/* -*- 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/. */

#include "VRDisplayPresentation.h"

#include "mozilla/dom/DocGroup.h"

#include "mozilla/Unused.h"

#include "VRDisplayClient.h"

#include "VRLayerChild.h"

using namespace mozilla;

using namespace mozilla::gfx;

VRDisplayPresentation::VRDisplayPresentation(VRDisplayClient *aDisplayClient,

                                             const nsTArray<mozilla::dom::VRLayer>& aLayers,

                                             uint32_t aGroup)

  : mDisplayClient(aDisplayClient)

  , mDOMLayers(aLayers)

  , mGroup(aGroup)

{

  CreateLayers();

}

void

VRDisplayPresentation::UpdateLayers(const nsTArray<mozilla::dom::VRLayer>& aLayers)

{

  mDOMLayers = aLayers;

  CreateLayers();

}

uint32_t

VRDisplayPresentation::GetGroup() const

{

  return mGroup;

}

void

VRDisplayPresentation::CreateLayers()

{

  VRManagerChild *manager = VRManagerChild::Get();

  if (!manager) {

    // This should not happen, but let's log it and avoid a crash in case

    // of regression.

    NS_WARNING("VRManagerChild::Get returned null!");

    return;

  }

  unsigned int iLayer=0;

  for (dom::VRLayer& layer : mDOMLayers) {

    dom::HTMLCanvasElement* canvasElement = layer.mSource;

    if (!canvasElement) {

      /// XXX In the future we will support WebVR in WebWorkers here

      continue;

    }

    Rect leftBounds(0.0, 0.0, 0.5, 1.0);

    if (layer.mLeftBounds.Length() == 4) {

      leftBounds.SetRect(layer.mLeftBounds[0],

                         layer.mLeftBounds[1],

                         layer.mLeftBounds[2],

                         layer.mLeftBounds[3]);

    } else if (layer.mLeftBounds.Length() != 0) {

      /**

       * We ignore layers with an incorrect number of values.

       * In the future, VRDisplay.requestPresent may throw in

       * this case.  See https://github.com/w3c/webvr/issues/71

       */

      continue;

    }

    Rect rightBounds(0.5, 0.0, 0.5, 1.0);

    if (layer.mRightBounds.Length() == 4) {

      rightBounds.SetRect(layer.mRightBounds[0], 

                          layer.mRightBounds[1],

                          layer.mRightBounds[2],

                          layer.mRightBounds[3]);

    } else if (layer.mRightBounds.Length() != 0) {

      /**

       * We ignore layers with an incorrect number of values.

       * In the future, VRDisplay.requestPresent may throw in

       * this case.  See https://github.com/w3c/webvr/issues/71

       */

      continue;

    }

    nsCOMPtr<nsIEventTarget> target;

    nsIDocument* doc;

    doc = canvasElement->OwnerDoc();

    if (doc) {

      target = doc->EventTargetFor(TaskCategory::Other);

    }

    if (mLayers.Length() <= iLayer) {

      // Not enough layers, let's add one

      RefPtr<VRLayerChild> vrLayer =

        static_cast<VRLayerChild*>(manager->CreateVRLayer(mDisplayClient->GetDisplayInfo().GetDisplayID(),

                                                          target, mGroup));

      if (!vrLayer) {

        NS_WARNING("CreateVRLayer returned null!");

        continue;

      }

      vrLayer->Initialize(canvasElement, leftBounds, rightBounds);

      mLayers.AppendElement(vrLayer);

    } else {

      // We already have a layer, let's update it

      mLayers[iLayer]->Initialize(canvasElement, leftBounds, rightBounds);

    }

    iLayer++;

  }

  // Truncate any excess layers that weren't included in the updated list

  mLayers.SetLength(iLayer);

}

void

VRDisplayPresentation::DestroyLayers()

{

  for (VRLayerChild* layer : mLayers) {

    if (layer->IsIPCOpen()) {

      Unused << layer->SendDestroy();

    }

  }

  mLayers.Clear();

}

void

VRDisplayPresentation::GetDOMLayers(nsTArray<dom::VRLayer>& result)

{

  result = mDOMLayers;

}

VRDisplayPresentation::~VRDisplayPresentation()

{

  DestroyLayers();

  mDisplayClient->PresentationDestroyed();

}

void VRDisplayPresentation::SubmitFrame()

{

  for (VRLayerChild *layer : mLayers) {

    layer->SubmitFrame(mDisplayClient->GetDisplayInfo());

    break; // Currently only one layer supported, submit only the first

  }

}