package de.intevation.flys.artifacts;

import java.util.ArrayList;
import java.util.List;

import org.apache.log4j.Logger;

import org.w3c.dom.Document;

import de.intevation.artifacts.Artifact;
import de.intevation.artifacts.ArtifactFactory;
import de.intevation.artifacts.CallMeta;

import de.intevation.flys.artifacts.model.CrossSectionFacet;

import de.intevation.flys.model.CrossSection;
import de.intevation.flys.model.CrossSectionLine;
import de.intevation.flys.artifacts.model.CrossSectionFactory;
import de.intevation.artifacts.common.ArtifactNamespaceContext;
import de.intevation.artifacts.common.utils.XMLUtils;

import de.intevation.flys.artifacts.states.StaticState;

import de.intevation.artifactdatabase.state.Facet;
import de.intevation.artifactdatabase.state.State;


/**
 * Artifact describing a cross-section.
 */
public class CrossSectionArtifact extends StaticFLYSArtifact {

    /** Access ids of doc. */
    public static final String XPATH_IDS = "/art:action/art:ids/@value";

    /** Name of Artifact. */
    public static final String CS_ARTIFACT_NAME = "cross_section";

    /** Name of state. */
    public static final String STATIC_STATE_NAME = "state.cross_section";

    /** Name of data item keeping the position. */
    public static final String DATA_KM = "cross_section.km";

    /** Name of data item keeping the database id of this c.s.. */
    public static final String DATA_DBID = "cross_section.dbid";

    /** Name of data item keeping the database id of this c.s.. */
    public static final String DATA_IS_MASTER = "cross_section.master?";

    /** Own logger. */
    private static final Logger logger =
        Logger.getLogger(CrossSectionArtifact.class);


    /** Return given name. */
    @Override
    public String getName() {
        return CS_ARTIFACT_NAME;
    }


    /** Store ids, create a CrossSectionFacet. */
    @Override
    public void setup(
        String          identifier,
        ArtifactFactory factory,
        Object          context,
        CallMeta        callMeta,
        Document        data)
    {
        logger.info("CrossSectionArtifact.setup");

        super.setup(identifier, factory, context, callMeta, data);

        String ids = XMLUtils.xpathString(
            data, XPATH_IDS, ArtifactNamespaceContext.INSTANCE);

        if (ids != null && ids.length() > 0) {
            addStringData(DATA_DBID, ids);
            logger.debug("CrossSectionArtifacts db-id: " + ids);
        }
        else {
            throw new IllegalArgumentException("No attribute 'ids' found!");
        }

        // Assume we start at km 0.
        addStringData(DATA_KM, "0");
        addStringData(DATA_IS_MASTER, "0");

        List<Facet> fs = new ArrayList<Facet>();
        CrossSection cs = CrossSectionFactory.getCrossSection(Integer.valueOf(ids));
        fs.add(new CrossSectionFacet(0, cs.getDescription()));

        StaticState state = (StaticState) getCurrentState(context);

        if (!fs.isEmpty()) {
            facets.put(getCurrentStateId(), fs);
        }
    }


    /** Do not copy data from daddyfact. */
    @Override
    protected void initialize(
        Artifact artifact,
        Object   context,
        CallMeta callMeta)
    {
        // do nothing
    }


    /**
     * Create and return a new StaticState with charting output.
     */
    @Override
    public State getCurrentState(Object cc) {
        final List<Facet> fs = facets.get(getCurrentStateId());

        StaticState state = new StaticState(STATIC_STATE_NAME) {
            @Override
            public Object staticCompute(List<Facet> facets) {
                if (facets != null) {
                    facets.addAll(fs);
                }
                return null;
            }
        };

        state.addDefaultChartOutput("cross_section", fs);

        return state;
    }


    /**
     * Get a list containing the one and only State.
     * @param  context ignored.
     * @return list with one and only state.
     */
    @Override
    protected List<State> getStates(Object context) {
        ArrayList<State> states = new ArrayList<State>();
        states.add(getCurrentState(context));

        return states;
    }

    // TODO all data access needs proper caching.

    /**
     * Get a DataItem casted to int (0 if fails).
     */
    public int getDataAsIntNull(String dataName) {
        String val = getDataAsString(dataName);
        try {
            return Integer.valueOf(val);
        }
        catch (NumberFormatException e) {
            logger.warn("Could not get data " + dataName + " as int", e);
            return 0;
        }
    }


    /** Returns database-id of cross-section (from data). */
    protected int getDBID() {
        return getDataAsIntNull(DATA_DBID);
    }


    /**
     * Return position (km) from data, 0 if not found.
     */
    protected double getKm() {
        String val = getDataAsString(DATA_KM);
        try {
            return Double.valueOf(val);
        }
        catch (NumberFormatException e) {
            logger.warn("Could not get data " + DATA_KM + " as double", e);
            return 0;
        }
    }


    /** Returns true if artifact is set to be a "master" (other facets will
     * refer to this). */
    public boolean isMaster() {
        return !getDataAsString(DATA_IS_MASTER).equals("0");
    }


    /**
     * Get points of Profile of cross section at given kilometer.
     *
     * @return an array holding coordinates of points of profile (
     *         in the form {{x1, x2} {y1, y2}} ).
     */
    public double [][] getCrossSectionData() {
        logger.info("getCrossSectionData() for cross_section.km "
            + getDataAsString(DATA_KM));
        CrossSectionLine line = searchCrossSectionLine();

        return line != null
               ? line.fetchCrossSectionProfile()
               : null;
    }


    /**
     * Get CrossSectionLine spatially closest to what is specified in the data
     * "cross_section.km".
     *
     * @return CrossSectionLine closest to "cross_section.km".
     */
    public CrossSectionLine searchCrossSectionLine() {
        double wishKM = getKm();

        CrossSection crossSection = CrossSectionFactory.getCrossSection(getDBID());
        logger.debug("dbid " + getDBID() + " : " + crossSection);
        List<CrossSectionLine> crossSectionLines =
            crossSection.getLines();
            
        // Get the cross section closest to requested km.
        // Naive, linear approach.
        CrossSectionLine oldLine = crossSectionLines.get(0);
        double oldDiff = Math.abs(wishKM - oldLine.getKm().doubleValue());
        for (CrossSectionLine line: crossSectionLines) {
            double diff = Math.abs(wishKM - line.getKm().doubleValue());
            if (diff > oldDiff) {
                break;
            }
            oldDiff = diff;
            oldLine = line;
        }
        return oldLine;
    }
}
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