/*
    * Copyright (C) 2018 Alberto Irurueta Carro (alberto@irurueta.com)
    *
    * Licensed under the Apache License, Version 2.0 (the "License");
    * you may not use this file except in compliance with the License.
    * You may obtain a copy of the License at
    *
    *         http://www.apache.org/licenses/LICENSE-2.0
    *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  package com.irurueta.navigation.indoor.radiosource;
  
  import com.irurueta.geometry.Accuracy2D;
  import com.irurueta.geometry.InhomogeneousPoint2D;
  import com.irurueta.geometry.Point2D;
  import com.irurueta.navigation.LockedException;
  import com.irurueta.navigation.indoor.Beacon;
  import com.irurueta.navigation.indoor.BeaconLocated2D;
  import com.irurueta.navigation.indoor.RadioSource;
  import com.irurueta.navigation.indoor.RadioSourceLocated;
  import com.irurueta.navigation.indoor.RangingReadingLocated;
  import com.irurueta.navigation.indoor.WifiAccessPoint;
  import com.irurueta.navigation.indoor.WifiAccessPointLocated2D;
  import com.irurueta.navigation.lateration.HomogeneousLinearLeastSquaresLateration2DSolver;
  import com.irurueta.navigation.lateration.InhomogeneousLinearLeastSquaresLateration2DSolver;
  import com.irurueta.navigation.lateration.NonLinearLeastSquaresLateration2DSolver;
  
  import java.util.List;
  
  /**
   * Estimates position of a radio source (e.g. Wi-Fi access point or bluetooth beacon)
   * by using ranging measurements.
   * Ranging measurements can be obtained by protocols such as ieee 802.11mc (Wi-Fi RTT) which
   * measures travel time of signal and converts the result into distances by taking into
   * account the speed of light as the propagation speed.
   *
   * @param <S> a {@link RadioSource} type.
   */
  @SuppressWarnings("DuplicatedCode")
  public class RangingRadioSourceEstimator2D<S extends RadioSource> extends RangingRadioSourceEstimator<S, Point2D> {
  
      /**
       * Constructor.
       */
      public RangingRadioSourceEstimator2D() {
          super();
      }
  
      /**
       * Constructor.
       * Sets radio signal ranging readings belonging to the same radio source.
       *
       * @param readings radio signal ranging readings belonging to the same radio source.
       * @throws IllegalArgumentException if readings are not valid.
       */
      public RangingRadioSourceEstimator2D(final List<? extends RangingReadingLocated<S, Point2D>> readings) {
          super(readings);
      }
  
      /**
       * Constructor.
       *
       * @param listener listener in charge of attending events raised by this instance.
       */
      public RangingRadioSourceEstimator2D(final RangingRadioSourceEstimatorListener<S, Point2D> listener) {
          super(listener);
      }
  
      /**
       * Constructor.
       * Sets radio signal readings belonging to the same radio source.
       *
       * @param readings radio signal readings belonging to the same radio source.
       * @param listener listener in charge of attending events raised by this instance.
       * @throws IllegalArgumentException if readings are not valid.
       */
      public RangingRadioSourceEstimator2D(
              final List<? extends RangingReadingLocated<S, Point2D>> readings,
              final RangingRadioSourceEstimatorListener<S, Point2D> listener) {
          super(readings, listener);
      }
  
      /**
       * Constructor.
       *
       * @param initialPosition initial position to start the estimation or radio
       *                        source position.
       */
      public RangingRadioSourceEstimator2D(final Point2D initialPosition) {
          super(initialPosition);
      }
  
      /**
       * Constructor.
      * Sets radio signal readings belonging to the same radio source.
      *
      * @param readings        radio signal readings belonging to the same radio source.
      * @param initialPosition initial position to start the estimation of radio
      *                        source position.
      * @throws IllegalArgumentException if readings are not valid.
      */
     public RangingRadioSourceEstimator2D(
             final List<? extends RangingReadingLocated<S, Point2D>> readings, final Point2D initialPosition) {
         super(readings, initialPosition);
     }
 
     /**
      * Constructor.
      *
      * @param initialPosition initial position to start the estimation of radio
      *                        source position.
      * @param listener        listener in charge of attending events raised by this instance.
      */
     public RangingRadioSourceEstimator2D(
             final Point2D initialPosition, final RangingRadioSourceEstimatorListener<S, Point2D> listener) {
         super(initialPosition, listener);
     }
 
     /**
      * Constructor.
      * Sets radio signal ranging readings belonging to the same radio source.
      *
      * @param readings        radio signal ranging readings belonging to the same radio source.
      * @param initialPosition initial position to start the estimation of radio source
      *                        position.
      * @param listener        listener in charge of attending events raised by this instance.
      * @throws IllegalArgumentException if readings are not valid.
      */
     public RangingRadioSourceEstimator2D(
             final List<? extends RangingReadingLocated<S, Point2D>> readings, final Point2D initialPosition,
             final RangingRadioSourceEstimatorListener<S, Point2D> listener) {
         super(readings, initialPosition, listener);
     }
 
     /**
      * Gets minimum required number of readings to estimate position of radio source,
      * which is 3 readings.
      *
      * @return minimum required number of readings.
      */
     @Override
     public int getMinReadings() {
         return Point2D.POINT2D_INHOMOGENEOUS_COORDINATES_LENGTH + 1;
     }
 
     /**
      * Gets number of dimensions of position points.
      * This is always 2.
      *
      * @return number of dimensions of position points.
      */
     @Override
     public int getNumberOfDimensions() {
         return Point2D.POINT2D_INHOMOGENEOUS_COORDINATES_LENGTH;
     }
 
     /**
      * Gets estimated radio source 2D position.
      *
      * @return estimated radio source 2D position.
      */
     @Override
     public Point2D getEstimatedPosition() {
         if (estimatedPositionCoordinates == null) {
             return null;
         }
 
         final var result = new InhomogeneousPoint2D();
         getEstimatedPosition(result);
         return result;
     }
 
     /**
      * Gets estimated located radio source.
      *
      * @return estimated located radio source or null.
      */
     @Override
     @SuppressWarnings("unchecked")
     public RadioSourceLocated<Point2D> getEstimatedRadioSource() {
         final var readings = getReadings();
         if (readings == null || readings.isEmpty()) {
             return null;
         }
         final var source = readings.get(0).getSource();
 
         final var estimatedPosition = getEstimatedPosition();
         if (estimatedPosition == null) {
             return null;
         }
 
         final var estimatedPositionCovariance = getEstimatedPositionCovariance();
 
         if (source instanceof WifiAccessPoint accessPoint) {
             return new WifiAccessPointLocated2D(accessPoint.getBssid(), accessPoint.getFrequency(),
                     accessPoint.getSsid(), estimatedPosition, estimatedPositionCovariance);
         } else if (source instanceof Beacon beacon) {
             return new BeaconLocated2D(beacon.getIdentifiers(), beacon.getTransmittedPower(), beacon.getFrequency(),
                     beacon.getBluetoothAddress(), beacon.getBeaconTypeCode(), beacon.getManufacturer(),
                     beacon.getServiceUuid(), beacon.getBluetoothName(), estimatedPosition, estimatedPositionCovariance);
         } else {
             return null;
         }
     }
 
     /**
      * Builds an instance of a linear lateration solver if needed.
      */
     @Override
     protected void buildLinearSolverIfNeeded() {
         if (initialPosition == null || !nonLinearSolverEnabled) {
             if (useHomogeneousLinearSolver && homogeneousLinearSolver == null) {
                 homogeneousLinearSolver = new HomogeneousLinearLeastSquaresLateration2DSolver();
             }
             if (!useHomogeneousLinearSolver && inhomogeneousLinearSolver == null) {
                 inhomogeneousLinearSolver = new InhomogeneousLinearLeastSquaresLateration2DSolver();
             }
         }
     }
 
     /**
      * Builds an instance of a non-linear lateration solver if needed.
      */
     @Override
     protected void buildNonLinearSolverIfNeeded() {
         if (nonLinearSolver == null && nonLinearSolverEnabled) {
             nonLinearSolver = new NonLinearLeastSquaresLateration2DSolver();
         }
     }
 
     /**
      * Build an instance of accuracy if needed.
      */
     @Override
     protected void buildAccuracyIfNeeded() {
         if (accuracy == null && useReadingPositionCovariances) {
             accuracy = new Accuracy2D();
 
             // to work with standard deviations, we need a unitary factor
             accuracy.setStandardDeviationFactor(1.0);
         }
     }
 
 
     /**
      * Sets positions, distances and standard deviations of distances on internal
      * lateration solver.
      *
      * @param positions                  positions to be set.
      * @param distances                  distances to be set.
      * @param distanceStandardDeviations standard deviations of distances to be set or
      *                                   null.
      * @throws LockedException if solvers are locked.
      */
     @Override
     protected void setPositionsDistancesAndDistanceStandardDeviations(
             final List<Point2D> positions, final List<Double> distances, final List<Double> distanceStandardDeviations)
             throws LockedException {
         final var size = positions.size();
         Point2D[] positionsArray = new InhomogeneousPoint2D[size];
         positionsArray = positions.toArray(positionsArray);
 
         final var distancesArray = new double[size];
         final var distanceStandardDeviationsArray = new double[size];
         for (var i = 0; i < size; i++) {
             distancesArray[i] = distances.get(i);
             distanceStandardDeviationsArray[i] = distanceStandardDeviations.get(i);
         }
 
         if (initialPosition == null || !nonLinearSolverEnabled) {
             if (homogeneousLinearSolver != null) {
                 homogeneousLinearSolver.setPositionsAndDistances(positionsArray, distancesArray);
             }
             if (inhomogeneousLinearSolver != null) {
                 inhomogeneousLinearSolver.setPositionsAndDistances(positionsArray, distancesArray);
             }
         }
 
         if (nonLinearSolver != null && nonLinearSolverEnabled) {
             nonLinearSolver.setPositionsDistancesAndStandardDeviations(positionsArray, distancesArray,
                     distanceStandardDeviationsArray);
         }
     }
 }