package de.intevation.flys.importer.parsers;

import java.io.File;
import java.io.IOException;
import java.text.NumberFormat;
import java.text.ParseException;
import java.util.ArrayList;
import java.util.List;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import org.apache.log4j.Logger;

import de.intevation.flys.importer.ImportUnit;
import de.intevation.flys.importer.ImportWaterlevelDifference;
import de.intevation.flys.importer.ImportWaterlevelDifferenceColumn;
import de.intevation.flys.importer.ImportWaterlevelDifferenceValue;


public class WaterlevelDifferencesParser extends LineParser {

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

    private static final NumberFormat nf =
        NumberFormat.getInstance(DEFAULT_LOCALE);

    public static final Pattern META_UNIT =
        Pattern.compile("^Einheit: \\[(.*)\\].*");


    private List<ImportWaterlevelDifference> differences;

    private ImportWaterlevelDifferenceColumn[] columns;

    private ImportWaterlevelDifference current;


    public WaterlevelDifferencesParser() {
        differences = new ArrayList<ImportWaterlevelDifference>();
    }


    public List<ImportWaterlevelDifference> getDifferences() {
        return differences;
    }


    @Override
    public void parse(File file) throws IOException {
        current = new ImportWaterlevelDifference(file.getName());

        super.parse(file);
    }


    @Override
    protected void reset() {
    }


    @Override
    protected void finish() {
        if (columns != null && current != null) {
            for (ImportWaterlevelDifferenceColumn col: columns) {
                current.addValue(col);
            }

            differences.add(current);
        }

        current = null;
        columns = null;
    }

    @Override
    protected void handleLine(int lineNum, String line) {
        if (line.startsWith(START_META_CHAR)) {
            handleMetaLine(stripMetaLine(line));
        }
        else {
            handleDataLine(line);
        }
    }


    private void handleMetaLine(String meta) {
        if (handleMetaUnit(meta)) {
            return;
        }
        else {
            handleMetaColumnNames(meta);
        }
    }


    private boolean handleMetaUnit(String meta) {
        Matcher m = META_UNIT.matcher(meta);

        if (m.matches()) {
            String unit = m.group(1);
            log.debug("Found unit: '" + unit + "'");

            current.setUnit(new ImportUnit(unit));

            return true;
        }

        return false;
    }


    private boolean handleMetaColumnNames(String meta) {
        Pattern META_COLUMN_NAMES = Pattern.compile("Fluss-km;(.*)");
        Matcher m = META_COLUMN_NAMES.matcher(meta);

        if (m.matches()) {
            String colStr = m.group(1);
            String[] cols = colStr.split(SEPERATOR_CHAR);

            log.debug("Found " + cols.length + " columns.");

            initColumns(cols);

            return true;
        }

        return false;
    }


    private void initColumns(String[] cols) {
        columns = new ImportWaterlevelDifferenceColumn[cols.length];

        for (int i = 0; i < cols.length; i++) {
            String name = cols[i].replace("\"", "");

            log.debug("Create new column '" + name + "'");
            columns[i] = new ImportWaterlevelDifferenceColumn(name);
        }
    }


    private void handleDataLine(String line) {
        String[] cols = line.split(SEPERATOR_CHAR);

        if (cols == null || cols.length < 2) {
            log.warn("skip invalid waterlevel line: '" + line + "'");
            return;
        }

        try {
            Double station = nf.parse(cols[0]).doubleValue();

            for (int i = 0; i < columns.length; i++) {
                int idx = i+1;

                if (idx >= cols.length) {
                    log.warn("Insufficient column numbers: " + line);
                    continue;
                }

                String value = cols[idx];

                try {
                    columns[i].addValue(new ImportWaterlevelDifferenceValue(
                        station,
                        nf.parse(value).doubleValue()
                    ));
                }
                catch (ParseException pe) {
                    log.warn("Error while parsing value: '" + value + "'");
                }
            }
        }
        catch (ParseException pe) {
            log.warn("Error while parsing station: '" + line + "'");
        }
    }
}
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