/* 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.sinfo.flowdepth;

import java.util.Collection;

import org.apache.commons.lang.math.DoubleRange;
import org.dive4elements.artifacts.CallContext;
import org.dive4elements.river.artifacts.model.Calculation;
import org.dive4elements.river.artifacts.model.CalculationResult;
import org.dive4elements.river.artifacts.model.WKms;
import org.dive4elements.river.artifacts.resources.Resources;
import org.dive4elements.river.artifacts.sinfo.SINFOArtifact;
import org.dive4elements.river.artifacts.sinfo.common.RiverInfoProvider;
import org.dive4elements.river.artifacts.sinfo.tkhcalculation.DischargeValuesFinder;
import org.dive4elements.river.artifacts.sinfo.tkhcalculation.TkhCalculator;
import org.dive4elements.river.artifacts.sinfo.tkhcalculation.WaterlevelValuesFinder;
import org.dive4elements.river.artifacts.sinfo.tkhstate.BedHeightsFinder;
import org.dive4elements.river.artifacts.sinfo.util.CalculationUtils;
import org.dive4elements.river.artifacts.sinfo.util.RiverInfo;
import org.dive4elements.river.artifacts.sinfo.util.WstInfo;
import org.dive4elements.river.artifacts.states.WaterlevelData;
import org.dive4elements.river.artifacts.states.WaterlevelFetcher;
import org.dive4elements.river.model.River;

class FlowDepthCalculation {

    // private static Logger log = Logger.getLogger(FlowDepthCalculation.class);

    private final CallContext context;

    public FlowDepthCalculation(final CallContext context) {
        this.context = context;
    }

    public CalculationResult calculate(final SINFOArtifact sinfo) {

        final String user = CalculationUtils.findArtifactUser(this.context, sinfo);

        /* access input data */
        final FlowDepthAccess access = new FlowDepthAccess(sinfo);
        final River river = access.getRiver();
        final RiverInfo riverInfo = new RiverInfo(river);

        final Collection<WstSoundingIdPair> diffPairs = access.getDifferencePairs();

        final DoubleRange calcRange = access.getRange();

        final boolean useTkh = access.isUseTransportBodies();

        /* calculate results for each diff pair */
        final Calculation problems = new Calculation();

        final RiverInfoProvider infoProvider = RiverInfoProvider.forRange(this.context, river, calcRange);

        final String calcModeLabel = Resources.getMsg(this.context.getMeta(), sinfo.getCalculationMode().name());

        final FlowDepthCalculationResults results = new FlowDepthCalculationResults(calcModeLabel, user, riverInfo, calcRange, useTkh);

        for (final WstSoundingIdPair diffPair : diffPairs) {
            final FlowDepthCalculationResult result = calculateResult(calcRange, diffPair, problems, infoProvider, useTkh);
            if (result != null)
                results.addResult(result);
        }

        return new CalculationResult(results, problems);
    }

    /**
     * Calculates one W-MSH differences pair.
     *
     * @param infoProvider
     */
    private FlowDepthCalculationResult calculateResult(final DoubleRange calcRange, final WstSoundingIdPair diffPair, final Calculation problems,
            final RiverInfoProvider infoProvider, final boolean useTkh) {

        /* access real input data from database */
        final String soundingId = diffPair.getSoundingId();
        final String wstId = diffPair.getWstId();

        final BedHeightsFinder bedHeight = BedHeightsFinder.forId(this.context, soundingId, calcRange, problems);
        if (bedHeight == null)
            return null;

        /* REMARK: fetch ALL wst kms, because we want to determine the original reference gauge */
        final WaterlevelData waterlevel = new WaterlevelFetcher().findWaterlevel(this.context, wstId, Double.NaN, Double.NaN, problems);
        if (waterlevel == null)
            return null;

        final WKms wstKms = waterlevel.getWkms();

        final String wspLabel = wstKms.getName();
        final String soundingLabel = bedHeight.getInfo().getDescription();
        final String label = String.format("%s - %s", wspLabel, soundingLabel);

        FlowDepthUtils.checkYearDifference(label, waterlevel, bedHeight.getInfo().getYear(), problems);
        checkWaterlevelDiscretisation(wstKms, calcRange, problems);
        // TODO: prüfen, ob sohlhöhen die calcRange abdecken/überschneiden

        /* re-determine the reference gauge, in the same way as the WaterlevelArtifact would do it */
        final RiverInfoProvider riverInfoProvider = infoProvider.forWaterlevel(waterlevel);

        final int wspYear = waterlevel.getYear();
        final WstInfo wstInfo = new WstInfo(wspLabel, wspYear, riverInfoProvider.getReferenceGauge());

        final WaterlevelValuesFinder waterlevelProvider = WaterlevelValuesFinder.fromKms(wstKms);
        final DischargeValuesFinder dischargeProvider = DischargeValuesFinder.fromKms(wstKms);

        final River river = riverInfoProvider.getRiver();
        final TkhCalculator tkhCalculator = TkhCalculator.buildTkhCalculator(useTkh, this.context, problems, label, river, calcRange, waterlevelProvider,
                dischargeProvider,
                bedHeight);

        final FlowDepthCalculator calculator = new FlowDepthCalculator(riverInfoProvider, wspLabel, bedHeight, tkhCalculator);
        return calculator.execute(label, wstInfo, calcRange);
    }

    /* Checks if the discretisation of the waterlevel exceeds 1000m */
    private void checkWaterlevelDiscretisation(final WKms wstKms, final DoubleRange calcRange, final Calculation problems) {

        final int size = wstKms.size();
        for (int i = 0; i < size - 2; i++) {
            final double kmPrev = wstKms.getKm(i);
            final double kmNext = wstKms.getKm(i + 1);

            /* only check if we are within the calculation range */
            if (calcRange.overlapsRange(new DoubleRange(kmPrev, kmNext))) {
                if (Math.abs(kmPrev - kmNext) > 1) {
                    final String label = wstKms.getName();

                    final String message = Resources.getMsg(this.context.getMeta(), "sinfo_calc_flow_depth.warning.waterlevel_discretisation", null, label);
                    problems.addProblem(kmPrev, message);
                }
            }
        }
    }
}