/*
 * Copyright 2024 The Android Open Source Project
 *
 * 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
 *
 *      http://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.
 */

#define LOG_TAG "android.hardware.bluetooth.service.default"

#include <cutils/properties.h>
#include <fcntl.h>
#include <hal/ffi.h>
#include <string.h>
#include <termios.h>

#include <future>
#include <memory>
#include <vector>

#include "async_fd_watcher.h"
#include "h4_protocol.h"
#include "log/log.h"
#include "net_bluetooth_mgmt.h"

namespace {
int SetTerminalRaw(int fd) {
  termios terminal_settings;
  int rval = tcgetattr(fd, &terminal_settings);
  if (rval < 0) {
    return rval;
  }
  cfmakeraw(&terminal_settings);
  rval = tcsetattr(fd, TCSANOW, &terminal_settings);
  return rval;
}
}  // namespace

using namespace ::android::hardware::bluetooth::hci;
using namespace ::android::hardware::bluetooth::async;

namespace aidl::android::hardware::bluetooth::impl {

std::optional<std::string> GetSystemProperty(const std::string& property) {
  std::array<char, PROPERTY_VALUE_MAX> value_array{0};
  auto value_len = property_get(property.c_str(), value_array.data(), nullptr);
  if (value_len <= 0) {
    return std::nullopt;
  }
  return std::string(value_array.data(), value_len);
}

bool starts_with(const std::string& str, const std::string& prefix) {
  return str.compare(0, prefix.length(), prefix) == 0;
}

class Hal {
 public:
  Hal(const std::string& dev_path = "/dev/hvc5") {
    char property_bytes[PROPERTY_VALUE_MAX];
    property_get("vendor.ser.bt-uart", property_bytes, dev_path.c_str());
    mDevPath = std::string(property_bytes);
  }

  static void Initialize(void* instance,
                         const struct hal_callbacks* callbacks) {
    static_cast<Hal*>(instance)->Initialize(callbacks);
  }

  static void Close(void* instance) { static_cast<Hal*>(instance)->Close(); }

  static void SendCommand(void* instance, const uint8_t* data, size_t len) {
    static_cast<Hal*>(instance)->SendCommand(
        std::vector<uint8_t>(data, data + len));
  }

  static void SendAcl(void* instance, const uint8_t* data, size_t len) {
    static_cast<Hal*>(instance)->SendAcl(
        std::vector<uint8_t>(data, data + len));
  }

  static void SendSco(void* instance, const uint8_t* data, size_t len) {
    static_cast<Hal*>(instance)->SendSco(
        std::vector<uint8_t>(data, data + len));
  }

  static void SendIso(void* instance, const uint8_t* data, size_t len) {
    static_cast<Hal*>(instance)->SendIso(
        std::vector<uint8_t>(data, data + len));
  }

  static void ClientDied(void* instance) {
    static_cast<Hal*>(instance)->ClientDied();
  }

 private:
  int getFdFromDevPath() {
    int fd = open(mDevPath.c_str(), O_RDWR);
    if (fd < 0) {
      ALOGE("Could not connect to bt: %s (%s)", mDevPath.c_str(),
            strerror(errno));
      return fd;
    }
    if (int ret = SetTerminalRaw(fd) < 0) {
      ALOGI("Could not make %s a raw terminal %d(%s)", mDevPath.c_str(), ret,
            strerror(errno));
    }
    return fd;
  }

  void reset() {
    // Send a reset command and wait until the command complete comes back.

    std::vector<uint8_t> reset = {0x03, 0x0c, 0x00};

    auto resetPromise = std::make_shared<std::promise<void>>();
    auto resetFuture = resetPromise->get_future();

    mH4 = std::make_shared<H4Protocol>(
        mFd,
        [](const std::vector<uint8_t>& raw_command) {
          ALOGI("Discarding %d bytes with command type",
                static_cast<int>(raw_command.size()));
        },
        [](const std::vector<uint8_t>& raw_acl) {
          ALOGI("Discarding %d bytes with acl type",
                static_cast<int>(raw_acl.size()));
        },
        [](const std::vector<uint8_t>& raw_sco) {
          ALOGI("Discarding %d bytes with sco type",
                static_cast<int>(raw_sco.size()));
        },
        [resetPromise](const std::vector<uint8_t>& raw_event) {
          std::vector<uint8_t> reset_complete = {0x0e, 0x04, 0x01,
                                                 0x03, 0x0c, 0x00};
          bool valid = raw_event.size() == 6 &&
                       raw_event[0] == reset_complete[0] &&
                       raw_event[1] == reset_complete[1] &&
                       // Don't compare the number of packets field.
                       raw_event[3] == reset_complete[3] &&
                       raw_event[4] == reset_complete[4] &&
                       raw_event[5] == reset_complete[5];
          if (valid) {
            resetPromise->set_value();
          } else {
            ALOGI("Discarding %d bytes with event type",
                  static_cast<int>(raw_event.size()));
          }
        },
        [](const std::vector<uint8_t>& raw_iso) {
          ALOGI("Discarding %d bytes with iso type",
                static_cast<int>(raw_iso.size()));
        },
        [this]() {
          ALOGI("HCI socket device disconnected while waiting for reset");
          mFdWatcher.StopWatchingFileDescriptors();
        });
    mFdWatcher.WatchFdForNonBlockingReads(mFd,
                                          [this](int) { mH4->OnDataReady(); });

    if (!send(PacketType::COMMAND, reset)) {
      ALOGE("Error sending reset command");
    }
    auto status = resetFuture.wait_for(std::chrono::seconds(1));
    mFdWatcher.StopWatchingFileDescriptors();
    if (status == std::future_status::ready) {
      ALOGI("HCI Reset successful");
    } else {
      ALOGE("HCI Reset Response not received in one second");
    }

    resetPromise.reset();
  }

  void Initialize(const struct hal_callbacks* callbacks) {
    ALOGI(__func__);

    HalState old_state = HalState::READY;
    {
      std::lock_guard<std::mutex> guard(mStateMutex);
      if (mState != HalState::READY) {
        old_state = mState;
      } else {
        mState = HalState::INITIALIZING;
      }
    }

    if (old_state != HalState::READY) {
      ALOGE("initialize: Unexpected State %d", static_cast<int>(old_state));
      Close();
      callbacks->initialization_complete(callbacks->handle,
                                         STATUS_ALREADY_INITIALIZED);
      return;
    }

    mCallbacks = std::make_unique<struct hal_callbacks>(*callbacks);
    management_.reset(new NetBluetoothMgmt);
    mFd = management_->openHci();
    if (mFd < 0) {
      management_.reset();

      ALOGI("Unable to open Linux interface, trying default path.");
      mFd = getFdFromDevPath();
      if (mFd < 0) {
        mState = HalState::READY;
        mCallbacks->initialization_complete(mCallbacks->handle,
                                            STATUS_UNABLE_TO_OPEN_INTERFACE);
        return;
      }
    }

    // TODO: HCI Reset on emulators since the bluetooth controller
    // cannot be powered on/off during the HAL setup; and the stack
    // might received spurious packets/events during boottime.
    // Proper solution would be to use bt-virtio or vsock to better
    // control the link to rootcanal and the controller lifetime.
    const std::string kBoardProperty = "ro.product.board";
    const std::string kCuttlefishBoard = "cutf";
    auto board_name = GetSystemProperty(kBoardProperty);
    if (board_name.has_value() &&
        (starts_with(board_name.value(), "cutf") ||
         starts_with(board_name.value(), "goldfish"))) {
      reset();
    }

    mH4 = std::make_shared<H4Protocol>(
        mFd,
        [](const std::vector<uint8_t>& /* raw_command */) {
          LOG_ALWAYS_FATAL("Unexpected command!");
        },
        [this](const std::vector<uint8_t>& raw_acl) {
          mCallbacks->acl_received(mCallbacks->handle, raw_acl.data(),
                                   raw_acl.size());
        },
        [this](const std::vector<uint8_t>& raw_sco) {
          mCallbacks->sco_received(mCallbacks->handle, raw_sco.data(),
                                   raw_sco.size());
        },
        [this](const std::vector<uint8_t>& raw_event) {
          mCallbacks->event_received(mCallbacks->handle, raw_event.data(),
                                     raw_event.size());
        },
        [this](const std::vector<uint8_t>& raw_iso) {
          mCallbacks->iso_received(mCallbacks->handle, raw_iso.data(),
                                   raw_iso.size());
        },
        [this]() {
          ALOGI("HCI socket device disconnected");
          mFdWatcher.StopWatchingFileDescriptors();
        });
    mFdWatcher.WatchFdForNonBlockingReads(mFd,
                                          [this](int) { mH4->OnDataReady(); });

    {
      std::lock_guard<std::mutex> guard(mStateMutex);
      mState = HalState::ONE_CLIENT;
    }

    ALOGI("initialization complete");
    mCallbacks->initialization_complete(mCallbacks->handle, STATUS_SUCCESS);
  }

  void Close() {
    ALOGI(__func__);
    {
      std::lock_guard<std::mutex> guard(mStateMutex);
      if (mState != HalState::ONE_CLIENT) {
        LOG_ALWAYS_FATAL_IF(mState == HalState::INITIALIZING,
                            "mState is INITIALIZING");
        ALOGI("Already closed");
        return;
      }
      mCallbacks.reset();
      mState = HalState::CLOSING;
    }

    mFdWatcher.StopWatchingFileDescriptors();

    if (management_) {
      management_->closeHci();
    } else {
      ::close(mFd);
    }

    {
      std::lock_guard<std::mutex> guard(mStateMutex);
      mState = HalState::READY;
      mH4 = nullptr;
    }
  }

  void SendCommand(const std::vector<uint8_t>& data) {
    send(PacketType::COMMAND, data);
  }
  void SendAcl(const std::vector<uint8_t>& data) {
    send(PacketType::ACL_DATA, data);
  }
  void SendSco(const std::vector<uint8_t>& data) {
    send(PacketType::SCO_DATA, data);
  }
  void SendIso(const std::vector<uint8_t>& data) {
    send(PacketType::ISO_DATA, data);
  }

  bool send(PacketType type, const std::vector<uint8_t>& v) {
    if (v.empty()) {
      ALOGE("Packet is empty, no data was found to be sent");
      return false;
    }

    std::lock_guard<std::mutex> guard(mStateMutex);
    if (mH4 == nullptr) {
      ALOGE("Illegal State");
      return false;
    }

    mH4->Send(type, v);
    return true;
  }

  void ClientDied() {
    ALOGE("Bluetooth client has died");
    Close();
  }

  std::unique_ptr<struct hal_callbacks> mCallbacks;
  std::string mDevPath;
  int mFd{-1};
  ::android::hardware::bluetooth::async::AsyncFdWatcher mFdWatcher;
  std::shared_ptr<::android::hardware::bluetooth::hci::H4Protocol> mH4;
  std::unique_ptr<NetBluetoothMgmt> management_{};

  // Don't close twice or open before close is complete
  std::mutex mStateMutex;
  enum class HalState {
    READY,
    INITIALIZING,
    ONE_CLIENT,
    CLOSING,
  } mState{HalState::READY};
};

}  // namespace aidl::android::hardware::bluetooth::impl

extern "C" {

using namespace aidl::android::hardware::bluetooth::impl;

struct hal_interface hal_new() {
  return (struct hal_interface){
      .handle = new Hal(),
      .initialize = &Hal::Initialize,
      .close = &Hal::Close,
      .send_command = &Hal::SendCommand,
      .send_acl = &Hal::SendAcl,
      .send_sco = &Hal::SendSco,
      .send_iso = &Hal::SendIso,
      .client_died = &Hal::ClientDied,
  };
}
}