package de.intevation.flys.artifacts.services;

import java.math.BigDecimal;
import java.util.List;

import org.apache.log4j.Logger;

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

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

import de.intevation.flys.artifacts.model.RiverFactory;
import de.intevation.flys.model.Gauge;
import de.intevation.flys.model.MinMaxWQ;
import de.intevation.flys.model.Range;
import de.intevation.flys.model.River;

/**
 * @author <a href="mailto:bjoern.ricks@intevation.de">Björn Ricks</a>
 */
public class GaugeOverviewInfoService extends FLYSService {

    private static final Logger logger = Logger.getLogger(
            GaugeOverviewInfoService.class);

    public static final String RIVER_XPATH = "/art:river/text()";

    @Override
    public Document doProcess(
        Document      data,
        GlobalContext globalContext,
        CallMeta      callMeta
    ) {
        logger.debug("GaugeOverviewInfoService.process");

        String riverstr = XMLUtils.xpathString(
            data, RIVER_XPATH, ArtifactNamespaceContext.INSTANCE);

        River river = RiverFactory.getRiver(riverstr);

        Document result = XMLUtils.newDocument();

        if (river == null) {
            logger.warn("No river with name " + riverstr + " found.");
            return result;
        }

        XMLUtils.ElementCreator ec = new XMLUtils.ElementCreator(
            result,
            ArtifactNamespaceContext.NAMESPACE_URI,
            ArtifactNamespaceContext.NAMESPACE_PREFIX);

        Element go = ec.create("gauge-info");

        double[] minmax  = river.determineMinMaxDistance();
        double[] minmaxq = river.determineMinMaxQ();

        Element r = ec.create("river");
        ec.addAttr(r, "name", river.getName(), true);
        ec.addAttr(r, "start", Double.toString(minmax[0]), true);
        ec.addAttr(r, "end", Double.toString(minmax[1]), true);
        ec.addAttr(r, "wstunit", river.getWstUnit().getName(), true);
        ec.addAttr(r, "kmup", Boolean.toString(river.getKmUp()), true);
        ec.addAttr(r, "minq", Double.toString(minmaxq[0]), true);
        ec.addAttr(r, "maxq", Double.toString(minmaxq[1]), true);

        Element egs = ec.create("gauges");

        List<Gauge> gauges = river.getGauges();

        if (logger.isDebugEnabled()) {
            logger.debug("Loaded gauges: " + gauges);
        }

        for (Gauge gauge: river.getGauges()) {
            Element eg = ec.create("gauge");

            String name = gauge.getName();
            if (name != null) {
                ec.addAttr(eg, "name", gauge.getName(), true);
            }

            String aeo = getGaugeValue(gauge.getAeo());
            if (aeo != null) {
                ec.addAttr(eg, "aeo", aeo, true);
            }

            String datum = getGaugeValue(gauge.getDatum());
            if (datum != null) {
                ec.addAttr(eg, "datum", datum, true);
            }

            Range range = gauge.getRange();
            if (range != null) {
                BigDecimal a = range.getA();
                if (a != null) {
                    double min = a.doubleValue();
                    ec.addAttr(eg, "start", Double.toString(min), true);
                }

                BigDecimal b = range.getB();
                if (b != null) {
                    double max = range.getB().doubleValue();
                    ec.addAttr(eg, "end", Double.toString(max), true);
                }
            }
            MinMaxWQ minmaxwq = gauge.fetchMaxMinWQ();
            String minw = getGaugeValue(minmaxwq.getMinW());
            String maxw = getGaugeValue(minmaxwq.getMaxW());
            String minq = getGaugeValue(minmaxwq.getMinQ());
            String maxq = getGaugeValue(minmaxwq.getMaxQ());

            if (minw != null) {
                ec.addAttr(eg, "minw", minw, true);
            }
            if (maxw != null) {
                ec.addAttr(eg, "maxw", maxw, true);
            }
            if (minq != null) {
                ec.addAttr(eg, "minq", minq, true);
            }
            if (maxq != null) {
                ec.addAttr(eg, "maxq", maxq, true);
            }

            String station = getGaugeValue(gauge.getStation());
            if (station != null) {
                ec.addAttr(eg, "station", station, true);
            }

            egs.appendChild(eg);
        }

        go.appendChild(r);
        go.appendChild(egs);
        result.appendChild(go);

        return result;
    }

    /**
     * Returns a Double from a BigDecimal value or null if value is null
     */
    private static String getGaugeValue(BigDecimal value) {
        return value != null
            ? Double.toString(value.doubleValue())
            : "";
    }
}