package de.intevation.flys.artifacts;

import java.util.List;
import java.util.Vector;

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


/**
 * 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());

        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(
            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 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(
            description,
            root,
            context,
            identifier());

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

        ui.appendChild(staticUI);

        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)
    {
        Vector<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);
            State state = engine.getState(stateId);

            List<Output> list = state.getOutputs();
            if (list == null || list.size() == 0) {
                continue;
            }

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

        // TODO If the current state is already filled with data, the output is
        // available as well! So we need some code to append the outputs of the
        // current already filled state.
    }


    /**
     * 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)
    {
        Vector<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(doc, ui, context, uuid));
        }

    }
}
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