// Copyright 2014 Dolphin Emulator Project
// Licensed under GPLv2+
// Refer to the license.txt file included.

#include <algorithm>
#include <libusb.h>
#include <mutex>

#include "Common/Flag.h"
#include "Common/Logging/Log.h"
#include "Common/Thread.h"
#include "Core/ConfigManager.h"
#include "Core/Core.h"
#include "Core/CoreTiming.h"
#include "Core/HW/SI/SI.h"
#include "Core/HW/SystemTimers.h"
#include "Core/NetPlayProto.h"

#include "InputCommon/GCAdapter.h"
#include "InputCommon/GCPadStatus.h"

namespace GCAdapter
{
static bool CheckDeviceAccess(libusb_device* device);
static void AddGCAdapter(libusb_device* device);
static void ResetRumbleLockNeeded();
static void Reset();
static void Setup();

static bool s_detected = false;
static libusb_device_handle* s_handle = nullptr;
static u8 s_controller_type[MAX_SI_CHANNELS] = {
    ControllerTypes::CONTROLLER_NONE, ControllerTypes::CONTROLLER_NONE,
    ControllerTypes::CONTROLLER_NONE, ControllerTypes::CONTROLLER_NONE};
static u8 s_controller_rumble[4];

static std::mutex s_mutex;
static u8 s_controller_payload[37];
static u8 s_controller_payload_swap[37];

static std::atomic<int> s_controller_payload_size = {0};

static std::thread s_adapter_thread;
static Common::Flag s_adapter_thread_running;

static std::mutex s_init_mutex;
static std::thread s_adapter_detect_thread;
static Common::Flag s_adapter_detect_thread_running;

static std::function<void(void)> s_detect_callback;

static bool s_libusb_driver_not_supported = false;
static libusb_context* s_libusb_context = nullptr;
#if defined(__FreeBSD__) && __FreeBSD__ >= 11
static bool s_libusb_hotplug_enabled = true;
#else
static bool s_libusb_hotplug_enabled = false;
#endif
#if defined(LIBUSB_API_VERSION) && LIBUSB_API_VERSION >= 0x01000102
static libusb_hotplug_callback_handle s_hotplug_handle;
#endif

static u8 s_endpoint_in = 0;
static u8 s_endpoint_out = 0;

static u64 s_last_init = 0;

static void Read()
{
  int payload_size = 0;
  while (s_adapter_thread_running.IsSet())
  {
    libusb_interrupt_transfer(s_handle, s_endpoint_in, s_controller_payload_swap,
                              sizeof(s_controller_payload_swap), &payload_size, 16);

    {
      std::lock_guard<std::mutex> lk(s_mutex);
      std::swap(s_controller_payload_swap, s_controller_payload);
      s_controller_payload_size.store(payload_size);
    }

    Common::YieldCPU();
  }
}

#if defined(LIBUSB_API_VERSION) && LIBUSB_API_VERSION >= 0x01000102
static int HotplugCallback(libusb_context* ctx, libusb_device* dev, libusb_hotplug_event event,
                           void* user_data)
{
  if (event == LIBUSB_HOTPLUG_EVENT_DEVICE_ARRIVED)
  {
    if (s_handle == nullptr && CheckDeviceAccess(dev))
    {
      std::lock_guard<std::mutex> lk(s_init_mutex);
      AddGCAdapter(dev);
    }
  }
  else if (event == LIBUSB_HOTPLUG_EVENT_DEVICE_LEFT)
  {
    if (s_handle != nullptr && libusb_get_device(s_handle) == dev)
      Reset();
  }
  return 0;
}
#endif

static void ScanThreadFunc()
{
  Common::SetCurrentThreadName("GC Adapter Scanning Thread");
  NOTICE_LOG(SERIALINTERFACE, "GC Adapter scanning thread started");

#if defined(LIBUSB_API_VERSION) && LIBUSB_API_VERSION >= 0x01000102
#ifndef __FreeBSD__
  s_libusb_hotplug_enabled = libusb_has_capability(LIBUSB_CAP_HAS_HOTPLUG) != 0;
#endif
  if (s_libusb_hotplug_enabled)
  {
    if (libusb_hotplug_register_callback(
            s_libusb_context, (libusb_hotplug_event)(LIBUSB_HOTPLUG_EVENT_DEVICE_ARRIVED |
                                                     LIBUSB_HOTPLUG_EVENT_DEVICE_LEFT),
            LIBUSB_HOTPLUG_ENUMERATE, 0x057e, 0x0337, LIBUSB_HOTPLUG_MATCH_ANY, HotplugCallback,
            nullptr, &s_hotplug_handle) != LIBUSB_SUCCESS)
      s_libusb_hotplug_enabled = false;
    if (s_libusb_hotplug_enabled)
      NOTICE_LOG(SERIALINTERFACE, "Using libUSB hotplug detection");
  }
#endif

  while (s_adapter_detect_thread_running.IsSet())
  {
    if (s_libusb_hotplug_enabled)
    {
      static timeval tv = {0, 500000};
      libusb_handle_events_timeout(s_libusb_context, &tv);
    }
    else
    {
      if (s_handle == nullptr)
      {
        std::lock_guard<std::mutex> lk(s_init_mutex);
        Setup();
        if (s_detected && s_detect_callback != nullptr)
          s_detect_callback();
      }
      Common::SleepCurrentThread(500);
    }
  }
  NOTICE_LOG(SERIALINTERFACE, "GC Adapter scanning thread stopped");
}

void SetAdapterCallback(std::function<void(void)> func)
{
  s_detect_callback = func;
}

void Init()
{
  if (s_handle != nullptr)
    return;

  if (Core::GetState() != Core::CORE_UNINITIALIZED)
  {
    if ((CoreTiming::GetTicks() - s_last_init) < SystemTimers::GetTicksPerSecond())
      return;

    s_last_init = CoreTiming::GetTicks();
  }

  s_libusb_driver_not_supported = false;

  int ret = libusb_init(&s_libusb_context);

  if (ret)
  {
    ERROR_LOG(SERIALINTERFACE, "libusb_init failed with error: %d", ret);
    s_libusb_driver_not_supported = true;
    Shutdown();
  }
  else
  {
    if (UseAdapter())
      StartScanThread();
  }
}

void StartScanThread()
{
  if (s_adapter_detect_thread_running.IsSet())
    return;

  s_adapter_detect_thread_running.Set(true);
  s_adapter_detect_thread = std::thread(ScanThreadFunc);
}

void StopScanThread()
{
  if (s_adapter_detect_thread_running.TestAndClear())
  {
    s_adapter_detect_thread.join();
  }
}

static void Setup()
{
  libusb_device** list;
  ssize_t cnt = libusb_get_device_list(s_libusb_context, &list);

  for (int i = 0; i < MAX_SI_CHANNELS; i++)
  {
    s_controller_type[i] = ControllerTypes::CONTROLLER_NONE;
    s_controller_rumble[i] = 0;
  }

  for (int d = 0; d < cnt; d++)
  {
    libusb_device* device = list[d];
    if (CheckDeviceAccess(device))
    {
      // Only connect to a single adapter in case the user has multiple connected
      AddGCAdapter(device);
      break;
    }
  }

  libusb_free_device_list(list, 1);
}

static bool CheckDeviceAccess(libusb_device* device)
{
  int ret;
  libusb_device_descriptor desc;
  int dRet = libusb_get_device_descriptor(device, &desc);
  if (dRet)
  {
    // could not acquire the descriptor, no point in trying to use it.
    ERROR_LOG(SERIALINTERFACE, "libusb_get_device_descriptor failed with error: %d", dRet);
    return false;
  }

  if (desc.idVendor == 0x057e && desc.idProduct == 0x0337)
  {
    NOTICE_LOG(SERIALINTERFACE, "Found GC Adapter with Vendor: %X Product: %X Devnum: %d",
               desc.idVendor, desc.idProduct, 1);

    u8 bus = libusb_get_bus_number(device);
    u8 port = libusb_get_device_address(device);
    ret = libusb_open(device, &s_handle);
    if (ret)
    {
      if (ret == LIBUSB_ERROR_ACCESS)
      {
        if (dRet)
        {
          ERROR_LOG(SERIALINTERFACE, "Dolphin does not have access to this device: Bus %03d Device "
                                     "%03d: ID ????:???? (couldn't get id).",
                    bus, port);
        }
        else
        {
          ERROR_LOG(
              SERIALINTERFACE,
              "Dolphin does not have access to this device: Bus %03d Device %03d: ID %04X:%04X.",
              bus, port, desc.idVendor, desc.idProduct);
        }
      }
      else
      {
        ERROR_LOG(SERIALINTERFACE, "libusb_open failed to open device with error = %d", ret);
        if (ret == LIBUSB_ERROR_NOT_SUPPORTED)
          s_libusb_driver_not_supported = true;
      }
      return false;
    }
    else if ((ret = libusb_kernel_driver_active(s_handle, 0)) == 1)
    {
      if ((ret = libusb_detach_kernel_driver(s_handle, 0)) && ret != LIBUSB_ERROR_NOT_SUPPORTED)
      {
        ERROR_LOG(SERIALINTERFACE, "libusb_detach_kernel_driver failed with error: %d", ret);
      }
    }
    // this split is needed so that we don't avoid claiming the interface when
    // detaching the kernel driver is successful
    if (ret != 0 && ret != LIBUSB_ERROR_NOT_SUPPORTED)
    {
      return false;
    }
    else if ((ret = libusb_claim_interface(s_handle, 0)))
    {
      ERROR_LOG(SERIALINTERFACE, "libusb_claim_interface failed with error: %d", ret);
    }
    else
    {
      return true;
    }
  }
  return false;
}

static void AddGCAdapter(libusb_device* device)
{
  libusb_config_descriptor* config = nullptr;
  libusb_get_config_descriptor(device, 0, &config);
  for (u8 ic = 0; ic < config->bNumInterfaces; ic++)
  {
    const libusb_interface* interfaceContainer = &config->interface[ic];
    for (int i = 0; i < interfaceContainer->num_altsetting; i++)
    {
      const libusb_interface_descriptor* interface = &interfaceContainer->altsetting[i];
      for (u8 e = 0; e < interface->bNumEndpoints; e++)
      {
        const libusb_endpoint_descriptor* endpoint = &interface->endpoint[e];
        if (endpoint->bEndpointAddress & LIBUSB_ENDPOINT_IN)
          s_endpoint_in = endpoint->bEndpointAddress;
        else
          s_endpoint_out = endpoint->bEndpointAddress;
      }
    }
  }

  int tmp = 0;
  unsigned char payload = 0x13;
  libusb_interrupt_transfer(s_handle, s_endpoint_out, &payload, sizeof(payload), &tmp, 16);

  s_adapter_thread_running.Set(true);
  s_adapter_thread = std::thread(Read);

  s_detected = true;
  if (s_detect_callback != nullptr)
    s_detect_callback();
  ResetRumbleLockNeeded();
}

void Shutdown()
{
  StopScanThread();
#if defined(LIBUSB_API_VERSION) && LIBUSB_API_VERSION >= 0x01000102
  if (s_libusb_hotplug_enabled)
    libusb_hotplug_deregister_callback(s_libusb_context, s_hotplug_handle);
#endif
  Reset();

  if (s_libusb_context)
  {
    libusb_exit(s_libusb_context);
    s_libusb_context = nullptr;
  }

  s_libusb_driver_not_supported = false;
}

static void Reset()
{
  std::unique_lock<std::mutex> lock(s_init_mutex, std::defer_lock);
  if (!lock.try_lock())
    return;
  if (!s_detected)
    return;

  if (s_adapter_thread_running.TestAndClear())
  {
    s_adapter_thread.join();
  }

  for (int i = 0; i < MAX_SI_CHANNELS; i++)
    s_controller_type[i] = ControllerTypes::CONTROLLER_NONE;

  s_detected = false;

  if (s_handle)
  {
    libusb_release_interface(s_handle, 0);
    libusb_close(s_handle);
    s_handle = nullptr;
  }
  if (s_detect_callback != nullptr)
    s_detect_callback();
  NOTICE_LOG(SERIALINTERFACE, "GC Adapter detached");
}

GCPadStatus Input(int chan)
{
  if (!UseAdapter())
    return {};

  if (s_handle == nullptr || !s_detected)
    return {};

  int payload_size = 0;
  u8 controller_payload_copy[37];

  {
    std::lock_guard<std::mutex> lk(s_mutex);
    std::copy(std::begin(s_controller_payload), std::end(s_controller_payload),
              std::begin(controller_payload_copy));
    payload_size = s_controller_payload_size.load();
  }

  GCPadStatus pad = {};
  if (payload_size != sizeof(controller_payload_copy) ||
      controller_payload_copy[0] != LIBUSB_DT_HID)
  {
    ERROR_LOG(SERIALINTERFACE, "error reading payload (size: %d, type: %02x)", payload_size,
              controller_payload_copy[0]);
    Reset();
  }
  else
  {
    bool get_origin = false;
    u8 type = controller_payload_copy[1 + (9 * chan)] >> 4;
    if (type != ControllerTypes::CONTROLLER_NONE &&
        s_controller_type[chan] == ControllerTypes::CONTROLLER_NONE)
    {
      NOTICE_LOG(SERIALINTERFACE, "New device connected to Port %d of Type: %02x", chan + 1,
                 controller_payload_copy[1 + (9 * chan)]);
      get_origin = true;
    }

    s_controller_type[chan] = type;

    if (s_controller_type[chan] != ControllerTypes::CONTROLLER_NONE)
    {
      u8 b1 = controller_payload_copy[1 + (9 * chan) + 1];
      u8 b2 = controller_payload_copy[1 + (9 * chan) + 2];

      if (b1 & (1 << 0))
        pad.button |= PAD_BUTTON_A;
      if (b1 & (1 << 1))
        pad.button |= PAD_BUTTON_B;
      if (b1 & (1 << 2))
        pad.button |= PAD_BUTTON_X;
      if (b1 & (1 << 3))
        pad.button |= PAD_BUTTON_Y;

      if (b1 & (1 << 4))
        pad.button |= PAD_BUTTON_LEFT;
      if (b1 & (1 << 5))
        pad.button |= PAD_BUTTON_RIGHT;
      if (b1 & (1 << 6))
        pad.button |= PAD_BUTTON_DOWN;
      if (b1 & (1 << 7))
        pad.button |= PAD_BUTTON_UP;

      if (b2 & (1 << 0))
        pad.button |= PAD_BUTTON_START;
      if (b2 & (1 << 1))
        pad.button |= PAD_TRIGGER_Z;
      if (b2 & (1 << 2))
        pad.button |= PAD_TRIGGER_R;
      if (b2 & (1 << 3))
        pad.button |= PAD_TRIGGER_L;

      if (get_origin)
        pad.button |= PAD_GET_ORIGIN;

      pad.stickX = controller_payload_copy[1 + (9 * chan) + 3];
      pad.stickY = controller_payload_copy[1 + (9 * chan) + 4];
      pad.substickX = controller_payload_copy[1 + (9 * chan) + 5];
      pad.substickY = controller_payload_copy[1 + (9 * chan) + 6];
      pad.triggerLeft = controller_payload_copy[1 + (9 * chan) + 7];
      pad.triggerRight = controller_payload_copy[1 + (9 * chan) + 8];
    }
    else if (!Core::g_want_determinism)
    {
      // This is a hack to prevent a desync due to SI devices
      // being different and returning different values.
      // The corresponding code in DeviceGCAdapter has the same check
      pad.button = PAD_ERR_STATUS;
    }
  }

  return pad;
}

bool DeviceConnected(int chan)
{
  return s_controller_type[chan] != ControllerTypes::CONTROLLER_NONE;
}

bool UseAdapter()
{
  return SConfig::GetInstance().m_SIDevice[0] == SIDEVICE_WIIU_ADAPTER ||
         SConfig::GetInstance().m_SIDevice[1] == SIDEVICE_WIIU_ADAPTER ||
         SConfig::GetInstance().m_SIDevice[2] == SIDEVICE_WIIU_ADAPTER ||
         SConfig::GetInstance().m_SIDevice[3] == SIDEVICE_WIIU_ADAPTER;
}

void ResetRumble()
{
  std::unique_lock<std::mutex> lock(s_init_mutex, std::defer_lock);
  if (!lock.try_lock())
    return;
  ResetRumbleLockNeeded();
}

// Needs to be called when s_init_mutex is locked in order to avoid
// being called while the libusb state is being reset
static void ResetRumbleLockNeeded()
{
  if (!UseAdapter() || (s_handle == nullptr || !s_detected))
  {
    return;
  }

  std::fill(std::begin(s_controller_rumble), std::end(s_controller_rumble), 0);

  unsigned char rumble[5] = {0x11, s_controller_rumble[0], s_controller_rumble[1],
                             s_controller_rumble[2], s_controller_rumble[3]};

  int size = 0;
  libusb_interrupt_transfer(s_handle, s_endpoint_out, rumble, sizeof(rumble), &size, 16);

  INFO_LOG(SERIALINTERFACE, "Rumble state reset");
}

void Output(int chan, u8 rumble_command)
{
  if (s_handle == nullptr || !UseAdapter() || !SConfig::GetInstance().m_AdapterRumble[chan])
    return;

  // Skip over rumble commands if it has not changed or the controller is wireless
  if (rumble_command != s_controller_rumble[chan] &&
      s_controller_type[chan] != ControllerTypes::CONTROLLER_WIRELESS)
  {
    s_controller_rumble[chan] = rumble_command;

    unsigned char rumble[5] = {0x11, s_controller_rumble[0], s_controller_rumble[1],
                               s_controller_rumble[2], s_controller_rumble[3]};
    int size = 0;

    libusb_interrupt_transfer(s_handle, s_endpoint_out, rumble, sizeof(rumble), &size, 16);
    // Netplay sends invalid data which results in size = 0x00.  Ignore it.
    if (size != 0x05 && size != 0x00)
    {
      ERROR_LOG(SERIALINTERFACE, "error writing rumble (size: %d)", size);
      Reset();
    }
  }
}

bool IsDetected()
{
  return s_detected;
}

bool IsDriverDetected()
{
  return !s_libusb_driver_not_supported;
}

}  // end of namespace GCAdapter