/** Copyright (C) 2017 by Bundesanstalt für Gewässerkunde
 * Software engineering by
 *  Björnsen Beratende Ingenieure GmbH
 *  Dr. Schumacher Ingenieurbüro für Wasser und Umwelt
 *
 * This file is Free Software under the GNU AGPL (>=v3)
 * and comes with ABSOLUTELY NO WARRANTY! Check out the
 * documentation coming with Dive4Elements River for details.
 */
package org.dive4elements.river.artifacts.states;

import java.util.Calendar;
import java.util.Date;
import java.util.List;

import org.apache.commons.lang.math.DoubleRange;
import org.apache.log4j.Logger;
import org.dive4elements.artifacts.CallContext;
import org.dive4elements.river.artifacts.D4EArtifact;
import org.dive4elements.river.artifacts.FixationArtifact;
import org.dive4elements.river.artifacts.StaticWKmsArtifact;
import org.dive4elements.river.artifacts.StaticWQKmsArtifact;
import org.dive4elements.river.artifacts.WINFOArtifact;
import org.dive4elements.river.artifacts.access.FixRealizingAccess;
import org.dive4elements.river.artifacts.model.Calculation;
import org.dive4elements.river.artifacts.model.CalculationResult;
import org.dive4elements.river.artifacts.model.Segment;
import org.dive4elements.river.artifacts.model.WKms;
import org.dive4elements.river.artifacts.model.WQKms;
import org.dive4elements.river.artifacts.model.WstColumnFactory;
import org.dive4elements.river.artifacts.model.fixings.FixRealizingCalculationExtended;
import org.dive4elements.river.artifacts.model.fixings.FixRealizingResult;
import org.dive4elements.river.artifacts.states.DefaultState.ComputeType;
import org.dive4elements.river.model.TimeInterval;
import org.dive4elements.river.model.WstColumn;
import org.dive4elements.river.utils.RiverUtils;

/**
 * Helper class that accesses existing waterlevels (in most cases) from the data-cage.
 * This is mainly a refaktoring of org.dive4elements.river.artifacts.states.WDifferencesState.getWKms(String,
 * CallContext, double, double), adding more infos to the fetched water levels.
 *
 * @author Gernot Belger
 */
public class WaterlevelFetcher {
    private static Logger log = Logger.getLogger(WaterlevelFetcher.class);

    /**
     * @param simulationRange
     *            This range is used to check if the found waterlevel covers it. It is NOT used to reduce the fetched data,
     *            because in case of waterlevels we always need to full set in order to determine the relevant gauge.
     */
    public WaterlevelData findWaterlevel(final CallContext context, final String mingle, final DoubleRange simulationRange, final Calculation problems) {

        final String[] def = mingle.split(";");
        final String uuid = def[0];
        // final String factory = def[1];
        final int idx = Integer.parseInt(def[2]);
        final String name = def[3];
        final D4EArtifact d4eArtifact = RiverUtils.getArtifact(uuid, context);
        if (d4eArtifact == null)
            return null;

        final WaterlevelData data = fetchWaterlevelFromArtifact(context, d4eArtifact, idx, Double.NaN, Double.NaN);
        if (data == null) {
            problems.addProblem("waterlevelfetcher.missing", mingle);
            return null;
        }

        if (!data.covers(simulationRange)) {
            problems.addProblem("waterlevelfetcher.empty", data.getName());
            return null;
        }

        return data.withName(name);
    }

    private WaterlevelData fetchWaterlevelFromArtifact(final CallContext context, final D4EArtifact d4eArtifact, final int idx, final double from,
            final double to) {

        if (d4eArtifact instanceof StaticWKmsArtifact) {
            return fetchStaticWKmsArtifactWaterlevel((StaticWKmsArtifact) d4eArtifact, idx, from, to);
        }

        if (d4eArtifact instanceof StaticWQKmsArtifact) {
            return fetchStaticWQKmsArtifactWaterlevel((StaticWQKmsArtifact) d4eArtifact, from, to);
        }

        if (d4eArtifact instanceof WINFOArtifact)
            return fetchWINFOArtifactWaterlevel(context, (WINFOArtifact) d4eArtifact, idx, from, to);

        if (d4eArtifact instanceof FixationArtifact)
            return fetchFixationArtifactWaterlevel(context, (FixationArtifact) d4eArtifact, idx, from, to);

        log.warn(String.format("Get Waterlevel from %s not implemented!", d4eArtifact.getClass().getSimpleName()));
        return null;
    }

    // REMARK: instead of several helper methods here this would be a good place for abstraction, in order to push
    // this logic back to the corresponding artifacts. However this will most certainly break existing
    // artifact-serialization

    private WaterlevelData fetchStaticWKmsArtifactWaterlevel(final StaticWKmsArtifact staticWKms, final int idx, final double from, final double to) {

        log.debug("WDifferencesState obtain data from StaticWKms");

        final WKms wkms = staticWKms.getWKms(idx, from, to);

        if (wkms != null) {
            final int year = fetchStaticWKmsYear(staticWKms);
            return new WaterlevelData(wkms, year);
        }

        log.error("No WKms from Static artifact for this range.");
        return null;
    }

    private WaterlevelData fetchStaticWQKmsArtifactWaterlevel(final StaticWQKmsArtifact staticWKms, final double from, final double to) {

        log.debug("WDifferencesState obtain data from StaticWQKms");

        final WQKms wkms = staticWKms.getWQKms(from, to);

        if (wkms != null) {
            final int year = fetchStaticWKmsYear(staticWKms);
            return new WaterlevelData(wkms, year);
        }

        log.error("No WKms from Static artifact for this range.");
        return null;
    }

    private WaterlevelData fetchWINFOArtifactWaterlevel(final CallContext context, final WINFOArtifact flys, final int idx, final double from,
            final double to) {
        log.debug("Get WKms from WINFOArtifact");

        final WKms[] wkms = (WKms[]) flys.getWaterlevelData(context).getData();

        if (wkms == null || wkms.length == 0) {
            log.warn("no waterlevels in artifact");
            return null;
        }

        if (wkms.length < idx + 1) {
            log.warn("Not enough waterlevels in artifact.");
            return null;
        }

        // REAMRK: W_INFO results does not know any 'year'
        final int year = -1;
        return new WaterlevelData(wkms[idx], year).filterByRange(from, to);
    }

    private WaterlevelData fetchFixationArtifactWaterlevel(final CallContext context, final FixationArtifact fixation, final int idx, final double from,
            final double to) {

        log.debug("Get WKms from FixationArtifact.");

        final CalculationResult r = (CalculationResult) fixation.compute(context, ComputeType.ADVANCE, false);
        final FixRealizingResult frR = (FixRealizingResult) r.getData();

        // Get W/Q input per gauge for this case.
        final FixRealizingAccess fixAccess = new FixRealizingAccess(fixation);
        final List<Segment> segments = fixAccess.getSegments();
        final boolean isFixRealize = (segments != null && !segments.isEmpty());

        /* ugly but necessary to keep this logic at least a bit inside the FixRealizing stuff */
        final FixRealizingCalculationExtended calculation = new FixRealizingCalculationExtended(fixAccess);
        final int year = calculation.determineMeanYear();

        // REMARK: same logic as in WaterlevelExporter
        final boolean showAllGauges = isFixRealize;

        return new WaterlevelData(frR.getWQKms()[idx], year, showAllGauges).filterByRange(from, to);
    }

    /**
     * Fetches the 'year' for a staticXXX-artifact.
     * REMARK: actually this should happen inside the staticWKms artifact and eventually in the WKmsFactory, but the code
     * there is already awful and it will also break the old artifact-serialization...
     */
    private int fetchStaticWKmsYear(final D4EArtifact staticWKms) {

        final int colPos = Integer.parseInt(staticWKms.getDataAsString("col_pos"));
        final int wstId = Integer.parseInt(staticWKms.getDataAsString("wst_id"));

        final WstColumn wstColumn = WstColumnFactory.getWstColumn(wstId, colPos);
        final TimeInterval timeInterval = wstColumn.getTimeInterval();
        if (timeInterval == null)
            return -1;

        final Date startTime = timeInterval.getStartTime();
        if (startTime == null)
            return -1;

        // REMARK: the times are stored without timezone in the DB, so it is unclear what hibernate makes of it.
        // We simply use the default timezone here and hope we never get problems...
        // Actually we always have 12:00 as time in the db data, so a smal timeshift due to winter/sommertime or UTC/GMT+1 will
        // no change anything regarding the year.
        final Calendar cal = Calendar.getInstance();
        cal.setTime(startTime);
        return cal.get(Calendar.YEAR);
    }
}