// Copyright 2017 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "helpers.h"

#include <endian.h>

#include <algorithm>
#include <iterator>
#include <unordered_set>

#include "fuchsia/bluetooth/sys/cpp/fidl.h"
#include "src/connectivity/bluetooth/core/bt-host/att/att.h"
#include "src/connectivity/bluetooth/core/bt-host/common/log.h"
#include "src/connectivity/bluetooth/core/bt-host/gap/discovery_filter.h"
#include "src/connectivity/bluetooth/core/bt-host/gap/gap.h"
#include "src/connectivity/bluetooth/core/bt-host/sco/sco.h"
#include "src/connectivity/bluetooth/core/bt-host/sm/types.h"
#include "src/lib/fxl/strings/split_string.h"
#include "src/lib/fxl/strings/string_number_conversions.h"

using fuchsia::bluetooth::Bool;
using fuchsia::bluetooth::Error;
using fuchsia::bluetooth::ErrorCode;
using fuchsia::bluetooth::Int8;
using fuchsia::bluetooth::Status;

namespace fble = fuchsia::bluetooth::le;
namespace fbredr = fuchsia::bluetooth::bredr;
namespace fbt = fuchsia::bluetooth;
namespace fgatt = fuchsia::bluetooth::gatt;
namespace fhost = fuchsia::bluetooth::host;
namespace fsys = fuchsia::bluetooth::sys;
namespace faudio = fuchsia::hardware::audio;

namespace bthost::fidl_helpers {
namespace {

fbt::AddressType AddressTypeToFidl(bt::DeviceAddress::Type type) {
  switch (type) {
    case bt::DeviceAddress::Type::kBREDR:
      [[fallthrough]];
    case bt::DeviceAddress::Type::kLEPublic:
      return fbt::AddressType::PUBLIC;
    case bt::DeviceAddress::Type::kLERandom:
      [[fallthrough]];
    case bt::DeviceAddress::Type::kLEAnonymous:
      return fbt::AddressType::RANDOM;
  }
  return fbt::AddressType::PUBLIC;
}

fbt::Address AddressToFidl(fbt::AddressType type, const bt::DeviceAddressBytes& value) {
  fbt::Address output;
  output.type = type;
  bt::MutableBufferView value_dst(output.bytes.data(), output.bytes.size());
  value_dst.Write(value.bytes());
  return output;
}

fbt::Address AddressToFidl(const bt::DeviceAddress& input) {
  return AddressToFidl(AddressTypeToFidl(input.type()), input.value());
}

bt::sm::SecurityProperties SecurityPropsFromFidl(const fsys::SecurityProperties& sec_prop) {
  auto level = bt::sm::SecurityLevel::kEncrypted;
  if (sec_prop.authenticated) {
    level = bt::sm::SecurityLevel::kAuthenticated;
  }
  return bt::sm::SecurityProperties(level, sec_prop.encryption_key_size,
                                    sec_prop.secure_connections);
}

fsys::SecurityProperties SecurityPropsToFidl(const bt::sm::SecurityProperties& sec_prop) {
  return fsys::SecurityProperties{
      .authenticated = sec_prop.authenticated(),
      .secure_connections = sec_prop.secure_connections(),

      // TODO(armansito): Declare the key size as uint8_t in bt::sm?
      .encryption_key_size = static_cast<uint8_t>(sec_prop.enc_key_size()),
  };
}

bt::sm::LTK LtkFromFidl(const fsys::Ltk& ltk) {
  return bt::sm::LTK(SecurityPropsFromFidl(ltk.key.security),
                     bt::hci::LinkKey(ltk.key.data.value, ltk.rand, ltk.ediv));
}

fsys::PeerKey LtkToFidlPeerKey(const bt::sm::LTK& ltk) {
  return fsys::PeerKey{
      .security = SecurityPropsToFidl(ltk.security()),
      .data = fsys::Key{ltk.key().value()},
  };
}

fsys::Ltk LtkToFidl(const bt::sm::LTK& ltk) {
  return fsys::Ltk{
      .key = LtkToFidlPeerKey(ltk),
      .ediv = ltk.key().ediv(),
      .rand = ltk.key().rand(),
  };
}

bt::sm::Key PeerKeyFromFidl(const fsys::PeerKey& key) {
  return bt::sm::Key(SecurityPropsFromFidl(key.security), key.data.value);
}

fsys::PeerKey PeerKeyToFidl(const bt::sm::Key& key) {
  return fsys::PeerKey{
      .security = SecurityPropsToFidl(key.security()),
      .data = {key.value()},
  };
}

fbt::DeviceClass DeviceClassToFidl(bt::DeviceClass input) {
  auto bytes = input.bytes();
  fbt::DeviceClass output{static_cast<uint32_t>(bytes[0] | (bytes[1] << 8) | (bytes[2] << 16))};
  return output;
}

std::optional<bt::sdp::DataElement> FidlToDataElement(const fbredr::DataElement& fidl) {
  bt::sdp::DataElement out;
  switch (fidl.Which()) {
    case fbredr::DataElement::Tag::kInt8:
      return bt::sdp::DataElement(fidl.int8());
    case fbredr::DataElement::Tag::kInt16:
      return bt::sdp::DataElement(fidl.int16());
    case fbredr::DataElement::Tag::kInt32:
      return bt::sdp::DataElement(fidl.int32());
    case fbredr::DataElement::Tag::kInt64:
      return bt::sdp::DataElement(fidl.int64());
    case fbredr::DataElement::Tag::kUint8:
      return bt::sdp::DataElement(fidl.uint8());
    case fbredr::DataElement::Tag::kUint16:
      return bt::sdp::DataElement(fidl.uint16());
    case fbredr::DataElement::Tag::kUint32:
      return bt::sdp::DataElement(fidl.uint32());
    case fbredr::DataElement::Tag::kUint64:
      return bt::sdp::DataElement(fidl.uint64());
    case fbredr::DataElement::Tag::kStr:
      return bt::sdp::DataElement(fidl.str());
    case fbredr::DataElement::Tag::kB:
      return bt::sdp::DataElement(fidl.b());
    case fbredr::DataElement::Tag::kUuid:
      out.Set(fidl_helpers::UuidFromFidl(fidl.uuid()));
    case fbredr::DataElement::Tag::kSequence: {
      std::vector<bt::sdp::DataElement> seq;
      for (const auto& fidl_elem : fidl.sequence()) {
        auto it = FidlToDataElement(*fidl_elem);
        if (!it) {
          return std::nullopt;
        }
        seq.emplace_back(std::move(it.value()));
      }
      out.Set(std::move(seq));
      break;
    }
    case fbredr::DataElement::Tag::kAlternatives: {
      std::vector<bt::sdp::DataElement> alts;
      for (const auto& fidl_elem : fidl.alternatives()) {
        auto elem = FidlToDataElement(*fidl_elem);
        if (!elem) {
          return std::nullopt;
        }
        alts.emplace_back(std::move(elem.value()));
      }
      out.SetAlternative(std::move(alts));
      break;
    }
    default:
      // Types not handled: Null datatype (never used) and Url data type (not supported by Set)
      bt_log(WARN, "fidl", "Encountered FidlToDataElement type not handled.");
      return std::nullopt;
  }
  return out;
}

bool AddProtocolDescriptorList(bt::sdp::ServiceRecord* rec,
                               bt::sdp::ServiceRecord::ProtocolListId id,
                               const ::std::vector<fbredr::ProtocolDescriptor>& descriptor_list) {
  bt_log(TRACE, "fidl", "ProtocolDescriptorList %d", id);
  for (auto& descriptor : descriptor_list) {
    bt::sdp::DataElement protocol_params;
    if (descriptor.params.size() > 1) {
      std::vector<bt::sdp::DataElement> params;
      for (auto& fidl_param : descriptor.params) {
        auto bt_param = FidlToDataElement(fidl_param);
        if (bt_param) {
          params.emplace_back(std::move(bt_param.value()));
        } else {
          return false;
        }
      }
      protocol_params.Set(std::move(params));
    } else if (descriptor.params.size() == 1) {
      auto param = FidlToDataElement(descriptor.params.front());
      if (param) {
        protocol_params = std::move(param).value();
      } else {
        return false;
      }
      protocol_params = FidlToDataElement(descriptor.params.front()).value();
    }

    bt_log(TRACE, "fidl", "Adding protocol descriptor: {%d : %s}",
           fidl::ToUnderlying(descriptor.protocol), protocol_params.ToString().c_str());
    rec->AddProtocolDescriptor(id, bt::UUID(static_cast<uint16_t>(descriptor.protocol)),
                               std::move(protocol_params));
  }
  return true;
}

// Returns true if the appearance value (in host byte order) is included in
// fuchsia.bluetooth.Appearance, which is a subset of Bluetooth Assigned Numbers, "Appearance
// Values" (https://www.bluetooth.com/specifications/assigned-numbers/).
//
// TODO(fxbug.dev/66358): Remove this compatibility check with the strict Appearance enum.
[[nodiscard]] bool IsAppearanceValid(uint16_t appearance_raw) {
  switch (appearance_raw) {
    case 0u:  // UNKNOWN
      [[fallthrough]];
    case 64u:  // PHONE
      [[fallthrough]];
    case 128u:  // COMPUTER
      [[fallthrough]];
    case 192u:  // WATCH
      [[fallthrough]];
    case 193u:  // WATCH_SPORTS
      [[fallthrough]];
    case 256u:  // CLOCK
      [[fallthrough]];
    case 320u:  // DISPLAY
      [[fallthrough]];
    case 384u:  // REMOTE_CONTROL
      [[fallthrough]];
    case 448u:  // EYE_GLASSES
      [[fallthrough]];
    case 512u:  // TAG
      [[fallthrough]];
    case 576u:  // KEYRING
      [[fallthrough]];
    case 640u:  // MEDIA_PLAYER
      [[fallthrough]];
    case 704u:  // BARCODE_SCANNER
      [[fallthrough]];
    case 768u:  // THERMOMETER
      [[fallthrough]];
    case 769u:  // THERMOMETER_EAR
      [[fallthrough]];
    case 832u:  // HEART_RATE_SENSOR
      [[fallthrough]];
    case 833u:  // HEART_RATE_SENSOR_BELT
      [[fallthrough]];
    case 896u:  // BLOOD_PRESSURE
      [[fallthrough]];
    case 897u:  // BLOOD_PRESSURE_ARM
      [[fallthrough]];
    case 898u:  // BLOOD_PRESSURE_WRIST
      [[fallthrough]];
    case 960u:  // HID
      [[fallthrough]];
    case 961u:  // HID_KEYBOARD
      [[fallthrough]];
    case 962u:  // HID_MOUSE
      [[fallthrough]];
    case 963u:  // HID_JOYSTICK
      [[fallthrough]];
    case 964u:  // HID_GAMEPAD
      [[fallthrough]];
    case 965u:  // HID_DIGITIZER_TABLET
      [[fallthrough]];
    case 966u:  // HID_CARD_READER
      [[fallthrough]];
    case 967u:  // HID_DIGITAL_PEN
      [[fallthrough]];
    case 968u:  // HID_BARCODE_SCANNER
      [[fallthrough]];
    case 1024u:  // GLUCOSE_METER
      [[fallthrough]];
    case 1088u:  // RUNNING_WALKING_SENSOR
      [[fallthrough]];
    case 1089u:  // RUNNING_WALKING_SENSOR_IN_SHOE
      [[fallthrough]];
    case 1090u:  // RUNNING_WALKING_SENSOR_ON_SHOE
      [[fallthrough]];
    case 1091u:  // RUNNING_WALKING_SENSOR_ON_HIP
      [[fallthrough]];
    case 1152u:  // CYCLING
      [[fallthrough]];
    case 1153u:  // CYCLING_COMPUTER
      [[fallthrough]];
    case 1154u:  // CYCLING_SPEED_SENSOR
      [[fallthrough]];
    case 1155u:  // CYCLING_CADENCE_SENSOR
      [[fallthrough]];
    case 1156u:  // CYCLING_POWER_SENSOR
      [[fallthrough]];
    case 1157u:  // CYCLING_SPEED_AND_CADENCE_SENSOR
      [[fallthrough]];
    case 3136u:  // PULSE_OXIMETER
      [[fallthrough]];
    case 3137u:  // PULSE_OXIMETER_FINGERTIP
      [[fallthrough]];
    case 3138u:  // PULSE_OXIMETER_WRIST
      [[fallthrough]];
    case 3200u:  // WEIGHT_SCALE
      [[fallthrough]];
    case 3264u:  // PERSONAL_MOBILITY
      [[fallthrough]];
    case 3265u:  // PERSONAL_MOBILITY_WHEELCHAIR
      [[fallthrough]];
    case 3266u:  // PERSONAL_MOBILITY_SCOOTER
      [[fallthrough]];
    case 3328u:  // GLUCOSE_MONITOR
      [[fallthrough]];
    case 5184u:  // SPORTS_ACTIVITY
      [[fallthrough]];
    case 5185u:  // SPORTS_ACTIVITY_LOCATION_DISPLAY
      [[fallthrough]];
    case 5186u:  // SPORTS_ACTIVITY_LOCATION_AND_NAV_DISPLAY
      [[fallthrough]];
    case 5187u:  // SPORTS_ACTIVITY_LOCATION_POD
      [[fallthrough]];
    case 5188u:  // SPORTS_ACTIVITY_LOCATION_AND_NAV_POD
      return true;
    default:
      return false;
  }
}

[[nodiscard]] std::optional<fbt::Appearance> AppearanceToFidl(uint16_t appearance_raw) {
  if (IsAppearanceValid(appearance_raw)) {
    return static_cast<fbt::Appearance>(appearance_raw);
  }
  return std::nullopt;
}

}  // namespace

std::optional<bt::PeerId> PeerIdFromString(const std::string& id) {
  uint64_t value;
  if (!fxl::StringToNumberWithError<decltype(value)>(id, &value, fxl::Base::k16)) {
    return std::nullopt;
  }
  return bt::PeerId(value);
}

std::optional<bt::DeviceAddressBytes> AddressBytesFromString(const std::string& addr) {
  if (addr.size() != 17)
    return std::nullopt;

  auto split = fxl::SplitString(std::string_view(addr.data(), addr.size()), ":",
                                fxl::kKeepWhitespace, fxl::kSplitWantAll);
  if (split.size() != 6)
    return std::nullopt;

  std::array<uint8_t, 6> bytes;
  size_t index = 5;
  for (const auto& octet_str : split) {
    uint8_t octet;
    if (!fxl::StringToNumberWithError<uint8_t>(octet_str, &octet, fxl::Base::k16))
      return std::nullopt;
    bytes[index--] = octet;
  }

  return bt::DeviceAddressBytes(bytes);
}

ErrorCode HostErrorToFidlDeprecated(bt::HostError host_error) {
  switch (host_error) {
    case bt::HostError::kFailed:
      return ErrorCode::FAILED;
    case bt::HostError::kTimedOut:
      return ErrorCode::TIMED_OUT;
    case bt::HostError::kInvalidParameters:
      return ErrorCode::INVALID_ARGUMENTS;
    case bt::HostError::kCanceled:
      return ErrorCode::CANCELED;
    case bt::HostError::kInProgress:
      return ErrorCode::IN_PROGRESS;
    case bt::HostError::kNotSupported:
      return ErrorCode::NOT_SUPPORTED;
    case bt::HostError::kNotFound:
      return ErrorCode::NOT_FOUND;
    case bt::HostError::kProtocolError:
      return ErrorCode::PROTOCOL_ERROR;
    default:
      break;
  }

  return ErrorCode::FAILED;
}

Status NewFidlError(ErrorCode error_code, std::string description) {
  Status status;
  status.error = Error::New();
  status.error->error_code = error_code;
  status.error->description = description;
  return status;
}

fsys::Error HostErrorToFidl(bt::HostError error) {
  ZX_DEBUG_ASSERT(error != bt::HostError::kNoError);
  switch (error) {
    case bt::HostError::kFailed:
      return fsys::Error::FAILED;
    case bt::HostError::kTimedOut:
      return fsys::Error::TIMED_OUT;
    case bt::HostError::kInvalidParameters:
      return fsys::Error::INVALID_ARGUMENTS;
    case bt::HostError::kCanceled:
      return fsys::Error::CANCELED;
    case bt::HostError::kInProgress:
      return fsys::Error::IN_PROGRESS;
    case bt::HostError::kNotSupported:
      return fsys::Error::NOT_SUPPORTED;
    case bt::HostError::kNotFound:
      return fsys::Error::PEER_NOT_FOUND;
    default:
      break;
  }
  return fsys::Error::FAILED;
}

fuchsia::bluetooth::gatt::Error GattStatusToFidl(bt::Status<bt::att::ErrorCode> status) {
  ZX_ASSERT(!status.is_success());
  switch (status.error()) {
    case bt::HostError::kPacketMalformed:
      return fuchsia::bluetooth::gatt::Error::INVALID_RESPONSE;
    case bt::HostError::kProtocolError:
      switch (status.protocol_error()) {
        case bt::att::ErrorCode::kInsufficientAuthorization:
          return fuchsia::bluetooth::gatt::Error::INSUFFICIENT_AUTHORIZATION;
        case bt::att::ErrorCode::kInsufficientAuthentication:
          return fuchsia::bluetooth::gatt::Error::INSUFFICIENT_AUTHENTICATION;
        case bt::att::ErrorCode::kInsufficientEncryptionKeySize:
          return fuchsia::bluetooth::gatt::Error::INSUFFICIENT_ENCRYPTION_KEY_SIZE;
        case bt::att::ErrorCode::kInsufficientEncryption:
          return fuchsia::bluetooth::gatt::Error::INSUFFICIENT_ENCRYPTION;
        case bt::att::ErrorCode::kReadNotPermitted:
          return fuchsia::bluetooth::gatt::Error::READ_NOT_PERMITTED;
        default:
          return fuchsia::bluetooth::gatt::Error::FAILURE;
      }
    default:
      return fuchsia::bluetooth::gatt::Error::FAILURE;
  }
}

bt::UUID UuidFromFidl(const fuchsia::bluetooth::Uuid& input) {
  // Conversion must always succeed given the defined size of |input|.
  static_assert(sizeof(input.value) == 16, "FIDL UUID definition malformed!");
  return bt::UUID(bt::BufferView(input.value.data(), input.value.size()));
}

fuchsia::bluetooth::Uuid UuidToFidl(const bt::UUID& uuid) {
  fuchsia::bluetooth::Uuid output;
  // Conversion must always succeed given the defined size of |input|.
  static_assert(sizeof(output.value) == 16, "FIDL UUID definition malformed!");
  output.value = uuid.value();
  return output;
}

bt::sm::IOCapability IoCapabilityFromFidl(fsys::InputCapability input,
                                          fsys::OutputCapability output) {
  if (input == fsys::InputCapability::NONE && output == fsys::OutputCapability::NONE) {
    return bt::sm::IOCapability::kNoInputNoOutput;
  } else if (input == fsys::InputCapability::KEYBOARD &&
             output == fsys::OutputCapability::DISPLAY) {
    return bt::sm::IOCapability::kKeyboardDisplay;
  } else if (input == fsys::InputCapability::KEYBOARD && output == fsys::OutputCapability::NONE) {
    return bt::sm::IOCapability::kKeyboardOnly;
  } else if (input == fsys::InputCapability::NONE && output == fsys::OutputCapability::DISPLAY) {
    return bt::sm::IOCapability::kDisplayOnly;
  } else if (input == fsys::InputCapability::CONFIRMATION &&
             output == fsys::OutputCapability::DISPLAY) {
    return bt::sm::IOCapability::kDisplayYesNo;
  }

  return bt::sm::IOCapability::kNoInputNoOutput;
}

bt::gap::LeSecurityMode LeSecurityModeFromFidl(const fsys::LeSecurityMode mode) {
  switch (mode) {
    case fsys::LeSecurityMode::MODE_1:
      return bt::gap::LeSecurityMode::Mode1;
    case fsys::LeSecurityMode::SECURE_CONNECTIONS_ONLY:
      return bt::gap::LeSecurityMode::SecureConnectionsOnly;
  }
  bt_log(WARN, "fidl", "FIDL security mode not recognized, defaulting to SecureConnectionsOnly");
  return bt::gap::LeSecurityMode::SecureConnectionsOnly;
}

std::optional<bt::sm::SecurityLevel> SecurityLevelFromFidl(const fsys::PairingSecurityLevel level) {
  switch (level) {
    case fsys::PairingSecurityLevel::ENCRYPTED:
      return bt::sm::SecurityLevel::kEncrypted;
    case fsys::PairingSecurityLevel::AUTHENTICATED:
      return bt::sm::SecurityLevel::kAuthenticated;
    default:
      return std::nullopt;
  };
}

fsys::TechnologyType TechnologyTypeToFidl(bt::gap::TechnologyType type) {
  switch (type) {
    case bt::gap::TechnologyType::kLowEnergy:
      return fsys::TechnologyType::LOW_ENERGY;
    case bt::gap::TechnologyType::kClassic:
      return fsys::TechnologyType::CLASSIC;
    case bt::gap::TechnologyType::kDualMode:
      return fsys::TechnologyType::DUAL_MODE;
    default:
      ZX_PANIC("invalid technology type: %u", static_cast<unsigned int>(type));
      break;
  }

  // This should never execute.
  return fsys::TechnologyType::DUAL_MODE;
}

fsys::HostInfo HostInfoToFidl(const bt::gap::Adapter& adapter) {
  fsys::HostInfo info;
  info.set_id(fbt::HostId{adapter.identifier().value()});
  info.set_technology(TechnologyTypeToFidl(adapter.state().type()));
  info.set_address(AddressToFidl(fbt::AddressType::PUBLIC, adapter.state().controller_address()));
  info.set_local_name(adapter.local_name());
  info.set_discoverable(adapter.IsDiscoverable());
  info.set_discovering(adapter.IsDiscovering());
  return info;
}

fsys::Peer PeerToFidl(const bt::gap::Peer& peer) {
  fsys::Peer output;
  output.set_id(fbt::PeerId{peer.identifier().value()});
  output.set_address(AddressToFidl(peer.address()));
  output.set_technology(TechnologyTypeToFidl(peer.technology()));
  output.set_connected(peer.connected());
  output.set_bonded(peer.bonded());

  if (peer.name()) {
    output.set_name(*peer.name());
  }

  if (peer.le()) {
    if (auto adv = bt::AdvertisingData::FromBytes(peer.le()->advertising_data())) {
      if (adv->appearance().has_value()) {
        if (auto appearance = AppearanceToFidl(adv->appearance().value())) {
          output.set_appearance(appearance.value());
        } else {
          bt_log(DEBUG, "fidl", "omitting unencodeable appearance %#.4x of peer %s",
                 adv->appearance().value(), bt_str(peer.identifier()));
        }
      }
      if (adv->tx_power()) {
        output.set_tx_power(adv->tx_power().value());
      }
    }
  }
  if (peer.bredr() && peer.bredr()->device_class()) {
    output.set_device_class(DeviceClassToFidl(*peer.bredr()->device_class()));
  }
  if (peer.rssi() != bt::hci::kRSSIInvalid) {
    output.set_rssi(peer.rssi());
  }

  if (peer.bredr()) {
    std::transform(peer.bredr()->services().begin(), peer.bredr()->services().end(),
                   std::back_inserter(*output.mutable_bredr_services()), UuidToFidl);
  }

  // TODO(fxbug.dev/57344): Populate le_service UUIDs based on GATT results as well as advertising
  // and inquiry data.

  return output;
}

std::optional<bt::DeviceAddress> AddressFromFidlBondingData(
    const fuchsia::bluetooth::sys::BondingData& bond) {
  bt::DeviceAddressBytes bytes(bond.address().bytes);
  bt::DeviceAddress::Type type;
  if (bond.has_bredr_bond()) {
    // A random identity address can only be present in a LE-only bond.
    if (bond.address().type == fbt::AddressType::RANDOM) {
      bt_log(WARN, "fidl", "BR/EDR or Dual-Mode bond cannot have a random identity address!");
      return std::nullopt;
    }
    // TODO(fxbug.dev/2761): We currently assign kBREDR as the address type for dual-mode bonds.
    // This makes address management for dual-mode devices a bit confusing as we have two "public"
    // address types (i.e. kBREDR and kLEPublic). We should align the stack address types with
    // the FIDL address types, such that both kBREDR and kLEPublic are represented as the same
    // kind of "PUBLIC".
    type = bt::DeviceAddress::Type::kBREDR;
  } else {
    type = bond.address().type == fbt::AddressType::RANDOM ? bt::DeviceAddress::Type::kLERandom
                                                           : bt::DeviceAddress::Type::kLEPublic;
  }

  return {bt::DeviceAddress(type, bytes)};
}

bt::sm::PairingData LePairingDataFromFidl(const fsys::LeBondData& data) {
  bt::sm::PairingData result;

  if (data.has_peer_ltk()) {
    result.peer_ltk = LtkFromFidl(data.peer_ltk());
  }
  if (data.has_local_ltk()) {
    result.local_ltk = LtkFromFidl(data.local_ltk());
  }
  if (data.has_irk()) {
    result.irk = PeerKeyFromFidl(data.irk());
  }
  if (data.has_csrk()) {
    result.csrk = PeerKeyFromFidl(data.csrk());
  }
  return result;
}

std::optional<bt::sm::LTK> BredrKeyFromFidl(const fsys::BredrBondData& data) {
  if (!data.has_link_key()) {
    return std::nullopt;
  }
  auto key = PeerKeyFromFidl(data.link_key());
  return bt::sm::LTK(key.security(), bt::hci::LinkKey(key.value(), 0, 0));
}

std::vector<bt::UUID> BredrServicesFromFidl(const fuchsia::bluetooth::sys::BredrBondData& data) {
  std::vector<bt::UUID> services_out;
  if (data.has_services()) {
    std::transform(data.services().begin(), data.services().end(), std::back_inserter(services_out),
                   UuidFromFidl);
  }
  return services_out;
}

fuchsia::bluetooth::sys::BondingData PeerToFidlBondingData(const bt::gap::Adapter& adapter,
                                                           const bt::gap::Peer& peer) {
  fsys::BondingData out;

  out.set_identifier(fbt::PeerId{peer.identifier().value()});
  out.set_local_address(
      AddressToFidl(fbt::AddressType::PUBLIC, adapter.state().controller_address()));
  out.set_address(AddressToFidl(peer.address()));

  if (peer.name()) {
    out.set_name(*peer.name());
  }

  // LE
  if (peer.le() && peer.le()->bond_data()) {
    fsys::LeBondData out_le;
    const bt::sm::PairingData& bond = *peer.le()->bond_data();

    // TODO(armansito): Store the peer's preferred connection parameters.
    // TODO(fxbug.dev/59645): Store GATT and AD service UUIDs.

    if (bond.local_ltk) {
      out_le.set_local_ltk(LtkToFidl(*bond.local_ltk));
    }
    if (bond.peer_ltk) {
      out_le.set_peer_ltk(LtkToFidl(*bond.peer_ltk));
    }
    if (bond.irk) {
      out_le.set_irk(PeerKeyToFidl(*bond.irk));
    }
    if (bond.csrk) {
      out_le.set_csrk(PeerKeyToFidl(*bond.csrk));
    }

    out.set_le_bond(std::move(out_le));
  }

  // BR/EDR
  if (peer.bredr() && peer.bredr()->link_key()) {
    fsys::BredrBondData out_bredr;

    // TODO(fxbug.dev/1262): Populate with history of role switches.

    const auto& services = peer.bredr()->services();
    std::transform(services.begin(), services.end(),
                   std::back_inserter(*out_bredr.mutable_services()), UuidToFidl);
    out_bredr.set_link_key(LtkToFidlPeerKey(*peer.bredr()->link_key()));
    out.set_bredr_bond(std::move(out_bredr));
  }

  return out;
}

fble::RemoteDevicePtr NewLERemoteDevice(const bt::gap::Peer& peer) {
  bt::AdvertisingData ad;
  if (!peer.le()) {
    return nullptr;
  }

  const auto& le = *peer.le();
  auto fidl_device = fble::RemoteDevice::New();
  fidl_device->identifier = peer.identifier().ToString();
  fidl_device->connectable = peer.connectable();

  // Initialize advertising data only if its non-empty.
  if (le.advertising_data().size() != 0u) {
    std::optional<bt::AdvertisingData> ad = bt::AdvertisingData::FromBytes(le.advertising_data());
    if (!ad.has_value()) {
      return nullptr;
    }
    auto data = fidl_helpers::AdvertisingDataToFidlDeprecated(ad.value());
    fidl_device->advertising_data =
        std::make_unique<fble::AdvertisingDataDeprecated>(std::move(data));
  }

  if (peer.rssi() != bt::hci::kRSSIInvalid) {
    fidl_device->rssi = Int8::New();
    fidl_device->rssi->value = peer.rssi();
  }

  return fidl_device;
}

bool IsScanFilterValid(const fble::ScanFilter& fidl_filter) {
  // |service_uuids| is the only field that can potentially contain invalid
  // data, since they are represented as strings.
  if (!fidl_filter.service_uuids)
    return true;

  for (const auto& uuid_str : *fidl_filter.service_uuids) {
    if (!bt::IsStringValidUuid(uuid_str))
      return false;
  }

  return true;
}

bool PopulateDiscoveryFilter(const fble::ScanFilter& fidl_filter,
                             bt::gap::DiscoveryFilter* out_filter) {
  ZX_DEBUG_ASSERT(out_filter);

  if (fidl_filter.service_uuids) {
    std::vector<bt::UUID> uuids;
    for (const auto& uuid_str : *fidl_filter.service_uuids) {
      bt::UUID uuid;
      if (!bt::StringToUuid(uuid_str, &uuid)) {
        bt_log(WARN, "fidl", "invalid service UUID given to scan filter: %s", uuid_str.c_str());
        return false;
      }
      uuids.push_back(uuid);
    }

    if (!uuids.empty())
      out_filter->set_service_uuids(uuids);
  }

  if (fidl_filter.connectable) {
    out_filter->set_connectable(fidl_filter.connectable->value);
  }

  if (fidl_filter.manufacturer_identifier) {
    out_filter->set_manufacturer_code(fidl_filter.manufacturer_identifier->value);
  }

  if (fidl_filter.name_substring && !fidl_filter.name_substring.value_or("").empty()) {
    out_filter->set_name_substring(fidl_filter.name_substring.value_or(""));
  }

  if (fidl_filter.max_path_loss) {
    out_filter->set_pathloss(fidl_filter.max_path_loss->value);
  }

  return true;
}

bt::gap::AdvertisingInterval AdvertisingIntervalFromFidl(fble::AdvertisingModeHint mode_hint) {
  switch (mode_hint) {
    case fble::AdvertisingModeHint::VERY_FAST:
      return bt::gap::AdvertisingInterval::FAST1;
    case fble::AdvertisingModeHint::FAST:
      return bt::gap::AdvertisingInterval::FAST2;
    case fble::AdvertisingModeHint::SLOW:
      return bt::gap::AdvertisingInterval::SLOW;
  }
  return bt::gap::AdvertisingInterval::SLOW;
}

std::optional<bt::AdvertisingData> AdvertisingDataFromFidl(const fble::AdvertisingData& input) {
  bt::AdvertisingData output;

  if (input.has_name()) {
    if (!output.SetLocalName(input.name())) {
      return std::nullopt;
    }
  }
  if (input.has_appearance()) {
    output.SetAppearance(static_cast<uint16_t>(input.appearance()));
  }
  if (input.has_tx_power_level()) {
    output.SetTxPower(input.tx_power_level());
  }
  if (input.has_service_uuids()) {
    for (const auto& uuid : input.service_uuids()) {
      bt::UUID bt_uuid = UuidFromFidl(uuid);
      if (!output.AddServiceUuid(bt_uuid)) {
        bt_log(WARN, "fidl",
               "Received more Service UUIDs than fit in a single AD - truncating UUID %s",
               bt_str(bt_uuid));
      }
    }
  }
  if (input.has_service_data()) {
    for (const auto& entry : input.service_data()) {
      if (!output.SetServiceData(UuidFromFidl(entry.uuid), bt::BufferView(entry.data))) {
        return std::nullopt;
      }
    }
  }
  if (input.has_manufacturer_data()) {
    for (const auto& entry : input.manufacturer_data()) {
      bt::BufferView data(entry.data);
      if (!output.SetManufacturerData(entry.company_id, data)) {
        return std::nullopt;
      }
    }
  }
  if (input.has_uris()) {
    for (const auto& uri : input.uris()) {
      if (!output.AddUri(uri)) {
        return std::nullopt;
      }
    }
  }

  return output;
}

fble::AdvertisingData AdvertisingDataToFidl(const bt::AdvertisingData& input) {
  fble::AdvertisingData output;

  if (input.local_name()) {
    output.set_name(*input.local_name());
  }
  if (input.appearance()) {
    // TODO(fxbug.dev/66358): Remove this to allow for passing arbitrary appearance values to
    // clients in a way that's forward-compatible with future BLE revisions.
    const uint16_t appearance_raw = input.appearance().value();
    if (auto appearance = AppearanceToFidl(appearance_raw)) {
      output.set_appearance(appearance.value());
    } else {
      bt_log(DEBUG, "fidl", "omitting unencodeable appearance %#.4x of peer %s", appearance_raw,
             input.local_name().value_or("").c_str());
    }
  }
  if (input.tx_power()) {
    output.set_tx_power_level(*input.tx_power());
  }
  std::unordered_set<bt::UUID> service_uuids = input.service_uuids();
  if (!service_uuids.empty()) {
    std::vector<fbt::Uuid> uuids;
    uuids.reserve(service_uuids.size());
    for (const auto& uuid : service_uuids) {
      uuids.push_back(fbt::Uuid{uuid.value()});
    }
    output.set_service_uuids(std::move(uuids));
  }
  if (!input.service_data_uuids().empty()) {
    std::vector<fble::ServiceData> entries;
    for (const auto& uuid : input.service_data_uuids()) {
      auto data = input.service_data(uuid);
      fble::ServiceData entry{fbt::Uuid{uuid.value()}, data.ToVector()};
      entries.push_back(std::move(entry));
    }
    output.set_service_data(std::move(entries));
  }
  if (!input.manufacturer_data_ids().empty()) {
    std::vector<fble::ManufacturerData> entries;
    for (const auto& id : input.manufacturer_data_ids()) {
      auto data = input.manufacturer_data(id);
      fble::ManufacturerData entry{id, data.ToVector()};
      entries.push_back(std::move(entry));
    }
    output.set_manufacturer_data(std::move(entries));
  }
  if (!input.uris().empty()) {
    std::vector<std::string> uris;
    for (const auto& uri : input.uris()) {
      uris.push_back(uri);
    }
    output.set_uris(std::move(uris));
  }

  return output;
}

fble::AdvertisingDataDeprecated AdvertisingDataToFidlDeprecated(const bt::AdvertisingData& input) {
  fble::AdvertisingDataDeprecated output;

  if (input.local_name()) {
    output.name = *input.local_name();
  }
  if (input.appearance()) {
    output.appearance = fbt::UInt16::New();
    output.appearance->value = *input.appearance();
  }
  if (input.tx_power()) {
    output.tx_power_level = fbt::Int8::New();
    output.tx_power_level->value = *input.tx_power();
  }
  if (!input.service_uuids().empty()) {
    output.service_uuids.emplace();
    for (const auto& uuid : input.service_uuids()) {
      output.service_uuids->push_back(uuid.ToString());
    }
  }
  if (!input.service_data_uuids().empty()) {
    output.service_data.emplace();
    for (const auto& uuid : input.service_data_uuids()) {
      auto data = input.service_data(uuid);
      fble::ServiceDataEntry entry{uuid.ToString(), data.ToVector()};
      output.service_data->push_back(std::move(entry));
    }
  }
  if (!input.manufacturer_data_ids().empty()) {
    output.manufacturer_specific_data.emplace();
    for (const auto& id : input.manufacturer_data_ids()) {
      auto data = input.manufacturer_data(id);
      fble::ManufacturerSpecificDataEntry entry{id, data.ToVector()};
      output.manufacturer_specific_data->push_back(std::move(entry));
    }
  }
  if (!input.uris().empty()) {
    output.uris.emplace();
    for (const auto& uri : input.uris()) {
      output.uris->push_back(uri);
    }
  }

  return output;
}

fble::Peer PeerToFidlLe(const bt::gap::Peer& peer) {
  ZX_ASSERT(peer.le());

  fble::Peer output;
  output.set_id(fbt::PeerId{peer.identifier().value()});
  output.set_connectable(peer.connectable());

  if (peer.rssi() != bt::hci::kRSSIInvalid) {
    output.set_rssi(peer.rssi());
  }

  if (peer.le()->advertising_data().size() != 0u) {
    // We populate |output|'s AdvertisingData field if we can parse the payload. We leave it blank
    // otherwise.
    if (auto unpacked = bt::AdvertisingData::FromBytes(peer.le()->advertising_data())) {
      output.set_advertising_data(fidl_helpers::AdvertisingDataToFidl(unpacked.value()));
    }
  }

  return output;
}

bt::gatt::ReliableMode ReliableModeFromFidl(const fgatt::WriteOptions& write_options) {
  return (write_options.has_reliable_mode() &&
          write_options.reliable_mode() == fgatt::ReliableMode::ENABLED)
             ? bt::gatt::ReliableMode::kEnabled
             : bt::gatt::ReliableMode::kDisabled;
}

// TODO(fxbug.dev/63438): The 64 bit `fidl_gatt_id` can overflow the 16 bits of a bt:att::Handle
// that underlies CharacteristicHandles when directly casted. Fix this.
bt::gatt::CharacteristicHandle CharacteristicHandleFromFidl(uint64_t fidl_gatt_id) {
  if (fidl_gatt_id > std::numeric_limits<bt::att::Handle>::max()) {
    bt_log(ERROR, "fidl",
           "Casting a 64-bit FIDL GATT ID with `bits[16, 63] != 0` (0x%lX) to 16-bit "
           "Characteristic Handle",
           fidl_gatt_id);
  }
  return bt::gatt::CharacteristicHandle(static_cast<bt::att::Handle>(fidl_gatt_id));
}

// TODO(fxbug.dev/63438): The 64 bit `fidl_gatt_id` can overflow the 16 bits of a bt:att::Handle
// that underlies DescriptorHandles when directly casted. Fix this.
bt::gatt::DescriptorHandle DescriptorHandleFromFidl(uint64_t fidl_gatt_id) {
  if (fidl_gatt_id > std::numeric_limits<bt::att::Handle>::max()) {
    bt_log(ERROR, "fidl",
           "Casting a 64-bit FIDL GATT ID with `bits[16, 63] != 0` (0x%lX) to 16-bit Descriptor "
           "Handle",
           fidl_gatt_id);
  }
  return bt::gatt::DescriptorHandle(static_cast<bt::att::Handle>(fidl_gatt_id));
}

fit::result<bt::sdp::ServiceRecord, fuchsia::bluetooth::ErrorCode> ServiceDefinitionToServiceRecord(
    const fuchsia::bluetooth::bredr::ServiceDefinition& definition) {
  bt::sdp::ServiceRecord rec;
  std::vector<bt::UUID> classes;

  if (!definition.has_service_class_uuids()) {
    bt_log(WARN, "fidl", "Advertised service contains no Service UUIDs");
    return fit::error(fuchsia::bluetooth::ErrorCode::INVALID_ARGUMENTS);
  }

  for (auto& uuid : definition.service_class_uuids()) {
    bt::UUID btuuid = fidl_helpers::UuidFromFidl(uuid);
    bt_log(TRACE, "fidl", "Setting Service Class UUID %s", bt_str(btuuid));
    classes.emplace_back(std::move(btuuid));
  }

  rec.SetServiceClassUUIDs(classes);

  if (definition.has_protocol_descriptor_list()) {
    if (!AddProtocolDescriptorList(&rec, bt::sdp::ServiceRecord::kPrimaryProtocolList,
                                   definition.protocol_descriptor_list())) {
      bt_log(ERROR, "fidl", "Failed to add protocol descriptor list");
      return fit::error(fuchsia::bluetooth::ErrorCode::INVALID_ARGUMENTS);
    }
  }

  if (definition.has_additional_protocol_descriptor_lists()) {
    // It's safe to iterate through this list with a ProtocolListId as ProtocolListId = uint8_t,
    // and std::numeric_limits<uint8_t>::max() == 255 == the MAX_SEQUENCE_LENGTH vector limit from
    // fuchsia.bluetooth.bredr/ServiceDefinition.additional_protocol_descriptor_lists.
    ZX_ASSERT(definition.additional_protocol_descriptor_lists().size() <=
              std::numeric_limits<bt::sdp::ServiceRecord::ProtocolListId>::max());
    bt::sdp::ServiceRecord::ProtocolListId protocol_list_id = 1;
    for (const auto& descriptor_list : definition.additional_protocol_descriptor_lists()) {
      if (!AddProtocolDescriptorList(&rec, protocol_list_id, descriptor_list)) {
        bt_log(ERROR, "fidl", "Failed to add additional protocol descriptor list");
        return fit::error(fuchsia::bluetooth::ErrorCode::INVALID_ARGUMENTS);
      }
      protocol_list_id++;
    }
  }

  if (definition.has_profile_descriptors()) {
    for (const auto& profile : definition.profile_descriptors()) {
      bt_log(TRACE, "fidl", "Adding Profile %#hx v%d.%d", profile.profile_id, profile.major_version,
             profile.minor_version);
      rec.AddProfile(bt::UUID(uint16_t(profile.profile_id)), profile.major_version,
                     profile.minor_version);
    }
  }

  if (definition.has_information()) {
    for (const auto& info : definition.information()) {
      if (!info.has_language()) {
        return fit::error(fuchsia::bluetooth::ErrorCode::INVALID_ARGUMENTS);
      }
      std::string language = info.language();
      std::string name, description, provider;
      if (info.has_name()) {
        name = info.name();
      }
      if (info.has_description()) {
        description = info.description();
      }
      if (info.has_provider()) {
        provider = info.provider();
      }
      bt_log(TRACE, "fidl", "Adding Info (%s): (%s, %s, %s)", language.c_str(), name.c_str(),
             description.c_str(), provider.c_str());
      rec.AddInfo(language, name, description, provider);
    }
  }

  if (definition.has_additional_attributes()) {
    for (const auto& attribute : definition.additional_attributes()) {
      auto elem = FidlToDataElement(attribute.element);
      if (elem) {
        bt_log(TRACE, "fidl", "Adding attribute %#x : %s", attribute.id,
               elem.value().ToString().c_str());
        rec.SetAttribute(attribute.id, std::move(elem.value()));
      }
    }
  }
  return fit::ok(std::move(rec));
}

bt::gap::BrEdrSecurityRequirements FidlToBrEdrSecurityRequirements(
    const fbredr::ChannelParameters& fidl) {
  bt::gap::BrEdrSecurityRequirements requirements{.authentication = false,
                                                  .secure_connections = false};
  if (fidl.has_security_requirements()) {
    if (fidl.security_requirements().has_authentication_required()) {
      requirements.authentication = fidl.security_requirements().authentication_required();
    }

    if (fidl.security_requirements().has_secure_connections_required()) {
      requirements.secure_connections = fidl.security_requirements().secure_connections_required();
    }
  }
  return requirements;
}

bt::sco::ParameterSet FidlToScoParameterSet(const fbredr::HfpParameterSet param_set) {
  switch (param_set) {
    case fbredr::HfpParameterSet::MSBC_T1:
      return bt::sco::kParameterSetMsbcT1;
    case fbredr::HfpParameterSet::MSBC_T2:
      return bt::sco::kParameterSetMsbcT2;
    case fbredr::HfpParameterSet::CVSD_S1:
      return bt::sco::kParameterSetCvsdS1;
    case fbredr::HfpParameterSet::CVSD_S2:
      return bt::sco::kParameterSetCvsdS2;
    case fbredr::HfpParameterSet::CVSD_S3:
      return bt::sco::kParameterSetCvsdS3;
    case fbredr::HfpParameterSet::CVSD_S4:
      return bt::sco::kParameterSetCvsdS4;
    case fbredr::HfpParameterSet::CVSD_D0:
      return bt::sco::kParameterSetCvsdD0;
    case fbredr::HfpParameterSet::CVSD_D1:
      return bt::sco::kParameterSetCvsdD1;
  }
}

bt::hci::VendorCodingFormat FidlToScoCodingFormat(const fbredr::CodingFormat format) {
  bt::hci::VendorCodingFormat out;
  // Set to 0 since vendor specific coding formats are not supported.
  out.company_id = 0;
  out.vendor_codec_id = 0;
  switch (format) {
    case fbredr::CodingFormat::ALAW:
      out.coding_format = bt::hci::CodingFormat::kALaw;
      break;
    case fbredr::CodingFormat::MULAW:
      out.coding_format = bt::hci::CodingFormat::kMuLaw;
      break;
    case fbredr::CodingFormat::CVSD:
      out.coding_format = bt::hci::CodingFormat::kCvsd;
      break;
    case fbredr::CodingFormat::LINEAR_PCM:
      out.coding_format = bt::hci::CodingFormat::kLinearPcm;
      break;
    case fbredr::CodingFormat::MSBC:
      out.coding_format = bt::hci::CodingFormat::kMSbc;
      break;
    case fbredr::CodingFormat::TRANSPARENT:
      out.coding_format = bt::hci::CodingFormat::kTransparent;
      break;
  }
  return out;
}

fit::result<bt::hci::PcmDataFormat> FidlToPcmDataFormat(const faudio::SampleFormat& format) {
  switch (format) {
    case faudio::SampleFormat::PCM_SIGNED:
      return fit::ok(bt::hci::PcmDataFormat::k2sComplement);
    case faudio::SampleFormat::PCM_UNSIGNED:
      return fit::ok(bt::hci::PcmDataFormat::kUnsigned);
    default:
      // Other sample formats are not supported by SCO.
      return fit::error();
  }
}

bt::hci::ScoDataPath FidlToScoDataPath(const fbredr::DataPath& path) {
  switch (path) {
    case fbredr::DataPath::HOST:
      return bt::hci::ScoDataPath::kHci;
    case fbredr::DataPath::OFFLOAD: {
      // TODO(fxbug.dev/58458): Use path from stack configuration file instead of this hardcoded
      // value. "6" is the data path usually used in Broadcom controllers.
      return static_cast<bt::hci::ScoDataPath>(6);
    }
    case fbredr::DataPath::TEST:
      return bt::hci::ScoDataPath::kAudioTestMode;
  }
}

fit::result<bt::hci::SynchronousConnectionParameters> FidlToScoParameters(
    const fbredr::ScoConnectionParameters& params) {
  bt::hci::SynchronousConnectionParameters out;

  if (!params.has_parameter_set()) {
    bt_log(WARN, "fidl", "SCO parameters missing parameter_set");
    return fit::error();
  }
  auto param_set = FidlToScoParameterSet(params.parameter_set());

  out.transmit_bandwidth = param_set.transmit_receive_bandwidth;
  out.receive_bandwidth = out.transmit_bandwidth;

  if (!params.has_air_coding_format()) {
    bt_log(WARN, "fidl", "SCO parameters missing air_coding_format");
    return fit::error();
  }
  auto air_coding_format = FidlToScoCodingFormat(params.air_coding_format());
  out.transmit_coding_format = air_coding_format;
  out.receive_coding_format = out.transmit_coding_format;

  if (!params.has_air_frame_size()) {
    bt_log(WARN, "fidl", "SCO parameters missing air_frame_size");
    return fit::error();
  }
  out.transmit_codec_frame_size_bytes = params.air_frame_size();
  out.receive_codec_frame_size_bytes = out.transmit_codec_frame_size_bytes;

  if (!params.has_io_bandwidth()) {
    bt_log(WARN, "fidl", "SCO parameters missing io_bandwidth");
    return fit::error();
  }
  out.input_bandwidth = params.io_bandwidth();
  out.output_bandwidth = out.input_bandwidth;

  if (!params.has_io_coding_format()) {
    bt_log(WARN, "fidl", "SCO parameters missing io_coding_format");
    return fit::error();
  }
  out.input_coding_format = FidlToScoCodingFormat(params.io_coding_format());
  out.output_coding_format = out.input_coding_format;

  if (!params.has_io_frame_size()) {
    bt_log(WARN, "fidl", "SCO parameters missing io_frame_size");
    return fit::error();
  }
  out.input_coded_data_size_bits = params.io_frame_size();
  out.output_coded_data_size_bits = out.input_coded_data_size_bits;

  if (params.has_io_pcm_data_format() &&
      out.input_coding_format.coding_format == bt::hci::CodingFormat::kLinearPcm) {
    auto io_pcm_format = FidlToPcmDataFormat(params.io_pcm_data_format());
    if (io_pcm_format.is_error()) {
      bt_log(WARN, "fidl", "Unsupported IO PCM data format in SCO parameters");
      return fit::error();
    }
    out.input_pcm_data_format = io_pcm_format.value();
    out.output_pcm_data_format = out.input_pcm_data_format;

  } else if (out.input_coding_format.coding_format == bt::hci::CodingFormat::kLinearPcm) {
    bt_log(WARN, "fidl",
           "SCO parameters missing io_pcm_data_format (required for linear PCM IO coding format)");
    return fit::error();
  } else {
    out.input_pcm_data_format = bt::hci::PcmDataFormat::kNotApplicable;
    out.output_pcm_data_format = out.input_pcm_data_format;
  }

  if (params.has_io_pcm_sample_payload_msb_position() &&
      out.input_coding_format.coding_format == bt::hci::CodingFormat::kLinearPcm) {
    out.input_pcm_sample_payload_msb_position = params.io_pcm_sample_payload_msb_position();
    out.output_pcm_sample_payload_msb_position = out.input_pcm_sample_payload_msb_position;
  } else {
    out.input_pcm_sample_payload_msb_position = 0u;
    out.output_pcm_sample_payload_msb_position = out.input_pcm_sample_payload_msb_position;
  }

  if (!params.has_path()) {
    bt_log(WARN, "fidl", "SCO parameters missing data path");
    return fit::error();
  }
  out.input_data_path = FidlToScoDataPath(params.path());
  out.output_data_path = out.input_data_path;

  // For HCI Host transport the transport unit size should be "0". For PCM transport the unit size
  // is vendor specific. A unit size of "0" indicates "not applicable".
  // TODO(fxbug.dev/58458): Use unit size from stack configuration file instead of hardcoding "not
  // applicable".
  out.input_transport_unit_size_bits = 0u;
  out.output_transport_unit_size_bits = out.input_transport_unit_size_bits;

  out.max_latency_ms = param_set.max_latency_ms;
  out.packet_types = param_set.packet_types;
  out.retransmission_effort = param_set.retransmission_effort;

  return fit::ok(out);
}

}  // namespace bthost::fidl_helpers

// static
std::vector<uint8_t> fidl::TypeConverter<std::vector<uint8_t>, bt::ByteBuffer>::Convert(
    const bt::ByteBuffer& from) {
  std::vector<uint8_t> to(from.size());
  bt::MutableBufferView view(to.data(), to.size());
  view.Write(from);
  return to;
}