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

 * 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  testTOAFactor.cpp
 *  @brief Unit tests for "Time of Arrival" factor
 *  @author Frank Dellaert
 *  @author Jay Chakravarty
 *  @date December 2014
 */

#include <gtsam_unstable/geometry/Event.h>
#include <gtsam/nonlinear/ExpressionFactorGraph.h>
#include <gtsam/nonlinear/expressions.h>
#include <gtsam/nonlinear/LevenbergMarquardtOptimizer.h>
#include <gtsam/base/numericalDerivative.h>

#include <CppUnitLite/TestHarness.h>
#include <boost/format.hpp>
#include <boost/bind.hpp>

using namespace std;
using namespace gtsam;

// typedefs
typedef Expression<Point3> Point3_;
typedef Expression<Event> Event_;

// units
static const double ms = 1e-3;
static const double cm = 1e-2;

// Create a noise model for the TOA error
static SharedNoiseModel model(noiseModel::Isotropic::Sigma(1, 0.5 * ms));

static const double timeOfEvent = 25;
static const Event exampleEvent(timeOfEvent, 1, 0, 0);
static const Point3 microphoneAt0(0,0,0);

//*****************************************************************************
TEST( TOAFactor, NewWay ) {
  Key key = 12;
  Event_ eventExpression(key);
  Point3_ microphoneConstant(microphoneAt0); // constant expression
  double measurement = 7;
  Double_ expression(&Event::toa, eventExpression, microphoneConstant);
  ExpressionFactor<double> factor(model, measurement, expression);
}

//*****************************************************************************
TEST( TOAFactor, WholeEnchilada ) {

  static const bool verbose = false;

  // Create microphones
  const double height = 0.5;
  vector<Point3> microphones;
  microphones.push_back(Point3(0, 0, height));
  microphones.push_back(Point3(403 * cm, 0, height));
  microphones.push_back(Point3(403 * cm, 403 * cm, height));
  microphones.push_back(Point3(0, 403 * cm, 2 * height));
  EXPECT_LONGS_EQUAL(4, microphones.size());
//  microphones.push_back(Point3(200 * cm, 200 * cm, height));

  // Create a ground truth point
  const double timeOfEvent = 0;
  Event groundTruthEvent(timeOfEvent, 245 * cm, 201.5 * cm, (212 - 45) * cm);

  // Simulate simulatedTOA
  size_t K = microphones.size();
  vector<double> simulatedTOA(K);
  for (size_t i = 0; i < K; i++) {
    simulatedTOA[i] = groundTruthEvent.toa(microphones[i]);
    if (verbose) {
      cout << "mic" << i << " = " << microphones[i] << endl;
      cout << "z" << i << " = " << simulatedTOA[i] / ms << endl;
    }
  }

  // Now, estimate using non-linear optimization
  ExpressionFactorGraph graph;
  Key key = 12;
  Event_ eventExpression(key);
  for (size_t i = 0; i < K; i++) {
    Point3_ microphone_i(microphones[i]); // constant expression
    Double_ predictTOA(&Event::toa, eventExpression, microphone_i);
    graph.addExpressionFactor(predictTOA, simulatedTOA[i], model);
  }

  /// Print the graph
  if (verbose)
    GTSAM_PRINT(graph);

  // Create initial estimate
  Values initialEstimate;
  //Event estimatedEvent(timeOfEvent -10, 200 * cm, 150 * cm, 350 * cm);
  Vector4 delta;
  delta << 0.1, 0.1, -0.1, 0.1;
  Event estimatedEvent = groundTruthEvent.retract(delta);
  initialEstimate.insert(key, estimatedEvent);

  // Print
  if (verbose)
    initialEstimate.print("Initial Estimate:\n");

  // Optimize using Levenberg-Marquardt optimization.
  LevenbergMarquardtParams params;
  params.setAbsoluteErrorTol(1e-10);
  if (verbose)
    params.setVerbosity("ERROR");
  LevenbergMarquardtOptimizer optimizer(graph, initialEstimate, params);
  Values result = optimizer.optimize();
  if (verbose)
    result.print("Final Result:\n");

  EXPECT(assert_equal(groundTruthEvent, result.at<Event>(key), 1e-6));
}
//*****************************************************************************
int main() {
  TestResult tr;
  return TestRegistry::runAllTests(tr);
}
//*****************************************************************************