import java.io.File;
import java.io.IOException;
import java.net.URL;
import javafx.application.Application;
import javafx.beans.value.ChangeListener;
import javafx.beans.value.ObservableValue;
import javafx.event.ActionEvent;
import javafx.event.EventHandler;
import javafx.scene.Group;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.Label;
import javafx.scene.control.ScrollPane;
import javafx.scene.control.Slider;
import javafx.scene.image.Image;
import javafx.scene.image.ImageView;
import javafx.scene.image.PixelWriter;
import javafx.scene.image.WritableImage;
import javafx.scene.paint.Color;
import javafx.scene.transform.Scale;
import javafx.stage.FileChooser;
import javafx.stage.Stage;

public class ManualMipmapTest extends Application {
    static final int NUM_SCALED=10;
    static FileChooser.ExtensionFilter imgfilter =
        new FileChooser.ExtensionFilter("Img", ".jpg", ".gif", ".jpeg", ".png");

    Image scaledImages[] = new Image[NUM_SCALED + 1];
    ImageView normalView;
    ImageView mipmapView;
    ScrollPane normalPane;
    ScrollPane mipmapPane;
    Label normalLabel;
    Label mipmapLabel;
    Button loadButton;
    Slider scaleSlider;
    Label scaleLabel;
    double scale = 1.0;
    Scene scene;
    Stage stage;

    @Override
    public void start(Stage stage) {
        normalView = new ImageView();
        mipmapView = new ImageView();

        loadButton = new Button("Load Image");
        loadButton.addEventHandler(ActionEvent.ACTION, new EventHandler<ActionEvent>() {
            @Override
            public void handle(ActionEvent event) {
                FileChooser dlg = new FileChooser();
                dlg.setSelectedExtensionFilter(imgfilter);
                File file = dlg.showOpenDialog(scene.getWindow());
                Image img = new Image(file.toURI().toString());
                setImage(img);
            }
        });

        scaleSlider = new Slider(0.0, 1.0, 1.0);
        scaleSlider.setShowTickLabels(true);
        scaleSlider.valueProperty().addListener(new ChangeListener<Number>() {
            @Override
            public void changed(ObservableValue<? extends Number> observable,
                                Number oldValue, Number newValue)
            {
                setScale(newValue.doubleValue());
            }
        });
        scaleLabel = new Label("Scale = 1.0");

        normalPane = new ScrollPane(normalView);
        mipmapPane = new ScrollPane(mipmapView);
        normalPane.setPrefSize(300, 300);
        mipmapPane.setPrefSize(300, 300);

        normalLabel = new Label("Normal Scaling");
        mipmapLabel = new Label("Mipmap Scaling");

        mipmapPane.setTranslateX(300);
        normalLabel.setTranslateX(75);
        normalLabel.setTranslateY(320);
        mipmapLabel.setTranslateX(375);
        mipmapLabel.setTranslateY(320);
        loadButton.setTranslateX(0);
        loadButton.setTranslateY(350);
        scaleSlider.setTranslateX(150);
        scaleSlider.setTranslateY(350);
        scaleLabel.setTranslateX(300);
        scaleLabel.setTranslateY(350);

        Group root = new Group(normalPane, mipmapPane,
                               normalLabel, mipmapLabel,
                               loadButton, scaleSlider, scaleLabel);
        scene = new Scene(root);
        stage.setScene(scene);
        this.stage = stage;

        stage.show();

        setSyntheticImage();
    }

    boolean isOn(int v) {
        if ((v & 7) == 0) return true;
        if (((v+1) & 31) < 2) return true;
        return (((v+2) & 127) < 4);
    }

    void setSyntheticImage() {
        int dim = 0xffe;
        WritableImage wimg = new WritableImage(dim, dim);
        PixelWriter pw = wimg.getPixelWriter();
        for (int y = 0; y < dim; y++) {
            for (int x = 0; x < dim; x++) {
                pw.setColor(x, y, isOn(x) || isOn(y) ? Color.BLACK : Color.WHITE);
            }
        }
        setImage(wimg);
    }

    void setImage(Image img) {
        scaledImages[0] = img;
        ImageView tmpview = new ImageView();
        tmpview.setScaleX(0.5);
        tmpview.setScaleY(0.5);
        for (int i = 1; i <= NUM_SCALED; i++) {
            tmpview.setImage(scaledImages[i-1]);
            scaledImages[i] = tmpview.snapshot(null, null);
        }
        setScale(scale);
    }

    void setScale(double scale) {
        this.scale = scale;
        scaleLabel.setText("Scale = "+scale);
        System.out.print("scaling to "+scale);
        normalView.setImage(scaledImages[0]);
        normalView.getTransforms().setAll(new Scale(scale, scale));
        int i = 0;
        while (i < NUM_SCALED) {
            if (scale > 0.5) break;
            scale *= 2.0;
            i++;
        }
        System.out.println(" using image "+i+" with scale of "+scale);
        mipmapView.setImage(scaledImages[i]);
        mipmapView.getTransforms().setAll(new Scale(scale, scale));
    }
}