package ij.gui;
import ij.*;
import java.awt.*;
import javax.swing.JComponent;
import javax.swing.JList;
import javax.swing.JTable;
import javax.swing.UIManager;

/** This class consists of static GUI utility methods. */
public class GUI {
    private static final Font DEFAULT_FONT = IJ.font12;
    private static Color lightGray = new Color(240,240,240);
    private static boolean isWindows8;
    private static Color scrollbarBackground = new Color(245,245,245);

    static {
        if (IJ.isWindows()) {
            String osname = System.getProperty("os.name");
            isWindows8 = osname.contains("unknown") || osname.contains("8");
        }
    }

    /** Positions the specified window in the center of the screen that contains target. */
    public static void center(Window win, Component target) {
        if (win == null)
            return;
        Rectangle bounds = getMaxWindowBounds(target);
        Dimension window = win.getSize();
        if (window.width == 0)
            return;
        int left = bounds.x + Math.max(0, (bounds.width - window.width) / 2);
        int top = bounds.y + Math.max(0, (bounds.height - window.height) / 4);
        win.setLocation(left, top);
    }
    
    /** Positions the specified window in the center of the
         screen containing the "ImageJ" window. */
    public static void centerOnImageJScreen(Window win) {
        center(win, IJ.getInstance());
    }

    public static void center(Window win) {
        center(win, win);
    }
    
    private static java.util.List<GraphicsConfiguration> getScreenConfigs() {
        java.util.ArrayList<GraphicsConfiguration> configs = new java.util.ArrayList<GraphicsConfiguration>();
        for (GraphicsDevice device : GraphicsEnvironment.getLocalGraphicsEnvironment().getScreenDevices()) {
            configs.add(device.getDefaultConfiguration());
        }
        return configs;
    }
    
    /**
     * Get maximum bounds for the screen that contains a given point.
     * @param point Coordinates of point.
     * @param accountForInsets Deduct the space taken up by menu and status bars, etc. (after point is found to be inside bonds)
     * @return Rectangle of bounds or <code>null</code> if point not inside of any screen.
     */
    public static Rectangle getScreenBounds(Point point, boolean accountForInsets) {
        if (GraphicsEnvironment.isHeadless())
            return new Rectangle(0,0,0,0);
        for (GraphicsConfiguration config : getScreenConfigs()) {
            Rectangle bounds = config.getBounds();
            if (bounds != null && bounds.contains(point)) {
                Insets insets = accountForInsets ? Toolkit.getDefaultToolkit().getScreenInsets(config) : null;
                return shrinkByInsets(bounds, insets);
            }
        }
        return null;        
    }
    
    /**
     * Get maximum bounds for the screen that contains a given component.
     * @param component An AWT component located on the desired screen.
     * If <code>null</code> is provided, the default screen is used.
     * @param accountForInsets Deduct the space taken up by menu and status bars, etc.
     * @return Rectangle of bounds.
     */ 
    public static Rectangle getScreenBounds(Component component, boolean accountForInsets) {
        if (GraphicsEnvironment.isHeadless())
            return new Rectangle(0,0,0,0);
        GraphicsEnvironment ge = GraphicsEnvironment.getLocalGraphicsEnvironment();     
        GraphicsConfiguration gc = component == null ? ge.getDefaultScreenDevice().getDefaultConfiguration() :
                                                       component.getGraphicsConfiguration();   
        Insets insets = accountForInsets ? Toolkit.getDefaultToolkit().getScreenInsets(gc) : null;
        return shrinkByInsets(gc.getBounds(), insets);
    }

    public static Rectangle getScreenBounds(Point point) {
        return getScreenBounds(point, false);
    }       

    public static Rectangle getScreenBounds(Component component) {
        return getScreenBounds(component, false);
    }           

    public static Rectangle getScreenBounds() {
        return getScreenBounds((Component)null);
    }           

    public static Rectangle getMaxWindowBounds(Point point) {
        return getScreenBounds(point, true);
    }

    public static Rectangle getMaxWindowBounds(Component component) {
        return getScreenBounds(component, true);
    }
    
    public static Rectangle getMaxWindowBounds() {
        return getMaxWindowBounds((Component)null);
    }
    
    private static Rectangle shrinkByInsets(Rectangle bounds, Insets insets) {
        Rectangle shrunk = new Rectangle(bounds);
        if (insets == null) return shrunk; 
        shrunk.x += insets.left;
        shrunk.y += insets.top;
        shrunk.width -= insets.left + insets.right;
        shrunk.height -= insets.top + insets.bottom;
        return shrunk;
    }
    
    public static Rectangle getZeroBasedMaxBounds() {
        for (GraphicsConfiguration config : getScreenConfigs()) {
            Rectangle bounds = config.getBounds();
            if (bounds != null && bounds.x == 0 && bounds.y == 0)
                return bounds;
        }
        return null;
    }
    
    public static Rectangle getUnionOfBounds() {
        Rectangle unionOfBounds = new Rectangle();
        for (GraphicsConfiguration config : getScreenConfigs()) {
            unionOfBounds = unionOfBounds.union(config.getBounds());
        }
        return unionOfBounds;
    }
    
    static private Frame frame;
    
    /** Obsolete */
    public static Image createBlankImage(int width, int height) {
        if (width==0 || height==0)
            throw new IllegalArgumentException("");
        if (frame==null) {
            frame = new Frame();
            frame.pack();
            frame.setBackground(Color.white);
        }
        Image img = frame.createImage(width, height);
        return img;
    }
    
    /** Lightens overly dark scrollbar background on Windows 8. */
    public static void fix(Scrollbar sb) {
    }
    
    public static boolean showCompositeAdvisory(ImagePlus imp, String title) {
        if (imp==null || imp.getCompositeMode()!=IJ.COMPOSITE || imp.getNChannels()==1 || IJ.macroRunning())
            return true;
        String msg = "Channel "+imp.getC()+" of this color composite image will be processed.";
        GenericDialog gd = new GenericDialog(title);
        gd.addMessage(msg);
        gd.showDialog();
        return !gd.wasCanceled();
    }
    
    /**
     * Scales an AWT component according to {@link Prefs#getGuiScale()}.
     * @param component the AWT component to be scaled. If a container, scaling is applied to all its child components
     */
    public static void scale(final Component component) {
        final float scale = (float)Prefs.getGuiScale();
        if (scale==1f)
            return;
        if (component instanceof Container)
            scaleComponents((Container)component, scale);
        else
            scaleComponent(component, scale);
    }

    private static void scaleComponents(final Container container, final float scale) {
        for (final Component child : container.getComponents()) {
            if (child instanceof Container)
                scaleComponents((Container) child, scale);
            else
                scaleComponent(child, scale);
        }
    }

    private static void scaleComponent(final Component component, final float scale) {
        Font font = component.getFont();
        if (font == null)
            font = DEFAULT_FONT;
        font = font.deriveFont(scale*font.getSize());
        component.setFont(font);
    }

    public static void scalePopupMenu(final PopupMenu popup) {
        final float scale = (float)Prefs.getGuiScale();
        if (scale==1f)
            return;
        Font font = popup.getFont();
        if (font == null)
            font = DEFAULT_FONT;
        font = font.deriveFont(scale*font.getSize());
        popup.setFont(font);
    }
    
    /**
     * Tries to detect if a Swing component is unscaled and scales it it according
     * to {@link #getGuiScale()}.
     * <p>
     * This is mainly relevant to linux: Swing components scale automatically on
     * most platforms, specially since Java 8. However there are still exceptions to
     * this on linux: e.g., In Ubuntu, Swing components do scale, but only under the
     * GTK L&F. (On the other hand AWT components do not scale <i>at all</i> on
     * hiDPI screens on linux).
     * </p>
     * <p>
     * This method tries to avoid exaggerated font sizes by detecting if a component
     * has been already scaled by the UIManager, applying only
     * {@link #getGuiScale()} to the component's font if not.
     * </p>
     *
     * @param component the component to be scaled
     * @return true, if component's font was resized
     */
    public static boolean scale(final JComponent component) {
        final double guiScale = Prefs.getGuiScale();
        if (guiScale == 1d)
            return false;
        Font font = component.getFont();
        if (font == null && component instanceof JList)
            font = UIManager.getFont("List.font");
        else if (font == null && component instanceof JTable)
            font = UIManager.getFont("Table.font");
        else if (font == null)
            font = UIManager.getFont("Label.font");
        if (font.getSize() > DEFAULT_FONT.getSize())
            return false;
        if (component instanceof JTable)
            ((JTable) component).setRowHeight((int) (((JTable) component).getRowHeight() * guiScale * 0.9));
        else if (component instanceof JList)
            ((JList<?>) component).setFixedCellHeight((int) (((JList<?>) component).getFixedCellHeight() * guiScale * 0.9));
        component.setFont(font.deriveFont((float) guiScale * font.getSize()));
        return true;
    }
    
    /** Works around an OpenJDK bug on Windows that
     * causes the scrollbar thumb color and background
     * color to be almost identical.
    */
    public static final void fixScrollbar(Scrollbar sb) {
        if (IJ.isWindows())
            sb.setBackground(scrollbarBackground);
    }
    
    /** Returns a new NonBlockingGenericDialog with the given title,
     *  except when Java is running in headless mode, in which case
     *  a GenericDialog is be returned.
    */
    public static GenericDialog newNonBlockingDialog(String title) {
        if (GraphicsEnvironment.isHeadless())
            return new GenericDialog(title);
        else
            return new NonBlockingGenericDialog(title);
    }

    /** Returns a new NonBlockingGenericDialog with the given title
     * if Prefs.nonBlockingFilterDialogs is 'true' and 'imp' is
     * displayed, otherwise returns a GenericDialog.
     * @param title Dialog title
     * @param imp The image associated with this dialog
    */
    public static GenericDialog newNonBlockingDialog(String title, ImagePlus imp) {
        if (Prefs.nonBlockingFilterDialogs && imp!=null && imp.getWindow()!=null) {
            NonBlockingGenericDialog gd = new NonBlockingGenericDialog(title);
            gd.imp = imp;
            return gd;
        } else
            return new GenericDialog(title);
    }

    
}