#include "tobii-eyex.hpp"
#include <cstdlib>
#include <cstdio>
#include <cmath>
#include <functional>
#include <vector>
#include <algorithm>
#include <iterator>
#include <QDebug>
#include <QMutexLocker>
#include <QMessageBox>

// XXX TODO whole opentrack needs different debug levels -sh 20160801

//#define TOBII_EYEX_DEBUG_PRINTF
#define TOBII_EYEX_VERBOSE_PRINTF

#ifdef TOBII_EYEX_VERBOSE_PRINTF
#   define dbg_verbose(msg) (qDebug() << "tobii-eyex:" << (msg))
#else
#   define dbg_verbose(msg) (QMessageLogger().noDebug() << (msg))
#endif

#ifdef TOBII_EYEX_DEBUG_PRINTF
#   define dbg_debug(msg) (qDebug() << "tobii-eyex:" << (msg))
#else
#   define dbg_debug(msg) (QMessageLogger().noDebug() << (msg))
#endif

#define dbg_notice(msg) (qDebug() << "tobii-eyex:" << (msg))

std::atomic_flag tobii_eyex_tracker::atexit_done = ATOMIC_FLAG_INIT;

static inline tobii_eyex_tracker& to_self(TX_USERPARAM param)
{
    return *reinterpret_cast<tobii_eyex_tracker*>(param);
}

template<typename t>
static constexpr t clamp(t datum, t min, t max)
{
    return ((datum > max) ? max : ((datum < min) ? min : datum));
}

void rel_settings::draw_spline()
{
    Map& spline = acc_mode_spline;

    spline.removeAllPoints();

    static constexpr float std_norm_expt = 1.f/3;
    const float norm_expt = std_norm_expt * float(expt_norm.get());
    static constexpr float std_norm_lin = 2.f/3;
    const float norm_lin = clamp<float>((1-norm_expt) * lin_norm.get() * std_norm_lin, 0, 1);

}

rel_settings::rel_settings() :
    opts("tobii-eyex-relative-mode"),
    speed(b, "speed", s(5, .1, 10)),
    dz_end_pt(b, "deadzone-length", s(4, 0, 15)),
    expt_slope(b, "exponent-slope", s(1.5, 1.25, 3)),
    expt_norm(b, "exponent-norm", s(1, .25, 4)),
    lin_norm(b, "linear-norm", s(1, .25, 4)),
    acc_mode_spline(100, 100)
{
    QObject::connect(&dz_end_pt,
                     static_cast<void(base_value::*)(const slider_value&)>(&base_value::valueChanged),
                     this,
                     &rel_settings::draw_spline);
    QObject::connect(&expt_slope,
                     static_cast<void(base_value::*)(const slider_value&)>(&base_value::valueChanged),
                     this,
                     &rel_settings::draw_spline);
    QObject::connect(&expt_norm,
                     static_cast<void(base_value::*)(const slider_value&)>(&base_value::valueChanged),
                     this,
                     &rel_settings::draw_spline);
    QObject::connect(&lin_norm,
                     static_cast<void(base_value::*)(const slider_value&)>(&base_value::valueChanged),
                     this,
                     &rel_settings::draw_spline);
    draw_spline();
}

tobii_eyex_tracker::tobii_eyex_tracker() :
    dev_ctx(TX_EMPTY_HANDLE),
    conn_state_changed_ticket(TX_INVALID_TICKET),
    event_handler_ticket(TX_INVALID_TICKET),
    state_snapshot(TX_EMPTY_HANDLE),
    display_state(TX_EMPTY_HANDLE),
    yaw(0),
    pitch(0),
    do_center(false)
{
}

void tobii_eyex_tracker::call_tx_deinit()
{
    dbg_notice("uninitialize in atexit at _fini time");
    (void) txUninitializeEyeX();
}

tobii_eyex_tracker::~tobii_eyex_tracker()
{
    dbg_verbose("dtor");

    (void) txDisableConnection(dev_ctx);
    (void) txReleaseObject(&state_snapshot);

    bool status = true;
    status &= txShutdownContext(dev_ctx, TX_CLEANUPTIMEOUT_FORCEIMMEDIATE, TX_FALSE) == TX_RESULT_OK;
    status &= txReleaseContext(&dev_ctx) == TX_RESULT_OK;

    // the API cleanup function needs to be called exactly once over image lifetime.
    // client software communicates with a service and a desktop program.
    // API is ambiguous as to what happens if the image doesn't call it or crashes.
    if (!atexit_done.test_and_set())
        std::atexit(call_tx_deinit);

    if (!status)
        dbg_notice("tobii-eyex: can't shutdown properly");
}

bool tobii_eyex_tracker::register_state_snapshot(TX_CONTEXTHANDLE dev_ctx, TX_HANDLE* state_snapshot_ptr)
{
    TX_HANDLE handle = TX_EMPTY_HANDLE;
    TX_GAZEPOINTDATAPARAMS params = { TX_GAZEPOINTDATAMODE_LIGHTLYFILTERED };

    bool status = true;

    status &= txCreateGlobalInteractorSnapshot(dev_ctx, client_id, state_snapshot_ptr, &handle) == TX_RESULT_OK;
    status &= txCreateGazePointDataBehavior(handle, &params) == TX_RESULT_OK;

    (void) txReleaseObject(&handle);

    return status;
}

void tobii_eyex_tracker::process_display_state(TX_HANDLE display_state_handle)
{
    TX_SIZE2 screen_res;

    if (txGetStateValueAsSize2(display_state_handle, TX_STATEPATH_EYETRACKINGSCREENBOUNDS, &screen_res) == TX_RESULT_OK)
    {
        dbg_verbose("got display resolution") << screen_res.Width << screen_res.Height;

        QMutexLocker l(&global_state_mtx);

        dev_state.display_res_x = screen_res.Width;
        dev_state.display_res_y = screen_res.Height;
    }
    else
        dbg_notice("can't get display resolution");
}

void tobii_eyex_tracker::display_state_handler(TX_CONSTHANDLE async_data_handle, TX_USERPARAM param)
{
    tobii_eyex_tracker& self = to_self(param);

    TX_RESULT result = TX_RESULT_UNKNOWN;
    TX_HANDLE state = TX_EMPTY_HANDLE;

    if (txGetAsyncDataResultCode(async_data_handle, &result) == TX_RESULT_OK &&
        txGetAsyncDataContent(async_data_handle, &state) == TX_RESULT_OK)
    {
        self.process_display_state(state);
        txReleaseObject(&state);
    }
    else
        dbg_notice("error in display state handler");
}

void tobii_eyex_tracker::snapshot_committed_handler(TX_CONSTHANDLE async_data_handle, TX_USERPARAM)
{
    TX_RESULT result = TX_RESULT_UNKNOWN;
    txGetAsyncDataResultCode(async_data_handle, &result);

    if (!(result == TX_RESULT_OK || result == TX_RESULT_CANCELLED))
        dbg_notice("snapshot bad result code") << result;
}

void tobii_eyex_tracker::connection_state_change_handler(TX_CONNECTIONSTATE state, TX_USERPARAM param)
{
    tobii_eyex_tracker& self = to_self(param);

    switch (state)
    {
    case TX_CONNECTIONSTATE_CONNECTED:
    {
        bool status = txCommitSnapshotAsync(self.state_snapshot, snapshot_committed_handler, param) == TX_RESULT_OK;
        if (!status)
            dbg_notice("connected but failed to initialize data stream");
        else
        {
            txGetStateAsync(self.dev_ctx, TX_STATEPATH_EYETRACKINGSCREENBOUNDS, display_state_handler, param);
            dbg_notice("connected, data stream ok");
        }
    }
        break;
    case TX_CONNECTIONSTATE_DISCONNECTED:
        dbg_notice("connection state is now disconnected");
        break;
    case TX_CONNECTIONSTATE_TRYINGTOCONNECT:
        dbg_verbose("trying to establish connection");
        break;
    case TX_CONNECTIONSTATE_SERVERVERSIONTOOLOW:
        dbg_notice("installed driver version too low");
        break;
    case TX_CONNECTIONSTATE_SERVERVERSIONTOOHIGH:
        dbg_notice("new driver came up, we need to update sdk");
        break;
    }
}

void tobii_eyex_tracker::gaze_data_handler(TX_HANDLE gaze_data_handle)
{
    TX_GAZEPOINTDATAEVENTPARAMS params;

    if (txGetGazePointDataEventParams(gaze_data_handle, &params) == TX_RESULT_OK)
    {
        {
            QMutexLocker l(&global_state_mtx);

            if (params.Timestamp > dev_state.last_timestamp &&
                dev_state.display_res_x > 0 &&
                // the API allows for events outside screen bounds to e.g. detect looking at keyboard.
                // closer to the screen bounds, the values get less accurate.
                // ignore events outside the screen bounds.
                params.X >= 0 && params.X < dev_state.display_res_x &&
                params.Y >= 0 && params.Y < dev_state.display_res_y)
            {
                dev_state.last_timestamp = params.Timestamp;
                dev_state.px = params.X;
                dev_state.py = params.Y;

#ifdef TOBII_EYEX_DEBUG_PRINTF
                char buf[256] = {0};
                (void) std::sprintf(buf, "gaze data: (%.1f, %.1f)", params.X, params.Y);
                dbg_debug(buf);
#endif

                dev_state.fresh = true;
            }
        }
    }
    else
    {
        dbg_notice("failed to interpret gaze data event packet");
    }
}

void tobii_eyex_tracker::event_handler(TX_CONSTHANDLE async_data_handle, TX_USERPARAM param)
{
    tobii_eyex_tracker& self = to_self(param);

    TX_HANDLE event_handle = TX_EMPTY_HANDLE;
    TX_HANDLE behavior_handle = TX_EMPTY_HANDLE;

    txGetAsyncDataContent(async_data_handle, &event_handle);

    if (txGetEventBehavior(event_handle, &behavior_handle, TX_BEHAVIORTYPE_GAZEPOINTDATA) == TX_RESULT_OK)
    {
        self.gaze_data_handler(behavior_handle);
        txReleaseObject(&behavior_handle);
    }

    txReleaseObject(&event_handle);
}

void tobii_eyex_tracker::start_tracker(QFrame*)
{
    dbg_verbose("start tracker");

    bool status = true;

    status &= txInitializeEyeX(TX_EYEXCOMPONENTOVERRIDEFLAG_NONE, nullptr, nullptr, nullptr, nullptr) == TX_RESULT_OK;
    status &= txCreateContext(&dev_ctx, TX_FALSE) == TX_RESULT_OK;
    status &= register_state_snapshot(dev_ctx, &state_snapshot);
    status &= txRegisterConnectionStateChangedHandler(dev_ctx, &conn_state_changed_ticket, connection_state_change_handler, reinterpret_cast<TX_USERPARAM>(this)) == TX_RESULT_OK;
    status &= txRegisterEventHandler(dev_ctx, &event_handler_ticket, event_handler, reinterpret_cast<TX_USERPARAM>(this)) == TX_RESULT_OK;
    status &= txEnableConnection(dev_ctx) == TX_RESULT_OK;

    if (!status)
        dbg_verbose("connection can't be established. device missing?");
    else
        dbg_verbose("api initialized");
}

// the gain function was prototyped in python with jupyter qtconsole.
// you can use qtconsole's inline matplotlib support to see the gain function.
// the `piecewise' function assumes monotonic growth or constant value for all functions.
/*

from math import *
from itertools import izip
import matplotlib
import matplotlib.pyplot as plt

try:
    import IPython
    IPython.get_ipython().magic(u'matplotlib inline')
except:
    pass

def frange(from_, to_, step_=1e-4):
    i = from_
    while True:
        yield i
        i += step_
        if i >= to_:
            break

def plot_fn(fn, from_=0., to_=1., step=None):
    if step is None:
        step = max(1e-4, (to_-from_)*1e-4)
    xs = [i for i in frange(from_, to_, step)]
    plt.plot(xs, map(fn, xs))

def piecewise(x, funs, bounds):
    y = 0.
    last_bound = 0.
    norm = 0.
    for fun in funs:
        norm += fun(1.)
    for fun, bound in izip(funs, bounds):
        if x > bound:
            y += fun(1.)
        else:
            b = bound - last_bound
            x_ = (x - last_bound) / b
            y += fun(x_)
            break
        last_bound = bound
    return y / norm

def f(x): return x**1.75
def g(x): return 1.75*1.75*x
def h(x): return log(1+x)/log(2.5)
def zero(x): return 0.

plot_fn(lambda x: piecewise(x, [zero, f, g, h], [.05, .25, .7, 1.]))

*/

tobii_eyex_tracker::num tobii_eyex_tracker::gain(num x_)
{
    return 1;
}

void tobii_eyex_tracker::data(double* data)
{
    TX_REAL px, py, dw, dh, x_, y_;
    bool fresh;

    {
        QMutexLocker l(&global_state_mtx);

        if (!dev_state.is_valid())
            return;

        px = dev_state.px;
        py = dev_state.py;
        dw = dev_state.display_res_x;
        dh = dev_state.display_res_y;

        fresh = dev_state.fresh;
        dev_state.fresh = false;
    }

    x_ = (px-dw/2.) / (dw/2.);
    y_ = (py-dh/2.) / (dh/2.);

    data[TX] = x_ * 50;
    data[TY] = y_ * -50;

    if (fresh)
    {
        const double dt = t.elapsed_seconds();
        t.start();
        // XXX TODO make slider
        static constexpr double v = 300;

        const double x = gain(x_);
        const double y = gain(y_);

        const double yaw_delta = (x * v) * dt;
        const double pitch_delta = (y * -v) * dt;

        yaw += yaw_delta;
        pitch += pitch_delta;

        yaw = clamp(yaw, -180., 180.);
        pitch = clamp(pitch, -60., 60.);
    }

    if (do_center)
    {
        do_center = false;
        yaw = 0;
        pitch = 0;
    }

    data[Yaw] = yaw;
    data[Pitch] = pitch;
    data[Roll] = 0;
    data[TZ] = 0; // XXX TODO

    // tan(x) in 0->.7 is almost linear. we don't need to adjust.
    // .7 is 40 degrees which is already quite a lot from the monitor.
}

OPENTRACK_DECLARE_TRACKER(tobii_eyex_tracker, tobii_eyex_dialog, tobii_eyex_metadata)