package de.intevation.flys.client.client.ui.chart;

import java.util.Date;

import com.google.gwt.core.client.GWT;
import com.google.gwt.user.client.rpc.AsyncCallback;

import com.smartgwt.client.widgets.Canvas;
import com.smartgwt.client.widgets.Img;

import com.smartgwt.client.widgets.layout.HLayout;
import com.smartgwt.client.widgets.layout.VLayout;

import com.smartgwt.client.widgets.events.ResizedEvent;
import com.smartgwt.client.widgets.events.ResizedHandler;

import de.intevation.flys.client.shared.Transform2D;
import de.intevation.flys.client.shared.model.Collection;
import de.intevation.flys.client.shared.model.OutputMode;
import de.intevation.flys.client.client.Config;
import de.intevation.flys.client.client.event.OutputParameterChangeEvent;
import de.intevation.flys.client.client.event.OutputParameterChangeHandler;
import de.intevation.flys.client.client.event.ZoomEvent;
import de.intevation.flys.client.client.event.ZoomHandler;
import de.intevation.flys.client.client.services.ChartInfoService;
import de.intevation.flys.client.client.services.ChartInfoServiceAsync;
import de.intevation.flys.client.client.ui.CollectionView;
import de.intevation.flys.client.client.ui.OutputTab;


/**
 * @author <a href="mailto:ingo.weinzierl@intevation.de">Ingo Weinzierl</a>
 */
public class ChartOutputTab
extends      OutputTab
implements   ResizedHandler, OutputParameterChangeHandler, ZoomHandler
{
    public static final int DEFAULT_CHART_WIDTH  = 600;
    public static final int DEFAULT_CHART_HEIGHT = 500;

    public static final int THEMEPANEL_MIN_WIDTH = 200;



    /** The service that is used to fetch chart information.*/
    protected ChartInfoServiceAsync info = GWT.create(ChartInfoService.class);

    /** The transformer used to transform image pixels into chart coordinates.*/
    protected Transform2D transformer;

    /** The collection view.*/
    protected CollectionView view;


    /** The canvas that wraps the chart toolbar.*/
    protected Canvas tbarPanel;

    /** The canvas that wraps the theme editor.*/
    protected Canvas left;

    /** The canvas that wraps the chart.*/
    protected Canvas right;


    /**
     * The default constructor to create a new ChartOutputTab.
     *
     * @param title The title of this tab.
     * @param collection The Collection which this chart belongs to.
     * @param mode The OutputMode.
     */
    public ChartOutputTab(
        String         title, 
        Collection     collection,
        OutputMode     mode,
        CollectionView collectionView
    ){
        super(title, collection, mode);

        view      = collectionView;
        left      = new Canvas();
        right     = new Canvas();
        tbarPanel = new ChartToolbar(collectionView, this);

        left.setBorder("1px solid black");
        left.setWidth(THEMEPANEL_MIN_WIDTH);
        left.setMinWidth(THEMEPANEL_MIN_WIDTH);
        right.setWidth("*");

        VLayout vLayout = new VLayout();
        vLayout.setMembersMargin(2);

        HLayout hLayout = new HLayout();
        hLayout.setWidth100();
        hLayout.setHeight100();
        hLayout.setMembersMargin(10);

        hLayout.addMember(left);
        hLayout.addMember(right);

        ChartThemePanel ctp = new ChartThemePanel(collection, mode);
        ctp.addOutputParameterChangeHandler(this);

        right.addChild(createChartPanel());
        left.addChild(ctp);

        vLayout.addMember(tbarPanel);
        vLayout.addMember(hLayout);

        setPane(vLayout);

        right.addResizedHandler(this);
    }


    /**
     * This method is called after the chart panel has resized. It removes the
     * chart - if existing - and requests a new one with adjusted size.
     *
     * @param event The resize event.
     */
    public void onResized(ResizedEvent event) {
        updateChartPanel();
        updateTransformer();
    }


    /**
     * Listens to change event in the chart them panel and updates chart after
     * receiving such an event.
     *
     * @param event The OutputParameterChangeEvent.
     */
    public void onOutputParameterChanged(OutputParameterChangeEvent event) {
        updateChartPanel();
    }


    /**
     * Listens to zoom events and refreshes the current chart in such case.
     *
     * @param evt The ZoomEvent that stores the coordinates for zooming.
     */
    public void onZoom(ZoomEvent evt) {
        double[] lower = transformer.transform(evt.getStartX(), evt.getStartY());
        double[] upper = transformer.transform(evt.getEndX(), evt.getEndY());

        double xmin = lower[0];
        double xmax = upper[0];
        double ymin = upper[1];
        double ymax = lower[1];

        // TODO Trigger the recreation of the chart
    }


    /**
     * Updates the Transform2D object using the chart info service.
     */
    public void updateTransformer() {
        Canvas chart = getChartPanel();

        Config config = Config.getInstance();
        String url    = config.getServerUrl();
        String locale = config.getLocale();

        info.getChartInfo(
            view.getCollection(),
            url,
            locale,
            mode.getName(),
            chart.getWidth(),
            chart.getHeight(),
            new AsyncCallback<Transform2D>() {
                public void onFailure(Throwable caught) {
                    GWT.log("ERROR: " + caught.getMessage());
                }

                public void onSuccess(Transform2D transformer) {
                    setTransformer(transformer);
                }
            });
    }


    public void updateChartPanel() {
        Canvas[] children = right.getChildren();
        for (Canvas child: children) {
            right.removeChild(child);
        }

        right.addChild(createChartPanel(right.getWidth(), right.getHeight()));
    }


    public Canvas getChartPanel() {
        Canvas[] children = right.getChildren();

        if (children == null || children.length == 0) {
            GWT.log("=> No chart image in the panel.");
            return right;
        }

        return children[0];
    }


    /**
     * Returns the Transform2D object used to transform image coordinates into
     * chart coordinates.
     *
     * @return the Transform2D object.
     */
    public Transform2D getTransformer() {
        return transformer;
    }


    /**
     * Set a new Transform2D object for the chart. This should be the case, only
     * if the chart image size has changed.
     *
     * @param transformer The new Transform2D object.
     */
    protected void setTransformer(Transform2D transformer) {
        this.transformer = transformer;
    }


    protected Canvas createChartPanel() {
        return createChartPanel(DEFAULT_CHART_WIDTH, DEFAULT_CHART_HEIGHT);
    }


    protected Canvas createChartPanel(int width, int height) {
        Img chart  = getChartImg(width, height);
        chart.setWidth100();
        chart.setHeight100();

        return chart;

    }


    /**
     * Builds the chart image and returns it.
     *
     * @param width The chart width.
     * @param height The chart height.
     *
     * @return the chart image.
     */
    protected Img getChartImg(int width, int height) {
        return new Img(getImgUrl(width, height));
    }


    /**
     * Builds the URL that points to the chart image.
     *
     * @param width The width of the requested chart.
     * @param height The height of the requested chart.
     *
     * @return the URL to the chart image.
     */
    protected String getImgUrl(int width, int height) {
        Config config = Config.getInstance();

        String imgUrl = GWT.getModuleBaseURL();
        imgUrl += "chart";
        imgUrl += "?uuid=" + collection.identifier();
        imgUrl += "&type=" + mode.getName();
        imgUrl += "&server=" + config.getServerUrl();
        imgUrl += "&locale=" + config.getLocale();
        imgUrl += "&timestamp=" + new Date().getTime();
        imgUrl += "&width=" + Integer.toString(width);
        imgUrl += "&height=" + Integer.toString(height);

        return imgUrl;
    }
}
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