package edu.hws.eck.mdbfx;

import javafx.application.Application;
import javafx.geometry.Rectangle2D;
import javafx.stage.Stage;
import javafx.scene.Scene;
import javafx.stage.Screen;
import java.util.prefs.*;

/**
 * This class is used to run the Mandelbrot viewer program. 
 * The start method shows a window containing a MandelbrotPane.
 * This class also works with "preferences."  When the window is closed,
 * an event handler saves the current window size and location to
 * the user's Java preferences.  It also saves the most recently selected
 * directory where the user saved or opened a file.  These values are restored 
 * from the user's preferences the next time the program starts.
 */
public class Main extends Application {
    
    /* The Mandelbrot program defined in package edu.hws.edu.mdbfx is a JavFX
     * port of an older Swing version of the program.  Some things could have
     * been done in a more JavaFX-like way, and since it is a fairly complex
     * program, it is likely that the port has introduced a few unnoticed bugs.
     * For a nicer Mandelbrot program in Java, see 
     *     https://math.hws.edu/eck/js/mandelbrot/java/MB-java.html
     * A pretty nice JavaScript version is at 
     *     https://math.hws.edu/eck/js/mandelbrot/MB.html
     */

    public static void main(String[] args) {
        launch(args);
    }

    /**
     * Open a window containing a MandelbrotPane, and apply preferences
     * from previous runs if possible.
     */
    public void start(Stage stage) {
        MandelbrotPane content = new MandelbrotPane();
        stage.setScene( new Scene(content) );
        stage.setOnHidden( e -> {
            content.closing();
            savePreferences(stage,content);
        } );
        applyPreferences(stage, content);
        stage.setMinHeight(240);
        stage.setMinWidth(240);
        stage.setTitle(I18n.tr("frame.title"));
        stage.show();
    }
    
    
    /**
     * Called when the program ends to try to save window bounds and current
     * directory to user's preferences, so they can be restored the next
     * time the program is run.  Since this is not a critical function, errors
     * are ignored.  If an error occurs, the data simply won't be saved.
     */
    private static void savePreferences(Stage window, MandelbrotPane content) {
        try {
            String pathName = "/edu/hws/eck/mdbfx";
               // The pathname uniquely identifies this program.  (It is unique
               // because it comes from the package name, which should not be used
               // for any other program under Java's package naming guidelines.
            Preferences root = Preferences.userRoot();
            Preferences node = root.node(pathName);
               // This "node" holds the preferences associated with the pathName.
               // Preferences take the form of key/value pairs, with put() and
               // get() operations for changing/reading values.
            String boundsString = (int)window.getX() + "," + (int)window.getY() + "," 
                                        + (int)window.getWidth() + "," + (int)window.getHeight();
            node.put("mandelbrot.window.bounds", boundsString);  
            Menus menus = content.getMenus();
            String currentDir = menus.getSelectedDirectoryInFileChooser();
            if (currentDir != null)
                node.put("mandelbrot.filechooser.directory", currentDir); 
        }
        catch (Exception e) {
        }
    }
    
    
    /**
     * This method is called when the program starts to read and apply the
     * preferences that were saved the last time the program ran.  Since
     * this is not a critical function, errors are ignored.  If an error
     * occurs, preferences will simply not be restored.
     */
    private static void applyPreferences(Stage window, MandelbrotPane content) {
        try {
            String pathName = "/edu/hws/eck/mdbfx";  // Identifies prefs for this program.
            Preferences root = Preferences.userRoot();
            if (! root.nodeExists(pathName) )
                return;  // There are no saved prefs for this program yet.
            Preferences node = root.node(pathName);
            String boundsString = node.get("mandelbrot.window.bounds",null);
            if (boundsString != null) {
                   // Try to restore window bounds, ignoring any error.
                String[] bounds = boundsString.split(",");
                try {  // set window bounds, after running some sanity checks
                    double x = Integer.parseInt(bounds[0]);
                    double y = Integer.parseInt(bounds[1]);
                    double w = Integer.parseInt(bounds[2]);
                    double h = Integer.parseInt(bounds[3]);
                    if (w <= 0 || h <= 0 || w > 5000 || h > 5000)
                        throw new NumberFormatException();  // unreasonable values.
                    Rectangle2D screen = Screen.getPrimary().getVisualBounds();
                    if (x < screen.getMinX() || x > screen.getMaxX() - 300)
                        x = screen.getMinX() + 20;
                    if (y < screen.getMinY() || y > screen.getMaxY() - 200)
                        y = screen.getMinY() + 20;
                    if (w < 300)
                        w = 300;
                    else if (x + w > screen.getMaxX())
                        w = screen.getMaxX() - x;
                    if (h < 200)
                        h = 200;
                    else if (y + h > screen.getMaxY())
                        h = screen.getMaxY() - y;
                    window.setX(x);
                    window.setY(y);
                    window.setWidth(w);
                    window.setHeight(h);
                }
                catch (NumberFormatException e) {
                    // in case of error, ignore the bounds
                }
            }
            Menus menus = content.getMenus();
            String directory = node.get("mandelbrot.filechooser.directory", null);
            if (directory != null) {
                   // Try to restore the current directory.
                menus.setSelectedDirectoryInFileChooser(directory);
            }
        }
        catch (Exception e) {
        }
    }
        
}