/*
    * Copyright (C) 2015 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.ar.epipolar.estimators;
  
  import com.irurueta.ar.epipolar.FundamentalMatrix;
  import com.irurueta.geometry.Point2D;
  import com.irurueta.geometry.estimators.LockedException;
  import com.irurueta.geometry.estimators.NotReadyException;
  import com.irurueta.numerical.robust.RANSACRobustEstimator;
  import com.irurueta.numerical.robust.RANSACRobustEstimatorListener;
  import com.irurueta.numerical.robust.RobustEstimator;
  import com.irurueta.numerical.robust.RobustEstimatorException;
  import com.irurueta.numerical.robust.RobustEstimatorMethod;
  
  import java.util.ArrayList;
  import java.util.List;
  
  /**
   * Finds the best fundamental matrix for provided collections of matched 2D
   * points using RANSAC algorithm.
   */
  public class RANSACFundamentalMatrixRobustEstimator extends FundamentalMatrixRobustEstimator {
  
      /**
       * Constant defining default threshold to determine whether points are
       * inliers or not.
       * By default, 1.0 is considered a good value for cases where measures are
       * done in pixels, since typically the minimum resolution is 1 pixel.
       */
      public static final double DEFAULT_THRESHOLD = 1.0;
  
      /**
       * Minimum value that can be set as threshold.
       * Threshold must be strictly greater than 0.0.
       */
      public static final double MIN_THRESHOLD = 0.0;
  
      /**
       * Indicates that by default inliers will only be computed but not kept.
       */
      public static final boolean DEFAULT_COMPUTE_AND_KEEP_INLIERS = false;
  
      /**
       * Indicates that by default residuals will only be computed but not kept.
       */
      public static final boolean DEFAULT_COMPUTE_AND_KEEP_RESIDUALS = false;
  
      /**
       * Threshold to determine whether pairs of matched points are inliers or not
       * when testing possible estimation solutions.
       * The threshold refers to the amount of error (i.e. distance) a given
       * point has respect to the epipolar line generated by its matched point.
       */
      private double threshold;
  
      /**
       * Indicates whether inliers must be computed and kept.
       */
      private boolean computeAndKeepInliers;
  
      /**
       * Indicates whether residuals must be computed and kept.
       */
      private boolean computeAndKeepResiduals;
  
      /**
       * Constructor.
       *
       * @param fundMatrixEstimatorMethod method for non-robust fundamental matrix
       *                                  estimator.
       */
      public RANSACFundamentalMatrixRobustEstimator(final FundamentalMatrixEstimatorMethod fundMatrixEstimatorMethod) {
          super(fundMatrixEstimatorMethod);
          threshold = DEFAULT_THRESHOLD;
          computeAndKeepInliers = DEFAULT_COMPUTE_AND_KEEP_INLIERS;
          computeAndKeepResiduals = DEFAULT_COMPUTE_AND_KEEP_RESIDUALS;
      }
  
      /**
       * Constructor.
       *
       * @param fundMatrixEstimatorMethod method for non-robust fundamental matrix
       *                                  estimator.
       * @param listener                  listener to be notified of events such as when
       *                                  estimation starts, ends or its progress significantly changes.
       */
     public RANSACFundamentalMatrixRobustEstimator(
             final FundamentalMatrixEstimatorMethod fundMatrixEstimatorMethod,
             final FundamentalMatrixRobustEstimatorListener listener) {
         super(fundMatrixEstimatorMethod, listener);
         threshold = DEFAULT_THRESHOLD;
         computeAndKeepInliers = DEFAULT_COMPUTE_AND_KEEP_INLIERS;
         computeAndKeepResiduals = DEFAULT_COMPUTE_AND_KEEP_RESIDUALS;
     }
 
     /**
      * Constructor.
      *
      * @param fundMatrixEstimatorMethod method for non-robust fundamental matrix
      *                                  estimator.
      * @param leftPoints                2D points on left view.
      * @param rightPoints               2D points on right view.
      * @throws IllegalArgumentException if provided list of points do not have
      *                                  the same length or their length is less than 7 points.
      */
     public RANSACFundamentalMatrixRobustEstimator(
             final FundamentalMatrixEstimatorMethod fundMatrixEstimatorMethod,
             final List<Point2D> leftPoints, final List<Point2D> rightPoints) {
         super(fundMatrixEstimatorMethod, leftPoints, rightPoints);
         threshold = DEFAULT_THRESHOLD;
         computeAndKeepInliers = DEFAULT_COMPUTE_AND_KEEP_INLIERS;
         computeAndKeepResiduals = DEFAULT_COMPUTE_AND_KEEP_RESIDUALS;
     }
 
     /**
      * Constructor.
      *
      * @param fundMatrixEstimatorMethod method for non-robust fundamental matrix
      *                                  estimator.
      * @param leftPoints                2D points on left view.
      * @param rightPoints               2D points on right view.
      * @param listener                  listener to be notified of events such as when estimation
      *                                  starts, ends or its progress significantly changes.
      * @throws IllegalArgumentException if provided list of points do not have
      *                                  the same length or their length is less than 7 points.
      */
     public RANSACFundamentalMatrixRobustEstimator(
             final FundamentalMatrixEstimatorMethod fundMatrixEstimatorMethod,
             final List<Point2D> leftPoints, final List<Point2D> rightPoints,
             final FundamentalMatrixRobustEstimatorListener listener) {
         super(fundMatrixEstimatorMethod, leftPoints, rightPoints, listener);
         threshold = DEFAULT_THRESHOLD;
         computeAndKeepInliers = DEFAULT_COMPUTE_AND_KEEP_INLIERS;
         computeAndKeepResiduals = DEFAULT_COMPUTE_AND_KEEP_RESIDUALS;
     }
 
     /**
      * Constructor.
      */
     public RANSACFundamentalMatrixRobustEstimator() {
         this(DEFAULT_FUNDAMENTAL_MATRIX_ESTIMATOR_METHOD);
     }
 
     /**
      * Constructor.
      *
      * @param listener listener to be notified of events such as when
      *                 estimation starts, ends or its progress significantly changes.
      */
     public RANSACFundamentalMatrixRobustEstimator(final FundamentalMatrixRobustEstimatorListener listener) {
         this(DEFAULT_FUNDAMENTAL_MATRIX_ESTIMATOR_METHOD, listener);
     }
 
     /**
      * Constructor.
      *
      * @param leftPoints  2D points on left view.
      * @param rightPoints 2D points on right view.
      * @throws IllegalArgumentException if provided list of points do not have
      *                                  the same length or their length is less than 7 points.
      */
     public RANSACFundamentalMatrixRobustEstimator(final List<Point2D> leftPoints, final List<Point2D> rightPoints) {
         this(DEFAULT_FUNDAMENTAL_MATRIX_ESTIMATOR_METHOD, leftPoints, rightPoints);
     }
 
     /**
      * Constructor.
      *
      * @param leftPoints  2D points on left view.
      * @param rightPoints 2D points on right view.
      * @param listener    listener to be notified of events such as when estimation
      *                    starts, ends or its progress significantly changes.
      * @throws IllegalArgumentException if provided list of points do not have
      *                                  the same length or their length is less than 7 points.
      */
     public RANSACFundamentalMatrixRobustEstimator(
             final List<Point2D> leftPoints, final List<Point2D> rightPoints,
             final FundamentalMatrixRobustEstimatorListener listener) {
         this(DEFAULT_FUNDAMENTAL_MATRIX_ESTIMATOR_METHOD, leftPoints, rightPoints, listener);
     }
 
     /**
      * Returns threshold to determine whether matched pairs of points are
      * inliers or not when testing possible estimation solutions.
      * The threshold refers to the amount of error (i.e. distance) a given
      * point has respect to the epipolar line generated by its matched point.
      *
      * @return threshold to determine whether matched pairs of points are
      * inliers or not.
      */
     public double getThreshold() {
         return threshold;
     }
 
     /**
      * Sets threshold to determine whether matched pairs of points are inliers
      * or not when testing possible estimation solutions.
      *
      * @param threshold threshold to be set.
      * @throws IllegalArgumentException if provided value is equal or less than
      *                                  zero.
      * @throws LockedException          if robust estimator is locked because an
      *                                  estimation is already in progress.
      */
     public void setThreshold(final double threshold) throws LockedException {
         if (isLocked()) {
             throw new LockedException();
         }
         if (threshold <= MIN_THRESHOLD) {
             throw new IllegalArgumentException();
         }
         this.threshold = threshold;
     }
 
     /**
      * Indicates whether inliers must be computed and kept.
      *
      * @return true if inliers must be computed and kept, false if inliers
      * only need to be computed but not kept.
      */
     public boolean isComputeAndKeepInliersEnabled() {
         return computeAndKeepInliers;
     }
 
     /**
      * Specifies whether inliers must be computed and kept.
      *
      * @param computeAndKeepInliers true if inliers must be computed and kept,
      *                              false if inliers only need to be computed but not kept.
      * @throws LockedException if estimator is locked.
      */
     public void setComputeAndKeepInliersEnabled(final boolean computeAndKeepInliers) throws LockedException {
         if (isLocked()) {
             throw new LockedException();
         }
         this.computeAndKeepInliers = computeAndKeepInliers;
     }
 
     /**
      * Indicates whether residuals must be computed and kept.
      *
      * @return true if residuals must be computed and kept, false if residuals
      * only need to be computed but not kept.
      */
     public boolean isComputeAndKeepResidualsEnabled() {
         return computeAndKeepResiduals;
     }
 
     /**
      * Specifies whether residuals must be computed and kept.
      *
      * @param computeAndKeepResiduals true if residuals must be computed and
      *                                kept, false if residuals only need to be computed but not kept.
      * @throws LockedException if estimator is locked.
      */
     public void setComputeAndKeepResidualsEnabled(final boolean computeAndKeepResiduals) throws LockedException {
         if (isLocked()) {
             throw new LockedException();
         }
         this.computeAndKeepResiduals = computeAndKeepResiduals;
     }
 
     /**
      * Estimates a radial distortion using a robust estimator and
      * the best set of matched 2D points found using the robust estimator.
      *
      * @return a radial distortion.
      * @throws LockedException          if robust estimator is locked because an
      *                                  estimation is already in progress.
      * @throws NotReadyException        if provided input data is not enough to start
      *                                  the estimation.
      * @throws RobustEstimatorException if estimation fails for any reason
      *                                  (i.e. numerical instability, no solution available, etc).
      */
     @SuppressWarnings("DuplicatedCode")
     @Override
     public FundamentalMatrix estimate() throws LockedException, NotReadyException, RobustEstimatorException {
         if (isLocked()) {
             throw new LockedException();
         }
         if (!isReady()) {
             throw new NotReadyException();
         }
 
         final var innerEstimator = new RANSACRobustEstimator<FundamentalMatrix>(new RANSACRobustEstimatorListener<>() {
 
             // subset of left points
             private final List<Point2D> subsetLeftPoints = new ArrayList<>();
 
             // subset of right points
             private final List<Point2D> subsetRightPoints = new ArrayList<>();
 
             @Override
             public double getThreshold() {
                 return threshold;
             }
 
             @Override
             public int getTotalSamples() {
                 return leftPoints.size();
             }
 
             @Override
             public int getSubsetSize() {
                 return getMinRequiredPoints();
             }
 
             @Override
             public void estimatePreliminarSolutions(
                     final int[] samplesIndices, final List<FundamentalMatrix> solutions) {
 
                 subsetLeftPoints.clear();
                 subsetRightPoints.clear();
                 for (final var samplesIndex : samplesIndices) {
                     subsetLeftPoints.add(leftPoints.get(samplesIndex));
                     subsetRightPoints.add(rightPoints.get(samplesIndex));
                 }
 
                 nonRobustEstimate(solutions, subsetLeftPoints, subsetRightPoints);
             }
 
             @Override
             public double computeResidual(final FundamentalMatrix currentEstimation, int i) {
                 final var leftPoint = leftPoints.get(i);
                 final var rightPoint = rightPoints.get(i);
                 return residual(currentEstimation, leftPoint, rightPoint);
             }
 
             @Override
             public boolean isReady() {
                 return RANSACFundamentalMatrixRobustEstimator.this.isReady();
             }
 
             @Override
             public void onEstimateStart(final RobustEstimator<FundamentalMatrix> estimator) {
                 if (listener != null) {
                     listener.onEstimateStart(RANSACFundamentalMatrixRobustEstimator.this);
                 }
             }
 
             @Override
             public void onEstimateEnd(final RobustEstimator<FundamentalMatrix> estimator) {
                 if (listener != null) {
                     listener.onEstimateEnd(RANSACFundamentalMatrixRobustEstimator.this);
                 }
             }
 
             @Override
             public void onEstimateNextIteration(
                     final RobustEstimator<FundamentalMatrix> estimator, final int iteration) {
                 if (listener != null) {
                     listener.onEstimateNextIteration(RANSACFundamentalMatrixRobustEstimator.this, iteration);
                 }
             }
 
             @Override
             public void onEstimateProgressChange(
                     final RobustEstimator<FundamentalMatrix> estimator, final float progress) {
                 if (listener != null) {
                     listener.onEstimateProgressChange(RANSACFundamentalMatrixRobustEstimator.this, progress);
                 }
             }
         });
 
         try {
             locked = true;
             inliersData = null;
             innerEstimator.setComputeAndKeepInliersEnabled(computeAndKeepInliers || refineResult);
             innerEstimator.setComputeAndKeepResidualsEnabled(computeAndKeepResiduals || refineResult);
             innerEstimator.setConfidence(confidence);
             innerEstimator.setMaxIterations(maxIterations);
             innerEstimator.setProgressDelta(progressDelta);
             final var result = innerEstimator.estimate();
             inliersData = innerEstimator.getInliersData();
             return attemptRefine(result);
         } catch (final com.irurueta.numerical.LockedException e) {
             throw new LockedException(e);
         } catch (final com.irurueta.numerical.NotReadyException e) {
             throw new NotReadyException(e);
         } finally {
             locked = false;
         }
     }
 
     /**
      * Returns method being used for robust estimation.
      *
      * @return method being used for robust estimation.
      */
     @Override
     public RobustEstimatorMethod getMethod() {
         return RobustEstimatorMethod.RANSAC;
     }
 
     /**
      * Gets standard deviation used for Levenberg-Marquardt fitting during
      * refinement.
      * Returned value gives an indication of how much variance each residual
      * has.
      * Typically, this value is related to the threshold used on each robust
      * estimation, since residuals of found inliers are within the range of
      * such threshold.
      *
      * @return standard deviation used for refinement.
      */
     @Override
     protected double getRefinementStandardDeviation() {
         return threshold;
     }
 }