/**
 * This file is part of ORB-SLAM2.
 *
 * Copyright (C) 2014-2016 Raúl Mur-Artal <raulmur at unizar dot es> (University of Zaragoza)
 * For more information see <https://github.com/raulmur/ORB_SLAM2>
 *
 * ORB-SLAM2 is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * ORB-SLAM2 is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with ORB-SLAM2. If not, see <http://www.gnu.org/licenses/>.
 */

#include <iostream>
#include <algorithm>
#include <fstream>
#include <chrono>
#include <unistd.h>
#include <opencv2/core/core.hpp>

#include <System.h>

using namespace std;

void LoadImages(const string &strAssociationFilename, vector<string> &vstrImageFilenamesRGB,
                vector<string> &vstrImageFilenamesD, vector<double> &vTimestamps);

void LoadLabel(const string &strLabelFilename, vector<vector<double>> &vLabel);

int main(int argc, char **argv)
{
    if (argc != 5)
    {
        cerr << endl
             << "Usage: ./rgbd_tum path_to_vocabulary path_to_settings path_to_sequence path_to_association" << endl;
        return 1;
    }

    // Retrieve paths to images
    vector<string> vstrImageFilenamesRGB;
    vector<string> vstrImageFilenamesD;
    vector<double> vTimestamps;
    string strAssociationFilename = string(argv[4]);
    LoadImages(strAssociationFilename, vstrImageFilenamesRGB, vstrImageFilenamesD, vTimestamps);

    // Check consistency in the number of images and depthmaps
    int nImages = vstrImageFilenamesRGB.size();
    if (vstrImageFilenamesRGB.empty())
    {
        cerr << endl
             << "No images found in provided path." << endl;
        return 1;
    }
    else if (vstrImageFilenamesD.size() != vstrImageFilenamesRGB.size())
    {
        cerr << endl
             << "Different number of images for rgb and depth." << endl;
        return 1;
    }

    // Create SLAM system. It initializes all system threads and gets ready to process frames.
    ORB_SLAM2::System SLAM(argv[1], argv[2], ORB_SLAM2::System::RGBD, true); // argv[1]: rgbd_tum     argv[2]:ORB_voc.txt

    // Vector for tracking time statistics
    vector<float> vTimesTrack;
    vTimesTrack.resize(nImages);

    cout << endl
         << "-------" << endl;
    cout << "Start processing sequence ..." << endl;
    cout << "Images in the sequence: " << nImages << endl
         << endl;

    // Main loop
    cv::Mat imRGB, imD;

    for (int ni = 0; ni < nImages; ni++)
    {
        vector<vector<double>> vLabel;
        // Read image and depthmap from file
        imRGB = cv::imread(string(argv[3]) + "/" + vstrImageFilenamesRGB[ni], CV_LOAD_IMAGE_UNCHANGED); // argv[3]:data/dynamic_objects/rgbd_dataset_freiburg3_walking_static
        imD = cv::imread(string(argv[3]) + "/" + vstrImageFilenamesD[ni], CV_LOAD_IMAGE_UNCHANGED);
        LoadLabel(string(argv[3]) + "/labels/" + to_string(vTimestamps[ni]) + ".txt", vLabel);

        double tframe = vTimestamps[ni];

        if (imRGB.empty())
        {
            cerr << endl
                 << "Failed to load image at: "
                 << string(argv[3]) << "/" << vstrImageFilenamesRGB[ni] << endl;
            return 1;
        }

#ifdef COMPILEDWITHC11
        std::chrono::steady_clock::time_point t1 = std::chrono::steady_clock::now();
#else
        std::chrono::monotonic_clock::time_point t1 = std::chrono::monotonic_clock::now();
#endif

        SLAM.TrackRGBD(imRGB, imD, tframe, vLabel);

#ifdef COMPILEDWITHC11
        std::chrono::steady_clock::time_point t2 = std::chrono::steady_clock::now();
#else
        std::chrono::monotonic_clock::time_point t2 = std::chrono::monotonic_clock::now();
#endif

        double ttrack = std::chrono::duration_cast<std::chrono::duration<double>>(t2 - t1).count();

        vTimesTrack[ni] = ttrack;

        // Wait to load the next frame
        double T = 0;
        if (ni < nImages - 1)
            T = vTimestamps[ni + 1] - tframe;
        else if (ni > 0)
            T = tframe - vTimestamps[ni - 1];

        if (ttrack < T)
            usleep((T - ttrack) * 1e6);
    }

    // Stop all threads
    SLAM.Shutdown();

    // Tracking time statistics
    sort(vTimesTrack.begin(), vTimesTrack.end());
    float totaltime = 0;
    for (int ni = 0; ni < nImages; ni++)
    {
        totaltime += vTimesTrack[ni];
    }
    cout << "-------" << endl
         << endl;
    cout << "median tracking time: " << vTimesTrack[nImages / 2] << endl;
    cout << "mean tracking time: " << totaltime / nImages << endl;

    // Save camera trajectory
    SLAM.SaveTrajectoryTUM("CameraTrajectory.txt");
    SLAM.SaveKeyFrameTrajectoryTUM("KeyFrameTrajectory.txt");

    return 0;
}

void LoadImages(const string &strAssociationFilename, vector<string> &vstrImageFilenamesRGB,
                vector<string> &vstrImageFilenamesD, vector<double> &vTimestamps)
{
    ifstream fAssociation;
    fAssociation.open(strAssociationFilename.c_str());
    while (!fAssociation.eof())
    {
        string s;
        getline(fAssociation, s);
        if (!s.empty())
        {
            stringstream ss;
            ss << s;
            double t;
            string sRGB, sD;
            ss >> t;
            vTimestamps.push_back(t);
            ss >> sRGB;
            vstrImageFilenamesRGB.push_back(sRGB);
            ss >> t;
            ss >> sD;
            vstrImageFilenamesD.push_back(sD);
        }
    }
}

void LoadLabel(const string &strLabelFilename, vector<vector<double>> &vLabel)
{
    ifstream fAssociation;
    fAssociation.open(strLabelFilename.c_str());
    while (!fAssociation.eof())
    {
        string s;
        getline(fAssociation, s);
        if (!s.empty())
        {
            stringstream ss;
            ss << s;
            double cls, x, y, w, h;
            vector<double> label;
            ss >> cls;
            label.push_back(cls);
            ss >> x;
            label.push_back(x);
            ss >> y;
            label.push_back(y);
            ss >> w;
            label.push_back(w);
            ss >> h;
            label.push_back(h);
            vLabel.push_back(label);
        }
    }
}