// 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 "base/check_op.h"
#include "base/notreached.h"

namespace media {

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";
  }
  NOTREACHED_NORETURN();
}

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);
  constexpr SVCScalabilityMode kSVCScalabilityModeMap[3][3][3] = {
      // 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},
      },
      {
          {SVCScalabilityMode::kL1T1, SVCScalabilityMode::kL1T2,
           SVCScalabilityMode::kL1T3},
          {SVCScalabilityMode::kL2T1Key, SVCScalabilityMode::kL2T2Key,
           SVCScalabilityMode::kL2T3Key},
          {SVCScalabilityMode::kL3T1Key, SVCScalabilityMode::kL3T2Key,
           SVCScalabilityMode::kL3T3Key},
      }};

  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)]
                            [num_spatial_layers - 1][num_temporal_layers - 1];
  CHECK_NE(mode, kInvalid);
  return mode;
}
}  // namespace media