#include <stdio.h>
#include "GCNTypes.hpp"
#include <memory>
#include <thread>
#include <queue>
#include "optional.hpp"
#include "hecl/hecl.hpp"
#include "jbus/Endpoint.hpp"
#include "jbus/Listener.hpp"

class CGBASupport
{
public:
    enum class EPhase
    {
        LoadClientPad,
        Standby,
        StartProbeTimeout,
        PollProbe,
        StartJoyBusBoot,
        PollJoyBusBoot,
        DataTransfer,
        Complete,
        Failed
    };

private:
    std::unique_ptr<jbus::Endpoint> m_endpoint;
    u32 x28_fileSize;
    std::unique_ptr<u8[]> x2c_buffer;
    EPhase x34_phase = EPhase::LoadClientPad;
    float x38_timeout = 0.f;
    u8 x3c_status = 0;
    u32 x40_siChan = -1;
    bool x44_fusionLinked = false;
    bool x45_fusionBeat = false;
    static CGBASupport* SharedInstance;

    static u8 CalculateFusionJBusChecksum(const u8* data, size_t len);

public:
    CGBASupport(const char* clientPadPath, std::unique_ptr<jbus::Endpoint>&& ep);
    ~CGBASupport();
    bool PollResponse();
    void Update(float dt);
    bool IsReady();
    void InitializeSupport();
    void StartLink();
    EPhase GetPhase() const { return x34_phase; }
    bool IsFusionLinked() const { return x44_fusionLinked; }
    bool IsFusionBeat() const { return x45_fusionBeat; }
};

CGBASupport* CGBASupport::SharedInstance;

CGBASupport::CGBASupport(const char* clientPadPath, std::unique_ptr<jbus::Endpoint>&& ep)
: m_endpoint(std::move(ep))
{
    FILE* fp = fopen(clientPadPath, "rb");
    if (!fp)
    {
        fprintf(stderr, "No file at %s\n", clientPadPath);
        exit(1);
    }
    fseek(fp, 0, SEEK_END);
    x28_fileSize = ftell(fp);
    fseek(fp, 0, SEEK_SET);
    x2c_buffer.reset(new u8[x28_fileSize]);
    fread(x2c_buffer.get(), 1, x28_fileSize, fp);
    fclose(fp);
    SharedInstance = this;
}

CGBASupport::~CGBASupport()
{
    SharedInstance = nullptr;
}

u8 CGBASupport::CalculateFusionJBusChecksum(const u8* data, size_t len)
{
    u32 sum = -1;
    for (int 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()
{
    u8 status;
    if (m_endpoint->GBAReset(&status) == jbus::GBA_NOT_READY)
        if (m_endpoint->GBAReset(&status) == jbus::GBA_NOT_READY)
            return false;

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

    u8 bytes[4];
    if (m_endpoint->GBARead(bytes, &status) == jbus::GBA_NOT_READY)
        return false;
    if (reinterpret_cast<u32&>(bytes) != SBIG('AMTE'))
        return false;

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

    if (m_endpoint->GBAWrite((unsigned char*)"AMTE", &status) == jbus::GBA_NOT_READY)
        return false;

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

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

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

    if (bytes[3] != CalculateFusionJBusChecksum(bytes, 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;

    case EPhase::PollProbe:
        /* SIProbe poll normally occurs here with 4 second timeout */
        x40_siChan = m_endpoint->GetChan();
        x34_phase = EPhase::StartJoyBusBoot;

    case EPhase::StartJoyBusBoot:
        x34_phase = EPhase::PollJoyBusBoot;
        if (m_endpoint->GBAJoyBootAsync(x40_siChan * 2, 2,
            x2c_buffer.get(), x28_fileSize, &x3c_status,
            std::bind(JoyBootDone,
                      std::placeholders::_1,
                      std::placeholders::_2)) != jbus::GBA_READY)
            x34_phase = EPhase::Failed;
        break;

    case EPhase::PollJoyBusBoot:
        u8 percent;
        if (m_endpoint->GBAGetProcessStatus(&percent) == jbus::GBA_BUSY)
            break;
        if (m_endpoint->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;

    x34_phase = EPhase::Standby;
    reinterpret_cast<u32&>(x2c_buffer[0xc8]) = u32(jbus::GetGCTicks());
    x2c_buffer[0xaf] = 'E';
    x2c_buffer[0xbd] = 0xc9;
    return true;
}

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;
}

int main(int argc, char** argv)
{
    jbus::Initialize();
    printf("Listening for client\n");
    jbus::Listener listener;
    listener.start();
    std::unique_ptr<jbus::Endpoint> endpoint;
    while (true)
    {
        s64 frameStart = jbus::GetGCTicks();
        endpoint = listener.accept();
        if (endpoint)
            break;
        s64 frameEnd = jbus::GetGCTicks();
        s64 waitTicks = jbus::GetGCTicksPerSec() / 60;
        if (waitTicks > 0)
            jbus::WaitGCTicks(waitTicks);
    }

    CGBASupport gba("client_pad.bin", std::move(endpoint));
    gba.Update(0.f);
    gba.InitializeSupport();
    gba.StartLink();

    printf("Waiting 5 sec\n");
    jbus::WaitGCTicks(jbus::GetGCTicksPerSec() * 5);

    printf("Connecting\n");
    while (gba.GetPhase() < CGBASupport::EPhase::Complete)
    {
        gba.Update(1.f / 60.f);
        s64 waitTicks = jbus::GetGCTicksPerSec() / 60;
        if (waitTicks > 0)
            jbus::WaitGCTicks(waitTicks);
    }

    CGBASupport::EPhase finalPhase = gba.GetPhase();
    printf("%s Linked: %d Beat: %d\n",
           finalPhase == CGBASupport::EPhase::Complete ? "Complete" : "Failed",
           gba.IsFusionLinked(), gba.IsFusionBeat());

    return 0;
}