package de.lmu.ifi.dbs.elki.application.geo;

/*
 This file is part of ELKI:
 Environment for Developing KDD-Applications Supported by Index-Structures

 Copyright (C) 2012
 Ludwig-Maximilians-Universität München
 Lehr- und Forschungseinheit für Datenbanksysteme
 ELKI Development Team

 This program is free software: you can redistribute it and/or modify
 it under the terms of the GNU Affero General Public License as published by
 the Free Software Foundation, either version 3 of the License, or
 (at your option) any later version.

 This program is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 GNU Affero General Public License for more details.

 You should have received a copy of the GNU Affero General Public License
 along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;

import javax.imageio.ImageIO;

import de.lmu.ifi.dbs.elki.application.AbstractApplication;
import de.lmu.ifi.dbs.elki.data.DoubleVector;
import de.lmu.ifi.dbs.elki.data.ModifiableHyperBoundingBox;
import de.lmu.ifi.dbs.elki.logging.Logging;
import de.lmu.ifi.dbs.elki.math.GeoUtil;
import de.lmu.ifi.dbs.elki.utilities.exceptions.AbortException;
import de.lmu.ifi.dbs.elki.utilities.exceptions.UnableToComplyException;
import de.lmu.ifi.dbs.elki.utilities.optionhandling.OptionID;
import de.lmu.ifi.dbs.elki.utilities.optionhandling.constraints.GreaterEqualConstraint;
import de.lmu.ifi.dbs.elki.utilities.optionhandling.parameterization.Parameterization;
import de.lmu.ifi.dbs.elki.utilities.optionhandling.parameters.EnumParameter;
import de.lmu.ifi.dbs.elki.utilities.optionhandling.parameters.IntParameter;

/**
 * Visualization function for Cross-track distance function
 * 
 * TODO: make resolution configurable.
 * 
 * TODO: make origin point / rectangle configurable.
 * 
 * @author Niels Dörre
 * @author Erich Schubert
 */
public class VisualizeGeodesicDistances extends AbstractApplication {
  /**
   * Get a logger for this class.
   */
  private final static Logging LOG = Logging.getLogger(VisualizeGeodesicDistances.class);

  /**
   * Visualization mode.
   * 
   * @author Erich Schubert
   * 
   * @apiviz.exclude
   */
  public static enum Mode {
    /** Cross track distance */
    CTD,
    /** Along track distance */
    ATD,
    /** Mindist */
    MINDIST
  }

  /**
   * Holds the file to print results to.
   */
  private File out;

  /**
   * Image size.
   */
  final int width = 2000, height = 1000;

  /**
   * Number of steps for shades.
   */
  protected int steps = 10;

  /**
   * Visualization mode
   */
  private Mode mode = Mode.CTD;

  /**
   * Constructor.
   * 
   * @param out Output filename
   * @param steps Number of steps in the color map
   * @param mode Visualization mode
   */
  public VisualizeGeodesicDistances(File out, int steps, Mode mode) {
    super();
    this.out = out;
    this.steps = steps;
    this.mode = mode;
  }

  @Override
  public void run() throws UnableToComplyException {
    // Format: Latitude, Longitude
    // München:
    DoubleVector stap = new DoubleVector(new double[] { 48.133333, 11.566667 });
    // New York:
    DoubleVector endp = new DoubleVector(new double[] { 40.712778, -74.005833 });
    // Bavaria:
    ModifiableHyperBoundingBox bb = new ModifiableHyperBoundingBox(new double[] { 47.27011150, 8.97634970 }, new double[] { 50.56471420, 13.83963710 });
    // Bavaria slice on lat
    // bb = new ModifiableHyperBoundingBox(new double[] { 47.27011150, -80 }, //
    // new double[] { 50.56471420, 80 });
    // Bavaria slice on lon
    // bb = new ModifiableHyperBoundingBox(new double[] { -10, 8.97634970 }, //
    // new double[] { 50, 13.83963710 });

    BufferedImage img = new BufferedImage(width, height, BufferedImage.TYPE_INT_ARGB);

    final double max;
    switch(mode) {
    case ATD:
      // Currently half the circumference - we're missing the sign
      max = GeoUtil.EARTH_RADIUS * Math.PI;
      break;
    case CTD:
      // Quarter (!) the circumference is the maximum CTD!
      max = .5 * GeoUtil.EARTH_RADIUS * Math.PI;
      break;
    case MINDIST:
      // Half the circumference
      max = GeoUtil.EARTH_RADIUS * Math.PI;
      break;
    default:
      throw new AbortException("Invalid mode: " + mode);
    }
    // Red: left off-course, green: right off-course
    int red = 0xffff0000;
    int green = 0xff00ff00;

    for (int x = 0; x < width; x++) {
      final double lon = x * 360. / width - 180.;
      for (int y = 0; y < height; y++) {
        final double lat = y * -180. / height + 90.;
        switch(mode) {
        case ATD: {
          final double atd = GeoUtil.alongTrackDistance(stap.doubleValue(0), stap.doubleValue(1), endp.doubleValue(0), endp.doubleValue(1), lat, lon);
          if (atd < 0) {
            img.setRGB(x, y, colorMultiply(red, -atd / max, false));
          } else {
            img.setRGB(x, y, colorMultiply(green, atd / max, false));
          }
          break;
        }
        case CTD: {
          final double ctd = GeoUtil.crossTrackDistance(stap.doubleValue(0), stap.doubleValue(1), endp.doubleValue(0), endp.doubleValue(1), lat, lon);
          if (ctd < 0) {
            img.setRGB(x, y, colorMultiply(red, -ctd / max, false));
          } else {
            img.setRGB(x, y, colorMultiply(green, ctd / max, false));
          }
          break;
        }
        case MINDIST: {
          final double dist = GeoUtil.latlngMinDistDeg(lat, lon, bb.getMin(0), bb.getMin(1), bb.getMax(0), bb.getMax(1));
          if (dist < 0) {
            img.setRGB(x, y, colorMultiply(red, -dist / max, true));
          } else {
            img.setRGB(x, y, colorMultiply(green, dist / max, true));
          }
          break;
        }
        }
      }
    }

    try {
      ImageIO.write(img, "png", out);
    } catch (IOException e) {
      LOG.exception(e);
    }
  }

  private int colorMultiply(int col, double reldist, boolean ceil) {
    if (steps > 0) {
      if (!ceil) {
        reldist = Math.round(reldist * steps) * 1. / steps;
      } else {
        reldist = Math.ceil(reldist * steps) / steps;
      }
    }
    int a = (col >> 24) & 0xFF, r = (col >> 16) & 0xFF, g = (col >> 8) & 0xFF, b = (col) & 0xFF;
    a = (int) (a * Math.sqrt(reldist)) & 0xFF;
    return a << 24 | r << 16 | g << 8 | b;
  }

  /**
   * Main method for application.
   * 
   * @param args Parameters
   */
  public static void main(String[] args) {
    VisualizeGeodesicDistances.runCLIApplication(VisualizeGeodesicDistances.class, args);
  }

  /**
   * Parameterization class.
   * 
   * @author Erich Schubert
   * 
   * @apiviz.exclude
   */
  public static class Parameterizer extends AbstractApplication.Parameterizer {
    /**
     * Number of steps in the distance map.
     */
    public static final OptionID STEPS_ID = new OptionID("ctdvis.steps", "Number of steps for the distance map.");

    /**
     * Visualization mode.
     */
    public static final OptionID MODE_ID = new OptionID("ctdvis.mode", "Visualization mode.");

    /**
     * Holds the file to print results to.
     */
    protected File out = null;

    /**
     * Number of steps in the color map
     */
    protected int steps = 0;

    /**
     * Visualization mode
     */
    protected Mode mode = Mode.CTD;

    @Override
    protected void makeOptions(Parameterization config) {
      super.makeOptions(config);
      out = super.getParameterOutputFile(config, "Output image file");
      IntParameter stepsP = new IntParameter(STEPS_ID);
      stepsP.setOptional(true);
      stepsP.addConstraint(new GreaterEqualConstraint(0));
      if (config.grab(stepsP)) {
        steps = stepsP.intValue();
      }
      EnumParameter<Mode> modeP = new EnumParameter<Mode>(MODE_ID, Mode.class, Mode.CTD);
      if (config.grab(modeP)) {
        mode = modeP.getValue();
      }
    }

    @Override
    protected VisualizeGeodesicDistances makeInstance() {
      return new VisualizeGeodesicDistances(out, steps, mode);
    }
  }
}