/*
    * Licensed to the Apache Software Foundation (ASF) under one or more
    * contributor license agreements.  See the NOTICE file distributed with
    * this work for additional information regarding copyright ownership.
    * The ASF licenses this file to You 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 org.apache.commons.imaging.formats.tiff.photometricinterpreters.floatingpoint;
  
  import java.awt.Color;
  import java.io.IOException;
  import java.util.ArrayList;
  import java.util.Comparator;
  import java.util.List;
  
  import org.apache.commons.imaging.ImagingException;
  import org.apache.commons.imaging.common.ImageBuilder;
  import org.apache.commons.imaging.formats.tiff.photometricinterpreters.PhotometricInterpreter;
  
  /**
   * Implements a custom photometric interpreter that can be supplied by applications in order to render Java images from real-valued TIFF data products. Most
   * TIFF files include a specification for a "photometric interpreter" that implements logic for transforming the raw data in a TIFF file to a rendered image.
   * But the TIFF standard does not include a specification for a photometric interpreter that can be used for rendering floating-point data. TIFF files are
   * sometimes used to specify non-image data as a floating-point raster. This approach is particularly common in GeoTIFF files (TIFF files that contain tags for
   * supporting geospatial reference metadata for Geographic Information Systems). Because of the limits of the stock photometric interpreters, most
   * floating-point TIFF files to not produce useful images.
   * <p>
   * This class allows an Apache Commons implementation to construct and specify a custom photometric interpreter when reading from a TIFF file. Applications may
   * supply their own palette that maps real-valued data to specified colors.
   * <p>
   * This class provides two constructors:
   * <ol>
   * <li>A simple constructor to support gray scales</li>
   * <li>A constructor to support a color palette (with potential interpolation)</li>
   * </ol>
   * <p>
   * To use this class, an application must access the TIFF file using the low-level, TIFF-specific API provided by the Apache Commons Imaging library.
   */
  public class PhotometricInterpreterFloat extends PhotometricInterpreter {
  
      ArrayList<PaletteEntry> rangePaletteEntries = new ArrayList<>();
      ArrayList<PaletteEntry> singleValuePaletteEntries = new ArrayList<>();
  
      float minFound = Float.POSITIVE_INFINITY;
      float maxFound = Float.NEGATIVE_INFINITY;
      int xMin;
      int yMin;
      int xMax;
      int yMax;
  
      double sumFound;
      int nFound;
  
      /**
       * Constructs a photometric interpreter that will produce a gray scale linearly distributed across the RGB color space for values in the range valueBlack to
       * valueWhite. Note that the two values may be given in either ascending order or descending order, but they must not be equal. Infinite values will not
       * result in proper numerical computations.
       *
       * @param valueBlack the value associated with the dark side of the gray scale
       * @param valueWhite the value associated with the light side of the gray scale
       */
      public PhotometricInterpreterFloat(final float valueBlack, final float valueWhite) {
          // The abstract base class requires that the following fields
          // be set in the constructor:
          // samplesPerPixel (int)
          // bits per sample (array of type int[samplesPerPixel])
          // predictor (int, not used by this class)
          // width (int)
          // height (int)
          super(1, new int[] { 32 }, // bits per sample
                  0, // not used by this class
                  32, // pro forma width value
                  32 // pro format height value
          );
  
          if (valueWhite > valueBlack) {
              final PaletteEntryForRange entry = new PaletteEntryForRange(valueBlack, valueWhite, Color.black, Color.white);
              rangePaletteEntries.add(entry);
          } else {
              final PaletteEntryForRange entry = new PaletteEntryForRange(valueWhite, valueBlack, Color.white, Color.black);
              rangePaletteEntries.add(entry);
          }
      }
  
      /**
       * Constructs a photometric interpreter that will use the specified palette to assign colors to floating-point values.
       * <p>
       * Although there is no prohibition against using palette entries with overlapping ranges, the behavior of such specifications is undefined and subject to
       * change in the future. Therefore, it is not recommended. The exception in the use of single-value palette entries which may be used to override the
       * specifications for ranges.
      *
      * @param paletteEntries a valid, non-empty list of palette entries
      */
     public PhotometricInterpreterFloat(final List<PaletteEntry> paletteEntries) {
         // The abstract base class requires that the following fields
         // be set in the constructor:
         // samplesPerPixel (int)
         // bits per sample (array of type int[samplesPerPixel])
         // predictor (int, not used by this class)
         // width (int)
         // height (int)
         super(1, new int[] { 32 }, // bits per sample
                 0, // not used by this class
                 32, // pro forma width value
                 32 // pro format height value
         );
 
         if (paletteEntries == null || paletteEntries.isEmpty()) {
             throw new IllegalArgumentException("Palette entries list must be non-null and non-empty");
         }
 
         for (final PaletteEntry entry : paletteEntries) {
             if (entry.coversSingleEntry()) {
                 singleValuePaletteEntries.add(entry);
             } else {
                 rangePaletteEntries.add(entry);
             }
         }
 
         final Comparator<PaletteEntry> comparator = (o1, o2) -> {
             if (o1.getLowerBound() == o2.getLowerBound()) {
                 return Double.compare(o1.getUpperBound(), o2.getUpperBound());
             }
             return Double.compare(o1.getLowerBound(), o2.getLowerBound());
         };
 
         rangePaletteEntries.sort(comparator);
         singleValuePaletteEntries.sort(comparator);
     }
 
     /**
      * Gets the maximum value found while rendering the image
      *
      * @return if data was processed, a valid value; otherwise, Negative Infinity
      */
     public float getMaxFound() {
         return maxFound;
     }
 
     /**
      * Gets the coordinates (x,y) at which the maximum value was identified during processing
      *
      * @return a valid array of length 2.
      */
     public int[] getMaxXY() {
         return new int[] { xMax, yMax };
     }
 
     /**
      * Gets the mean of the values found while processing
      *
      * @return if data was processed, a valid mean value; otherwise, a zero.
      */
     public float getMeanFound() {
         if (nFound == 0) {
             return 0;
         }
         return (float) (sumFound / nFound);
     }
 
     /**
      * Gets the minimum value found while rendering the image
      *
      * @return if data was processed, a valid value; otherwise, Positive Infinity
      */
     public float getMinFound() {
         return minFound;
     }
 
     /**
      * Gets the coordinates (x,y) at which the minimum value was identified during processing
      *
      * @return a valid array of length 2.
      */
     public int[] getMinXY() {
         return new int[] { xMin, yMin };
     }
 
     @Override
     public void interpretPixel(final ImageBuilder imageBuilder, final int[] samples, final int x, final int y) throws ImagingException, IOException {
 
         final float f = Float.intBitsToFloat(samples[0]);
         // in the event of NaN, do not store entry in the image builder.
 
         // only the single bound palette entries support NaN
         for (final PaletteEntry entry : singleValuePaletteEntries) {
             if (entry.isCovered(f)) {
                 final int p = entry.getArgb(f);
                 imageBuilder.setRgb(x, y, p);
                 return;
             }
         }
 
         if (Float.isNaN(f)) {
             // if logic reaches here, there is no definition
             // for a NaN.
             return;
         }
         if (f < minFound) {
             minFound = f;
             xMin = x;
             yMin = y;
         }
         if (f > maxFound) {
             maxFound = f;
             xMax = x;
             yMax = y;
         }
         nFound++;
         sumFound += f;
 
         for (final PaletteEntry entry : singleValuePaletteEntries) {
             if (entry.isCovered(f)) {
                 final int p = entry.getArgb(f);
                 imageBuilder.setRgb(x, y, p);
                 return;
             }
         }
 
         for (final PaletteEntry entry : rangePaletteEntries) {
             if (entry.isCovered(f)) {
                 final int p = entry.getArgb(f);
                 imageBuilder.setRgb(x, y, p);
                 break;
             }
         }
     }
 
     /**
      * Provides a method for mapping a pixel value to an integer (ARGB) value. This method is not defined for the standard photometric interpreters and is
      * provided as a convenience to applications that are processing data outside the standard TIFF image-reading modules.
      *
      * @param f the floating point value to be mapped to an ARGB value
      * @return a valid ARGB value, or zero if no palette specification covers the input value.
      */
     public int mapValueToArgb(final float f) {
 
         // The single-value palette entries can accept a Float.NaN as
         // a target while the range-of-values entries cannot. So
         // check the single-values before testing for Float.isNaN()
         // because NaN may have special treatment.
         for (final PaletteEntry entry : singleValuePaletteEntries) {
             if (entry.isCovered(f)) {
                 return entry.getArgb(f);
             }
         }
 
         if (Float.isNaN(f)) {
             // if logic reaches here, there is no definition
             // for a NaN.
             return 0;
         }
 
         for (final PaletteEntry entry : rangePaletteEntries) {
             if (entry.isCovered(f)) {
                 return entry.getArgb(f);
             }
         }
         return 0;
     }
 
 }