozilla Public

 * License, v. 2.0. If a copy of the MPL was not distributed with this

 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#ifndef MobileViewportManager_h_

#define MobileViewportManager_h_

#include "mozilla/Maybe.h"

#include "nsCOMPtr.h"

#include "nsIDOMEventListener.h"

#include "nsIObserver.h"

#include "Units.h"

class nsIDOMEventTarget;

class nsIDocument;

class nsIPresShell;

class nsViewportInfo;

class MobileViewportManager final : public nsIDOMEventListener,

                                    public nsIObserver {

 public:

  NS_DECL_ISUPPORTS

  NS_DECL_NSIDOMEVENTLISTENER

  NS_DECL_NSIOBSERVER

  MobileViewportManager(nsIPresShell* aPresShell, nsIDocument* aDocument);

  void Destroy();

  /* Provide a resolution to use during the first paint instead of the default

   * resolution computed from the viewport info metadata. This is in the same

   * "units" as the argument to nsDOMWindowUtils::SetResolutionAndScaleTo.

   * Also takes the previous display dimensions as they were at the time the

   * resolution was stored in order to correctly adjust the resolution if the

   * device was rotated in the meantime. */

  void SetRestoreResolution(float aResolution,

                            mozilla::LayoutDeviceIntSize aDisplaySize);

 private:

  void SetRestoreResolution(float aResolution);

 public:

  /* Notify the MobileViewportManager that a reflow was requested in the

   * presShell.*/

  void RequestReflow();

  /* Notify the MobileViewportManager that the resolution on the presShell was

   * updated, and the SPCSPS needs to be updated. */

  void ResolutionUpdated();

 private:

  ~MobileViewportManager();

  /* Called to compute the initial viewport on page load or before-first-paint,

   * whichever happens first. */

  void SetInitialViewport();

  /* Main helper method to update the CSS viewport and any other properties that

   * need updating. */

  void RefreshViewportSize(bool aForceAdjustResolution);

  /* Secondary main helper method to update just the SPCSPS. */

  void RefreshSPCSPS();

  /* Helper to clamp the given zoom by the min/max in the viewport info. */

  mozilla::CSSToScreenScale ClampZoom(const mozilla::CSSToScreenScale& aZoom,

                                      const nsViewportInfo& aViewportInfo);

  /* Helper to update the given resolution according to changed display and

   * viewport widths. */

  mozilla::LayoutDeviceToLayerScale ScaleResolutionWithDisplayWidth(

      const mozilla::LayoutDeviceToLayerScale& aRes,

      const float& aDisplayWidthChangeRatio,

      const mozilla::CSSSize& aNewViewport,

      const mozilla::CSSSize& aOldViewport);

  /* Updates the presShell resolution and returns the new zoom. */

  mozilla::CSSToScreenScale UpdateResolution(

      const nsViewportInfo& aViewportInfo,

      const mozilla::ScreenIntSize& aDisplaySize,

      const mozilla::CSSSize& aViewport,

      const mozilla::Maybe<float>& aDisplayWidthChangeRatio);

  /* Updates the scroll-position-clamping scrollport size */

  void UpdateSPCSPS(const mozilla::ScreenIntSize& aDisplaySize,

                    const mozilla::CSSToScreenScale& aZoom);

  /* Updates the displayport margins for the presShell's root scrollable frame

   */

  void UpdateDisplayPortMargins();

  nsCOMPtr<nsIDocument> mDocument;

  nsIPresShell* MOZ_NON_OWNING_REF

      mPresShell;  // raw ref since the presShell owns this

  nsCOMPtr<nsIDOMEventTarget> mEventTarget;

  bool mIsFirstPaint;

  bool mPainted;

  mozilla::LayoutDeviceIntSize mDisplaySize;

  mozilla::CSSSize mMobileViewportSize;

  mozilla::Maybe<float> mRestoreResolution;

  mozilla::Maybe<mozilla::ScreenIntSize> mRestoreDisplaySize;

};

#endif