package ch.epfl.alpano;

import java.io.File;

import javax.imageio.ImageIO;

import ch.epfl.alpano.dem.ContinuousElevationModel;
import ch.epfl.alpano.dem.DiscreteElevationModel;
import ch.epfl.alpano.dem.HgtDiscreteElevationModel;

import static java.lang.Math.max;
import static java.lang.Math.min;
import static java.lang.Math.toRadians;

import java.awt.image.BufferedImage;

final class DrawPanorama {
  final static File HGT_FILE = new File("HGT"+File.separatorChar+"N46E007.hgt");

  final static int IMAGE_WIDTH = 500;
  final static int IMAGE_HEIGHT = 200;

  final static double ORIGIN_LON = toRadians(7.65);
  final static double ORIGIN_LAT = toRadians(46.73);
  final static int ELEVATION = 600;
  final static double CENTER_AZIMUTH = toRadians(180);
  final static double HORIZONTAL_FOV = toRadians(60);
  final static int MAX_DISTANCE = 100_000;

  final static PanoramaParameters PARAMS =
    new PanoramaParameters(new GeoPoint(ORIGIN_LON,
                                        ORIGIN_LAT),
                           ELEVATION,
                           CENTER_AZIMUTH,
                           HORIZONTAL_FOV,
                           MAX_DISTANCE,
                           IMAGE_WIDTH,
                           IMAGE_HEIGHT);

  public static void main(String[] as) throws Exception {
    try (DiscreteElevationModel dDEM =
         new HgtDiscreteElevationModel(HGT_FILE)) {
      ContinuousElevationModel cDEM =
        new ContinuousElevationModel(dDEM);
      Panorama p = new PanoramaComputer(cDEM)
        .computePanorama(PARAMS);

      BufferedImage i =
        new BufferedImage(IMAGE_WIDTH,
                          IMAGE_HEIGHT,
                          BufferedImage.TYPE_INT_RGB);

      for (int x = 0; x < IMAGE_WIDTH; ++x) {
        for (int y = 0; y < IMAGE_HEIGHT; ++y) {
          float d = p.distanceAt(x, y);
          int c = (d == Float.POSITIVE_INFINITY)
            ? 0x87_CE_EB
            : gray((d - 2_000) / 15_000);
          i.setRGB(x, y, c);
        }
      }

      ImageIO.write(i, "png", new File("tests/ch/epfl/alpano/niesen.png"));
    }
  }
  private static int gray(double v) {
      double clampedV = max(0, min(v, 1));
      int gray = (int) (255.9999 * clampedV);
      return (gray << 16) | (gray << 8) | gray;
  }
}