// Copyright 2021 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "media/base/svc_scalability_mode.h"

#include <algorithm>
#include <array>

#include "base/check_op.h"
#include "base/compiler_specific.h"
#include "base/containers/flat_set.h"
#include "base/notreached.h"

namespace media {
namespace {
constexpr std::array<SVCScalabilityMode, 3 * 3 * 3> kSVCScalabilityModeMap = {
    {// kOff.
     SVCScalabilityMode::kL1T1, SVCScalabilityMode::kL1T2,
     SVCScalabilityMode::kL1T3, SVCScalabilityMode::kS2T1,
     SVCScalabilityMode::kS2T2, SVCScalabilityMode::kS2T3,
     SVCScalabilityMode::kS3T1, SVCScalabilityMode::kS3T2,
     SVCScalabilityMode::kS3T3,
     // kOn.
     SVCScalabilityMode::kL1T1, SVCScalabilityMode::kL1T2,
     SVCScalabilityMode::kL1T3, SVCScalabilityMode::kL2T1,
     SVCScalabilityMode::kL2T2, SVCScalabilityMode::kL2T3,
     SVCScalabilityMode::kL3T1, SVCScalabilityMode::kL3T2,
     SVCScalabilityMode::kL3T3,
     // kOnKeyPic.
     SVCScalabilityMode::kL1T1, SVCScalabilityMode::kL1T2,
     SVCScalabilityMode::kL1T3, SVCScalabilityMode::kL2T1Key,
     SVCScalabilityMode::kL2T2Key, SVCScalabilityMode::kL2T3Key,
     SVCScalabilityMode::kL3T1Key, SVCScalabilityMode::kL3T2Key,
     SVCScalabilityMode::kL3T3Key}};
}  // namespace

base::flat_set<SVCScalabilityMode>
GetSupportedScalabilityModesByHWEncoderForTesting() {
  auto supported_svcs = base::flat_set<SVCScalabilityMode>(
      kSVCScalabilityModeMap.begin(), kSVCScalabilityModeMap.end());
  CHECK_EQ(supported_svcs.size(), 21u);
  return supported_svcs;
}

SVCScalabilityMode GetSVCScalabilityMode(
    const size_t num_spatial_layers,
    const size_t num_temporal_layers,
    SVCInterLayerPredMode inter_layer_pred) {
  constexpr SVCScalabilityMode kInvalid = static_cast<SVCScalabilityMode>(-1);
  CHECK(0 < num_spatial_layers && num_spatial_layers <= 3);
  CHECK(0 < num_temporal_layers && num_temporal_layers <= 3);
  CHECK(static_cast<int>(inter_layer_pred) >= 0 &&
        static_cast<int>(inter_layer_pred) < 3);
  auto mode = kSVCScalabilityModeMap[static_cast<int>(inter_layer_pred) * 9 +
                                     (num_spatial_layers - 1) * 3 +
                                     (num_temporal_layers - 1)];
  CHECK_NE(mode, kInvalid);
  return mode;
}

const char* GetScalabilityModeName(SVCScalabilityMode scalability_mode) {
  switch (scalability_mode) {
    case SVCScalabilityMode::kL1T1:
      return "L1T1";
    case SVCScalabilityMode::kL1T2:
      return "L1T2";
    case SVCScalabilityMode::kL1T3:
      return "L1T3";
    case SVCScalabilityMode::kL2T1:
      return "L2T1";
    case SVCScalabilityMode::kL2T2:
      return "L2T2";
    case SVCScalabilityMode::kL2T3:
      return "L2T3";
    case SVCScalabilityMode::kL3T1:
      return "L3T1";
    case SVCScalabilityMode::kL3T2:
      return "L3T2";
    case SVCScalabilityMode::kL3T3:
      return "L3T3";
    case SVCScalabilityMode::kL2T1h:
      return "L2T1h";
    case SVCScalabilityMode::kL2T2h:
      return "L2T2h";
    case SVCScalabilityMode::kL2T3h:
      return "L2T3h";
    case SVCScalabilityMode::kS2T1:
      return "S2T1";
    case SVCScalabilityMode::kS2T2:
      return "S2T2";
    case SVCScalabilityMode::kS2T3:
      return "S2T3";
    case SVCScalabilityMode::kS2T1h:
      return "S2T1h";
    case SVCScalabilityMode::kS2T2h:
      return "S2T2h";
    case SVCScalabilityMode::kS2T3h:
      return "S2T3h";
    case SVCScalabilityMode::kS3T1:
      return "S3T1";
    case SVCScalabilityMode::kS3T2:
      return "S3T2";
    case SVCScalabilityMode::kS3T3:
      return "S3T3";
    case SVCScalabilityMode::kS3T1h:
      return "S3T1h";
    case SVCScalabilityMode::kS3T2h:
      return "S3T2h";
    case SVCScalabilityMode::kS3T3h:
      return "S3T3h";
    case SVCScalabilityMode::kL2T1Key:
      return "L2T1_KEY";
    case SVCScalabilityMode::kL2T2Key:
      return "L2T2_KEY";
    case SVCScalabilityMode::kL2T2KeyShift:
      return "L2T2_KEY_SHIFT";
    case SVCScalabilityMode::kL2T3Key:
      return "L2T3_KEY";
    case SVCScalabilityMode::kL2T3KeyShift:
      return "L2T3_KEY_SHIFT";
    case SVCScalabilityMode::kL3T1Key:
      return "L3T1_KEY";
    case SVCScalabilityMode::kL3T2Key:
      return "L3T2_KEY";
    case SVCScalabilityMode::kL3T2KeyShift:
      return "L3T2_KEY_SHIFT";
    case SVCScalabilityMode::kL3T3Key:
      return "L3T3_KEY";
    case SVCScalabilityMode::kL3T3KeyShift:
      return "L3T3_KEY_SHIFT";
    case SVCScalabilityMode::kL3T1h:
      return "L3T1h";
    case SVCScalabilityMode::kL3T2h:
      return "L3T2h";
    case SVCScalabilityMode::kL3T3h:
      return "L3T3h";
  }
  NOTREACHED();
}
}  // namespace media