package de.intevation.flys.artifacts;

import java.util.List;

import org.apache.log4j.Logger;

import org.w3c.dom.Document;

import de.intevation.artifacts.ArtifactFactory;
import de.intevation.artifacts.CallContext;

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

import de.intevation.artifactdatabase.DefaultArtifact;
import de.intevation.artifactdatabase.data.StateData;
import de.intevation.artifactdatabase.state.State;
import de.intevation.artifactdatabase.state.StateEngine;

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


/**
 * The defaul FLYS artifact.
 *
 * @author <a href="mailto:ingo.weinzierl@intevation.de">Ingo Weinzierl</a>
 */
public abstract class FLYSArtifact extends DefaultArtifact {

    /** The logger that is used in this artifact.*/
    private static Logger logger = Logger.getLogger(FLYSArtifact.class);


    /** The XPath to the name of the artifact in its configuration. */
    public static final String XPATH_ARTIFACT_NAME = "@name";


    /** The identifier of the current state. */
    protected String currentStateId;

    /** The name of the artifact.*/
    protected String name;


    /**
     * Initialize the artifact and insert new data if <code>data</code> contains
     * information necessary for this artifact.
     *
     * @param identifier The UUID.
     * @param factory The factory that is used to create this artifact.
     * @param context The CallContext.
     * @param data Some optional data.
     */
    @Override
    public void setup(
        String          identifier,
        ArtifactFactory factory,
        Object          context,
        Document        data)
    {
        logger.debug("Setup this artifact with the uuid: " + identifier);

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

        String name = XMLUtils.xpathString(
            data, XPATH_ARTIFACT_NAME, ArtifactNamespaceContext.INSTANCE);
        setName(name);

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

        List<State> states = engine.getStates(name);

        setCurrentState(states.get(0));
    }


    /**
     * Insert new data included in <code>input</code> into the current state.
     *
     * @param target XML document that contains new data.
     * @param context The CallContext.
     *
     * @return a document that contains a SUCCESS or FAILURE message.
     */
    @Override
    public Document feed(Document target, CallContext context) {
        Document result = XMLUtils.newDocument();

        // TODO IMPLEMENT ME

        return result;
    }


    /**
     * This method returns the name of the concrete artifact.
     *
     * @return the name of the concrete artifact.
     */
    public String getName() {
        return name;
    }



    /**
     * This method sets the name of this artifact.
     *
     * @param name the name for this artifact.
     */
    protected void setName(String name) {
        this.name = name;
    }


    /**
     * Returns the identifier of the current state.
     *
     * @return the identifier of the current state.
     */
    protected String getCurrentStateId() {
        return currentStateId;
    }


    /**
     * Sets the identifier of the current state.
     *
     * @param id the identifier of a state.
     */
    protected void setCurrentStateId(String id) {
        currentStateId = id;
    }



    /**
     * Set the current state of this artifact. <b>NOTE</b>We don't store the
     * State object itself - which is not necessary - but its identifier. So
     * this method will just call the setCurrentStateId() method with the
     * identifier of <i>state</i>.
     *
     * @param state The new current state.
     */
    protected void setCurrentState(State state) {
        setCurrentStateId(state.getID());
    }


    /**
     * Returns the current state of the artifact.
     *
     * @return the current State of the artifact.
     */
    protected State getCurrentState(Object context) {
        FLYSContext flysContext = (FLYSContext) context;
        StateEngine engine      = (StateEngine) flysContext.get(
            FLYSContext.STATE_ENGINE_KEY);

        return engine.getState(getCurrentStateId());
    }


    /**
     * This method extracts the data that is contained in the FEED document.
     *
     * @param feed The FEED document.
     * @param xpath The XPath that points to the data nodes.
     *
     * @return a StateData array.
     */
    public StateData[] extractData(Document feed, String xpath) {

        // TODO IMPLEMENT ME
        return null;
    }
}
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