[fisherfaces]

#include "opencv2/core/core.hpp"
#include "opencv2/contrib/contrib.hpp"
#include "opencv2/highgui/highgui.hpp"

#include <iostream>
#include <fstream>
#include <sstream>

using namespace cv;
using namespace std;

static Mat norm_0_255(InputArray _src) {
    Mat src = _src.getMat();
    // Create and return normalized image:
    Mat dst;
    switch(src.channels()) {
    case 1:
        cv::normalize(_src, dst, 0, 255, NORM_MINMAX, CV_8UC1);
        break;
    case 3:
        cv::normalize(_src, dst, 0, 255, NORM_MINMAX, CV_8UC3);
        break;
    default:
        src.copyTo(dst);
        break;
    }
    return dst;
}

static void read_csv(const string& filename, vector<Mat>& images, vector<int>& labels, char separator = ';') {
    std::ifstream file(filename.c_str(), ifstream::in);
    if (!file) {
        string error_message = "No valid input file was given, please check the given filename.";
        CV_Error(CV_StsBadArg, error_message);
    }
    string line, path, classlabel;
    while (getline(file, line)) {
        stringstream liness(line);
        getline(liness, path, separator);
        getline(liness, classlabel);
        if(!path.empty() && !classlabel.empty()) {
            Mat t = imread(path,0);
            if (t.rows < 1) {
                continue;
            } else {
                cout << path << endl;
                images.push_back(t);
                labels.push_back(atoi(classlabel.c_str()));
            }
        }
    }
}

int main(int argc, const char *argv[]) {
    if (argc < 2) {
        cout << "usage: " << argv[0] << " <csv.ext> <output_folder> " << endl;
        exit(1);
    }
    string output_folder = ".";
    if (argc == 3) {
        output_folder = string(argv[2]);
    }
    string fn_csv = string(argv[1]);

    vector<Mat> images;
    vector<int> labels;

    try {
        read_csv(fn_csv, images, labels);
    } catch (cv::Exception& e) {
        cerr << "Error opening file \"" << fn_csv << "\". Reason: " << e.msg << endl;
        exit(1);
    }

    if(images.size() <= 1) {
        string error_message = "This demo needs at least 2 images to work. Please add more images to your data set!";
        CV_Error(CV_StsError, error_message);
    }

    int height = images[0].rows;

    //Mat testSample = images[images.size() - 1];
    //int testLabel = labels[labels.size() - 1];
    //images.pop_back();
    //labels.pop_back();

    Ptr<FaceRecognizer> model = createFisherFaceRecognizer();
    model->train(images, labels);

    Mat eigenvalues = model->getMat("eigenvalues");

    Mat W = model->getMat("eigenvectors");

    Mat mean = model->getMat("mean");

    if(argc == 2) {
        imshow("mean", norm_0_255(mean.reshape(1, images[0].rows)));
    } else {
        imwrite(format("%s/mean.png", output_folder.c_str()), norm_0_255(mean.reshape(1, images[0].rows)));
    }

    for (int i = 0; i < min(10, W.cols); i++) {
        Mat ev = W.col(i).clone();
        Mat grayscale = norm_0_255(ev.reshape(1, height));
        Mat cgrayscale;
        applyColorMap(grayscale, cgrayscale, COLORMAP_BONE);
        if(argc == 2) {
            imshow(format("fisherface_%d", i), cgrayscale);
        } else {
            imwrite(format("%s/fisherface_%d.png", output_folder.c_str(), i), norm_0_255(cgrayscale));
        }
    }
    if(argc == 2) {
        waitKey(0);
    }
    return 0;
}