package de.intevation.flys.artifacts;

import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;

import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;

import org.apache.log4j.Logger;

import de.intevation.artifacts.ArtifactNamespaceContext;
import de.intevation.artifacts.CallContext;

import de.intevation.artifactdatabase.ProtocolUtils;
import de.intevation.artifactdatabase.state.DefaultOutput;
import de.intevation.artifactdatabase.state.Facet;
import de.intevation.artifactdatabase.state.Output;
import de.intevation.artifactdatabase.state.State;
import de.intevation.artifactdatabase.state.StateEngine;
import de.intevation.artifactdatabase.transition.TransitionEngine;

import de.intevation.artifacts.common.utils.XMLUtils;

import de.intevation.flys.model.Gauge;
import de.intevation.flys.model.River;

import de.intevation.flys.artifacts.states.DefaultState;
import de.intevation.flys.artifacts.context.FLYSContext;

import de.intevation.flys.artifacts.model.DischargeTables;
import de.intevation.flys.artifacts.model.MainValuesFactory;
import de.intevation.flys.artifacts.model.WQDay;
import de.intevation.flys.artifacts.model.WQKms;
import de.intevation.flys.artifacts.model.WstValueTable;
import de.intevation.flys.artifacts.model.WstValueTableFactory;
import de.intevation.flys.artifacts.model.Calculation1;
import de.intevation.flys.artifacts.model.Calculation2;
import de.intevation.flys.artifacts.model.Calculation3;
import de.intevation.flys.artifacts.model.Calculation4;
import de.intevation.flys.artifacts.model.Segment;

import gnu.trove.TDoubleArrayList;

/**
 * The default WINFO artifact.
 *
 * @author <a href="mailto:ingo.weinzierl@intevation.de">Ingo Weinzierl</a>
 */
public class WINFOArtifact extends FLYSArtifact {

    /** The logger for this class */
    private static Logger logger = Logger.getLogger(WINFOArtifact.class);


    /** The name of the artifact.*/
    public static final String ARTIFACT_NAME = "winfo";

    /** XPath */
    public static final String XPATH_STATIC_UI ="/art:result/art:ui/art:static";


    /**
     * The default constructor.
     */
    public WINFOArtifact() {
    }


    /**
     * This method returns a description of this artifact.
     *
     * @param data Some data.
     * @param context The CallContext.
     *
     * @return the description of this artifact.
     */
    public Document describe(Document data, CallContext context) {
        logger.debug("Describe: the current state is: " + getCurrentStateId());

        if (logger.isDebugEnabled()) {
            dumpArtifact();
        }

        FLYSContext flysContext = null;
        if (context instanceof FLYSContext) {
            flysContext = (FLYSContext) context;
        }
        else {
            flysContext = (FLYSContext) context.globalContext();
        }

        StateEngine stateEngine = (StateEngine) flysContext.get(
            FLYSContext.STATE_ENGINE_KEY);

        TransitionEngine transitionEngine = (TransitionEngine) flysContext.get(
            FLYSContext.TRANSITION_ENGINE_KEY);

        List<State> reachable = transitionEngine.getReachableStates(
            this, getCurrentState(context), stateEngine);

        Document description            = XMLUtils.newDocument();
        XMLUtils.ElementCreator creator = new XMLUtils.ElementCreator(
            description,
            ArtifactNamespaceContext.NAMESPACE_URI,
            ArtifactNamespaceContext.NAMESPACE_PREFIX);

        Element root = ProtocolUtils.createRootNode(creator);
        description.appendChild(root);

        State current = getCurrentState(context);

        ProtocolUtils.appendDescribeHeader(creator, root, identifier(), hash());
        ProtocolUtils.appendState(creator, root, current);
        ProtocolUtils.appendReachableStates(creator, root, reachable);

        Element name = ProtocolUtils.createArtNode(
            creator, "name",
            new String[] { "value" },
            new String[] { getName() });

        Element ui = ProtocolUtils.createArtNode(
            creator, "ui", null, null);

        Element staticUI  = ProtocolUtils.createArtNode(
            creator, "static", null, null);

        Element outs = ProtocolUtils.createArtNode(
            creator, "outputmodes", null, null);
        appendOutputModes(description, outs, context, identifier());

        appendStaticUI(description, staticUI, context, identifier());

        Element dynamic = current.describe(
            this,
            description,
            root,
            context,
            identifier());

        if (dynamic != null) {
            ui.appendChild(dynamic);
        }

        ui.appendChild(staticUI);

        root.appendChild(name);
        root.appendChild(ui);
        root.appendChild(outs);

        return description;
    }


    /**
     * Returns the name of the concrete artifact.
     *
     * @return the name of the concrete artifact.
     */
    public String getName() {
        return ARTIFACT_NAME;
    }


    protected void appendOutputModes(
        Document    doc,
        Element     outs,
        CallContext context,
        String      uuid)
    {
        List<String> stateIds = getPreviousStateIds();

        XMLUtils.ElementCreator creator = new XMLUtils.ElementCreator(
            doc,
            ArtifactNamespaceContext.NAMESPACE_URI,
            ArtifactNamespaceContext.NAMESPACE_PREFIX);

        FLYSContext flysContext = getFlysContext(context);
        StateEngine engine      = (StateEngine) flysContext.get(
            FLYSContext.STATE_ENGINE_KEY);

        for (String stateId: stateIds) {
            logger.debug("Append output modes for state: " + stateId);
            DefaultState state = (DefaultState) engine.getState(stateId);

            List<Output> list = state.getOutputs();
            if (list == null || list.size() == 0) {
                logger.debug("-> No output modes for this state.");
                continue;
            }

            List<Facet>  fs = facets.get(stateId);
            if (fs == null || fs.size() == 0) {
                logger.debug("No facets found.");
                continue;
            }

            logger.debug("Found " + fs.size() + " facets in previous states.");

            List<Output> generated = generateOutputs(list, fs);

            ProtocolUtils.appendOutputModes(creator, outs, generated);
        }

        try {
            DefaultState cur = (DefaultState) getCurrentState(context);
            if (cur.validate(this, context)) {
                List<Output> list = cur.getOutputs();
                if (list != null && list.size() > 0) {
                    logger.debug(
                        "Append output modes for state: " + cur.getID());

                    List<Facet>  fs = facets.get(cur.getID());
                    if (fs != null && fs.size() > 0) {
                        List<Output> generated = generateOutputs(list, fs);

                        logger.debug("Found " + fs.size() + " current facets.");

                        ProtocolUtils.appendOutputModes(
                            creator, outs, generated);
                    }
                    else {
                        logger.debug("No facets found for the current state.");
                    }

                }
            }
        }
        catch (IllegalArgumentException iae) {
            // state is not valid, so we do not append its outputs.
        }
    }


    protected List<Output> generateOutputs(List<Output> list, List<Facet> fs) {
        List<Output> generated = new ArrayList<Output>();

        for (Output out: list) {
            Output o = new DefaultOutput(
                out.getName(),
                out.getDescription(),
                out.getMimeType());

            Set<String> outTypes = new HashSet<String>();

            for (Facet f: out.getFacets()) {
                outTypes.add(f.getName());
            }

            for (Facet f: fs) {
                String type = f.getName();

                if (outTypes.contains(type)) {
                    o.addFacet(f);
                }
            }

            generated.add(o);
        }

        return generated;
    }


    /**
     * This method appends the static data - that has already been inserted by
     * the user - to the static node of the DESCRIBE document.
     *
     * @param doc The document.
     * @param ui The root node.
     * @param context The CallContext.
     * @param uuid The identifier of the artifact.
     */
    protected void appendStaticUI(
        Document    doc,
        Node        ui,
        CallContext context,
        String uuid)
    {
        List<String> stateIds = getPreviousStateIds();

        FLYSContext flysContext = getFlysContext(context);
        StateEngine engine      = (StateEngine) flysContext.get(
            FLYSContext.STATE_ENGINE_KEY);

        for (String stateId: stateIds) {
            logger.debug("Append static data for state: " + stateId);
            DefaultState state = (DefaultState) engine.getState(stateId);

            ui.appendChild(state.describeStatic(this, doc, ui, context, uuid));
        }
    }


    //
    // METHODS FOR RETRIEVING COMPUTED DATA FOR DIFFERENT CHART TYPES
    //

    /**
     * Returns the data that is computed by a waterlevel computation.
     *
     * @return an array of data triples that consist of W, Q and Kms.
     */
    public WQKms[] getWaterlevelData()
    throws NullPointerException
    {
        logger.debug("WINFOArtifact.getWaterlevelData");

        River river = getRiver();
        if (river == null) {
            throw new NullPointerException("No river selected.");
        }

        double[] kms = getKms();
        if (kms == null) {
            throw new NullPointerException("No Kms selected.");
        }

        double[] qs   = getQs();
        double[] ws   = null;
        boolean  qSel = true;

        if (qs == null) {
            logger.debug("Determine Q values based on a set of W values.");
            qSel = false;
            ws   = getWs();
            qs   = getQsForWs(ws);
        }

        WstValueTable wst = WstValueTableFactory.getTable(river);
        if (wst == null) {
            throw new NullPointerException("No Wst found for selected river.");
        }

        WQKms[] results = computeWaterlevelData(
            kms, qs, ws, wst, river.getKmUp());

        // TODO Introduce a caching mechanism here!

        return results;
    }

    /**
     * Computes the data of a waterlevel computation based on the interpolation
     * in WstValueTable.
     *
     * @param kms The kilometer values.
     * @param qa The discharge values.
     * @param wst The WstValueTable used for the interpolation.
     *
     * @return an array of data triples that consist of W, Q and Kms.
     */
    public static WQKms[] computeWaterlevelData(
        double []     kms,
        double []     qs,
        double []     ws,
        WstValueTable wst,
        boolean       up
    ) {
        logger.info("WINFOArtifact.computeWaterlevelData");

        Calculation1 calculation = new Calculation1(kms, qs, ws, up);

        WQKms[] wqkms = calculation.calculate(wst);

        // TODO: report problems to user

        return wqkms;
    }


    /**
     * Returns the data that is computed by a duration curve computation.
     *
     * @return the data computed by a duration curve computation.
     */
    public WQDay getDurationCurveData()
    throws NullPointerException
    {
        logger.debug("WINFOArtifact.getDurationCurveData");

        River r = getRiver();

        if (r == null) {
            throw new NullPointerException("Cannot determine river.");
        }

        Gauge g = getGauge();

        if (g == null) {
            throw new NullPointerException("Cannot determine gauge.");
        }

        double[] locations = getLocations();

        if (locations == null) {
            throw new NullPointerException("Cannot determine location.");
        }

        WstValueTable wst = WstValueTableFactory.getTable(r);
        if (wst == null) {
            throw new NullPointerException("No Wst found for selected river.");
        }

        // TODO Introduce a caching mechanism here!

        return computeDurationCurveData(g, wst, locations[0]);
    }


    /**
     * Computes the data used to create duration curves.
     *
     * @param gauge The selected gauge.
     * @param location The selected location.
     *
     * @return the computed data.
     */
    public static WQDay computeDurationCurveData(
        Gauge           gauge,
        WstValueTable   wst,
        double          location)
    {
        logger.info("WINFOArtifact.computeDurationCurveData");

        Object[] obj = MainValuesFactory.getDurationCurveData(gauge);

        int[]    days = (int[]) obj[0];
        double[] qs   = (double[]) obj[1];

        Calculation3 calculation = new Calculation3(location, days, qs);

        // TODO: report the errors to the user.
        return calculation.calculate(wst);
    }


    /**
     * Returns the data that is used to create discharge curves.
     *
     * @return a map where the key is the name of the gauge and a double[][]
     * which are the values.
     */
    public Map<String, double[][]> getDischargeCurveData() {
        River       river  = getRiver();
        List<Gauge> gauges = getGauges();

        if (gauges == null) {
            logger.warn("No gauges found for the current kilometer range.");
            return null;
        }

        int num = gauges.size();

        logger.debug("Found " + num + " gauges.");

        String[] gaugeNames = new String[num];

        for (int i = 0; i < num; i++) {
            gaugeNames[i] = gauges.get(i).getName();
        }

        DischargeTables dt = new DischargeTables(river.getName(), gaugeNames);

        return dt.getValues(100d);
    }


    /**
     * Returns the data that is computed by a discharge curve computation.
     *
     * @return the data computed by a discharge curve computation.
     */
    public WQKms getComputedDischargeCurveData()
    throws NullPointerException
    {
        logger.debug("WINFOArtifact.getComputedDischargeCurveData");

        River r = getRiver();

        if (r == null) {
            throw new NullPointerException("Cannot determine river.");
        }

        double[] locations = getLocations();

        if (locations == null) {
            throw new NullPointerException("Cannot determine location.");
        }

        WstValueTable wst = WstValueTableFactory.getTable(r);
        if (wst == null) {
            throw new NullPointerException("No Wst found for selected river.");
        }

        WQKms wqkms = computeDischargeCurveData(wst, locations[0]);

        // TODO Introduce a caching mechanism here!

        return wqkms;
    }


    /**
     * Computes the data used to create computed discharge curves.
     *
     * @param wst The WstValueTable that is used for the interpolation.
     * @param location The location where the computation should be based on.
     *
     * @return an object that contains tuples of W/Q values at the specified
     * location.
     */
    public static WQKms computeDischargeCurveData(
        WstValueTable wst,
        double location)
    {
        logger.info("WINFOArtifact.computeDischargeCurveData");

        Calculation2 calculation = new Calculation2(location);

        WQKms wqkms = calculation.calculate(wst);

        // TODO: Report errors to the user

        return wqkms;
    }

    private static final double [] getBounds(double [][] segments) {
        boolean down = true;
        double min =  Double.MAX_VALUE;
        double max = -Double.MAX_VALUE;

        for (double [] segment: segments) {
            if (down = segment[0] > segment[1]) {
                if (segment[1] < min) min = segment[1];
                if (segment[0] > max) max = segment[0];
            }
            else {
                if (segment[0] < min) min = segment[0];
                if (segment[1] > max) max = segment[1];
            }
        }

        return down
            ?  new double [] { max, min }
            :  new double [] { min, max };

    }

    protected static double [] extractBoundsKm(River river, double [][] segments) {

        if (segments.length == 2) {
            return getBounds(segments);
        }

        TDoubleArrayList bounds = new TDoubleArrayList();

        bounds.add(Math.min(segments[0][0], segments[0][1]));

        for (int i = 1; i < segments.length-1; ++i) {
            double [] segment = segments[i];

            Gauge gauge = river.determineGauge(segment[0], segment[1]);

            if (gauge == null) {
                logger.warn("no gauge found between " + 
                    segment[0] + " and " + segment[1]);
                bounds.add(0.5*(segment[0] + segment[1]));
            }
            else {
                bounds.add(gauge.getStation().doubleValue());
            }
        }

        bounds.add(Math.max(
            segments[segments.length-1][0],
            segments[segments.length-1][1]));

        return bounds.toNativeArray();
    }

    /**
     * Returns the data computed by the discharge longitudinal section
     * computation.
     *
     * @return an array of WQKms object - one object for each given Q value.
     */
    public WQKms [] getDischargeLongitudinalSectionData() {

        logger.debug("WINFOArtifact.getDischargeLongitudinalSectionData");

        River river = getRiver();
        if (river == null) {
            logger.error("No river selected.");
            return new WQKms[0];
        }

        WstValueTable table = WstValueTableFactory.getTable(river);
        if (table == null) {
            logger.error("No wst found for selected river.");
            return new WQKms[0];
        }

        List<Segment> segments = getSegments();

        if (segments == null) {
            logger.error("Cannot create segments.");
            return new WQKms[0];
        }

        double [] range = getFromToStep();

        if (range == null) {
            logger.error("Cannot figure out range.");
            return new WQKms[0];
        }

        Calculation4 calc4 = new Calculation4(segments, river, isQ());

        WQKms [] results = calc4.calculate(table, range[0], range[1], range[2]);

        return results;
    }
}
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