/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 2 -*-
 * 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 <math.h>

#include "prlink.h"
#include "prmem.h"
#include "prenv.h"
#include "gfxPrefs.h"
#include "nsString.h"
#include "mozilla/Preferences.h"

#include "mozilla/gfx/Quaternion.h"

#ifdef XP_WIN
#include "../layers/d3d11/CompositorD3D11.h"
#include "../layers/d3d11/TextureD3D11.h"
#endif

#include "gfxVROSVR.h"

#ifndef M_PI
#define M_PI 3.14159265358979323846
#endif

using namespace mozilla::layers;
using namespace mozilla::gfx;
using namespace mozilla::gfx::impl;

namespace {
// need to typedef functions that will be used in the code below
extern "C" {
typedef OSVR_ClientContext (*pfn_osvrClientInit)(
  const char applicationIdentifier[], uint32_t flags);
typedef OSVR_ReturnCode (*pfn_osvrClientShutdown)(OSVR_ClientContext ctx);
typedef OSVR_ReturnCode (*pfn_osvrClientUpdate)(OSVR_ClientContext ctx);
typedef OSVR_ReturnCode (*pfn_osvrClientCheckStatus)(OSVR_ClientContext ctx);
typedef OSVR_ReturnCode (*pfn_osvrClientGetInterface)(
  OSVR_ClientContext ctx, const char path[], OSVR_ClientInterface* iface);
typedef OSVR_ReturnCode (*pfn_osvrClientFreeInterface)(
  OSVR_ClientContext ctx, OSVR_ClientInterface iface);
typedef OSVR_ReturnCode (*pfn_osvrGetOrientationState)(
  OSVR_ClientInterface iface, OSVR_TimeValue* timestamp,
  OSVR_OrientationState* state);
typedef OSVR_ReturnCode (*pfn_osvrGetPositionState)(OSVR_ClientInterface iface,
                                                    OSVR_TimeValue* timestamp,
                                                    OSVR_PositionState* state);
typedef OSVR_ReturnCode (*pfn_osvrClientGetDisplay)(OSVR_ClientContext ctx,
                                                    OSVR_DisplayConfig* disp);
typedef OSVR_ReturnCode (*pfn_osvrClientFreeDisplay)(OSVR_DisplayConfig disp);
typedef OSVR_ReturnCode (*pfn_osvrClientGetNumEyesForViewer)(
  OSVR_DisplayConfig disp, OSVR_ViewerCount viewer, OSVR_EyeCount* eyes);
typedef OSVR_ReturnCode (*pfn_osvrClientGetViewerEyePose)(
  OSVR_DisplayConfig disp, OSVR_ViewerCount viewer, OSVR_EyeCount eye,
  OSVR_Pose3* pose);
typedef OSVR_ReturnCode (*pfn_osvrClientGetDisplayDimensions)(
  OSVR_DisplayConfig disp, OSVR_DisplayInputCount displayInputIndex,
  OSVR_DisplayDimension* width, OSVR_DisplayDimension* height);
typedef OSVR_ReturnCode (
  *pfn_osvrClientGetViewerEyeSurfaceProjectionClippingPlanes)(
  OSVR_DisplayConfig disp, OSVR_ViewerCount viewer, OSVR_EyeCount eye,
  OSVR_SurfaceCount surface, double* left, double* right, double* bottom,
  double* top);
typedef OSVR_ReturnCode (*pfn_osvrClientGetRelativeViewportForViewerEyeSurface)(
  OSVR_DisplayConfig disp, OSVR_ViewerCount viewer, OSVR_EyeCount eye,
  OSVR_SurfaceCount surface, OSVR_ViewportDimension* left,
  OSVR_ViewportDimension* bottom, OSVR_ViewportDimension* width,
  OSVR_ViewportDimension* height);
typedef OSVR_ReturnCode (*pfn_osvrClientGetViewerEyeSurfaceProjectionMatrixf)(
  OSVR_DisplayConfig disp, OSVR_ViewerCount viewer, OSVR_EyeCount eye,
  OSVR_SurfaceCount surface, float near, float far,
  OSVR_MatrixConventions flags, float* matrix);
typedef OSVR_ReturnCode (*pfn_osvrClientCheckDisplayStartup)(
  OSVR_DisplayConfig disp);
typedef OSVR_ReturnCode (*pfn_osvrClientSetRoomRotationUsingHead)(
  OSVR_ClientContext ctx);
}

static pfn_osvrClientInit osvr_ClientInit = nullptr;
static pfn_osvrClientShutdown osvr_ClientShutdown = nullptr;
static pfn_osvrClientUpdate osvr_ClientUpdate = nullptr;
static pfn_osvrClientCheckStatus osvr_ClientCheckStatus = nullptr;
static pfn_osvrClientGetInterface osvr_ClientGetInterface = nullptr;
static pfn_osvrClientFreeInterface osvr_ClientFreeInterface = nullptr;
static pfn_osvrGetOrientationState osvr_GetOrientationState = nullptr;
static pfn_osvrGetPositionState osvr_GetPositionState = nullptr;
static pfn_osvrClientGetDisplay osvr_ClientGetDisplay = nullptr;
static pfn_osvrClientFreeDisplay osvr_ClientFreeDisplay = nullptr;
static pfn_osvrClientGetNumEyesForViewer osvr_ClientGetNumEyesForViewer =
  nullptr;
static pfn_osvrClientGetViewerEyePose osvr_ClientGetViewerEyePose = nullptr;
static pfn_osvrClientGetDisplayDimensions osvr_ClientGetDisplayDimensions =
  nullptr;
static pfn_osvrClientGetViewerEyeSurfaceProjectionClippingPlanes
  osvr_ClientGetViewerEyeSurfaceProjectionClippingPlanes = nullptr;
static pfn_osvrClientGetRelativeViewportForViewerEyeSurface
  osvr_ClientGetRelativeViewportForViewerEyeSurface = nullptr;
static pfn_osvrClientGetViewerEyeSurfaceProjectionMatrixf
  osvr_ClientGetViewerEyeSurfaceProjectionMatrixf = nullptr;
static pfn_osvrClientCheckDisplayStartup osvr_ClientCheckDisplayStartup =
  nullptr;
static pfn_osvrClientSetRoomRotationUsingHead
  osvr_ClientSetRoomRotationUsingHead = nullptr;

bool
LoadOSVRRuntime()
{
  static PRLibrary* osvrUtilLib = nullptr;
  static PRLibrary* osvrCommonLib = nullptr;
  static PRLibrary* osvrClientLib = nullptr;
  static PRLibrary* osvrClientKitLib = nullptr;
  //this looks up the path in the about:config setting, from greprefs.js or modules\libpref\init\all.js
  nsAdoptingCString osvrUtilPath =
    mozilla::Preferences::GetCString("gfx.vr.osvr.utilLibPath");
  nsAdoptingCString osvrCommonPath =
    mozilla::Preferences::GetCString("gfx.vr.osvr.commonLibPath");
  nsAdoptingCString osvrClientPath =
    mozilla::Preferences::GetCString("gfx.vr.osvr.clientLibPath");
  nsAdoptingCString osvrClientKitPath =
    mozilla::Preferences::GetCString("gfx.vr.osvr.clientKitLibPath");

  //we need all the libs to be valid
  if ((!osvrUtilPath) || (!osvrCommonPath) || (!osvrClientPath) ||
      (!osvrClientKitPath)) {
    return false;
  }

  osvrUtilLib = PR_LoadLibrary(osvrUtilPath.BeginReading());
  osvrCommonLib = PR_LoadLibrary(osvrCommonPath.BeginReading());
  osvrClientLib = PR_LoadLibrary(osvrClientPath.BeginReading());
  osvrClientKitLib = PR_LoadLibrary(osvrClientKitPath.BeginReading());

  if (!osvrUtilLib) {
    printf_stderr("[OSVR] Failed to load OSVR Util library!\n");
    return false;
  }
  if (!osvrCommonLib) {
    printf_stderr("[OSVR] Failed to load OSVR Common library!\n");
    return false;
  }
  if (!osvrClientLib) {
    printf_stderr("[OSVR] Failed to load OSVR Client library!\n");
    return false;
  }
  if (!osvrClientKitLib) {
    printf_stderr("[OSVR] Failed to load OSVR ClientKit library!\n");
    return false;
  }

// make sure all functions that we'll be using are available
#define REQUIRE_FUNCTION(_x)                                                   \
  do {                                                                         \
    *(void**) & osvr_##_x =                                                    \
      (void*)PR_FindSymbol(osvrClientKitLib, "osvr" #_x);                      \
    if (!osvr_##_x) {                                                          \
      printf_stderr("osvr" #_x " symbol missing\n");                           \
      goto fail;                                                               \
    }                                                                          \
  } while (0)

  REQUIRE_FUNCTION(ClientInit);
  REQUIRE_FUNCTION(ClientShutdown);
  REQUIRE_FUNCTION(ClientUpdate);
  REQUIRE_FUNCTION(ClientCheckStatus);
  REQUIRE_FUNCTION(ClientGetInterface);
  REQUIRE_FUNCTION(ClientFreeInterface);
  REQUIRE_FUNCTION(GetOrientationState);
  REQUIRE_FUNCTION(GetPositionState);
  REQUIRE_FUNCTION(ClientGetDisplay);
  REQUIRE_FUNCTION(ClientFreeDisplay);
  REQUIRE_FUNCTION(ClientGetNumEyesForViewer);
  REQUIRE_FUNCTION(ClientGetViewerEyePose);
  REQUIRE_FUNCTION(ClientGetDisplayDimensions);
  REQUIRE_FUNCTION(ClientGetViewerEyeSurfaceProjectionClippingPlanes);
  REQUIRE_FUNCTION(ClientGetRelativeViewportForViewerEyeSurface);
  REQUIRE_FUNCTION(ClientGetViewerEyeSurfaceProjectionMatrixf);
  REQUIRE_FUNCTION(ClientCheckDisplayStartup);
  REQUIRE_FUNCTION(ClientSetRoomRotationUsingHead);

#undef REQUIRE_FUNCTION

  return true;

fail:
  return false;
}

} // namespace

mozilla::gfx::VRFieldOfView
SetFromTanRadians(double left, double right, double bottom, double top)
{
  mozilla::gfx::VRFieldOfView fovInfo;
  fovInfo.leftDegrees = atan(left) * 180.0 / M_PI;
  fovInfo.rightDegrees = atan(right) * 180.0 / M_PI;
  fovInfo.upDegrees = atan(top) * 180.0 / M_PI;
  fovInfo.downDegrees = atan(bottom) * 180.0 / M_PI;
  return fovInfo;
}

VRDisplayOSVR::VRDisplayOSVR(OSVR_ClientContext* context,
                         OSVR_ClientInterface* iface,
                         OSVR_DisplayConfig* display)
  : VRDisplayHost(VRDeviceType::OSVR)
  , m_ctx(context)
  , m_iface(iface)
  , m_display(display)
{

  MOZ_COUNT_CTOR_INHERITED(VRDisplayOSVR, VRDisplayHost);

  mDisplayInfo.mIsConnected = true;
  mDisplayInfo.mDisplayName.AssignLiteral("OSVR HMD");
  mDisplayInfo.mCapabilityFlags = VRDisplayCapabilityFlags::Cap_None;
  mDisplayInfo.mCapabilityFlags =
    VRDisplayCapabilityFlags::Cap_Orientation | VRDisplayCapabilityFlags::Cap_Position;

  mDisplayInfo.mCapabilityFlags |= VRDisplayCapabilityFlags::Cap_External;
  mDisplayInfo.mCapabilityFlags |= VRDisplayCapabilityFlags::Cap_Present;

  // XXX OSVR display topology allows for more than one viewer
  // will assume only one viewer for now (most likely stay that way)

  OSVR_EyeCount numEyes;
  osvr_ClientGetNumEyesForViewer(*m_display, 0, &numEyes);

  for (uint8_t eye = 0; eye < numEyes; eye++) {
    double left, right, bottom, top;
    // XXX for now there is only one surface per eye
    osvr_ClientGetViewerEyeSurfaceProjectionClippingPlanes(
      *m_display, 0, eye, 0, &left, &right, &bottom, &top);
    mDisplayInfo.mEyeFOV[eye] =
      SetFromTanRadians(-left, right, -bottom, top);
  }

  // XXX Assuming there is only one display input for now
  // however, it's possible to have more than one (dSight with 2 HDMI inputs)
  OSVR_DisplayDimension width, height;
  osvr_ClientGetDisplayDimensions(*m_display, 0, &width, &height);


  for (uint8_t eye = 0; eye < numEyes; eye++) {

    OSVR_ViewportDimension l, b, w, h;
    osvr_ClientGetRelativeViewportForViewerEyeSurface(*m_display, 0, eye, 0, &l,
                                                      &b, &w, &h);
    mDisplayInfo.mEyeResolution.width = w;
    mDisplayInfo.mEyeResolution.height = h;
    OSVR_Pose3 eyePose;
    // Viewer eye pose may not be immediately available, update client context until we get it
    OSVR_ReturnCode ret =
      osvr_ClientGetViewerEyePose(*m_display, 0, eye, &eyePose);
    while (ret != OSVR_RETURN_SUCCESS) {
      osvr_ClientUpdate(*m_ctx);
      ret = osvr_ClientGetViewerEyePose(*m_display, 0, eye, &eyePose);
    }
    mDisplayInfo.mEyeTranslation[eye].x = eyePose.translation.data[0];
    mDisplayInfo.mEyeTranslation[eye].y = eyePose.translation.data[1];
    mDisplayInfo.mEyeTranslation[eye].z = eyePose.translation.data[2];
  }
}

void
VRDisplayOSVR::Destroy()
{
  // destroy non-owning pointers
  m_ctx = nullptr;
  m_iface = nullptr;
  m_display = nullptr;
}

void
VRDisplayOSVR::ZeroSensor()
{
  // recenter pose aka reset yaw
  osvr_ClientSetRoomRotationUsingHead(*m_ctx);
}

VRHMDSensorState
VRDisplayOSVR::GetSensorState()
{

  //update client context before anything
  //this usually goes into app's mainloop
  osvr_ClientUpdate(*m_ctx);

  VRHMDSensorState result;
  OSVR_TimeValue timestamp;
  result.Clear();

  OSVR_OrientationState orientation;

  OSVR_ReturnCode ret =
    osvr_GetOrientationState(*m_iface, &timestamp, &orientation);

  result.timestamp = timestamp.seconds;

  if (ret == OSVR_RETURN_SUCCESS) {
    result.flags |= VRDisplayCapabilityFlags::Cap_Orientation;
    result.orientation[0] = orientation.data[1];
    result.orientation[1] = orientation.data[2];
    result.orientation[2] = orientation.data[3];
    result.orientation[3] = orientation.data[0];
  }

  OSVR_PositionState position;
  ret = osvr_GetPositionState(*m_iface, &timestamp, &position);
  if (ret == OSVR_RETURN_SUCCESS) {
    result.flags |= VRDisplayCapabilityFlags::Cap_Position;
    result.position[0] = position.data[0];
    result.position[1] = position.data[1];
    result.position[2] = position.data[2];
  }

  return result;
}

VRHMDSensorState
VRDisplayOSVR::GetImmediateSensorState()
{
  return GetSensorState();
}

#if defined(XP_WIN)

void
VRDisplayOSVR::SubmitFrame(TextureSourceD3D11* aSource,
  const IntSize& aSize,
  const VRHMDSensorState& aSensorState,
  const gfx::Rect& aLeftEyeRect,
  const gfx::Rect& aRightEyeRect)
{
  // XXX Add code to submit frame
}

#endif

void
VRDisplayOSVR::StartPresentation()
{
  // XXX Add code to start VR Presentation
}

void
VRDisplayOSVR::StopPresentation()
{
  // XXX Add code to end VR Presentation
}

already_AddRefed<VRDisplayManagerOSVR>
VRDisplayManagerOSVR::Create()
{
  MOZ_ASSERT(NS_IsMainThread());

  if (!gfxPrefs::VREnabled() || !gfxPrefs::VROSVREnabled()) {
    return nullptr;
  }
  if (!LoadOSVRRuntime()) {
    return nullptr;
  }
  RefPtr<VRDisplayManagerOSVR> manager = new VRDisplayManagerOSVR();
  return manager.forget();
}

void
VRDisplayManagerOSVR::CheckOSVRStatus()
{
  if (mOSVRInitialized) {
    return;
  }

  // client context must be initialized first
  InitializeClientContext();

  // update client context
  osvr_ClientUpdate(m_ctx);

  // initialize interface and display if they are not initialized yet
  InitializeInterface();
  InitializeDisplay();

  // OSVR is fully initialized now
  if (mClientContextInitialized && mDisplayConfigInitialized &&
      mInterfaceInitialized) {
    mOSVRInitialized = true;
  }
}

void
VRDisplayManagerOSVR::InitializeClientContext()
{
  // already initialized
  if (mClientContextInitialized) {
    return;
  }

  // first time creating
  if (!m_ctx) {
    // get client context
    m_ctx = osvr_ClientInit("com.osvr.webvr", 0);
    // update context
    osvr_ClientUpdate(m_ctx);
    // verify we are connected
    if (OSVR_RETURN_SUCCESS == osvr_ClientCheckStatus(m_ctx)) {
      mClientContextInitialized = true;
    }
  }
  // client context exists but not up and running yet
  else {
    // update context
    osvr_ClientUpdate(m_ctx);
    if (OSVR_RETURN_SUCCESS == osvr_ClientCheckStatus(m_ctx)) {
      mClientContextInitialized = true;
    }
  }
}

void
VRDisplayManagerOSVR::InitializeInterface()
{
  // already initialized
  if (mInterfaceInitialized) {
    return;
  }
  //Client context must be initialized before getting interface
  if (mClientContextInitialized) {
    // m_iface will remain nullptr if no interface is returned
    if (OSVR_RETURN_SUCCESS ==
        osvr_ClientGetInterface(m_ctx, "/me/head", &m_iface)) {
      mInterfaceInitialized = true;
    }
  }
}

void
VRDisplayManagerOSVR::InitializeDisplay()
{
  // display is fully configured
  if (mDisplayConfigInitialized) {
    return;
  }

  //Client context must be initialized before getting interface
  if (mClientContextInitialized) {
    // first time creating display object
    if (m_display == nullptr) {

      OSVR_ReturnCode ret = osvr_ClientGetDisplay(m_ctx, &m_display);

      if (ret == OSVR_RETURN_SUCCESS) {
        osvr_ClientUpdate(m_ctx);
        // display object may have been created but not fully startup
        if (OSVR_RETURN_SUCCESS == osvr_ClientCheckDisplayStartup(m_display)) {
          mDisplayConfigInitialized = true;
        }
      }

      // Typically once we get Display object, pose data is available after
      // clientUpdate but sometimes it takes ~ 200 ms to get
      // a succesfull connection, so we might have to run a few update cycles
    } else {

      if (OSVR_RETURN_SUCCESS == osvr_ClientCheckDisplayStartup(m_display)) {
        mDisplayConfigInitialized = true;
      }
    }
  }
}

bool
VRDisplayManagerOSVR::Init()
{

  // OSVR server should be running in the background
  // It would load plugins and take care of detecting HMDs
  if (!mOSVRInitialized) {
    nsIThread* thread = nullptr;
    NS_GetCurrentThread(&thread);
    mOSVRThread = already_AddRefed<nsIThread>(thread);

    // initialize client context
    InitializeClientContext();
    // try to initialize interface
    InitializeInterface();
    // try to initialize display object
    InitializeDisplay();
    // verify all components are initialized
    CheckOSVRStatus();
  }

  return mOSVRInitialized;
}

void
VRDisplayManagerOSVR::Destroy()
{
  if (mOSVRInitialized) {
    MOZ_ASSERT(NS_GetCurrentThread() == mOSVRThread);
    mOSVRThread = nullptr;
    mHMDInfo = nullptr;
    mOSVRInitialized = false;
  }
  // client context may not have been initialized
  if (m_ctx) {
    osvr_ClientFreeDisplay(m_display);
  }
  // osvr checks that m_ctx or m_iface are not null
  osvr_ClientFreeInterface(m_ctx, m_iface);
  osvr_ClientShutdown(m_ctx);
}

void
VRDisplayManagerOSVR::GetHMDs(nsTArray<RefPtr<VRDisplayHost>>& aHMDResult)
{
  // make sure context, interface and display are initialized
  CheckOSVRStatus();

  if (!mOSVRInitialized) {
    return;
  }

  mHMDInfo = new VRDisplayOSVR(&m_ctx, &m_iface, &m_display);

  if (mHMDInfo) {
    aHMDResult.AppendElement(mHMDInfo);
  }
}
