package de.intevation.flys.importer;

import java.util.ArrayList;
import java.util.Map;
import java.util.HashMap;

import java.io.File;
import java.io.IOException;
import java.io.LineNumberReader;
import java.io.InputStreamReader;
import java.io.FileInputStream;

import java.text.NumberFormat;

import org.apache.log4j.Logger;

import de.intevation.flys.utils.StringUtil;

public class WstParser
{
    private static Logger log = Logger.getLogger(WstParser.class);

    public static final String COLUMN_BEZ_TEXT   = "column-bez-text";
    public static final String COLUMN_BEZ_BREITE = "column-bez-breite";
    public static final String COLUMN_QUELLE     = "column-quelle";
    public static final String COLUMN_DATUM      = "column-datum";

    public static final Double UNDEFINED_ZERO = Double.valueOf(0.0);

    public static final String ENCODING = "ISO-8859-1";

    public WstParser() {
    }

    public void parse(File file) throws IOException {

        log.info("Parsing WST file '" + file + "'");

        LineNumberReader in = null;
        try {
            in =
                new LineNumberReader(
                new InputStreamReader(
                new FileInputStream(file), ENCODING));

            String input;
            boolean first = true;
            int columnCount = 0;

            String [] lsHeader       = null;
            String [] lsBezeichner   = null;
            String [] langBezeichner = null;
            int    [] colNaWidths    = null;
            String [] quellen        = null;
            String [] daten          = null;
            double [] aktAbfluesse   = null;
            double [] firstAbfluesse = null;

            double minKm =  Double.MAX_VALUE;
            double maxKm = -Double.MAX_VALUE;

            boolean bFirstComment = true;
            boolean columnHeaderChecked = false;

            double lastKm = Double.MAX_VALUE;

            String einheit = "Wassserstand [NN + m]";

            HashMap<String, Double> oldEscapeLine = null;

            while ((input = in.readLine()) != null) {
                String line = input;
                if (first) { // fetch number of columns
                    if ((line = line.trim()).length() == 0) {
                        continue;
                    }
                    try {
                        columnCount = Integer.parseInt(line);
                        if (columnCount <= 0) {
                            throw new NumberFormatException(
                                "number columns <= 0");
                        }
                        log.debug("Number of columns: " + columnCount);
                        lsBezeichner = new String[columnCount];
                        lsHeader     = new String[columnCount];
                        aktAbfluesse = new double[columnCount];
                    }
                    catch (NumberFormatException nfe) {
                        log.warn(nfe);
                        continue;
                    }
                    first = false;
                    continue;
                }

                line = line.replace(',', '.');

                if (line.startsWith("*\u001f")) {
                    Double [] data =
                        parseLineAsDouble(line, columnCount, false, true);

                    if (oldEscapeLine != null) {
                        addInterval(minKm, maxKm, oldEscapeLine);
                        minKm =  Double.MAX_VALUE;
                        maxKm = -Double.MAX_VALUE;
                    }

                    oldEscapeLine = new HashMap<String, Double>();
                    for (int i = 0; i < columnCount; ++i) {
                        if (lsHeader[i] != null) {
                            oldEscapeLine.put(lsHeader[i], data[i]);
                        }
                    }

                    for (int i = Math.min(data.length, aktAbfluesse.length)-1;
                         i >= 0; --i) {
                        aktAbfluesse[i] = data[i].doubleValue();
                    }

                    if (firstAbfluesse == null) {
                        firstAbfluesse = (double [])aktAbfluesse.clone();
                    }
                    continue;
                }

                if (line.startsWith("*!")) {
                    String spezial = line.substring(2).trim();

                    if (spezial.length() == 0) {
                        continue;
                    }

                    if (spezial.startsWith(COLUMN_BEZ_TEXT)) {
                        spezial = spezial.substring(COLUMN_BEZ_TEXT.length()).trim();
                        if (spezial.length() == 0) {
                            continue;
                        }
                        langBezeichner = StringUtil.splitQuoted(spezial, '"');
                    }
                    else if (spezial.startsWith(COLUMN_BEZ_BREITE)) {
                        spezial = spezial.substring(COLUMN_BEZ_BREITE.length()).trim();

                        if (spezial.length() == 0) {
                            continue;
                        }

                        String[] split = spezial.split("\\s+");

                        colNaWidths = new int[split.length];
                        for (int i=0; i < split.length; i++) {
                            colNaWidths[i] = Integer.parseInt(split[i]);
                        }
                    }
                    else if (spezial.startsWith(COLUMN_QUELLE)) {
                        if (spezial.length() == 0) {
                            continue;
                        }
                        quellen = StringUtil.splitQuoted(spezial, '"');
                    }
                    else if (spezial.startsWith(COLUMN_DATUM)) {
                        spezial = spezial.substring(COLUMN_DATUM.length()).trim();
                        if (spezial.length() == 0) {
                            continue;
                        }
                        daten = StringUtil.splitQuoted(spezial, '"');
                    }
                    continue;
                }

                if (line.startsWith("*")) {
                    if (bFirstComment && line.length() >= 11) {
                        String yAxis = line.substring(10).trim();
                        if (yAxis.length() > 0) {
                            einheit = yAxis;
                        }
                        bFirstComment = false;
                    }
                    continue;
                }

                if (firstAbfluesse != null) {
                    if (!columnHeaderChecked) {
                        int unknownCount = 0;
                        for (int i = 0; i < lsHeader.length; ++i) {
                            if (lsBezeichner[i] == null
                            || lsBezeichner[i].length() == 0) {
                                double q = firstAbfluesse[i];
                                if (q < 0.001) {
                                    lsBezeichner[i] =
                                        "<unbekannt#" + unknownCount + ">";
                                    ++unknownCount;
                                }
                                else {
                                    lsBezeichner[i] = "Q="+format(q);
                                }
                            }
                            lsHeader[i] = lsBezeichner[i] + " " + einheit;
                        }
                        columnHeaderChecked = true;
                    }

                    Double [] data =
                        parseLineAsDouble(line, columnCount, true, false);

                    double kaem = data[0];

                    if (kaem < minKm) {
                        minKm = kaem;
                    }
                    if (kaem > maxKm) {
                        maxKm = kaem;
                    }

                    lastKm = kaem;

                    // extract values
                    for (int i = 0; i < columnCount; ++i) {
                        addValue(kaem, data[i].doubleValue(), lsBezeichner[i]);
                    }

                }
                else { // firstAbfluesse == null
                    if (langBezeichner != null) {
                        lsBezeichner = StringUtil.fitArray(
                            langBezeichner, lsBezeichner);
                    }
                    else if (colNaWidths != null) {
                        for (int j = 0, i = 0, N = input.length();
                             j < colNaWidths.length && i < N;
                             i += colNaWidths[j++]
                        ) {
                            lsBezeichner[j] = input.substring(
                                i, i+colNaWidths[j]).trim();
                        }
                    }
                    else {
                        // first column begins at position 8 in line
                        for (int i = 8, col = 0; i < input.length(); i += 9) {
                            if ((i + 9) > input.length()) {
                                i = input.length() - 10;
                            }
                            // one column header is 9 chars wide
                            lsBezeichner[col++] =
                                input.substring(i, i + 9).trim();

                            if (col == lsBezeichner.length) {
                                break;
                            }
                        }
                    }
                }

            }
            addInterval(minKm, maxKm, oldEscapeLine);
        }
        finally {
            if (in != null) {
                in.close();
            }
        }
    }

    protected void addValue(double km, double w, String columnName) {
        // TODO: store me!
    }

    protected static String format(double value) {
        NumberFormat nf = NumberFormat.getInstance();
        nf.setMinimumFractionDigits(2);
        nf.setMaximumFractionDigits(2);
        return nf.format(value);
    }

    protected void addInterval(
        double              from,
        double              to, 
        Map<String, Double> values
    ) {
        log.debug("addInterval: " + from + " " + to);
        if (values == null) {
            return;
        }
    }

    private static final Double [] parseLineAsDouble(
        String  line, 
        int     count, 
        boolean bStation,
        boolean bParseEmptyAsZero
    ) {
        String [] tokens = parseLine(line, count, bStation);

        Double [] doubles = new Double[tokens.length];

        for (int i = 0; i < doubles.length; ++i) {
            String token = tokens[i].trim();
            if (token.length() != 0) {
                doubles[i] = Double.valueOf(token);
            }
            else if (bParseEmptyAsZero) {
                doubles[i] = UNDEFINED_ZERO;
            }
        }

        return doubles;
    }

    private static String [] parseLine(
        String  line, 
        int     tokenCount,
        boolean bParseStation
    ) {
        ArrayList<String> strings = new ArrayList<String>();

        if (bParseStation) {
            if (line.length() < 8) {
                throw new IllegalArgumentException("station too short");
            }
            strings.add(line.substring(0, 8));
        }

        int pos = 9;
        for (int i = 0; i < tokenCount; ++i) {
            if (line.length() >= pos + 8) {
                strings.add(line.substring(pos, pos + 8));
            }
            else {
                strings.add("");
            }
            pos += 9;
        }

        return strings.toArray(new String[strings.size()]);
    }
}
// vim:set ts=4 sw=4 si et sta sts=4 fenc=utf8 :