// Copyright 2024 The Pigweed Authors
//
// Licensed under the Apache License, Version 2.0 (the "License"); you may not
// use this file except in compliance with the License. You may obtain a copy of
// the License at
//
//     https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
// WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
// License for the specific language governing permissions and limitations under
// the License.

#include "emulator.h"

#include <fidl/fuchsia.driver.framework/cpp/fidl.h>
#include <fidl/fuchsia.hardware.bluetooth/cpp/fidl.h>
#include <lib/driver/logging/cpp/logger.h>
#include <lib/fdf/cpp/dispatcher.h>

#include "emulated_peer.h"
#include "pw_bluetooth_sapphire/internal/host/common/random.h"
#include "pw_bluetooth_sapphire/internal/host/testing/fake_controller.h"
#include "pw_bluetooth_sapphire/internal/host/testing/fake_peer.h"

namespace fhbt = fuchsia_hardware_bluetooth;

using bt::DeviceAddress;
using bt::testing::FakeController;

namespace bt_hci_virtual {

namespace {

FakeController::Settings SettingsFromFidl(const fhbt::EmulatorSettings& input) {
  FakeController::Settings settings;
  if (input.hci_config().has_value() &&
      input.hci_config().value() == fhbt::HciConfig::kLeOnly) {
    settings.ApplyLEOnlyDefaults();
  } else {
    settings.ApplyDualModeDefaults();
  }

  if (input.address().has_value()) {
    settings.bd_addr =
        DeviceAddress(DeviceAddress::Type::kBREDR, input.address()->bytes());
  }

  // TODO(armansito): Don't ignore "extended_advertising" setting when
  // supported.
  if (input.acl_buffer_settings().has_value()) {
    fhbt::AclBufferSettings acl_settings = input.acl_buffer_settings().value();

    if (acl_settings.data_packet_length().has_value()) {
      settings.acl_data_packet_length =
          acl_settings.data_packet_length().value();
    }

    if (acl_settings.total_num_data_packets().has_value()) {
      settings.total_num_acl_data_packets =
          acl_settings.total_num_data_packets().value();
    }
  }

  if (input.le_acl_buffer_settings().has_value()) {
    fhbt::AclBufferSettings le_acl_settings =
        input.le_acl_buffer_settings().value();

    if (le_acl_settings.data_packet_length().has_value()) {
      settings.le_acl_data_packet_length =
          le_acl_settings.data_packet_length().value();
    }

    if (le_acl_settings.total_num_data_packets().has_value()) {
      settings.le_total_num_acl_data_packets =
          le_acl_settings.total_num_data_packets().value();
    }
  }

  return settings;
}

std::optional<fuchsia_bluetooth::AddressType> LeOwnAddressTypeToFidl(
    pw::bluetooth::emboss::LEOwnAddressType type) {
  std::optional<fuchsia_bluetooth::AddressType> res;

  switch (type) {
    case pw::bluetooth::emboss::LEOwnAddressType::PUBLIC:
    case pw::bluetooth::emboss::LEOwnAddressType::PRIVATE_DEFAULT_TO_PUBLIC:
      res.emplace(fuchsia_bluetooth::AddressType::kPublic);
      return res;
    case pw::bluetooth::emboss::LEOwnAddressType::RANDOM:
    case pw::bluetooth::emboss::LEOwnAddressType::PRIVATE_DEFAULT_TO_RANDOM:
      res.emplace(fuchsia_bluetooth::AddressType::kRandom);
      return res;
  }

  ZX_PANIC("unsupported own address type");
  return res;
}

}  // namespace

EmulatorDevice::EmulatorDevice()
    : pw_dispatcher_(fdf::Dispatcher::GetCurrent()->async_dispatcher()),
      fake_device_(pw_dispatcher_),
      emulator_devfs_connector_(
          fit::bind_member<&EmulatorDevice::ConnectEmulator>(this)),
      vendor_devfs_connector_(
          fit::bind_member<&EmulatorDevice::ConnectVendor>(this)) {}

EmulatorDevice::~EmulatorDevice() { fake_device_.Stop(); }

zx_status_t EmulatorDevice::Initialize(std::string_view name,
                                       AddChildCallback callback,
                                       ShutdownCallback shutdown) {
  shutdown_cb_ = std::move(shutdown);

  bt::set_random_generator(&rng_);

  // Initialize |fake_device_|
  auto init_complete_cb = [](pw::Status status) {
    if (!status.ok()) {
      FDF_LOG(WARNING,
              "FakeController failed to initialize: %s",
              pw_StatusString(status));
    }
  };
  auto error_cb = [this](pw::Status status) {
    FDF_LOG(WARNING, "FakeController error: %s", pw_StatusString(status));
    UnpublishHci();
  };
  fake_device_.Initialize(init_complete_cb, error_cb);

  fake_device_.set_controller_parameters_callback(
      fit::bind_member<&EmulatorDevice::OnControllerParametersChanged>(this));
  fake_device_.set_advertising_state_callback(
      fit::bind_member<&EmulatorDevice::OnLegacyAdvertisingStateChanged>(this));
  fake_device_.set_connection_state_callback(
      fit::bind_member<&EmulatorDevice::OnPeerConnectionStateChanged>(this));

  // Create args to add emulator as a child node on behalf of VirtualController
  zx::result connector = emulator_devfs_connector_.Bind(
      fdf::Dispatcher::GetCurrent()->async_dispatcher());
  if (connector.is_error()) {
    FDF_LOG(ERROR,
            "Failed to bind devfs connecter to dispatcher: %u",
            connector.status_value());
    return connector.error_value();
  }

  fidl::Arena args_arena;
  auto devfs =
      fuchsia_driver_framework::wire::DevfsAddArgs::Builder(args_arena)
          .connector(std::move(connector.value()))
          .connector_supports(fuchsia_device_fs::ConnectionType::kController)
          .class_name("bt-emulator")
          .Build();
  auto args = fuchsia_driver_framework::wire::NodeAddArgs::Builder(args_arena)
                  .name(name.data())
                  .devfs_args(devfs)
                  .Build();
  callback(args);

  return ZX_OK;
}

void EmulatorDevice::Shutdown() {
  fake_device_.Stop();
  peers_.clear();

  if (shutdown_cb_) {
    shutdown_cb_();
  }
}

void EmulatorDevice::Publish(PublishRequest& request,
                             PublishCompleter::Sync& completer) {
  if (hci_node_controller_.is_valid()) {
    FDF_LOG(INFO, "bt-hci-device is already published");
    completer.Reply(fit::error(fhbt::EmulatorError::kHciAlreadyPublished));
    return;
  }

  FakeController::Settings settings = SettingsFromFidl(request);
  fake_device_.set_settings(settings);

  zx_status_t status = AddHciDeviceChildNode();
  if (status != ZX_OK) {
    FDF_LOG(WARNING, "Failed to publish bt-hci-device node");
    completer.Reply(fit::error(fhbt::EmulatorError::kFailed));
  } else {
    FDF_LOG(INFO, "Successfully published bt-hci-device node");
    completer.Reply(fit::success());
  }
}

void EmulatorDevice::AddLowEnergyPeer(
    AddLowEnergyPeerRequest& request,
    AddLowEnergyPeerCompleter::Sync& completer) {
  auto result = EmulatedPeer::NewLowEnergy(
      std::move(request),
      &fake_device_,
      fdf::Dispatcher::GetCurrent()->async_dispatcher());
  if (result.is_error()) {
    completer.Reply(fit::error(result.error()));
    return;
  }

  AddPeer(result.take_value());
  completer.Reply(fit::success());
}

void EmulatorDevice::AddBredrPeer(AddBredrPeerRequest& request,
                                  AddBredrPeerCompleter::Sync& completer) {
  auto result =
      EmulatedPeer::NewBredr(std::move(request),
                             &fake_device_,
                             fdf::Dispatcher::GetCurrent()->async_dispatcher());
  if (result.is_error()) {
    completer.Reply(fit::error(result.error()));
    return;
  }

  AddPeer(result.take_value());
  completer.Reply(fit::success());
}

void EmulatorDevice::WatchControllerParameters(
    WatchControllerParametersCompleter::Sync& completer) {
  controller_parameters_completer_.emplace(completer.ToAsync());
  MaybeUpdateControllerParametersChanged();
}

void EmulatorDevice::WatchLeScanStates(
    WatchLeScanStatesCompleter::Sync& completer) {}

void EmulatorDevice::WatchLegacyAdvertisingStates(
    WatchLegacyAdvertisingStatesCompleter::Sync& completer) {
  legacy_adv_states_completers_.emplace(completer.ToAsync());
  MaybeUpdateLegacyAdvertisingStates();
}

void EmulatorDevice::handle_unknown_method(
    fidl::UnknownMethodMetadata<fhbt::Emulator> metadata,
    fidl::UnknownMethodCompleter::Sync& completer) {
  FDF_LOG(
      ERROR,
      "Unknown method in Emulator request, closing with ZX_ERR_NOT_SUPPORTED");
  completer.Close(ZX_ERR_NOT_SUPPORTED);
}

void EmulatorDevice::GetFeatures(GetFeaturesCompleter::Sync& completer) {
  completer.Reply(fuchsia_hardware_bluetooth::wire::VendorFeatures());
}

void EmulatorDevice::EncodeCommand(EncodeCommandRequestView request,
                                   EncodeCommandCompleter::Sync& completer) {
  completer.ReplyError(ZX_ERR_INVALID_ARGS);
}

void EmulatorDevice::OpenHciTransport(
    OpenHciTransportCompleter::Sync& completer) {
  // Sets FakeController to respond with event, ACL, and ISO packet types when
  // it receives an incoming packet of the appropriate type
  fake_device_.SetEventFunction(
      fit::bind_member<&EmulatorDevice::SendEventToHost>(this));
  fake_device_.SetReceiveAclFunction(
      fit::bind_member<&EmulatorDevice::SendAclPacketToHost>(this));
  fake_device_.SetReceiveIsoFunction(
      fit::bind_member<&EmulatorDevice::SendIsoPacketToHost>(this));

  auto endpoints = fidl::CreateEndpoints<fhbt::HciTransport>();
  if (endpoints.is_error()) {
    FDF_LOG(ERROR,
            "Failed to create endpoints: %s",
            zx_status_get_string(endpoints.error_value()));
    completer.ReplyError(endpoints.error_value());
    return;
  }

  hci_transport_bindings_.AddBinding(
      fdf::Dispatcher::GetCurrent()->async_dispatcher(),
      std::move(endpoints->server),
      this,
      fidl::kIgnoreBindingClosure);
  completer.ReplySuccess(std::move(endpoints->client));
}

void EmulatorDevice::OpenSnoop(OpenSnoopCompleter::Sync& completer) {
  completer.ReplyError(ZX_ERR_NOT_SUPPORTED);
}

void EmulatorDevice::handle_unknown_method(
    fidl::UnknownMethodMetadata<fhbt::Vendor> metadata,
    fidl::UnknownMethodCompleter::Sync& completer) {
  FDF_LOG(
      ERROR,
      "Unknown method in Vendor request, closing with ZX_ERR_NOT_SUPPORTED");
  completer.Close(ZX_ERR_NOT_SUPPORTED);
}

void EmulatorDevice::Send(SendRequest& request,
                          SendCompleter::Sync& completer) {
  switch (request.Which()) {
    case fhbt::SentPacket::Tag::kCommand: {
      std::vector<uint8_t> command_data = request.command().value();
      pw::span<const std::byte> buffer = bt::BufferView(command_data).subspan();
      fake_device_.SendCommand(buffer);
      completer.Reply();
      return;
    }
    case fhbt::SentPacket::Tag::kAcl: {
      std::vector<uint8_t> acl_data = request.acl().value();
      pw::span<const std::byte> buffer = bt::BufferView(acl_data).subspan();
      fake_device_.SendAclData(buffer);
      completer.Reply();
      return;
    }
    case fhbt::SentPacket::Tag::kIso: {
      std::vector<uint8_t> iso_data = request.iso().value();
      pw::span<const std::byte> buffer = bt::BufferView(iso_data).subspan();
      fake_device_.SendIsoData(buffer);
      completer.Reply();
      return;
    }
    default: {
      FDF_LOG(ERROR,
              "Received unknown packet type %lu",
              static_cast<uint64_t>(request.Which()));
      return;
    }
  }
}

void EmulatorDevice::ConfigureSco(
    ConfigureScoRequest& request,
    fidl::Server<fuchsia_hardware_bluetooth::HciTransport>::
        ConfigureScoCompleter::Sync& completer) {
  // This interface is not implemented.
  completer.Close(ZX_ERR_NOT_SUPPORTED);
}

void EmulatorDevice::handle_unknown_method(
    ::fidl::UnknownMethodMetadata<fuchsia_hardware_bluetooth::HciTransport>
        metadata,
    ::fidl::UnknownMethodCompleter::Sync& completer) {
  FDF_LOG(ERROR,
          "Unknown method in HciTransport request, closing with "
          "ZX_ERR_NOT_SUPPORTED");
  completer.Close(ZX_ERR_NOT_SUPPORTED);
}

void EmulatorDevice::ConnectEmulator(fidl::ServerEnd<fhbt::Emulator> request) {
  emulator_binding_group_.AddBinding(
      fdf::Dispatcher::GetCurrent()->async_dispatcher(),
      std::move(request),
      this,
      fidl::kIgnoreBindingClosure);
}

void EmulatorDevice::ConnectVendor(fidl::ServerEnd<fhbt::Vendor> request) {
  vendor_binding_group_.AddBinding(
      fdf::Dispatcher::GetCurrent()->async_dispatcher(),
      std::move(request),
      this,
      fidl::kIgnoreBindingClosure);
}

zx_status_t EmulatorDevice::AddHciDeviceChildNode() {
  // Create args to add bt-hci-device as a child node on behalf of
  // VirtualController
  zx::result connector = vendor_devfs_connector_.Bind(
      fdf::Dispatcher::GetCurrent()->async_dispatcher());
  if (connector.is_error()) {
    FDF_LOG(ERROR,
            "Failed to bind devfs connecter to dispatcher: %u",
            connector.status_value());
    return connector.error_value();
  }

  fidl::Arena args_arena;
  auto devfs =
      fuchsia_driver_framework::wire::DevfsAddArgs::Builder(args_arena)
          .connector(std::move(connector.value()))
          .connector_supports(fuchsia_device_fs::ConnectionType::kController)
          .class_name("bt-hci")
          .Build();
  auto args = fuchsia_driver_framework::wire::NodeAddArgs::Builder(args_arena)
                  .name("bt-hci-device")
                  .devfs_args(devfs)
                  .Build();

  // Create the endpoints of fuchsia_driver_framework::NodeController protocol
  auto controller_endpoints =
      fidl::CreateEndpoints<fuchsia_driver_framework::NodeController>();
  if (controller_endpoints.is_error()) {
    FDF_LOG(ERROR,
            "Create node controller endpoints failed: %s",
            zx_status_get_string(controller_endpoints.error_value()));
    return controller_endpoints.error_value();
  }

  // Create the endpoints of fuchsia_driver_framework::Node protocol for the
  // child node, and hold the client end of it, because no driver will bind to
  // the child node.
  auto child_node_endpoints =
      fidl::CreateEndpoints<fuchsia_driver_framework::Node>();
  if (child_node_endpoints.is_error()) {
    FDF_LOG(ERROR,
            "Create child node endpoints failed: %s",
            zx_status_get_string(child_node_endpoints.error_value()));
    return child_node_endpoints.error_value();
  }

  // Add bt-hci-device as a child node of the EmulatorDevice
  ZX_DEBUG_ASSERT(emulator_child_node()->is_valid());
  auto child_result = emulator_child_node()->sync()->AddChild(
      std::move(args),
      std::move(controller_endpoints->server),
      std::move(child_node_endpoints->server));
  if (!child_result.ok()) {
    FDF_LOG(ERROR,
            "Failed to add bt-hci-device node, FIDL error: %s",
            child_result.status_string());
    return child_result.status();
  }

  if (child_result->is_error()) {
    FDF_LOG(ERROR,
            "Failed to add bt-hci-device node: %u",
            static_cast<uint32_t>(child_result->error_value()));
    return ZX_ERR_INTERNAL;
  }

  // |hci_child_node_| does not need to create more child nodes so we do not
  // need an event_handler and we do not need to worry about it being re-bound
  hci_child_node_.Bind(std::move(child_node_endpoints->client),
                       fdf::Dispatcher::GetCurrent()->async_dispatcher());
  hci_node_controller_.Bind(std::move(controller_endpoints->client),
                            fdf::Dispatcher::GetCurrent()->async_dispatcher());

  return ZX_OK;
}

void EmulatorDevice::AddPeer(std::unique_ptr<EmulatedPeer> peer) {
  auto address = peer->address();
  peer->set_closed_callback([this, address] { peers_.erase(address); });
  peers_[address] = std::move(peer);
}

void EmulatorDevice::OnControllerParametersChanged() {
  fhbt::ControllerParameters fidl_value;
  fidl_value.local_name(fake_device_.local_name());

  const auto& device_class_bytes = fake_device_.device_class().bytes();
  uint32_t device_class = 0;
  device_class |= device_class_bytes[0];
  device_class |= static_cast<uint32_t>(device_class_bytes[1]) << 8;
  device_class |= static_cast<uint32_t>(device_class_bytes[2]) << 16;

  std::optional<fuchsia_bluetooth::DeviceClass> device_class_option =
      fuchsia_bluetooth::DeviceClass{device_class};
  fidl_value.device_class(device_class_option);

  controller_parameters_.emplace(fidl_value);
  MaybeUpdateControllerParametersChanged();
}

void EmulatorDevice::MaybeUpdateControllerParametersChanged() {
  if (!controller_parameters_.has_value() ||
      !controller_parameters_completer_.has_value()) {
    return;
  }
  controller_parameters_completer_->Reply(
      std::move(controller_parameters_.value()));
  controller_parameters_.reset();
  controller_parameters_completer_.reset();
}

void EmulatorDevice::OnLegacyAdvertisingStateChanged() {
  // We have requests to resolve. Construct the FIDL table for the current
  // state.
  fhbt::LegacyAdvertisingState fidl_state;
  const FakeController::LEAdvertisingState& adv_state =
      fake_device_.legacy_advertising_state();
  fidl_state.enabled(adv_state.enabled);

  // Populate the rest only if advertising is enabled.
  fidl_state.type(static_cast<fhbt::LegacyAdvertisingType>(
      bt::hci::LowEnergyAdvertiser::
          AdvertisingEventPropertiesToLEAdvertisingType(adv_state.properties)));
  fidl_state.address_type(LeOwnAddressTypeToFidl(adv_state.own_address_type));

  if (adv_state.interval_min) {
    fidl_state.interval_min(adv_state.interval_min);
  }
  if (adv_state.interval_max) {
    fidl_state.interval_max(adv_state.interval_max);
  }

  if (adv_state.data_length) {
    std::vector<uint8_t> output(adv_state.data,
                                adv_state.data + adv_state.data_length);

    if (!fidl_state.advertising_data().has_value()) {
      fidl_state.advertising_data() = fhbt::AdvertisingData();
    }
    fidl_state.advertising_data()->data(output);
  }
  if (adv_state.scan_rsp_length) {
    std::vector<uint8_t> output(
        adv_state.scan_rsp_data,
        adv_state.scan_rsp_data + adv_state.scan_rsp_length);
    if (!fidl_state.scan_response().has_value()) {
      fidl_state.scan_response() = fhbt::AdvertisingData();
    }
    fidl_state.scan_response()->data(output);
  }

  legacy_adv_states_.emplace_back(fidl_state);
  MaybeUpdateLegacyAdvertisingStates();
}

void EmulatorDevice::MaybeUpdateLegacyAdvertisingStates() {
  if (legacy_adv_states_.empty() || legacy_adv_states_completers_.empty()) {
    return;
  }
  while (!legacy_adv_states_completers_.empty()) {
    legacy_adv_states_completers_.front().Reply(legacy_adv_states_);
    legacy_adv_states_completers_.pop();
  }
  legacy_adv_states_.clear();
}

void EmulatorDevice::OnPeerConnectionStateChanged(
    const DeviceAddress& address,
    bt::hci_spec::ConnectionHandle handle,
    bool connected,
    bool canceled) {
  FDF_LOG(TRACE,
          "Peer connection state changed: %s (handle: %#.4x) (connected: %s) "
          "(canceled: %s):\n",
          address.ToString().c_str(),
          handle,
          (connected ? "true" : "false"),
          (canceled ? "true" : "false"));

  auto iter = peers_.find(address);
  if (iter != peers_.end()) {
    iter->second->UpdateConnectionState(connected);
  }
}

void EmulatorDevice::UnpublishHci() {
  // Unpublishing the bt-hci-device child node shuts down the associated bt-host
  // component
  auto status = hci_node_controller_->Remove();
  if (!status.ok()) {
    FDF_LOG(ERROR,
            "Could not remove bt-hci-device child node: %s",
            status.status_string());
  }
}

void EmulatorDevice::SendEventToHost(pw::span<const std::byte> buffer) {
  if (hci_transport_bindings_.size() == 0) {
    FDF_LOG(ERROR, "No HciTransport bindings");
    return;
  }
  // Using HciTransport protocol (i.e. |cmd_channel_| is not set)
  hci_transport_bindings_.ForEachBinding(
      [buffer](
          const fidl::ServerBinding<fuchsia_hardware_bluetooth::HciTransport>&
              binding) {
        // Send the event to bt-host
        std::vector<uint8_t> data = bt::BufferView(buffer).ToVector();
        fhbt::ReceivedPacket event = fhbt::ReceivedPacket::WithEvent(data);
        fit::result<::fidl::OneWayError> status =
            fidl::SendEvent(binding)->OnReceive(event);
        if (!status.is_ok()) {
          FDF_LOG(ERROR,
                  "Failed to send OnReceive event to bt-host: %s",
                  status.error_value().status_string());
        }
      });
}

void EmulatorDevice::SendAclPacketToHost(pw::span<const std::byte> buffer) {
  if (hci_transport_bindings_.size() == 0) {
    FDF_LOG(ERROR, "No HciTransport bindings");
    return;
  }
  // Using HciTransport protocol (i.e. |acl_channel_| is not set)
  hci_transport_bindings_.ForEachBinding(
      [buffer](
          const fidl::ServerBinding<fuchsia_hardware_bluetooth::HciTransport>&
              binding) {
        // Send the event to bt-host
        std::vector<uint8_t> data = bt::BufferView(buffer).ToVector();
        fhbt::ReceivedPacket event = fhbt::ReceivedPacket::WithAcl(data);
        fit::result<::fidl::OneWayError> status =
            fidl::SendEvent(binding)->OnReceive(event);
        if (!status.is_ok()) {
          FDF_LOG(ERROR,
                  "Failed to send OnReceive event to bt-host: %s",
                  status.error_value().status_string());
        }
      });
}

void EmulatorDevice::SendIsoPacketToHost(pw::span<const std::byte> buffer) {
  if (hci_transport_bindings_.size() == 0) {
    FDF_LOG(ERROR, "No HciTransport bindings");
    return;
  }
  // Using HciTransport protocol (i.e. |iso_channel_| is not set)
  hci_transport_bindings_.ForEachBinding(
      [buffer](
          const fidl::ServerBinding<fuchsia_hardware_bluetooth::HciTransport>&
              binding) {
        // Send the event to bt-host
        std::vector<uint8_t> data = bt::BufferView(buffer).ToVector();
        fhbt::ReceivedPacket event = fhbt::ReceivedPacket::WithIso(data);
        fit::result<::fidl::OneWayError> status =
            fidl::SendEvent(binding)->OnReceive(event);
        if (!status.is_ok()) {
          FDF_LOG(ERROR,
                  "Failed to send OnReceive event to bt-host: %s",
                  status.error_value().status_string());
        }
      });
}

}  // namespace bt_hci_virtual