/* ================================================================
 * Delft FEWS
 * ================================================================
 *
 * Project Info:  http://www.wldelft.nl/soft/fews/index.html
 * Project Lead:  Karel Heynert (karel.heynert@wldelft.nl)
 *
 * (C) Copyright 2008, by Deltares (Delft Hydraulics)
 *                        P.O. Box 177
 *                        2600 MH  Delft
 *                        The Netherlands
 *                        http://www.wldelft.nl
 *
 * DELFT-FEWS is a sophisticated collection of modules designed
 * for building a FEWS customised to the specific requirements
 * of individual agencies. An open modelling approach allows users
 * to add their own modules in an efficient way.
 *
 * ----------------------------------------------------------------
 * HydamsXMLTimeSeriesParser.java
 * ----------------------------------------------------------------
 * (C) Copyright 2008, by Deltares
 *
 * Original Author:  Saskia Vermeer
 * Contributor(s):
 *
 * Changes:
 * --------
 * 04 jan 2011 Version 1 ();
 */
package nl.wldelft.timeseriesparsers;

import nl.wldelft.util.FileUtils;
import nl.wldelft.util.TextUtils;
import nl.wldelft.util.io.XmlParser;
import nl.wldelft.util.timeseries.DefaultTimeSeriesHeader;
import nl.wldelft.util.timeseries.TimeSeriesContentHandler;

import javax.xml.stream.XMLStreamConstants;
import javax.xml.stream.XMLStreamException;
import javax.xml.stream.XMLStreamReader;
import java.io.IOException;

/*
* TimeSeries reader for HyDaMS xml files.
* <p/>
* Each file contains a single location/parameter combination, the values of which are determined by the filename:
*   <externalLocationId>_<externalParameterId>.xml
* <p/>
* <pre>
* Example
*    <TSD RELEASE="1">
*      <DEF REIHENART="Z" TEXT="Nein" DEFART="I" EINHEIT="cm" LEN="0" ANZ="289" />
*      <DATA><![CDATA[
*        2010-12-19T13:30:00Z 518
*        2010-12-19T13:45:00Z 517.5
*        2010-12-19T14:00:00Z 516.83331
*        ...
*    ]]></DATA>
*    </TSD>
* </pre>
*/

public class HydamsXMLTimeSeriesParser implements XmlParser<TimeSeriesContentHandler> {
    private TimeSeriesContentHandler contentHandler = null;
    private String virtualFileName = null;
    private XMLStreamReader reader = null;
    private DefaultTimeSeriesHeader header = null;
    private static final String MISSING_VALUE = "RWLuecke";


    @Override
    public void parse(XMLStreamReader reader, String virtualFileName, TimeSeriesContentHandler contentHandler) throws Exception {
        this.reader = reader;
        this.virtualFileName = virtualFileName;
        this.contentHandler = contentHandler;
        //FEWS-5400: (Simone Patzke) Entries with values RWLuecke should be skipped instead of set to missingValue
        //this.contentHandler.addMissingValue(MISSING_VALUE);

        parseHeaderFromFileName();

        reader.require(XMLStreamConstants.START_DOCUMENT, null, null);
        reader.nextTag();
        reader.require(XMLStreamConstants.START_ELEMENT, null, "TSD");
        reader.nextTag();

        while (!reader.isEndElement()) {
            parseDefTag();
            if (header != null) {
                this.contentHandler.createTimeSeriesHeaderAlias(0, header);
            }
            parseData();
        }

        reader.require(XMLStreamConstants.END_ELEMENT, null, "TSD");
        reader.next();
        reader.require(XMLStreamConstants.END_DOCUMENT, null, null);

    }

    /**
     * Parse the attributes of the DEF element
     *   <DEF REIHENART="Z" TEXT="Nein" DEFART="I" EINHEIT="cm" LEN="0" ANZ="289" />
     * @throws XMLStreamException
     */
    private void parseDefTag() throws XMLStreamException {
        if (!reader.isStartElement()) return;
        if (!TextUtils.equals(reader.getLocalName(), "DEF")) return;
        String unit = reader.getAttributeValue(null, "EINHEIT");

        header.setUnit(unit);

        reader.nextTag();

    }

    /**
     * Parse the data within the DATA tag
     * @throws XMLStreamException
     */
    private void parseData() throws XMLStreamException {
        reader.nextTag();
        if (!reader.isStartElement()) return;
        if (!TextUtils.equals(reader.getLocalName(), "DATA")) return;
        reader.next();
        while (!reader.isEndElement()) {
            readTimeSeries(reader.getText());
            if (reader.hasNext()) reader.next();
        }
        reader.nextTag();
    }

    /**
     * Parse the data found in the <code>text</code>, which must have the following format:
     * date-value pairs are separated by newLine
     * between date and value there are one or more spaces
     * @param text String containing the data to be parsed to the current timeSeriesHeader
     */
    private void readTimeSeries(String text) {
        String[] result = text.split("\\n");
        for (int i=0; i<result.length; i++) {
            String line = result[i];
            if (line.length() == 0) continue;
            String[] buffer = line.split(" +");
            if (buffer.length != 2) continue;
            //FEWS-5400: (Simone Patzke) Entries with values RWLuecke should be skipped instead of set to missingValue
            if (MISSING_VALUE.equals(buffer[1])) continue;

            contentHandler.setTimeSeriesHeader(0);
            contentHandler.setTime(contentHandler.getDefaultTimeZone(), "yyyy-MM-dd'T'HH:mm:ss'Z'", buffer[0]);
            contentHandler.setValue('.', buffer[1]);
            contentHandler.applyCurrentFields();

        }
    }

    /**
     * Retrieve the externalLocation and externalParameter from the file name and pass it to the TimeSeriesHeader
     * @throws IOException
     */
    private void parseHeaderFromFileName() throws IOException {
        header = new DefaultTimeSeriesHeader();

        String fileName = FileUtils.getNameWithoutExt(this.virtualFileName);

        //Check if filename contains the file name separator
        String[] fileNameParts = TextUtils.split(fileName, '_');
        if (fileNameParts.length != 2) {
            throw new IOException("File name has incorrect format for parsing, should be <externalLocation>_<externalParameter>.xml, but found: " + virtualFileName);
        }
        // split on underscore - first item is the externalLocationId, second is the externalParameter
        header.setLocationId(fileNameParts[0]);
        header.setParameterId(fileNameParts[1]);

    }

}