/* Copyright (c) 2019 Stephane Lenclud
 *
 * Permission to use, copy, modify, and/or distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 */

#include "tracker-easy.h"
#include "video/video-widget.hpp"
#include "compat/math-imports.hpp"
#include "compat/check-visible.hpp"
#include "point-extractor.h"

#include <QHBoxLayout>
#include <QDebug>
#include <QFile>
#include <QCoreApplication>

#include <opencv2/calib3d.hpp>
#include <opencv2/highgui/highgui.hpp>

#include <iostream>

using namespace options;

// Disable debug
#define dbgout if (true) {} else std::cout
//#define infout if (true) {} else std::cout
// Enable debug
//#define dbgout if (false) {} else std::cout
#define infout if (false) {} else std::cout

namespace EasyTracker
{

    Tracker::Tracker() :
        iSettings{ KModuleName },
        iPreview{ preview_width, preview_height }
    {
        cv::setBreakOnError(true);
        cv::setNumThreads(1);

        connect(iSettings.b.get(), &bundle_::saving, this, &Tracker::maybe_reopen_camera, Qt::DirectConnection);
        connect(iSettings.b.get(), &bundle_::reloading, this, &Tracker::maybe_reopen_camera, Qt::DirectConnection);

        connect(&iSettings.fov, value_::value_changed<int>(), this, &Tracker::set_fov, Qt::DirectConnection);
        set_fov(iSettings.fov);
        // We could not get this working, nevermind
        //connect(&iSettings.cam_fps, value_::value_changed<int>(), this, &Tracker::SetFps, Qt::DirectConnection);

        CreateModelFromSettings();
    }

    Tracker::~Tracker()
    {
        cv::destroyWindow("Preview");

        iThread.exit();
        iThread.wait();        

        QMutexLocker l(&camera_mtx);
        camera->stop();        
    }


    // Compute Euler angles from rotation matrix
    void getEulerAngles(cv::Mat &rotCamerMatrix, cv::Vec3d &eulerAngles)
    {

        cv::Mat cameraMatrix, rotMatrix, transVect, rotMatrixX, rotMatrixY, rotMatrixZ;
        double* _r = rotCamerMatrix.ptr<double>();
        double projMatrix[12] = { _r[0],_r[1],_r[2],0,
                              _r[3],_r[4],_r[5],0,
                              _r[6],_r[7],_r[8],0 };

        cv::decomposeProjectionMatrix(cv::Mat(3, 4, CV_64FC1, projMatrix),
            cameraMatrix,
            rotMatrix,
            transVect,
            rotMatrixX,
            rotMatrixY,
            rotMatrixZ,
            eulerAngles);
    }

    ///
    void Tracker::CreateModelFromSettings()
    {
        // Construct the points defining the object we want to detect based on settings.
        // We are converting them from millimeters to centimeters.
        // TODO: Need to support clip too. That's cap only for now.
        // s.active_model_panel != PointModel::Clip
        iModel.clear();
        iModel.push_back(cv::Point3f(iSettings.cap_x / 10.0, iSettings.cap_z / 10.0, -iSettings.cap_y / 10.0)); // Right
        iModel.push_back(cv::Point3f(-iSettings.cap_x / 10.0, iSettings.cap_z / 10.0, -iSettings.cap_y / 10.0)); // Left
        iModel.push_back(cv::Point3f(0, 0, 0)); // Top
    }

    ///
    void Tracker::CreateCameraIntrinsicsMatrices()
    {
        // Create our camera matrix                
        iCameraMatrix.create(3, 3, CV_64FC1);
        iCameraMatrix.setTo(cv::Scalar(0));
        iCameraMatrix.at<double>(0, 0) = iCameraInfo.focalLengthX;
        iCameraMatrix.at<double>(1, 1) = iCameraInfo.focalLengthY;
        iCameraMatrix.at<double>(0, 2) = iCameraInfo.principalPointX;
        iCameraMatrix.at<double>(1, 2) = iCameraInfo.principalPointY;
        iCameraMatrix.at<double>(2, 2) = 1;

        // Create distortion cooefficients
        iDistCoeffsMatrix = cv::Mat::zeros(8, 1, CV_64FC1);
        // As per OpenCV docs they should be thus: k1, k2, p1, p2, k3, k4, k5, k6
        iDistCoeffsMatrix.at<double>(0, 0) = 0; // Radial first order
        iDistCoeffsMatrix.at<double>(1, 0) = iCameraInfo.radialDistortionSecondOrder; // Radial second order
        iDistCoeffsMatrix.at<double>(2, 0) = 0; // Tangential first order
        iDistCoeffsMatrix.at<double>(3, 0) = 0; // Tangential second order
        iDistCoeffsMatrix.at<double>(4, 0) = 0; // Radial third order
        iDistCoeffsMatrix.at<double>(5, 0) = iCameraInfo.radialDistortionFourthOrder; // Radial fourth order
        iDistCoeffsMatrix.at<double>(6, 0) = 0; // Radial fith order
        iDistCoeffsMatrix.at<double>(7, 0) = iCameraInfo.radialDistortionSixthOrder; // Radial sixth order
    }

    ///
    ///
    ///
    void Tracker::ProcessFrame()
    {
        // Create OpenCV matrix from our frame
        // TODO: Assert channel size is one or two
        iMatFrame = cv::Mat(iFrame.height, iFrame.width, CV_MAKETYPE((iFrame.channelSize == 2 ? CV_16U : CV_8U), iFrame.channels), iFrame.data, iFrame.stride);
        iFrameCount++;

        bool doPreview = check_is_visible();
        if (doPreview)
        {
            iPreview = iMatFrame;
        }

        iPoints.clear();
        iPointExtractor.ExtractPoints(iMatFrame, (doPreview ? &iPreview.iFrameRgb : nullptr), iPoints);

        const bool success = iPoints.size() >= KPointCount;

        int topPointIndex = -1;

        {
            QMutexLocker l(&center_lock);

            if (success)
            {
                ever_success.store(true, std::memory_order_relaxed);

                // Solve P3P problem with OpenCV

                //Bitmap origin is top left
                iTrackedPoints.clear();
                // Tracked points must match the order of the object model points.
                // Find top most point, that's the one with min Y as we assume our guy's head is not up side down
                int minY = std::numeric_limits<int>::max();
                for (int i = 0; i < 3; i++)
                {
                    if (iPoints[i].y < minY)
                    {
                        minY = iPoints[i].y;
                        topPointIndex = i;
                    }
                }

                int rightPointIndex = -1;
                int maxX = 0;

                // Find right most point 
                for (int i = 0; i < 3; i++)
                {
                    // Excluding top most point
                    if (i != topPointIndex && iPoints[i].x > maxX)
                    {
                        maxX = iPoints[i].x;
                        rightPointIndex = i;
                    }
                }

                // Find left most point
                int leftPointIndex = -1;
                for (int i = 0; i < 3; i++)
                {
                    // Excluding top most point
                    if (i != topPointIndex && i != rightPointIndex)
                    {
                        leftPointIndex = i;
                        break;
                    }
                }

                //
                iTrackedPoints.push_back(iPoints[rightPointIndex]);
                iTrackedPoints.push_back(iPoints[leftPointIndex]);
                iTrackedPoints.push_back(iPoints[topPointIndex]);

                dbgout << "Object: " << iModel << "\n";
                dbgout << "Points: " << iTrackedPoints << "\n";


                // TODO: try SOLVEPNP_AP3P too, make it a settings option?
                iAngles.clear();
                iBestSolutionIndex = -1;
                int solutionCount = cv::solveP3P(iModel, iTrackedPoints, iCameraMatrix, iDistCoeffsMatrix, iRotations, iTranslations, cv::SOLVEPNP_P3P);

                if (solutionCount > 0)
                {
                    dbgout << "Solution count: " << solutionCount << "\n";
                    int minPitch = std::numeric_limits<int>::max();
                    // Find the solution we want amongst all possible ones
                    for (int i = 0; i < solutionCount; i++)
                    {
                        dbgout << "Translation:\n";
                        dbgout << iTranslations.at(i);
                        dbgout << "\n";
                        dbgout << "Rotation:\n";
                        //dbgout << rvecs.at(i);
                        cv::Mat rotationCameraMatrix;
                        cv::Rodrigues(iRotations[i], rotationCameraMatrix);
                        cv::Vec3d angles;
                        getEulerAngles(rotationCameraMatrix, angles);
                        iAngles.push_back(angles);

                        // Check if pitch is closest to zero
                        int absolutePitch = std::abs(angles[0]);
                        if (minPitch > absolutePitch)
                        {
                            // The solution with pitch closest to zero is the one we want
                            minPitch = absolutePitch;
                            iBestSolutionIndex = i;
                        }

                        dbgout << angles;
                        dbgout << "\n";
                    }

                    dbgout << "\n";
                }
            }

                        
            if (iBestSolutionIndex != -1)
            {
                // Best translation
                cv::Vec3d translation = iTranslations[iBestSolutionIndex];
                // Best angles
                cv::Vec3d angles = iAngles[iBestSolutionIndex];

                // Pass solution through our kalman filter
                iKf.Update(translation[0], translation[1], translation[2], angles[2], angles[0], angles[1]);

                // Send solution data back to main thread
                QMutexLocker l2(&data_lock);
                iBestAngles = angles;
                iBestTranslation = translation;
            }

        }

        if (doPreview)
        {
            std::ostringstream ss;
            ss << "FPS: " << iFps << "/" << iSkippedFps;
            iPreview.DrawInfo(ss.str());

            //
            if (topPointIndex != -1)
            {
                // Render a cross to indicate which point is the head
                iPreview.DrawCross(iPoints[topPointIndex]);
            }

            // Show full size preview pop-up
            if (iSettings.debug)
            {
                cv::imshow("Preview", iPreview.iFrameRgb);
                cv::waitKey(1);
            }

            // Update preview widget
            widget->update_image(iPreview.get_bitmap());

            auto[w, h] = widget->preview_size();
            if (w != preview_width || h != preview_height)
            {
                // Resize preivew if widget size has changed
                preview_width = w; preview_height = h;
                iPreview = Preview(w, h);
            }
        }
        else
        {
            // No preview, destroy preview pop-up
            if (iSettings.debug)
            {
                cv::destroyWindow("Preview");
            }
        }

        dbgout << "Frame time:" << iTimer.elapsed_seconds() << "\n";

    }

    ///
    ///
    ///
    void Tracker::Tick()
    {
        maybe_reopen_camera();
      
        iTimer.start();

        bool new_frame = false;
        {
            QMutexLocker l(&camera_mtx);

            if (camera)
            {
                std::tie(iFrame, new_frame) = camera->get_frame();
            }
                    
        }

        if (new_frame)
        {
            ProcessFrame();
        }
        else
        {
            iSkippedFrameCount++;
        }

        // Compute FPS
        double elapsed = iFpsTimer.elapsed_seconds();
        if (elapsed >= 1.0)
        {
            iFps = iFrameCount / elapsed;
            iSkippedFps = iSkippedFrameCount / elapsed;
            iFrameCount = 0;
            iSkippedFrameCount = 0;
            iFpsTimer.start();
        }
        
    }

    bool Tracker::maybe_reopen_camera()
    {
        QMutexLocker l(&camera_mtx);

        if (camera->is_open())
        {
            return true;
        }

        iCameraInfo.fps = iSettings.cam_fps;
        iCameraInfo.width = iSettings.cam_res_x;
        iCameraInfo.height = iSettings.cam_res_y;

        bool res = camera->start(iCameraInfo);
        // We got new our camera intrinsics, create corresponding matrices
        CreateCameraIntrinsicsMatrices();

        // If ever the camera implementation provided an FPS now is the time to apply it
        DoSetFps(iCameraInfo.fps);

        return res;
    }

    void Tracker::set_fov(int value)
    {
        QMutexLocker l(&camera_mtx);

    }

    // Calling this from another thread than the one it belongs too after it's started somehow breaks our timer
    void Tracker::SetFps(int aFps)
    {
        QMutexLocker l(&camera_mtx);
        DoSetFps(aFps);
    }

    void Tracker::DoSetFps(int aFps)
    {
        // Aplly FPS to timer
        iTicker.setInterval(1000 / aFps + 1);

        // Reset Kalman filter
        //int nStates = 18;            // the number of states
        //int nMeasurements = 6;       // the number of measured states
        //int nInputs = 0;             // the number of control actions
        //double dt = 0.125;           // time between measurements (1/FPS)
        double dt = 1000.0 / aFps;
        iKf.Init(18, 6, 0, dt);
    }


    module_status Tracker::start_tracker(QFrame* video_frame)
    {
        //video_frame->setAttribute(Qt::WA_NativeWindow);

        widget = std::make_unique<video_widget>(video_frame);
        layout = std::make_unique<QHBoxLayout>(video_frame);
        layout->setContentsMargins(0, 0, 0, 0);
        layout->addWidget(widget.get());
        video_frame->setLayout(layout.get());
        //video_widget->resize(video_frame->width(), video_frame->height());
        video_frame->show();

        // Create our camera
        camera = video::make_camera(iSettings.camera_name);
        // Precise timer is needed otherwise the interval is not really respected
        iTicker.setTimerType(Qt::PreciseTimer);
        SetFps(iSettings.cam_fps);
        iTicker.moveToThread(&iThread);
        // Connect timer timeout signal to our tick slot
        connect(&iTicker, SIGNAL(timeout()), SLOT(Tick()), Qt::DirectConnection);
        // Start our timer once our thread is started
        iTicker.connect(&iThread, SIGNAL(started()), SLOT(start()));
        iFpsTimer.start(); // Kick off our FPS counter
        iThread.setObjectName("EasyTrackerThread");
        iThread.setPriority(QThread::HighPriority); // Do we really want that?
        iThread.start();

        return {};
    }

    //
    // That's called around 250 times per second.
    // Therefore we better not do anything here other than provide current data.
    //
    void Tracker::data(double *data)
    {
        if (ever_success.load(std::memory_order_relaxed))
        {
            // Get data back from tracker thread
            QMutexLocker l(&data_lock);
            data[Yaw] = iBestAngles[1];
            data[Pitch] = iBestAngles[0];
            data[Roll] = iBestAngles[2];
            data[TX] = iBestTranslation[0];
            data[TY] = iBestTranslation[1];
            data[TZ] = iBestTranslation[2];
        }
    }

    bool Tracker::center()
    {
        QMutexLocker l(&center_lock);
        //TODO: Do we need to do anything there?
        return false;
    }


}