/* 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.importer.sinfo.parsers;

import java.io.File;
import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Date;
import java.util.EnumMap;
import java.util.HashMap;
import java.util.List;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import org.apache.log4j.Logger;
import org.dive4elements.river.importer.Config;
import org.dive4elements.river.importer.ImportRiver;
import org.dive4elements.river.importer.ImporterSession;
import org.dive4elements.river.importer.common.AbstractParser;
import org.dive4elements.river.importer.common.ParsingState;
import org.dive4elements.river.importer.sinfo.importitem.CollisionKmLineImport;
import org.dive4elements.river.importer.sinfo.importitem.CollisionSeriesImport;
import org.dive4elements.river.importer.sinfo.importitem.CollisionTypeImport;
import org.dive4elements.river.model.sinfo.Collision;
import org.dive4elements.river.model.sinfo.CollisionType;
import org.dive4elements.river.model.sinfo.CollisionValue;
import org.hibernate.Session;

/**
 * Reads and parses a collision file
 *
 * @author Matthias Schäfer
 *
 */
public class CollisionParser extends AbstractParser<Collision, CollisionValue, CollisionKmLineImport, CollisionSeriesImport> {

    /***** FIELDS *****/

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

    private static final Pattern META_YEAR = Pattern.compile("^#\\sJahr:\\s*([12]\\d\\d\\d).*", Pattern.CASE_INSENSITIVE);

    private enum ColTitlePattern {
        DATE("Datum.*"), //
        GAUGE_W("Pegelstand\\s*\\[cm\\].*"), //
        GAUGE_NAME("Bezugspegel.*"), //
        TYPE("Unfallart.*");

        private final Pattern pattern;

        ColTitlePattern(final String regexp) {
            this.pattern = Pattern.compile(regexp, Pattern.CASE_INSENSITIVE);
        }

        public Pattern getPattern() {
            return this.pattern;
        }
    }

    private static final DateFormat dateFormat = new SimpleDateFormat("dd.MM.yyyy");

    private final EnumMap<ColTitlePattern, Integer> cols = new EnumMap<>(ColTitlePattern.class);

    private final HashMap<String, CollisionTypeImport> types;


    /***** CONSTRUCTORS *****/

    public CollisionParser(final File importPath, final File rootRelativePath, final ImportRiver river) {
        super(importPath, rootRelativePath, river);
        logDebug("CollisionParser.new: calling ImporterSession.getInstance");
        final Session session = ImporterSession.getInstance().getDatabaseSession();
        this.types = new HashMap<>();
        for (final CollisionType type : CollisionType.getTypes(session))
            this.types.put(type.getName().trim().toLowerCase(), new CollisionTypeImport(type.getName()));
    }


    /***** METHODS *****/

    @Override
    protected Logger getLog() {
        return log;
    }

    /**
     * Whether this import type shall be skipped
     */
    public static boolean shallSkip() {
        return Config.INSTANCE.skipSInfoCollision();
    }

    /**
     * Creates a list of parsers for all collision import files in a directory
     */
    public static List<CollisionParser> createParsers(final File importDir, final File relativeDir, final ImportRiver river) {
        final List<CollisionParser> parsers = new ArrayList<>();
        if (importDir.exists()) {
            for (final File file : listFiles(importDir, ".csv"))
                parsers.add(new CollisionParser(file, new File(relativeDir, file.getName()), river));
        }
        return parsers;
    }

    @Override
    protected CollisionSeriesImport createSeriesImport(final String filename) {
        return new CollisionSeriesImport(filename);
    }

    @Override
    protected KmMode kmMode() {
        return KmMode.DUPLICATES;
    }

    @Override
    protected boolean handleMetaOther() {
        if (handleMetaYear())
            return true;
        else
            return false;
    }

    private boolean handleMetaYear() {
        final Matcher m = META_YEAR.matcher(this.currentLine);
        if (m.matches()) {
            this.metaPatternsMatched.add(META_YEAR);
            this.seriesHeader.setYear(Integer.parseInt(m.group(1)));
            return true;
        }
        return false;
    }

    @Override
    protected boolean handleMetaColumnTitles() {
        if (!super.handleMetaColumnTitles())
            return false;
        for (final ColTitlePattern col : ColTitlePattern.values())
            this.cols.put(col, -1);
        for (int i = 1; i <= this.columnTitles.size() - 1; i++) {
            for (final ColTitlePattern col : ColTitlePattern.values()) {
                if (col.getPattern().matcher(this.columnTitles.get(i)).matches()) {
                    this.cols.put(col, i);
                    break;
                }
            }
        }
        if (this.cols.get(ColTitlePattern.DATE) < 0) {
            logLineError("Column of the event dates could not be identified, missing column title 'Datum'");
            this.headerParsingState = ParsingState.STOP;
            return true;
        }
        if (this.cols.get(ColTitlePattern.GAUGE_W) < 0) {
            logLineError("Column of the waterlevel could not be identified, missing column title 'Pegelstand [cm]'");
            this.headerParsingState = ParsingState.STOP;
            return true;
        }
        if (this.cols.get(ColTitlePattern.GAUGE_W) < 0) {
            logLineError("Column of the reference gauge could not be identified, missing column title 'Bezugspegel'");
            this.headerParsingState = ParsingState.STOP;
            return true;
        }
        if (this.cols.get(ColTitlePattern.TYPE) < 0) {
            logLineError("Column of the collision types could not be identified, missing column title 'Unfallart'");
            this.headerParsingState = ParsingState.STOP;
            return true;
        }
        if (!this.metaPatternsMatched.contains(META_YEAR)) {
            logError("Required meta info for the year is missing");
            this.headerParsingState = ParsingState.STOP;
            return true;
        }
        return true;
    }

    @Override
    protected CollisionKmLineImport createKmLineImport(final Double km, final String[] values) {
        Date eventDate = null;
        try {
            eventDate = dateFormat.parse(values[this.cols.get(ColTitlePattern.DATE)]);
        }
        catch (final Exception e) {
            logLineWarning("Invalid or missing date");
            return null;
        }
        final String typeName = values[this.cols.get(ColTitlePattern.TYPE)].trim();
        final String typeKey = typeName.toLowerCase();
        CollisionTypeImport type = null;
        if (this.types.containsKey(typeKey))
            type = this.types.get(typeKey);
        else {
            type = new CollisionTypeImport(typeName);
            this.types.put(typeKey, type);
        }
        String gaugeName = null;
        gaugeName = values[this.cols.get(ColTitlePattern.GAUGE_NAME)].trim();
        final Number gaugeW = parseDoubleCheckNull(values, this.cols.get(ColTitlePattern.GAUGE_W));
        if ((gaugeW == null) || Double.isNaN(gaugeW.doubleValue())) {
            logLineWarning(INVALID_VALUE_ERROR_FORMAT, "waterlevel");
            return null;
        }
        return new CollisionKmLineImport(km, type, eventDate, gaugeName, gaugeW.doubleValue());
    }
}