/** 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.common;

import java.text.DateFormat;
import java.text.NumberFormat;
import java.util.Date;
import java.util.HashMap;
import java.util.Locale;
import java.util.Map;

import org.apache.commons.lang.StringUtils;
import org.dive4elements.artifacts.CallContext;
import org.dive4elements.artifacts.CallMeta;
import org.dive4elements.river.artifacts.resources.Resources;

/**
 * @author Domenico Nardi Tironi
 */
public abstract class AbstractResultType implements IResultType {

    /* Cache for formatters because Formatter will always create new formats (which is very expensive) */
    private final Map<Locale, NumberFormat> formatters = new HashMap<>();

    private final String unit;

    private final String csvHeader;

    private final String pdfHeader;

    protected AbstractResultType(final String unit, final String csvHeader, final String pdfHeader) {
        this.unit = unit;
        this.csvHeader = csvHeader;
        this.pdfHeader = pdfHeader;

    }

    @Override
    public abstract String exportValue(final CallContext context, final Object value);

    protected final String exportStringValue(final Object value) {

        if (value == null)
            return StringUtils.EMPTY;

        if (!(value instanceof String))
            throw new IllegalStateException();

        return (String) value;
    }

    @Override
    public final double asDouble(final Object value) {
        if (value == null)
            return Double.NaN;

        if (!(value instanceof Number))
            throw new IllegalStateException();

        final Number number = (Number) value;
        return number.doubleValue();
    }

    protected final String exportDoubleValue(final CallContext context, final double value) {
        if (Double.isNaN(value))
            return StringUtils.EMPTY;

        final NumberFormat formatter = getFormatter(context);
        return formatter.format(value);
    }

    private NumberFormat getFormatter(final CallContext context) {
        final CallMeta meta = context.getMeta();
        final Locale locale = Resources.getLocale(meta);

        if (!this.formatters.containsKey(locale))
            this.formatters.put(locale, createFormatter(context));

        return this.formatters.get(locale);
    }

    protected abstract NumberFormat createFormatter(CallContext context);

    protected final String exportDateValue(final CallContext context, final Date value) {
        final Locale locale = Resources.getLocale(context.getMeta());
        final DateFormat df = DateFormat.getDateInstance(DateFormat.MEDIUM, locale);
        return df.format(value);
    }

    @Override
    public final String getCsvHeader() {
        return this.csvHeader;
    }

    public final String getCsvHeader(final CallMeta meta) {
        return Resources.getMsg(meta, this.csvHeader, this.csvHeader);
    }

    @Override
    public final String getPdfHeader(final CallMeta meta) {
        return Resources.getMsg(meta, this.pdfHeader, this.pdfHeader);
    }

    @Override
    public final String getUnit() {
        return this.unit;
    }
}