package ch.epfl.alpano.dem;

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

import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;

import javax.imageio.ImageIO;
import ch.epfl.alpano.GeoPoint;
import static java.lang.Math.toRadians;

final class DrawHgtDEM {
    final static File HGT_FILE = new File("HGT"+File.separatorChar+"N46E006.hgt");
    final static double ORIGIN_LON = toRadians(6.25);
    final static double ORIGIN_LAT = toRadians(46.25);
    final static double WIDTH = toRadians(0.5);
    final static int IMAGE_SIZE = 300;
    final static double MIN_ELEVATION = 200;
    final static double MAX_ELEVATION = 1_500;

    public static void main(String[] as) throws Exception {
      DiscreteElevationModel dDEM =
        new HgtDiscreteElevationModel(HGT_FILE);
      ContinuousElevationModel cDEM =
        new ContinuousElevationModel(dDEM);

      double step = WIDTH / (IMAGE_SIZE - 1);
      BufferedImage i = new BufferedImage(IMAGE_SIZE,
                                          IMAGE_SIZE,
                                          BufferedImage.TYPE_INT_RGB);
      for (int x = 0; x < IMAGE_SIZE; ++x) {
        double lon = ORIGIN_LON + x * step;
        for (int y = 0; y < IMAGE_SIZE; ++y) {
          double lat = ORIGIN_LAT + y * step;
          GeoPoint p = new GeoPoint(lon, lat);
          double el =
            (cDEM.elevationAt(p) - MIN_ELEVATION)
            / (MAX_ELEVATION - MIN_ELEVATION);
          i.setRGB(x, IMAGE_SIZE - 1 - y, gray(el));
        }
      }
      dDEM.close();


        ImageIO.write(i, "png", new File("tests/ch/epfl/alpano/dem/dem.png"));
    }
    
    public static  void drawDem(ContinuousElevationModel cDem){
        
        double step = WIDTH / (IMAGE_SIZE - 1);
        BufferedImage i = new BufferedImage(IMAGE_SIZE,
                                            IMAGE_SIZE,
                                            BufferedImage.TYPE_INT_RGB);
        for (int x = 0; x < IMAGE_SIZE; ++x) {
          double lon = ORIGIN_LON + x * step;
          for (int y = 0; y < IMAGE_SIZE; ++y) {
            double lat = ORIGIN_LAT + y * step;
            GeoPoint p = new GeoPoint(lon, lat);
            double el =
              (cDem.elevationAt(p) - MIN_ELEVATION)
              / (MAX_ELEVATION - MIN_ELEVATION);
            i.setRGB(x, IMAGE_SIZE - 1 - y, gray(el));
          }
        }
       


          try {
            ImageIO.write(i, "png", new File("tests/ch/epfl/alpano/dem/dem.png"));
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    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;
    }

}