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#include "AlgorithmGrayCode.h"

#include <cmath>

#include "cvtools.h"

#ifndef log2f

#define log2f(x) (log(x)/log(2.0))

#endif

//using namespace std;

/*

 * The purpose of this function is to convert an unsigned

 * binary number to reflected binary Gray code.

 *

 * The operator >> is shift right. The operator ^ is exclusive or.

 * Source: http://en.wikipedia.org/wiki/Gray_code

 */

static unsigned int binaryToGray(unsigned int num) {

    return (num >> 1) ^ num;

}

/*

 * From Wikipedia: http://en.wikipedia.org/wiki/Gray_code

 * The purpose of this function is to convert a reflected binary

 * Gray code number to a binary number.

 */

static unsigned grayToBinary(unsigned num, unsigned numBits)

{

    for (unsigned shift = 1; shift < numBits; shift <<= 1){

        num ^= num >> shift;

    }

    return num;

}

/*

 * Function takes the decimal number

 * Function takes the Nth bit (1 to 31)

 * Return the value of Nth bit from decimal

 * Source: http://icfun.blogspot.com/2009/04/get-n-th-bit-value-of-any-integer.html

 */

static int get_bit(int decimal, int N){

    // Shifting the 1 for N-1 bits

    int constant = 1 << (N-1);

    // If the bit is set, return 1

    if( decimal & constant ){

        return 1;

    }

    // If the bit is not set, return 0

    return 0;

}

static inline int powi(int num, unsigned int exponent){

    // NOT EQUIVALENT TO pow()

    if(exponent == 0)

        return 1;

    float res = num;

    for(unsigned int i=0; i<exponent-1; i++)

        res *= num;

    return res;

}

// Algorithm

AlgorithmGrayCode::AlgorithmGrayCode(unsigned int _screenCols, unsigned int _screenRows, CodingDir _dir) : Algorithm(_screenCols, _screenRows, _dir){

    // on/off patterns

    Nbits = ceilf(log2f((float)screenCols));

    N = 2 + Nbits*2;

    // all on pattern

    cv::Mat allOn(1, screenCols, CV_8UC3, cv::Scalar::all(255));

    patterns.push_back(allOn);

    // all off pattern

    cv::Mat allOff(1, screenCols, CV_8UC3, cv::Scalar::all(0));

    patterns.push_back(allOff);

    // horizontally encoding patterns

    for(unsigned int p=0; p<Nbits; p++){

        cv::Mat pattern(1, screenCols, CV_8UC3);

        cv::Mat patternInv(1, screenCols, CV_8UC3);

        for(unsigned int j=0; j<screenCols; j++){

            unsigned int jGray = binaryToGray(j);

            // Amplitude of channels

            int bit = get_bit(jGray, Nbits-p);

            pattern.at<cv::Vec3b>(0,j) = cv::Vec3b(255.0*bit,255.0*bit,255.0*bit);

            int invBit = bit^1;

            patternInv.at<cv::Vec3b>(0,j) = cv::Vec3b(255.0*invBit,255.0*invBit,255.0*invBit);

        }

        patterns.push_back(pattern);

        patterns.push_back(patternInv);

    }

}

cv::Mat AlgorithmGrayCode::getEncodingPattern(unsigned int depth){

    return patterns[depth];

}

bool sortingLarger(cv::Vec4f i,cv::Vec4f j){ return (i[3]<j[3]);}

bool sortingEqual(cv::Vec4f i,cv::Vec4f j){ return (i[3]==j[3]);}

void getEdgeLabels(const cv::Mat& scanLine, int Nbits, std::vector<cv::Vec4f>& edges){

    int nCols = scanLine.cols;

    const short *data = scanLine.ptr<const short>(0);

    short labelLeft;

    short labelRight = data[0];

    for(int col=1; col<nCols; col++){

        labelLeft = labelRight;

        labelRight = data[col];

        if(labelLeft != -1 && labelRight != -1 && labelLeft != labelRight){

            int orderingRelation = (2 << Nbits)*labelLeft + labelRight;

            edges.push_back(cv::Vec4f(col, labelLeft, labelRight, orderingRelation));

        }

    }

    // sort

    std::sort(edges.begin(), edges.end(), sortingLarger);

    // remove duplicates

    std::vector<cv::Vec4f>::iterator it;

    it = std::unique(edges.begin(), edges.end(), sortingEqual);

    edges.resize(std::distance(edges.begin(),it));

}

void AlgorithmGrayCode::get3DPoints(SMCalibrationParameters calibration, const std::vector<cv::Mat>& frames0, const std::vector<cv::Mat>& frames1, std::vector<cv::Point3f>& Q, std::vector<cv::Vec3b>& color){

    assert(frames0.size() == N);

    assert(frames1.size() == N);

    int frameRows = frames0[0].rows;

    int frameCols = frames0[0].cols;

    // convert to gray-scale

    std::vector<cv::Mat> frames0Gray(N);

    std::vector<cv::Mat> frames1Gray(N);

    for(int i=0; i<N; i++){

        cv::cvtColor(frames0[i], frames0Gray[i], CV_RGB2GRAY);

        cv::cvtColor(frames1[i], frames1Gray[i], CV_RGB2GRAY);

    }

    // occlusion maps

    cv::Mat occlusion0, occlusion1;

    cv::subtract(frames0Gray[0], frames0Gray[1], occlusion0);

    occlusion0 = occlusion0 > 50;

    cv::subtract(frames1Gray[0], frames1Gray[1], occlusion1);

    occlusion1 = occlusion1 > 50;

//    cvtools::writeMat(occlusion0, "occlusion0.mat", "occlusion0");

//    cvtools::writeMat(occlusion1, "occlusion1.mat", "occlusion1");

    // decoded patterns

    cv::Mat code0(frameRows, frameCols, CV_16S, cv::Scalar(-1)), code1(frameRows, frameCols, CV_16S, cv::Scalar(-1));

    cvtools::writeMat(code0, "code0.mat", "code0");

    cvtools::writeMat(code1, "code1.mat", "code1");

    for(int i=0; i<Nbits; i++){

        cv::Mat bit0;

        cv::subtract(frames0Gray[i*2+2], frames0Gray[i*2+3], bit0);

        bit0 = bit0 > 50;

//    cvtools::writeMat(bit0, "bit0.mat", "bit0");

        cv::add(code0, bit0/255*powi(2,i), code0, occlusion0, CV_16S);

//    cvtools::writeMat(code0, "code0.mat", "code0");

        cv::Mat bit1;

        cv::subtract(frames1Gray[i*2+2], frames1Gray[i*2+3], bit1);

        bit1 = bit1 > 50;

        cv::add(code1, bit1/255*powi(2,i), code1, occlusion1, CV_16S);

    }

    cvtools::writeMat(code0, "code0.mat", "code0");

    cvtools::writeMat(code1, "code1.mat", "code1");

    // rectifying homographies (rotation+projections)

    cv::Size frameSize(frameCols, frameRows);

    cv::Mat R, T;

    // stereoRectify segfaults unless R is double precision

    cv::Mat(calibration.R1).convertTo(R, CV_64F);

    cv::Mat(calibration.T1).convertTo(T, CV_64F);

    cv::Mat R0, R1, P0, P1, QRect;

    cv::stereoRectify(calibration.K0, calibration.k0, calibration.K1, calibration.k1, frameSize, R, T, R0, R1, P0, P1, QRect, 0);

    // interpolation maps

    cv::Mat map0X, map0Y, map1X, map1Y;

    cv::initUndistortRectifyMap(calibration.K0, calibration.k0, R0, P0, frameSize, CV_32F, map0X, map0Y);

    cv::initUndistortRectifyMap(calibration.K1, calibration.k1, R1, P1, frameSize, CV_32F, map1X, map1Y);

    // remap

    cv::Mat code0Rect, code1Rect, color0Rect, color1Rect;

    cv::remap(code0, code0Rect, map0X, map0Y, cv::INTER_NEAREST);

    cv::remap(code1, code1Rect, map1X, map1Y, cv::INTER_NEAREST);

    cv::remap(frames0[0], color0Rect, map0X, map0Y, cv::INTER_CUBIC);

    cv::remap(frames1[0], color1Rect, map1X, map1Y, cv::INTER_CUBIC);

cvtools::writeMat(code0Rect, "code0Rect.mat", "code0Rect");

cvtools::writeMat(code1Rect, "code1Rect.mat", "code1Rect");

//cvtools::writeMat(color0Rect, "color0.mat", "color0");

//cvtools::writeMat(color1Rect, "color1.mat", "color1");

    int nRows = code0Rect.rows;

    int nCols = code0Rect.cols;

    // matching

    std::vector<cv::Vec2f> q0Rect, q1Rect;

    for(int row=0; row<nRows; row++){

        std::vector<cv::Vec4f> edges0, edges1;

        getEdgeLabels(code0Rect.row(row), Nbits, edges0);

        getEdgeLabels(code1Rect.row(row), Nbits, edges1);

        int i=0, j=0;

        while(i<edges0.size() && j<edges1.size()){

            if(edges0[i][3] == edges1[j][3]){

                q0Rect.push_back(cv::Vec2f(edges0[i][0], row));

                q1Rect.push_back(cv::Vec2f(edges1[j][0], row));

                i += 1;

                j += 1;

            } else if(edges0[i][3] < edges1[j][3]){

                i += 1;

            } else if(edges0[i][3] > edges1[j][3]){

                j += 1;

            }

        }

    }

    // retrieve color information

    int nMatches = q0Rect.size();

    color.resize(nMatches);

    for(int i=0; i<nMatches; i++){

        cv::Vec3b c0 = color0Rect.at<cv::Vec3b>(q0Rect[i][1], q0Rect[i][0]);

        cv::Vec3b c1 = color1Rect.at<cv::Vec3b>(q1Rect[i][1], q1Rect[i][0]);

        color[i] = 0.5*(c0 + c1);

    }

    // triangulate points

    cv::Mat QMatHomogenous, QMat;

    cv::triangulatePoints(P0, P1, q0Rect, q1Rect, QMatHomogenous);

    cvtools::convertMatFromHomogeneous(QMatHomogenous, QMat);

    cvtools::matToPoints3f(QMat, Q);

}