/* 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 "FFVPXRuntimeLinker.h"

#include "FFmpegLibWrapper.h"
#include "FFmpegLog.h"
#include "mozilla/FileUtils.h"
#include "mozilla/ToString.h"
#include "nsLocalFile.h"
#include "nsXPCOMPrivate.h"
#include "prlink.h"

namespace mozilla {

template <int V>
class FFmpegDecoderModule {
 public:
  static void Init(const FFmpegLibWrapper*);
  static already_AddRefed<PlatformDecoderModule> Create(
      const FFmpegLibWrapper*);
};

template <int V>
class FFmpegEncoderModule {
 public:
  static void Init(const FFmpegLibWrapper*);
  static already_AddRefed<PlatformEncoderModule> Create(
      const FFmpegLibWrapper*);
};

static FFmpegLibWrapper sFFVPXLib;

StaticMutex FFVPXRuntimeLinker::sMutex;

FFVPXRuntimeLinker::LinkStatus FFVPXRuntimeLinker::sLinkStatus =
    LinkStatus_INIT;

static PRLibrary* MozAVLink(nsIFile* aFile) {
  PRLibSpec lspec;
  PathString path = aFile->NativePath();
#ifdef XP_WIN
  lspec.type = PR_LibSpec_PathnameU;
  lspec.value.pathname_u = path.get();
#else
#  if defined(XP_OPENBSD)
  /* on OpenBSD, libmozavcodec.so and libmozavutil.so are preloaded before
   * sandboxing so make sure only the filename is passed to
   * PR_LoadLibraryWithFlags(), dlopen() will return the preloaded library
   * handle instead of failing to find it due to sandboxing */
  nsAutoCString leaf;
  nsresult rv = aFile->GetNativeLeafName(leaf);
  if (NS_SUCCEEDED(rv)) {
    path = PathString(leaf);
  }
#  endif  // defined(XP_OPENBSD)
  lspec.type = PR_LibSpec_Pathname;
  lspec.value.pathname = path.get();
#endif
#ifdef MOZ_WIDGET_ANDROID
  PRLibrary* lib = PR_LoadLibraryWithFlags(lspec, PR_LD_NOW | PR_LD_GLOBAL);
#else
  PRLibrary* lib = PR_LoadLibraryWithFlags(lspec, PR_LD_NOW | PR_LD_LOCAL);
#endif
  if (!lib) {
    FFMPEGV_LOG("unable to load library {}", aFile->HumanReadablePath().get());
  }
  return lib;
}

/* static */
void FFVPXRuntimeLinker::PrefCallbackLogLevel(const char* aPref, void* aData) {
  sFFVPXLib.UpdateLogLevel();
}

/* static */
bool FFVPXRuntimeLinker::Init() {
  // Enter critical section to set up ffvpx.
  StaticMutexAutoLock lock(sMutex);

  if (sLinkStatus) {
    if (sLinkStatus == LinkStatus_SUCCEEDED) {
      FFmpegDecoderModule<FFVPX_VERSION>::Init(&sFFVPXLib);
      FFmpegEncoderModule<FFVPX_VERSION>::Init(&sFFVPXLib);
    }
    return sLinkStatus == LinkStatus_SUCCEEDED;
  }

  sLinkStatus = LinkStatus_FAILED;

#ifdef XP_WIN
  PathString path =
      GetLibraryFilePathname(LXUL_DLL, (PRFuncPtr)&FFVPXRuntimeLinker::Init);
#elif defined(ANDROID)
  // On Android, libxul is either pulled from the APK or from a temporary folder
  // for gtests/fuzzing. libmozavutil and libmozavcodec are always in the APK,
  // so let's use libmozglue instead to find the base pathname.
  PathString path = GetLibraryFilePathname(
      MOZ_DLL_PREFIX "mozglue" MOZ_DLL_SUFFIX, (PRFuncPtr)&malloc);
#else
  PathString path =
      GetLibraryFilePathname(XUL_DLL, (PRFuncPtr)&FFVPXRuntimeLinker::Init);
#endif
  if (path.IsEmpty()) {
    return false;
  }
  nsCOMPtr<nsIFile> libFile;
  if (NS_FAILED(NS_NewPathStringLocalFile(path, getter_AddRefs(libFile)))) {
    return false;
  }

#ifndef ANDROID
  if (getenv("MOZ_RUN_GTEST")
#  ifdef FUZZING
      || getenv("FUZZER")
#  endif
  ) {
    // The condition above is the same as in
    // xpcom/glue/standalone/nsXPCOMGlue.cpp. This means we can't reach here
    // without the gtest libxul being loaded. In turn, that means the path to
    // libxul leads to a subdirectory of where the libmozav* libraries are, so
    // we get the parent.
    nsCOMPtr<nsIFile> parent;
    if (NS_FAILED(libFile->GetParent(getter_AddRefs(parent)))) {
      return false;
    }
    libFile = parent;
  }
#endif

  if (NS_FAILED(libFile->SetNativeLeafName(MOZ_DLL_PREFIX
                                           "mozavutil" MOZ_DLL_SUFFIX ""_ns))) {
    return false;
  }
  sFFVPXLib.mAVUtilLib = MozAVLink(libFile);

  if (NS_FAILED(libFile->SetNativeLeafName(
          MOZ_DLL_PREFIX "mozavcodec" MOZ_DLL_SUFFIX ""_ns))) {
    return false;
  }
  sFFVPXLib.mAVCodecLib = MozAVLink(libFile);
  FFmpegLibWrapper::LinkResult res = sFFVPXLib.Link();
  FFMPEGP_LOG("Link result: {}", ToString(res).c_str());
  if (res == FFmpegLibWrapper::LinkResult::Success) {
    sLinkStatus = LinkStatus_SUCCEEDED;
    FFmpegDecoderModule<FFVPX_VERSION>::Init(&sFFVPXLib);
    FFmpegEncoderModule<FFVPX_VERSION>::Init(&sFFVPXLib);
    return true;
  }
  return false;
}

/* static */
already_AddRefed<PlatformDecoderModule> FFVPXRuntimeLinker::CreateDecoder() {
  if (!Init()) {
    return nullptr;
  }
  return FFmpegDecoderModule<FFVPX_VERSION>::Create(&sFFVPXLib);
}

/* static */
already_AddRefed<PlatformEncoderModule> FFVPXRuntimeLinker::CreateEncoder() {
  if (!Init()) {
    return nullptr;
  }
  return FFmpegEncoderModule<FFVPX_VERSION>::Create(&sFFVPXLib);
}

/* static */
void FFVPXRuntimeLinker::GetFFTFuncs(FFmpegFFTFuncs* aOutFuncs) {
  []() MOZ_NO_THREAD_SAFETY_ANALYSIS {
    MOZ_ASSERT(sLinkStatus != LinkStatus_INIT);
  }();
  MOZ_ASSERT(sFFVPXLib.av_tx_init && sFFVPXLib.av_tx_uninit);
  aOutFuncs->init = sFFVPXLib.av_tx_init;
  aOutFuncs->uninit = sFFVPXLib.av_tx_uninit;
}

}  // namespace mozilla