import com.google.common.collect.ImmutableSet;
import com.google.common.math.StatsAccumulator;
import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.util.Set;
import javax.imageio.ImageIO;
import javax.imageio.ImageReadParam;
import javax.imageio.ImageReader;
import javax.imageio.stream.ImageInputStream;
import javax.swing.Icon;
import javax.swing.ImageIcon;

// Note: Before running this benchmark, be sure to disable Intel SpeedStep in the BIOS.
public class SVGBenchmark {
  private static final Set<String> ICON_NAMES = ImmutableSet.of(
      "warning", "arrow_down", "arrow_up", "cursoredit_data", "cursoredit_formula",
      "cursoredit_label", "cursoredit_none", "database", "field_collapsed_join",
      "field_new_primitive_data", "field_new_primitive_formula", "field_new_relation",
      "field_primitive_data", "field_primitive_formula", "field_relation_noinst", "field_relation",
      "fields_relation_only", "filter_range", "folder_closed", "folder_open", "general_minus",
      "general_plus", "project_perspective", "project_table", "project_logo", "toolbar_edit",
      "toolbar_redo", "toolbar_refresh", "toolbar_stop", "toolbar_undo", "toolbar_zoom_in",
      "toolbar_zoom_original", "toolbar_zoom_out");

  private static final ImageReader PNG_READER;

  static {
    ImageIO.setUseCache(false);
    PNG_READER = ImageIO.getImageReadersByMIMEType("image/png").next();
  }

  private static URL getResourceURL(String iconName, boolean svg) {
    String path = "com/somepackage/project/icons/" + iconName + "." + (svg ? "svg" : "png");
    URL ret = SVGBenchmark.class.getClassLoader().getResource(path);
    if (ret == null)
      throw new RuntimeException("Resource not found");
    return ret;
  }

  private static void loadAndPaintOneIcon(String iconName, boolean svg) {
    final URL url = getResourceURL(iconName, svg);
    final Icon icon;
    if (svg) {
      try {
        icon = SVGIcon.load(url);
      } catch (IOException e) {
        throw new RuntimeException(e);
      }
    } else {
      Image image;
      // Load in the same way as ImageUtilities opens PNG files.
      try (ImageInputStream stream = ImageIO.createImageInputStream(url.openStream())) {
        ImageReadParam param = PNG_READER.getDefaultReadParam();
        PNG_READER.setInput(stream, true, true);
        image = PNG_READER.read(0, param);
      } catch (IOException e) {
          throw new RuntimeException(e);
      }
      icon = new ImageIcon(image);
    }
    BufferedImage img = new BufferedImage(
        icon.getIconWidth(), icon.getIconHeight(), BufferedImage.TYPE_INT_ARGB_PRE);
    Graphics2D g = img.createGraphics();
    // Assume the Component parameter isn't used by the underlying implementation.
    icon.paintIcon(null, g, 0, 0);
    g.dispose();
  }

  private static void measureOneSample(StatsAccumulator svgStats, StatsAccumulator pngStats) {
    boolean order[] = Math.random() < 0.5
        ? new boolean[] {false, true}
        : new boolean[] {true, false};
    //boolean order[] = new boolean[] {true};
    for (boolean svg : order) {
      long bef = System.nanoTime();
      for (String iconName : ICON_NAMES)
        loadAndPaintOneIcon(iconName, svg);
      long aft = System.nanoTime();
      (svg ? svgStats : pngStats).add(aft - bef);
    }
  }
  private static void printStats(StatsAccumulator stats, boolean svg) {
    double mean = (stats.count() == 0) ? Double.NaN : stats.mean();
    double standardError = stats.count() < 2 ? Double.NaN :
        (stats.sampleStandardDeviation() / Math.sqrt(stats.count()));
    double standardErrorPercentage = 100 * (standardError / mean);
    double meanPerIcon = mean / ICON_NAMES.size();
    System.out.printf("Loading and painting %s took %.2f microseconds per icon +/- %.02f%%\n",
        svg ? "SVG" : "PNG", (meanPerIcon / 1000.0), standardErrorPercentage);
  }

  private static void measure() {
    StatsAccumulator svgStats = new StatsAccumulator();
    StatsAccumulator pngStats = new StatsAccumulator();
    // Warmup.
    for (int i = 0; i < 300; i++)
      measureOneSample(svgStats, pngStats);
    // Throw away the warmup stats and start fresh.
    svgStats = new StatsAccumulator();
    pngStats = new StatsAccumulator();
    // Now do the actual measurements.
    for (int i = 0; i < 500; i++)
      measureOneSample(svgStats, pngStats);
    printStats(svgStats, true);
    printStats(pngStats, false);
  }

  private static final void printFileSizeStats(boolean svg) {
    StatsAccumulator sizeStats = new StatsAccumulator();
    for (String iconName : ICON_NAMES) {
      URL url = getResourceURL(iconName, svg);
      try (InputStream is = url.openStream()) {
        sizeStats.add(is.readAllBytes().length);
      } catch (IOException e) {
        throw new RuntimeException(e);
      }
    }
    System.out.println("Average size of " + (svg ? "SVG" : "PNG") + " icon file is " +
        Math.round(sizeStats.mean()) + " bytes (max was " + (int) sizeStats.max() + " bytes)");
  }

  public static final void main(String args[]) {
    printFileSizeStats(true);
    printFileSizeStats(false);
    measure();
  }
}