package de.intevation.flys.exports;

import java.io.IOException;
import java.io.OutputStream;
import java.text.NumberFormat;
import java.util.ArrayList;
import java.util.List;

import org.w3c.dom.Document;

import org.apache.log4j.Logger;

import au.com.bytecode.opencsv.CSVWriter;

import de.intevation.artifacts.Artifact;
import de.intevation.artifacts.CallContext;

import de.intevation.flys.artifacts.WINFOArtifact;
import de.intevation.flys.artifacts.model.WQKms;
import de.intevation.flys.utils.Formatter;


/**
 * @author <a href="mailto:ingo.weinzierl@intevation.de">Ingo Weinzierl</a>
 */
public class WaterlevelExporter extends AbstractExporter {

    /** The logger used in this exporter.*/
    private static Logger logger = Logger.getLogger(WaterlevelExporter.class);


    public static final String FACET_WST = "wst";


    public static final String CSV_KM_HEADER =
        "export.waterlevel.csv.header.km";

    public static final String CSV_W_HEADER =
        "export.waterlevel.csv.header.w";

    public static final String CSV_Q_HEADER =
        "export.waterlevel.csv.header.q";

    public static final String DEFAULT_CSV_KM_HEADER = "Fluss-Km";
    public static final String DEFAULT_CSV_W_HEADER  = "W [NN + m]";
    public static final String DEFAULT_CSV_Q_HEADER  = "Q [m\u00b3/s]";


    /** The storage that contains all WQKms objects for the different facets.*/
    protected List<WQKms[]> data;


    public void init(Document request, OutputStream out, CallContext context) {
        logger.debug("WaterlevelExporter.init");

        super.init(request, out, context);

        this.data = new ArrayList<WQKms[]>();
    }


    @Override
    public void generate()
    throws IOException
    {
        logger.debug("WaterlevelExporter.generate");

        if (facet != null && facet.equals(AbstractExporter.FACET_CSV)) {
            generateCSV();
        }
        else if (facet != null && facet.equals(FACET_WST)) {
            generateWST();
        }
        else {
            throw new IOException("invalid facet for exporter");
        }
    }


    @Override
    protected void addData(Object d) {
        if (d instanceof WQKms []) {
            data.add((WQKms [])d);
        }
    }


    /**
     * Returns the waterlevel data computed by the WINFOArtifact.
     *
     * @param artifact The WINFOArtifact.
     *
     * @return the computed waterlevel data.
     */
    protected WQKms[] getWaterlevelData(Artifact artifact) {
        WINFOArtifact winfoArtifact = (WINFOArtifact) artifact;
        WQKms[]       wqkms         = winfoArtifact.getWaterlevelData();

        logger.debug("Got " + wqkms.length + " WQKms objects.");

        return wqkms;
    }


    @Override
    protected void writeCSVData(CSVWriter writer) {
        logger.info("WaterlevelExporter.writeData");

        writeCSVHeader(writer);

        for (WQKms[] tmp: data) {
            for (WQKms wqkms: tmp) {
                wQKms2CSV(writer, wqkms);
            }
        }
    }


    protected void writeCSVHeader(CSVWriter writer) {
        logger.info("WaterlevelExporter.writeCSVHeader");

        writer.writeNext(new String[] {
            msg(CSV_KM_HEADER, DEFAULT_CSV_KM_HEADER),
            msg(CSV_W_HEADER, DEFAULT_CSV_W_HEADER),
            msg(CSV_Q_HEADER, DEFAULT_CSV_Q_HEADER)
        });
    }


    protected void wQKms2CSV(CSVWriter writer, WQKms wqkms) {
        logger.debug("WaterlevelExporter.wQKms2CSV");

        NumberFormat kmf = getKmFormatter();
        NumberFormat wf  = getWFormatter();
        NumberFormat qf  = getQFormatter();

        int      size   = wqkms.size();
        double[] result = new double[3];

        for (int i = 0; i < size; i ++) {
            result = wqkms.get(i, result);

            writer.writeNext(new String[] {
                kmf.format(result[2]),
                wf.format(result[0]),
                qf.format(result[1])
            });
        }
    }


    /**
     * Generates the output in WST format.
     */
    protected void generateWST()
    throws    IOException
    {
        logger.info("WaterlevelExporter.generateWST");

        int cols = data.get(0).length;
        WstWriter writer = new WstWriter(cols);

        writeWSTData(writer);

        writer.write(out);
    }


    protected void writeWSTData(WstWriter writer) {
        logger.debug("WaterlevelExporter.writeWSTData");

        double[] result = new double[3];

        for (WQKms[] tmp: data) {
            for (WQKms wqkms: tmp) {
                int size = wqkms != null ? wqkms.size() : 0;

                addWSTColumn(writer, wqkms);

                for (int i = 0; i < size; i++) {
                    result = wqkms.get(i, result);

                    writer.add(result);
                }
            }
        }
    }


    protected void addWSTColumn(WstWriter writer, WQKms wqkms) {
        writer.addColumn(wqkms.getName());
    }


    /**
     * Returns the number formatter for kilometer values.
     *
     * @return the number formatter for kilometer values.
     */
    protected NumberFormat getKmFormatter() {
        return Formatter.getWaterlevelKM(context);
    }


    /**
     * Returns the number formatter for W values.
     *
     * @return the number formatter for W values.
     */
    protected NumberFormat getWFormatter() {
        return Formatter.getWaterlevelW(context);
    }


    /**
     * Returns the number formatter for Q values.
     *
     * @return the number formatter for Q values.
     */
    protected NumberFormat getQFormatter() {
        return Formatter.getWaterlevelQ(context);
    }
}
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