package com.objectnexus.rcp.preferences.page;

import org.eclipse.jface.preference.FieldEditor;
import org.eclipse.swt.SWT;
import org.eclipse.swt.events.ModifyEvent;
import org.eclipse.swt.events.ModifyListener;
import org.eclipse.swt.events.PaintEvent;
import org.eclipse.swt.events.PaintListener;
import org.eclipse.swt.events.SelectionEvent;
import org.eclipse.swt.events.SelectionListener;
import org.eclipse.swt.events.VerifyEvent;
import org.eclipse.swt.events.VerifyListener;
import org.eclipse.swt.graphics.Color;
import org.eclipse.swt.graphics.GC;
import org.eclipse.swt.graphics.Point;
import org.eclipse.swt.layout.FormAttachment;
import org.eclipse.swt.layout.FormData;
import org.eclipse.swt.layout.FormLayout;
import org.eclipse.swt.layout.GridData;
import org.eclipse.swt.widgets.Canvas;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Group;
import org.eclipse.swt.widgets.Label;
import org.eclipse.swt.widgets.MessageBox;
import org.eclipse.swt.widgets.Scale;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.swt.widgets.Text;

public class ImageScaleFieldEditor extends FieldEditor
{
    private static final int INIT_SCALE = 50;
    private static final int MIN_SCALE = 0;
    private static final int MAX_SCALE = 100;

    private static final int MIN_IMG_SIZE = 2;

    private Composite pageComposite = null;
    private Group grp = null;
    private Scale scale = null;
    private Text valueTxt = null;
    private Canvas canvas = null;
    private Label percentLbl = null;

    private CanvasPaintListener paintListener = null;

    public ImageScaleFieldEditor( String name, String labelText, Composite parent )
    {
        super( name, labelText, parent );
    }

    @Override
    protected void adjustForNumColumns( int numColumns )
    {
        ( (GridData) pageComposite.getLayoutData() ).horizontalSpan = numColumns;
    }

    @Override
    protected void doFillIntoGrid( Composite parent, int numColumns )
    {
        pageComposite = parent;

        grp = new Group( pageComposite, SWT.SHADOW_ETCHED_OUT );
        grp.setText( getLabelText() );

        FormLayout lout = new FormLayout();
        lout.marginWidth = 5;
        lout.marginHeight = 5;

        grp.setLayout( lout );

        canvas = new Canvas( grp, SWT.NONE );
        paintListener = new CanvasPaintListener( canvas, INIT_SCALE );
        canvas.addPaintListener( paintListener );

        scale = new Scale( grp, SWT.HORIZONTAL );
        scale.setMaximum( MAX_SCALE );
        scale.setMinimum( 0 );

        valueTxt = new Text( grp, SWT.SINGLE | SWT.CENTER );
        PercentVerifyListener pctVerifyListener = new PercentVerifyListener();
        valueTxt.addVerifyListener( pctVerifyListener );
        PercentModifyListener pctModifyListener = new PercentModifyListener( scale, paintListener );
        valueTxt.addModifyListener( pctModifyListener );

        percentLbl = new Label( grp, SWT.LEFT );
        percentLbl.setText( "%" );

        ScaleSelectionListener scaleListener = new ScaleSelectionListener( valueTxt, paintListener );
        scale.addSelectionListener( scaleListener );
        scale.setSelection( INIT_SCALE );

        valueTxt.setText( String.valueOf( INIT_SCALE ) );

        // do layout
        FormData fdata = new FormData();
        fdata.left = new FormAttachment( 0, 5 );
        fdata.top = new FormAttachment( 0, 5 );
        fdata.right = new FormAttachment( 55, -5 );
        scale.setLayoutData( fdata );

        // define the preferred width of the valueTxt field
        GC gc = new GC( valueTxt );
        Point p = gc.textExtent( String.valueOf( MAX_SCALE ) );
        gc.dispose();

        fdata = new FormData();
        fdata.width = p.x;
        fdata.left = new FormAttachment( scale, 5 );
        fdata.top = new FormAttachment( scale, 0, SWT.CENTER );
        valueTxt.setLayoutData( fdata );

        fdata = new FormData();
        fdata.left = new FormAttachment( valueTxt, 0 );
        fdata.top = new FormAttachment( valueTxt, 0, SWT.CENTER );
        percentLbl.setLayoutData( fdata );

        fdata = new FormData();
        fdata.left = new FormAttachment( percentLbl, 10 );
        fdata.top = new FormAttachment( percentLbl, 0, SWT.CENTER );
        canvas.setLayoutData( fdata );

        // page layout
        GridData gd = new GridData( GridData.FILL_HORIZONTAL );
        gd.horizontalSpan = numColumns;
        grp.setLayoutData( gd );

    }

    @Override
    protected void doLoad()
    {
        int scaleValue = getPreferenceStore().getInt( getPreferenceName() );
        scale.setSelection( scaleValue );
    }

    @Override
    protected void doLoadDefault()
    {
        int scaleValue = getPreferenceStore().getDefaultInt( getPreferenceName() );
        scale.setSelection( scaleValue );
    }

    @Override
    protected void doStore()
    {
        int scaleValue = scale.getSelection();
        getPreferenceStore().setValue( getPreferenceName(), scaleValue );
    }

    @Override
    public int getNumberOfControls()
    {
        return 5;
    }

    private class CanvasPaintListener implements PaintListener
    {
        private int scaleFactor = 0;
        private Canvas canvas = null;

        public CanvasPaintListener( Canvas canvas, int scaleFactor )
        {
            this.canvas = canvas;
            setScaleFactor( scaleFactor );
        }

        public void setScaleFactor( int scaleFactor )
        {
            this.scaleFactor = scaleFactor;
        }

        public int getScaleFactor()
        {
            return scaleFactor;
        }

        public Canvas getCanvas()
        {
            return canvas;
        }

        @Override
        public void paintControl( PaintEvent e )
        {
            GC gc = e.gc;
            Color borderColor = e.display.getSystemColor( SWT.COLOR_BLACK );
            gc.setBackground( borderColor );

            int maxWidth = e.width - 1;
            int maxHeight = e.height - 1;
            gc.drawRectangle( e.x, e.y, maxWidth, maxHeight );

            Color sqColor = e.display.getSystemColor( SWT.COLOR_DARK_GREEN );
            int centerX = e.x + e.width / 2;
            int centerY = e.y + e.height / 2;

            // if ( getScaleFactor() < 20 )
            // setScaleFactor( 20 );

            int scaledWidth = (int) maxWidth * getScaleFactor() / MAX_SCALE;
            int scaledHeight = (int) maxHeight * getScaleFactor() / MAX_SCALE;

            if ( scaledWidth > e.width )
                scaledWidth = e.width - 1;

            if ( scaledHeight > e.height )
                scaledHeight = e.height - 1;

            if ( scaledWidth < MIN_IMG_SIZE || scaledHeight < MIN_IMG_SIZE )
                scaledWidth = scaledHeight = MIN_IMG_SIZE;

            int sqX = centerX - scaledWidth / 2;
            int sqY = centerY - scaledHeight / 2;

            gc.setBackground( sqColor );
            gc.fillRectangle( sqX, sqY, scaledWidth, scaledHeight );

        }

    }

    private class ScaleSelectionListener implements SelectionListener
    {
        private Text valueTxt;
        private CanvasPaintListener paintListener;

        public ScaleSelectionListener( Text txt, CanvasPaintListener listener )
        {
            valueTxt = txt;
            paintListener = listener;
        }

        @Override
        public void widgetSelected( SelectionEvent e )
        {
            Scale scale = (Scale) e.widget;
            int value = scale.getSelection();

            if ( value < MIN_SCALE )
            {
                scale.setSelection( MIN_SCALE );
                value = MIN_SCALE;
            }

            valueTxt.setText( String.valueOf( value ) );

            paintListener.setScaleFactor( value );
            paintListener.getCanvas().redraw();
        }

        @Override
        public void widgetDefaultSelected( SelectionEvent e )
        {
        }

    }

    private class PercentVerifyListener implements VerifyListener
    {

        @Override
        public void verifyText( VerifyEvent e )
        {
            String value = e.text;
            try
            {
                Integer.parseInt( value );
            }
            catch ( Exception ex )
            {
                e.doit = false;
            }
        }

    }

    private class PercentModifyListener implements ModifyListener
    {
        private Scale scale;
        private CanvasPaintListener paintListener;

        public PercentModifyListener( Scale sc, CanvasPaintListener listener )
        {
            scale = sc;
            paintListener = listener;
        }

        @Override
        public void modifyText( ModifyEvent e )
        {
            Text txtWidget = (Text) e.widget;
            String txt = txtWidget.getText();

            int newValue = Integer.parseInt( txt );
            if ( newValue < MIN_SCALE || newValue > MAX_SCALE )
            {
                Shell shell = e.display.getActiveShell();
                MessageBox msgBox = new MessageBox( shell, SWT.ERROR | SWT.OK );
                msgBox.setMessage( "Value out of Range" );
                msgBox.open();

                // reset view to initial default
                txtWidget.setText( String.valueOf( INIT_SCALE ) );
                txtWidget.selectAll();
                scale.setSelection( INIT_SCALE );
                paintListener.setScaleFactor( INIT_SCALE );
                paintListener.getCanvas().redraw();
            }
            else
            {
                scale.setSelection( newValue );
                paintListener.setScaleFactor( newValue );
                paintListener.getCanvas().redraw();
            }

        }

    }

}