/*
 * Copyright (c) 2010 by Intevation GmbH
 *
 * This program is free software under the LGPL (>=v2.1)
 * Read the file LGPL.txt coming with the software for details
 * or visit http://www.gnu.org/licenses/ if it does not exist.
 */

package de.intevation.gnv.state;

import java.io.OutputStream;
import java.util.ArrayList;
import java.util.Collection;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Locale;

import javax.xml.xpath.XPathConstants;

import net.sf.ehcache.Cache;

import org.apache.log4j.Logger;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;

import de.intevation.artifacts.common.utils.Config;
import de.intevation.artifacts.common.utils.XMLUtils;
import de.intevation.artifacts.CallContext;
import de.intevation.artifacts.CallMeta;
import de.intevation.gnv.artifacts.cache.CacheFactory;
import de.intevation.gnv.artifacts.ressource.RessourceFactory;
import de.intevation.gnv.geobackend.base.Result;
import de.intevation.gnv.geobackend.base.query.QueryExecutor;
import de.intevation.gnv.geobackend.base.query.QueryExecutorFactory;
import de.intevation.gnv.geobackend.base.query.exception.QueryException;
import de.intevation.gnv.state.describedata.MinMaxDescribeData;
import de.intevation.gnv.state.exception.StateException;
import de.intevation.gnv.utils.InputValidator;

/**
 * This is the default implementation of <code>OutputState</code>. Artifacts
 * having reached this state or a subclass of this state are able to produce
 * some output (e.g. chart, histograms, statistic, etc).
 *
 * @author <a href="mailto:tim.englich@intevation.de">Tim Englich</a>
 * @author <a href="mailto:ingo.weinzierl@intevation.de">Ingo Weinzierl</a>
 *
 */
public abstract class OutputStateBase
extends               StateBase
implements            OutputState
{
    public static final String XPATH_OUTPUT_MODE =
        "/art:action/art:out/@name";

    public static final String XPATH_EXPORT_MODE =
        "/art:action/art:out/art:export/@name";

    public static final String XPATH_MIME_TYPE   =
        "/art:action/art:out/art:mime-type/@value";

    public static final String XPATH_EXPORTS =
        "exportModes/export";

    /**
     * The UID of this Class
     */
    private static final long serialVersionUID = -1718732895737303823L;

    /**
     * the logger, used to log exceptions and additonaly information
     */
    private static Logger log = Logger.getLogger(OutputStateBase.class);

    /**
     * The different Outputmodes which are provided by an OutputState
     */
    protected Collection<OutputMode> outputModes = null;

    protected String queryODVID = null;

    /**
     * Constructor
     */
    public OutputStateBase() {
        super();
    }

    public Collection<OutputMode> getOutputModes() {
        log.debug("OutputStateBase.getOutputModes");
        return this.outputModes;
    }


    @Override
    public void setup(Node configuration) {
        log.debug("OutputStateBase.setup");
        super.setup(configuration);

        this.queryODVID = Config.getStringXPath(configuration,"queryID-odv");

        NodeList outputModeList = Config.getNodeSetXPath(configuration,
                "outputsModes/outputsMode");
        if (outputModeList != null) {
            log.debug(outputModeList.getLength() + " were found.");
            this.outputModes = new ArrayList<OutputMode>(outputModeList
                    .getLength());
            for (int i = 0; i < outputModeList.getLength(); i++) {
                Element currentNode = (Element)outputModeList.item(i);
                String name = currentNode.getAttribute("name");
                String description =currentNode.getAttribute("description");
                String mimeType = currentNode.getAttribute("mime-type");
                NodeList inputValuesList = Config.getNodeSetXPath(currentNode,
                        "parameters/inputvalue");
                Collection<InputValue> inputParameters = null;
                if (inputValuesList != null) {
                    inputParameters = new ArrayList<InputValue>(inputValuesList
                            .getLength());
                    for (int j = 0; j < inputValuesList.getLength(); j++) {
                        Element currentInputValuesNode = (Element)inputValuesList.item(j);
                        String inputValueName = currentInputValuesNode.getAttribute("name");
                        String inputValueType = currentInputValuesNode.getAttribute("type");
                        String defaultValue =currentInputValuesNode.getAttribute("value");
                        boolean isMultiselect = false;
                        InputValue inputValue = new DefaultInputValue(
                                inputValueName, inputValueType, defaultValue,
                                isMultiselect);
                        inputParameters.add(inputValue);
                    }
                }

                // parse export modes
                List<ExportMode> exportList = null;
                NodeList exports = (NodeList) XMLUtils.xpath(
                    currentNode, XPATH_EXPORTS, XPathConstants.NODESET);

                if (exports != null) {
                    int exportSize   = exports.getLength();

                    exportList = new ArrayList<ExportMode>(exportSize);
                    for (int k = 0; k < exportSize; k++) {
                        Element exp    = (Element) exports.item(k);
                        String expName = exp.getAttribute("name");
                        String expDesc = exp.getAttribute("description");
                        String expMime = exp.getAttribute("mime-type");

                        exportList.add(
                            new DefaultExportMode(expName, expDesc, expMime));
                    }
                }

                OutputMode outputMode = new DefaultOutputMode(name,
                        description, mimeType, inputParameters, exportList);
                log.debug(outputMode.toString());
                this.outputModes.add(outputMode);

            }
        }
    }


    @Override
    public void advance(String uuid, CallContext context)
    throws StateException
    {
    }


    @Override
    public void initialize(String uuid, CallContext context)
    throws StateException
    {
    }

    /**
     * This method needs to be defined by concrete subclasses. Nothing is done
     * here.
     */
    public void out(
        Document              format,
        Collection<InputData> inputData,
        OutputStream          outputStream,
        String                uuid,
        CallMeta              callMeta
    )
    throws StateException
    {
    }

    /**
     * This method needs to be defined by concrete subclasses. Nothing is done
     * here.
     */
    public void out(String outputMode, Collection<InputData> inputData,
                    OutputStream outputStream) throws StateException {
    }

    /**
     * Returns the data used to create charts. If a cache is configured, try to
     * fetch the data from cache. The database is queried if the data is not in
     * cache yet, or if no cache is configured. If the cache is configured, but
     * the data is not in cache yet, put it into cache for a faster access
     * in a later time.
     *
     * @param uuid The uuid of an artifact.
     * @param callContext The CallContext.
     * @return the chart data.
     */
    protected Object getChartResult(String uuid, CallContext callContext) {
        log.debug("OutputStateBase.getChartResult");
        CacheFactory factory = CacheFactory.getInstance();

        if (factory.isInitialized()) {
            // we use a cache
            log.info("Using cache.");
            Cache cache = factory.getCache();
            String key  = "chart_" + getHash();

            net.sf.ehcache.Element value = cache.get(key);
            if (value != null) {
                log.debug("Found element in cache.");
                return value.getObjectValue();
            }
            else {
                log.debug("Element not in cache, we need to ask the database");
                Object result = getData(queryID);
                cache.put(new net.sf.ehcache.Element(key, result));

                return result;
            }
        }
        else {
            // we don't use a cache, so we have to query the database every
            // single time
            log.info("Not using a cache.");
            return getData(queryID);
        }
    }

    /**
     * This method should no longer be used, because it is not good to put a
     * chart into cache. Parameter changes done by the user wouldn't be detected
     * proper.
     * @deprecated
     */
    protected Object getChartFromCache(String uuid, CallContext callContext) {
        log.debug("Fetch chart [" + uuid + "] from cache");
        CacheFactory cacheFactory = CacheFactory.getInstance();
        if (cacheFactory.isInitialized()) {
            String key = "chart_" + getHash();
            net.sf.ehcache.Element object = cacheFactory.getCache().get(key);

            if (object != null) {
                return object.getObjectValue();
            }
        }
        return null;
    }

    /**
     * Retrieves the data used to create an ODV export.
     *
     * @param uuid
     * @return odv data.
     */
    protected Collection<Result> getODVResult(String uuid) {
        log.debug("OutputStateBase.getODVResult");
        // TODO add Caching? I think it's not nessessary
        Collection<Result> returnValue = null;
        if (this.queryODVID != null){
            returnValue = this.getData(this.queryODVID);
        }else{
            log.warn("No Query for ODV Data is defined.");
        }
        return returnValue;
    }

    /**
     * Retrieve data from database with help of queryID.
     *
     * @param queryID A query id defined in sql statements properties file.
     * @return some data.
     */
    protected Collection<Result> getData(String queryID) {
        log.debug("OutputStateBase.getData");
        Collection<Result> returnValue = null;
        try {
            String[] filterValues = this.generateFilterValuesFromInputData();
            try {
                QueryExecutor queryExecutor = QueryExecutorFactory
                                              .getInstance()
                                              .getQueryExecutor();
                returnValue  = queryExecutor.executeQuery(queryID,filterValues);
            } catch (RuntimeException e) {
                log.error(e, e);
            }
        } catch (QueryException e) {
            log.error(e, e);
        }
        return returnValue;
    }

    /**
     * This method removes the data used for creating charts from cache.
     *
     */
    protected void removeChartResult(String uuid) {
        log.debug("OutputStateBase.getChartResult");
        if (CacheFactory.getInstance().isInitialized()) {
            String key = "chart_" + getHash();
            log.debug("Hash for Queryelements: " + key);
            net.sf.ehcache.Element value = CacheFactory.getInstance().getCache().get(key);
            if (value != null) {
                CacheFactory.getInstance().getCache().remove(key);
            }
        }
    }

    /**
     * This method should no longer be used. It removes a chart from cache.
     *
     * @deprecated
     */
    protected void removeChart(String uuid) {
        log.debug("OutputStateBase.removeChart from cache");

        CacheFactory cacheFactory = CacheFactory.getInstance();
        if (cacheFactory.isInitialized()) {
            String key = "chart_" + getHash();
            net.sf.ehcache.Element object = cacheFactory.getCache().get(key);
            if (object != null)
                cacheFactory.getCache().remove(key);
        }
    }

    /**
     * This is an internal method used while database query.
     */
    protected void purifyChart(Object chart, String uuid) {
        log.debug("Prufify chart [" + uuid + "]");
        CacheFactory cacheFactory = CacheFactory.getInstance();
        if (cacheFactory.isInitialized()) {
            String key = "chart_" + getHash();
            cacheFactory.getCache().put(new net.sf.ehcache.Element(key, chart));
        }
    }


    /**
     * Use this method to feed a state with new data.
     */
    @Override
    public Document feed(
        CallContext           context,
        Collection<InputData> inputData,
        String                uuid)
    throws StateException
    {
        putInputData(inputData, uuid);

        return feedSuccess();
    }

    /**
     * This method is used to put new data into a next state. The difference
     * between this method and feed is, that this method should be used to
     * transfer some old input data required by this state. New data need to be
     * inserted via feed!
     */
    @Override
    public void putInputData(Collection<InputData> inputData,
                             String uuid)
                                         throws StateException {
        log.debug("OutputStateBase.putInputData");
        this.removeChartResult(uuid);
        this.removeChart(uuid);

        if (inputData != null) {
            Iterator<InputData> it = inputData.iterator();
            InputValidator iv = new InputValidator();
            while (it.hasNext()) {
                InputData tmpItem     = it.next();
                Object    tmpObj      = tmpItem.getObject();
                InputValue inputValue = this.inputValues.get(tmpItem.getName());
                if (inputValue != null) {
                    if (this.inputData == null) {
                        this.inputData = new HashMap<String, InputData>(
                                inputData.size());
                    }

                    boolean valid = InputValidator.isInputValid(tmpItem.getValue(),
                            inputValue.getType());
                    if (valid) {
                        if (tmpItem.getName().equals(MINVALUEFIELDNAME)){
                            String minValue = tmpItem.getValue();
                            String maxValue = getInputValue4ID(inputData, MAXVALUEFIELDNAME);
                            valid = InputValidator.isInputValid(maxValue,inputValue.getType());
                            if (!valid){
                                String errMsg = "Wrong input for " + tmpItem.getValue()
                                                + " is not an " + inputValue.getType()
                                                + " Value.";
                                log.warn(errMsg);
                                throw new StateException(errMsg);
                            }

                            valid = InputValidator.isInputValid(minValue,
                                    maxValue,
                                    inputValue.getType());
                            if (!valid){
                                String errMsg = "MaxValue-Input is less than MinValue-Input ";
                                log.warn(errMsg);
                                throw new StateException(errMsg);
                            }
                        }else if (tmpItem.getName().equals(MAXVALUEFIELDNAME)){
                            String minValue = getInputValue4ID(inputData, MINVALUEFIELDNAME);
                            String maxValue = tmpItem.getValue();
                            valid = InputValidator.isInputValid(minValue,inputValue.getType());
                            if (!valid){
                                String errMsg = "Wrong input for " + tmpItem.getValue()
                                                + " is not an " + inputValue.getType()
                                                + " Value.";
                                log.warn(errMsg);
                                throw new StateException(errMsg);
                            }

                            valid = InputValidator.isInputValid(minValue,
                                                    maxValue,
                                                    inputValue.getType());
                            if (!valid){
                                String errMsg = "MaxValue-Input is less than MinValue-Input ";
                                log.warn(errMsg);
                                throw new StateException(errMsg);
                            }
                        }
                        this.inputData.put(tmpItem.getName(), tmpItem);
                    } else {
                        String errMsg = "Wrong input for " + tmpItem.getValue()
                                        + " is not an " + inputValue.getType()
                                        + " Value.";
                        log.warn(errMsg);
                        throw new StateException(errMsg);
                    }

                }
                else if (tmpObj != null && tmpObj instanceof MinMaxDescribeData) {
                    MinMaxDescribeData data = (MinMaxDescribeData) tmpObj;
                    if (this.inputData == null) {
                        this.inputData = new HashMap<String, InputData>(inputData.size());
                    }
                    this.inputData.put(tmpItem.getName(), tmpItem);
                    this.inputData.put("minvalue", new DefaultInputData("minvalue", (String) data.getMinValue()));
                    this.inputData.put("maxvalue", new DefaultInputData("maxvalue", (String) data.getMaxValue()));
                }
                else {

                    String errMsg = "No Inputvalue given for Inputdata "
                                    + tmpItem.getName();
                    log.warn(errMsg + "Value will be ignored");

                }
            }
        } else {
            log.warn("No Inputdata given");
        }
        setHash(uuid);
    }


    public void out(
        String                outputMode,
        Collection<InputData> inputData,
        OutputStream          outputStream,
        String                uuid,
        CallMeta              callMeta)
    throws StateException { }


    /**
     * Retrieves a message from resource bundle specified by locale.
     *
     * @param locale Locale to use.
     * @param key The key of the message.
     * @param value The default value.
     * @return The value.
     */
    protected String getMessage(Locale locale, String key, String value) {
        return RessourceFactory.getInstance().getRessource(
            locale,
            key,
            value
        );
    }
}
// vim:set ts=4 sw=4 si et sta sts=4 fenc=utf8 :