package de.intevation.flys.artifacts.model.sq;

import de.intevation.flys.artifacts.access.SQRelationAccess;

import de.intevation.flys.artifacts.math.fitting.Function;
import de.intevation.flys.artifacts.math.fitting.FunctionFactory;

import de.intevation.flys.artifacts.model.Calculation;
import de.intevation.flys.artifacts.model.CalculationResult;
import de.intevation.flys.artifacts.model.DateRange;
import de.intevation.flys.artifacts.model.Parameters;

import de.intevation.flys.backend.SedDBSessionHolder;

import java.util.ArrayList;
import java.util.List;

import org.apache.log4j.Logger;

public class SQRelationCalculation extends Calculation {

    private static final Logger log =
        Logger.getLogger(SQRelationCalculation.class);

    public static final String SQ_FUNCTION_NAME = "sq-pow";

    protected String    river;
    protected double    location;
    protected DateRange period;
    protected double    outliers;

    public SQRelationCalculation() {
    }

    public SQRelationCalculation(SQRelationAccess access) {

        String    river    = access.getRiver();
        Double    location = access.getLocation();
        DateRange period   = access.getPeriod();
        Double    outliers = access.getOutliers();

        //river = "Rhein";

        if (river == null) {
            // TODO: i18n
            addProblem("sq.missing.river");
        }

        if (location == null) {
            // TODO: i18n
            addProblem("sq.missing.location");
        }

        if (period == null) {
            // TODO: i18n
            addProblem("sq.missing.periods");
        }

        if (outliers == null) {
            // TODO: i18n
            addProblem("sq.missing.outliers");
        }

        if (!hasProblems()) {
            this.river    = river;
            this.location = location;
            this.period   = period;
            this.outliers = outliers;
        }
    }


    public CalculationResult calculate() {
        log.debug("SQRelationCalculation.calculate");

        if (hasProblems()) {
            return new CalculationResult(this);
        }

        SedDBSessionHolder.acquire();
        try {
            return internalCalculate();
        }
        finally {
            SedDBSessionHolder.release();
        }
    }

    protected CalculationResult internalCalculate() {

        boolean debug = log.isDebugEnabled();

        Function function = FunctionFactory
            .getInstance()
            .getFunction(SQ_FUNCTION_NAME);

        if (function == null) {
            log.error("No '" + SQ_FUNCTION_NAME + "' function found.");
            // TODO: i18n
            addProblem("sq.missing.sq.function");
        }

        String [] parameterNames = function.getParameterNames();

        Measurements measurements =
            MeasurementFactory.getMeasurements(river, location, period);

        SQFractionResult [] fractionResults =
            new SQFractionResult[SQResult.NUMBER_FRACTIONS];

        for (int i = 0; i < fractionResults.length; ++i) {
            List<SQ> sqs = measurements.getSQs(i);

            SQFractionResult fractionResult;

            List<SQFractionResult.Iteration> iterations =
                doFitting(function, sqs);

            if (iterations == null) {
                // TODO: i18n
                addProblem("sq.fitting.failed." + i);
                fractionResult = new SQFractionResult();
            }
            else {
                fractionResult = new SQFractionResult(
                    sqs.toArray(new SQ[sqs.size()]),
                    iterations);
            }

            fractionResults[i] = fractionResult;
        }

        return new CalculationResult(
            new SQResult[] { new SQResult(location, fractionResults) },
            this);
    }

    protected List<SQFractionResult.Iteration> doFitting(
        final Function function,
        List<SQ> sqs
    ) {
        final List<SQFractionResult.Iteration> iterations =
            new ArrayList<SQFractionResult.Iteration>();

        boolean success = new Fitting(function, outliers).fit(
            sqs,
            new Fitting.Callback() {
                @Override
                public void afterIteration(
                    double [] coeffs,
                    SQ []     measurements,
                    SQ []     outliers,
                    double    standardDeviation,
                    double    chiSqr
                ) {
                    Parameters parameters = createParameters(
                        function.getParameterNames(),
                        coeffs,
                        standardDeviation,
                        chiSqr);
                    iterations.add(new SQFractionResult.Iteration(
                        parameters,
                        measurements,
                        outliers));
                }
            });

        return success ? iterations : null;
    }

    public static final Parameters createParameters(
        String [] names,
        double [] values,
        double    standardDeviation,
        double    chiSqr
    ) {
        String [] columns = new String[names.length + 2];
        columns[0] = "chi_sqr";
        columns[1] = "std_dev";
        System.arraycopy(names, 0, columns, 2, names.length);
        Parameters parameters = new Parameters(columns);
        int row = parameters.newRow();
        parameters.set(row, names, values);
        parameters.set(row, "chi_sqr", chiSqr);
        parameters.set(row, "std_dev", standardDeviation);
        return parameters;
    }
}
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