#include "CGBASupport.hpp"

#include <cstring>

#include "CBasics.hpp"
#include "CDvdRequest.hpp"

#include <jbus/Endpoint.hpp>
#include <jbus/Listener.hpp>

namespace urde::MP1 {

static jbus::Listener g_JbusListener;
static std::unique_ptr<jbus::Endpoint> g_JbusEndpoint;

void CGBASupport::Initialize() {
  jbus::Initialize();
  g_JbusListener.start();
}

void CGBASupport::GlobalPoll() {
  if (g_JbusEndpoint && !g_JbusEndpoint->connected())
    g_JbusEndpoint.reset();
  if (!g_JbusEndpoint) {
    g_JbusEndpoint = g_JbusListener.accept();
    if (g_JbusEndpoint)
      g_JbusEndpoint->setChan(3);
  }
}

CGBASupport::CGBASupport() : CDvdFile("client_pad.bin") {
  x28_fileSize = ROUND_UP_32(Length());
  x2c_buffer.reset(new u8[x28_fileSize]);
  x30_dvdReq = AsyncRead(x2c_buffer.get(), x28_fileSize);
}

CGBASupport::~CGBASupport() {
  if (x30_dvdReq)
    x30_dvdReq->PostCancelRequest();
}

u8 CGBASupport::CalculateFusionJBusChecksum(const u8* data, size_t len) {
  u32 sum = -1;
  for (size_t i = 0; i < len; ++i) {
    u8 ch = *data++;
    sum ^= ch;
    for (int j = 0; j < 8; ++j) {
      if ((sum & 1)) {
        sum >>= 1;
        sum ^= 0xb010;
      } else
        sum >>= 1;
    }
  }
  return sum;
}

bool CGBASupport::PollResponse() {
  if (!g_JbusEndpoint)
    return false;

  u8 status;
  if (g_JbusEndpoint->GBAReset(&status) == jbus::GBA_NOT_READY)
    if (g_JbusEndpoint->GBAReset(&status) == jbus::GBA_NOT_READY)
      return false;

  if (g_JbusEndpoint->GBAGetStatus(&status) == jbus::GBA_NOT_READY)
    return false;
  if (status != (jbus::GBA_JSTAT_PSF1 | jbus::GBA_JSTAT_SEND))
    return false;

  jbus::ReadWriteBuffer bytes;
  if (g_JbusEndpoint->GBARead(bytes, &status) == jbus::GBA_NOT_READY) {
    return false;
  }

  u32 bytesU32;
  std::memcpy(&bytesU32, bytes.data(), sizeof(bytes));
  if (bytesU32 != SBIG('AMTE')) {
    return false;
  }

  if (g_JbusEndpoint->GBAGetStatus(&status) == jbus::GBA_NOT_READY) {
    return false;
  }
  if (status != jbus::GBA_JSTAT_PSF1) {
    return false;
  }

  if (g_JbusEndpoint->GBAWrite({'A', 'M', 'T', 'E'}, &status) == jbus::GBA_NOT_READY) {
    return false;
  }

  if (g_JbusEndpoint->GBAGetStatus(&status) == jbus::GBA_NOT_READY)
    return false;
  if ((status & jbus::GBA_JSTAT_FLAGS_MASK) != jbus::GBA_JSTAT_FLAGS_MASK)
    return false;

  u64 profStart = jbus::GetGCTicks();
  const u64 timeToSpin = jbus::GetGCTicksPerSec() / 8000;
  for (;;) {
    u64 curTime = jbus::GetGCTicks();
    if (curTime - profStart > timeToSpin)
      return true;

    if (g_JbusEndpoint->GBAGetStatus(&status) == jbus::GBA_NOT_READY)
      continue;
    if (!(status & jbus::GBA_JSTAT_SEND))
      continue;

    if (g_JbusEndpoint->GBAGetStatus(&status) == jbus::GBA_NOT_READY)
      continue;
    if (status != (jbus::GBA_JSTAT_FLAGS_MASK | jbus::GBA_JSTAT_SEND))
      continue;
    break;
  }

  if (g_JbusEndpoint->GBARead(bytes, &status) != jbus::GBA_READY) {
    return false;
  }

  if (bytes[3] != CalculateFusionJBusChecksum(bytes.data(), 3)) {
    return false;
  }

  x44_fusionLinked = (bytes[2] & 0x2) == 0;
  if (x44_fusionLinked && (bytes[2] & 0x1) != 0)
    x45_fusionBeat = true;

  return true;
}

static void JoyBootDone(jbus::ThreadLocalEndpoint& endpoint, jbus::EJoyReturn status) {}

void CGBASupport::Update(float dt) {
  switch (x34_phase) {
  case EPhase::LoadClientPad:
    IsReady();
    break;

  case EPhase::StartProbeTimeout:
    x38_timeout = 4.f;
    x34_phase = EPhase::PollProbe;
    [[fallthrough]];

  case EPhase::PollProbe:
    /* SIProbe poll normally occurs here with 4 second timeout */
    if (!g_JbusEndpoint) {
      x34_phase = EPhase::Failed;
      break;
    }
    x40_siChan = g_JbusEndpoint->getChan();
    x34_phase = EPhase::StartJoyBusBoot;
    [[fallthrough]];

  case EPhase::StartJoyBusBoot:
    x34_phase = EPhase::PollJoyBusBoot;
    if (!g_JbusEndpoint || g_JbusEndpoint->GBAJoyBootAsync(x40_siChan * 2, 2, x2c_buffer.get(), x28_fileSize,
                                                           &x3c_status, JoyBootDone) != jbus::GBA_READY) {
      x34_phase = EPhase::Failed;
    }
    break;

  case EPhase::PollJoyBusBoot:
    u8 percent;
    if (g_JbusEndpoint && g_JbusEndpoint->GBAGetProcessStatus(percent) == jbus::GBA_BUSY)
      break;
    if (!g_JbusEndpoint || g_JbusEndpoint->GBAGetStatus(&x3c_status) == jbus::GBA_NOT_READY) {
      x34_phase = EPhase::Failed;
      break;
    }
    x38_timeout = 4.f;
    x34_phase = EPhase::DataTransfer;
    break;

  case EPhase::DataTransfer:
    if (PollResponse()) {
      x34_phase = EPhase::Complete;
      break;
    }
    x38_timeout = std::max(0.f, x38_timeout - dt);
    if (x38_timeout == 0.f)
      x34_phase = EPhase::Failed;
    break;

  default:
    break;
  }
}

bool CGBASupport::IsReady() {
  if (x34_phase != EPhase::LoadClientPad)
    return true;

  if (x30_dvdReq->IsComplete()) {
    x30_dvdReq.reset();
    x34_phase = EPhase::Standby;
    /* Conveniently already little-endian */
    reinterpret_cast<u32&>(x2c_buffer[0xc8]) = u32(CBasics::GetGCTicks());
    x2c_buffer[0xaf] = 'E';
    x2c_buffer[0xbd] = 0xc9;
    return true;
  }
  return false;
}

void CGBASupport::InitializeSupport() {
  x34_phase = EPhase::Standby;
  x38_timeout = 0.f;
  x3c_status = false;
  x40_siChan = -1;
  x44_fusionLinked = false;
  x45_fusionBeat = false;
}

void CGBASupport::StartLink() {
  x34_phase = EPhase::StartProbeTimeout;
  x40_siChan = -1;
}

} // namespace urde::MP1