/* ----------------------------------------------------------------------------

 * GTSAM Copyright 2010, Georgia Tech Research Corporation,
 * Atlanta, Georgia 30332-0415
 * All Rights Reserved
 * Authors: Frank Dellaert, et al. (see THANKS for the full author list)

 * See LICENSE for the license information

 * -------------------------------------------------------------------------- */

/**
 * @file SmartProjectionFactorExample_kitti.cpp
 * @brief Example usage of SmartProjectionFactor using real dataset
 * @date August, 2013
 * @author Zsolt Kira
 */

// Both relative poses and recovered trajectory poses will be stored as Pose2 objects
#include <gtsam/geometry/Pose3.h>

// Each variable in the system (poses and landmarks) must be identified with a unique key.
// We can either use simple integer keys (1, 2, 3, ...) or symbols (X1, X2, L1).
// Here we will use Symbols
#include <gtsam/nonlinear/Symbol.h>

// We want to use iSAM2 to solve the range-SLAM problem incrementally
#include <gtsam/nonlinear/ISAM2.h>

// iSAM2 requires as input a set set of new factors to be added stored in a factor graph,
// and initial guesses for any new variables used in the added factors
#include <gtsam/nonlinear/NonlinearFactorGraph.h>
#include <gtsam/nonlinear/Values.h>

// We will use a non-liear solver to batch-inituialize from the first 150 frames
#include <gtsam/nonlinear/LevenbergMarquardtOptimizer.h>

// In GTSAM, measurement functions are represented as 'factors'. Several common factors
// have been provided with the library for solving robotics SLAM problems.
#include <gtsam/slam/PriorFactor.h>
#include <gtsam_unstable/slam/SmartProjectionFactor.h>

// Standard headers, added last, so we know headers above work on their own
#include <boost/foreach.hpp>
#include <fstream>
#include <iostream>

using namespace std;
using namespace gtsam;
namespace NM = gtsam::noiseModel;

using symbol_shorthand::X;
using symbol_shorthand::L;

typedef PriorFactor<Pose3> Pose3Prior;

static SharedNoiseModel prior_model(noiseModel::Diagonal::Sigmas(Vector_(6, 0.01, 0.01, 0.01, 0.01, 0.01, 0.01)));

Values::shared_ptr loadPoseValues(const string& filename) {
  Values::shared_ptr values(new Values());

  // read in camera poses
  string full_filename = filename;
  ifstream fin;
  fin.open(full_filename.c_str());

  int pose_id;
  while (fin >> pose_id) {
    double pose_matrix[16];
    for (int i = 0; i < 16; i++) {
      fin >> pose_matrix[i];
    }
    values->insert(Symbol('x',pose_id), Pose3(Matrix_(4, 4, pose_matrix)));
  }

  fin.close();
  return values;
}

/* ************************************************************************* */
Values::shared_ptr loadPoseValues(const string& filename, list<Key> keys) {
  Values::shared_ptr values(new Values());
  std::list<Key>::iterator kit;

  // read in camera poses
  string full_filename = filename;
  ifstream fin;
  fin.open(full_filename.c_str());

  int pose_id;
  while (fin >> pose_id) {
    double pose_matrix[16];
    for (int i = 0; i < 16; i++) {
      fin >> pose_matrix[i];
    }
    kit = find (keys.begin(), keys.end(), X(pose_id));
    if (kit != keys.end()) {
      cout << " Adding " << X(pose_id) << endl;
      values->insert(Symbol('x',pose_id), Pose3(Matrix_(4, 4, pose_matrix)));
    }
  }

  fin.close();
  return values;
}

// main
int main(int argc, char** argv) {

  bool debug = false;
  unsigned int minimumNumViews = 1;

  string HOME = getenv("HOME");
  //string input_dir = HOME + "/data/kitti/loop_closures_merged/";
  string input_dir = HOME + "/data/KITTI_00_200/";
  Cal3_S2::shared_ptr K(new Cal3_S2(718.856, 718.856, 0.0, 607.1928, 185.2157));

  typedef SmartProjectionFactor<Pose3, Point3, Cal3_S2> SmartFactor;

  // Read in kitti dataset
  // load stereo factors and initialize landmarks when first seen
  ifstream fin;
  fin.open((input_dir+"stereo_factors.txt").c_str());
  if(!fin) {
    cerr << "Could not open stereo_factors.txt" << endl;
    exit(1);
  }

  static SharedNoiseModel pixel_sigma(noiseModel::Unit::Create(3));
  static SharedNoiseModel prior_model(noiseModel::Diagonal::Sigmas(Vector_(6, 0.01, 0.01, 0.01, 0.01, 0.01, 0.01)));
  NonlinearFactorGraph graph;

  // read all measurements tracked by VO
  cout << "Loading stereo_factors.txt" << endl;
  int count = 0;
  Key currentLandmark = 0;
  int numLandmarks = 0;
  Key r, l;
  double uL, uR, v, x, y, z;
  std::list<Key> allViews;
  std::vector<Key> views;
  std::vector<Point2> measurements;
  Values values;
  while (fin >> r >> l >> uL >> uR >> v >> x >> y >> z) {
    if (debug) cout << "CurrentLandmark " << currentLandmark << " Landmark " << l << std::endl;

    if (currentLandmark != l && views.size() < minimumNumViews) {
      // New landmark.  Not enough views for previous landmark so move on.
      if (debug) cout << "New landmark " << l << " with not enough view for previous one" << std::endl;
      currentLandmark = l;
      views.clear();
      measurements.clear();
    } else if (currentLandmark != l) {
      // New landmark.  Add previous landmark and associated views to new factor
      if (debug) cout << "New landmark " << l << " with "<< views.size() << " views for previous landmark " << currentLandmark << std::endl;

      if (debug) cout << "Keys ";
      BOOST_FOREACH(const Key& k, views) {
        allViews.push_back(k);
        if (debug) cout << k << " ";
      }
      if (debug) cout << endl;

      if (debug) {
        cout << "Measurements ";
        BOOST_FOREACH(const Point2& p, measurements) {
           cout << p << " ";
        }
        cout << endl;
      }

      numLandmarks++;
      SmartFactor::shared_ptr smartFactor(new SmartFactor(measurements, pixel_sigma, views, K));
      graph.push_back(smartFactor);

      currentLandmark = l;
      views.clear();
      measurements.clear();
    } else {
      // We have new view for current landmark, so add it to the list later
      if (debug) cout << "New view for landmark " << l << " (" << views.size() << " total)" << std::endl;
    }

    // Add view for new landmark
    views += X(r);
    measurements += Point2(uL,v);

    count++;
    if(count==100000) {
      cout << "Loading graph... " << graph.size() << endl;
      count=0;
    }
  }

  cout << "Graph size: " << graph.size() << endl;
  gtsam::Values::shared_ptr loaded_values = loadPoseValues(input_dir+"camera_poses.txt");
  graph.add(Pose3Prior(X(0),loaded_values->at<Pose3>(X(0)), prior_model));

  // Get all view in the graph and populate poses from VO output
  // TODO: Handle loop closures properly
  cout << "All Keys (" << allViews.size() << ")" << endl;
  allViews.unique();
  cout << "All Keys (" << allViews.size() << ")" << endl;

  /*
  values = *loadPoseValues(input_dir+"camera_poses.txt", allViews);
  BOOST_FOREACH(const Key& k, allViews) {
    if (debug) cout << k << " ";
  }
  cout << endl;
  */

  cout << "Optimizing... " << endl;

  // Optimize!
  LevenbergMarquardtParams params;
  params.verbosityLM = LevenbergMarquardtParams::TRYLAMBDA;
  params.verbosity = NonlinearOptimizerParams::ERROR;

  Values result;
  gttic_(SmartProjectionFactorExample_kitti);
  LevenbergMarquardtOptimizer optimizer(graph, *loaded_values, params);
  result = optimizer.optimize();
  gttoc_(SmartProjectionFactorExample_kitti);
  tictoc_finishedIteration_();

  cout << "===================================================" << endl;
  values.print("before optimization ");
  result.print("results of kitti optimization ");
  tictoc_print_();
  cout << "===================================================" << endl;

  exit(0);
}