package tim.prune.save;

import java.awt.BorderLayout;
import java.awt.Component;
import java.awt.FlowLayout;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStreamWriter;
import java.io.Writer;

import javax.swing.BorderFactory;
import javax.swing.Box;
import javax.swing.BoxLayout;
import javax.swing.ButtonGroup;
import javax.swing.JButton;
import javax.swing.JCheckBox;
import javax.swing.JDialog;
import javax.swing.JFileChooser;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JRadioButton;
import javax.swing.JTextField;
import javax.swing.border.EtchedBorder;

import tim.prune.App;
import tim.prune.GenericFunction;
import tim.prune.GpsPrune;
import tim.prune.I18nManager;
import tim.prune.UpdateMessageBroker;
import tim.prune.config.Config;
import tim.prune.data.AudioClip;
import tim.prune.data.Coordinate;
import tim.prune.data.DataPoint;
import tim.prune.data.Field;
import tim.prune.data.MediaObject;
import tim.prune.data.Photo;
import tim.prune.data.RecentFile;
import tim.prune.data.Timestamp;
import tim.prune.data.TrackInfo;
import tim.prune.data.UnitSetLibrary;
import tim.prune.gui.DialogCloser;
import tim.prune.load.GenericFileFilter;
import tim.prune.save.xml.GpxCacherList;
import tim.prune.save.xml.XmlUtils;


/**
 * Class to export track information
 * into a specified Gpx file
 */
public class GpxExporter extends GenericFunction implements Runnable
{
	private TrackInfo _trackInfo = null;
	private JDialog _dialog = null;
	private JTextField _nameField = null;
	private JTextField _descriptionField = null;
	private PointTypeSelector _pointTypeSelector = null;
	private JCheckBox _timestampsCheckbox = null;
	private JCheckBox _copySourceCheckbox = null;
	private JPanel _encodingsPanel = null;
	private JRadioButton _useSystemRadio = null, _forceUtf8Radio = null;
	private File _exportFile = null;

	/** this program name */
	private static final String GPX_CREATOR = "GpsPrune v" + GpsPrune.VERSION_NUMBER + " activityworkshop.net";


	/**
	 * Constructor
	 * @param inApp app object
	 */
	public GpxExporter(App inApp)
	{
		super(inApp);
		_trackInfo = inApp.getTrackInfo();
	}

	/** Get name key */
	public String getNameKey() {
		return "function.exportgpx";
	}

	/**
	 * Show the dialog to select options and export file
	 */
	public void begin()
	{
		// Make dialog window
		if (_dialog == null)
		{
			_dialog = new JDialog(_parentFrame, I18nManager.getText(getNameKey()), true);
			_dialog.setLocationRelativeTo(_parentFrame);
			_dialog.setDefaultCloseOperation(JDialog.DISPOSE_ON_CLOSE);
			_dialog.getContentPane().add(makeDialogComponents());
			_dialog.pack();
		}
		_pointTypeSelector.init(_app.getTrackInfo());
		_encodingsPanel.setVisible(!XmlUtils.isSystemUtf8());
		if (!XmlUtils.isSystemUtf8())
		{
			String systemEncoding = XmlUtils.getSystemEncoding();
			_useSystemRadio.setText(I18nManager.getText("dialog.exportgpx.encoding.system")
				+ " (" + (systemEncoding == null ? "unknown" : systemEncoding) + ")");
		}
		_dialog.setVisible(true);
	}


	/**
	 * Create dialog components
	 * @return Panel containing all gui elements in dialog
	 */
	private Component makeDialogComponents()
	{
		JPanel dialogPanel = new JPanel();
		dialogPanel.setLayout(new BorderLayout());
		JPanel mainPanel = new JPanel();
		mainPanel.setLayout(new BoxLayout(mainPanel, BoxLayout.Y_AXIS));
		// Make a panel for the name/desc text boxes
		JPanel descPanel = new JPanel();
		descPanel.setLayout(new GridLayout(2, 2));
		descPanel.add(new JLabel(I18nManager.getText("dialog.exportgpx.name")));
		_nameField = new JTextField(10);
		descPanel.add(_nameField);
		descPanel.add(new JLabel(I18nManager.getText("dialog.exportgpx.desc")));
		_descriptionField = new JTextField(10);
		descPanel.add(_descriptionField);
		mainPanel.add(descPanel);
		mainPanel.add(Box.createVerticalStrut(5));
		// point type selection (track points, waypoints, photo points)
		_pointTypeSelector = new PointTypeSelector();
		mainPanel.add(_pointTypeSelector);
		// checkboxes for timestamps and copying
		JPanel checkPanel = new JPanel();
		_timestampsCheckbox = new JCheckBox(I18nManager.getText("dialog.exportgpx.includetimestamps"));
		_timestampsCheckbox.setSelected(true);
		checkPanel.add(_timestampsCheckbox);
		_copySourceCheckbox = new JCheckBox(I18nManager.getText("dialog.exportgpx.copysource"));
		_copySourceCheckbox.setSelected(true);
		checkPanel.add(_copySourceCheckbox);
		mainPanel.add(checkPanel);
		// panel for selecting character encoding
		_encodingsPanel = new JPanel();
		if (!XmlUtils.isSystemUtf8())
		{
			// only add this panel if system isn't utf8 (or can't be identified yet)
			_encodingsPanel.setBorder(BorderFactory.createCompoundBorder(
				BorderFactory.createEtchedBorder(EtchedBorder.LOWERED), BorderFactory.createEmptyBorder(4, 4, 4, 4)));
			_encodingsPanel.setLayout(new BorderLayout());
			_encodingsPanel.add(new JLabel(I18nManager.getText("dialog.exportgpx.encoding")), BorderLayout.NORTH);
			JPanel radioPanel = new JPanel();
			radioPanel.setLayout(new FlowLayout());
			ButtonGroup radioGroup = new ButtonGroup();
			_useSystemRadio = new JRadioButton(I18nManager.getText("dialog.exportgpx.encoding.system"));
			_forceUtf8Radio = new JRadioButton(I18nManager.getText("dialog.exportgpx.encoding.utf8"));
			radioGroup.add(_useSystemRadio);
			radioGroup.add(_forceUtf8Radio);
			radioPanel.add(_useSystemRadio);
			radioPanel.add(_forceUtf8Radio);
			_useSystemRadio.setSelected(true);
			_encodingsPanel.add(radioPanel, BorderLayout.CENTER);
			mainPanel.add(_encodingsPanel);
		}
		dialogPanel.add(mainPanel, BorderLayout.CENTER);

		// close dialog if escape pressed
		_nameField.addKeyListener(new DialogCloser(_dialog));
		// button panel at bottom
		JPanel buttonPanel = new JPanel();
		buttonPanel.setLayout(new FlowLayout(FlowLayout.RIGHT));
		JButton okButton = new JButton(I18nManager.getText("button.ok"));
		ActionListener okListener = new ActionListener() {
			public void actionPerformed(ActionEvent e)
			{
				startExport();
			}
		};
		okButton.addActionListener(okListener);
		_descriptionField.addActionListener(okListener);
		buttonPanel.add(okButton);
		JButton cancelButton = new JButton(I18nManager.getText("button.cancel"));
		cancelButton.addActionListener(new ActionListener() {
			public void actionPerformed(ActionEvent e) {
				_dialog.dispose();
			}
		});
		buttonPanel.add(cancelButton);
		dialogPanel.add(buttonPanel, BorderLayout.SOUTH);
		dialogPanel.setBorder(BorderFactory.createEmptyBorder(10, 10, 10, 15));
		return dialogPanel;
	}


	/**
	 * Start the export process based on the input parameters
	 */
	private void startExport()
	{
		// OK pressed, so check selections
		if (!_pointTypeSelector.getAnythingSelected())
		{
			JOptionPane.showMessageDialog(_parentFrame, I18nManager.getText("dialog.save.notypesselected"),
				I18nManager.getText("dialog.saveoptions.title"), JOptionPane.WARNING_MESSAGE);
			return;
		}
		// Choose output file
		File saveFile = chooseGpxFile(_parentFrame);
		if (saveFile != null)
		{
			// New file or overwrite confirmed, so initiate export in separate thread
			_exportFile = saveFile;
			new Thread(this).start();
		}
	}


	/**
	 * Select a GPX file to save to
	 * @param inParentFrame parent frame for file chooser dialog
	 * @return selected File, or null if selection cancelled
	 */
	public static File chooseGpxFile(JFrame inParentFrame)
	{
		File saveFile = null;
		JFileChooser fileChooser = new JFileChooser();
		fileChooser.setDialogType(JFileChooser.SAVE_DIALOG);
		fileChooser.setFileFilter(new GenericFileFilter("filetype.gpx", new String[] {"gpx"}));
		fileChooser.setAcceptAllFileFilterUsed(false);
		// start from directory in config which should be set
		String configDir = Config.getConfigString(Config.KEY_TRACK_DIR);
		if (configDir != null) {fileChooser.setCurrentDirectory(new File(configDir));}

		// Allow choose again if an existing file is selected
		boolean chooseAgain = false;
		do
		{
			chooseAgain = false;
			if (fileChooser.showSaveDialog(inParentFrame) == JFileChooser.APPROVE_OPTION)
			{
				// OK pressed and file chosen
				File file = fileChooser.getSelectedFile();
				// Check file extension
				if (!file.getName().toLowerCase().endsWith(".gpx"))
				{
					file = new File(file.getAbsolutePath() + ".gpx");
				}
				// Check if file exists and if necessary prompt for overwrite
				Object[] buttonTexts = {I18nManager.getText("button.overwrite"), I18nManager.getText("button.cancel")};
				if (!file.exists() || JOptionPane.showOptionDialog(inParentFrame,
						I18nManager.getText("dialog.save.overwrite.text"),
						I18nManager.getText("dialog.save.overwrite.title"), JOptionPane.YES_NO_OPTION,
						JOptionPane.WARNING_MESSAGE, null, buttonTexts, buttonTexts[1])
					== JOptionPane.YES_OPTION)
				{
					// new file or overwrite confirmed
					saveFile = file;
				}
				else
				{
					// file exists and overwrite cancelled - select again
					chooseAgain = true;
				}
			}
		} while (chooseAgain);
		return saveFile;
	}


	/**
	 * Run method for controlling separate thread for exporting
	 */
	public void run()
	{
		// Instantiate source file cachers in case we want to copy output
		GpxCacherList gpxCachers = null;
		if (_copySourceCheckbox.isSelected()) {
			gpxCachers = new GpxCacherList(_trackInfo.getFileInfo());
		}
		OutputStreamWriter writer = null;
		try
		{
			// normal writing to file - firstly specify UTF8 encoding if requested
			if (_forceUtf8Radio != null && _forceUtf8Radio.isSelected())
				writer = new OutputStreamWriter(new FileOutputStream(_exportFile), "UTF-8");
			else
				writer = new OutputStreamWriter(new FileOutputStream(_exportFile));
			final boolean[] saveFlags = {_pointTypeSelector.getTrackpointsSelected(), _pointTypeSelector.getWaypointsSelected(),
				_pointTypeSelector.getPhotopointsSelected(), _pointTypeSelector.getAudiopointsSelected(),
				_pointTypeSelector.getJustSelection(), _timestampsCheckbox.isSelected()};
			// write file
			final int numPoints = exportData(writer, _trackInfo, _nameField.getText(),
				_descriptionField.getText(), saveFlags, gpxCachers);

			// close file
			writer.close();
			// Store directory in config for later
			Config.setConfigString(Config.KEY_TRACK_DIR, _exportFile.getParentFile().getAbsolutePath());
			// Add to recent file list
			Config.getRecentFileList().addFile(new RecentFile(_exportFile, true));
			// Show confirmation
			UpdateMessageBroker.informSubscribers();
			UpdateMessageBroker.informSubscribers(I18nManager.getText("confirm.save.ok1")
				 + " " + numPoints + " " + I18nManager.getText("confirm.save.ok2")
				 + " " + _exportFile.getAbsolutePath());
			// export successful so need to close dialog and return
			_dialog.dispose();
			return;
		}
		catch (IOException ioe)
		{
			// System.out.println("Exception: " + ioe.getClass().getName() + " - " + ioe.getMessage());
			try {
				if (writer != null) writer.close();
			}
			catch (IOException ioe2) {}
			JOptionPane.showMessageDialog(_parentFrame,
				I18nManager.getText("error.save.failed") + " : " + ioe.getMessage(),
				I18nManager.getText("error.save.dialogtitle"), JOptionPane.ERROR_MESSAGE);
		}
		// if not returned already, export failed so need to recall the file selection
		startExport();
	}


	/**
	 * Export the information to the given writer
	 * @param inWriter writer object
	 * @param inInfo track info object
	 * @param inName name of track (optional)
	 * @param inDesc description of track (optional)
	 * @param inSaveFlags array of booleans to export tracks, waypoints, photos, audios, selection, timestamps
	 * @param inGpxCachers list of Gpx cachers containing input data
	 * @return number of points written
	 * @throws IOException if io errors occur on write
	 */
	public static int exportData(OutputStreamWriter inWriter, TrackInfo inInfo, String inName,
		String inDesc, boolean[] inSaveFlags, GpxCacherList inGpxCachers) throws IOException
	{
		// Write or copy headers
		inWriter.write(getXmlHeaderString(inWriter));
		final String gpxHeader = getGpxHeaderString(inGpxCachers);
		final boolean isVersion1_1 = (gpxHeader.toUpperCase().indexOf("GPX/1/1") > 0);
		inWriter.write(gpxHeader);
		// Name field
		String trackName = (inName != null && !inName.equals("")) ? inName : "GpsPruneTrack";
		writeNameAndDescription(inWriter, inName, inDesc, isVersion1_1);

		int i = 0;
		DataPoint point = null;
		final boolean exportTrackpoints = inSaveFlags[0];
		final boolean exportWaypoints = inSaveFlags[1];
		final boolean exportPhotos = inSaveFlags[2];
		final boolean exportAudios = inSaveFlags[3];
		final boolean exportSelection = inSaveFlags[4];
		final boolean exportTimestamps = inSaveFlags[5];
		// Examine selection
		int selStart = -1, selEnd = -1;
		if (exportSelection) {
			selStart = inInfo.getSelection().getStart();
			selEnd = inInfo.getSelection().getEnd();
		}
		// Loop over waypoints
		final int numPoints = inInfo.getTrack().getNumPoints();
		int numSaved = 0;
		for (i=0; i<numPoints; i++)
		{
			point = inInfo.getTrack().getPoint(i);
			if (!exportSelection || (i>=selStart && i<=selEnd))
			{
				// Make a wpt element for each waypoint
				if (point.isWaypoint() && exportWaypoints)
				{
					String pointSource = (inGpxCachers == null? null : getPointSource(inGpxCachers, point));
					if (pointSource != null)
					{
						// If timestamp checkbox is off, strip time
						if (!exportTimestamps) {
							pointSource = stripTime(pointSource);
						}
						inWriter.write('\t');
						inWriter.write(pointSource);
						inWriter.write('\n');
					}
					else {
						exportWaypoint(point, inWriter, exportTimestamps, exportPhotos, exportAudios);
					}
					numSaved++;
				}
			}
		}
		// Export both route points and then track points
		if (exportTrackpoints || exportPhotos || exportAudios)
		{
			// Output all route points (if any)
			numSaved += writeTrackPoints(inWriter, inInfo, exportSelection, exportTrackpoints, exportPhotos,
				exportAudios, exportTimestamps, true, inGpxCachers, "<rtept", "\t<rte><number>1</number>\n",
				null, "\t</rte>\n");
			// Output all track points, if any
			String trackStart = "\t<trk>\n\t\t<name>" + trackName + "</name>\n\t\t<number>1</number>\n\t\t<trkseg>\n";
			numSaved += writeTrackPoints(inWriter, inInfo, exportSelection, exportTrackpoints, exportPhotos,
				exportAudios, exportTimestamps, false, inGpxCachers, "<trkpt", trackStart,
				"\t</trkseg>\n\t<trkseg>\n", "\t\t</trkseg>\n\t</trk>\n");
		}

		inWriter.write("</gpx>\n");
		return numSaved;
	}


	/**
	 * Write the name and description according to the GPX version number
	 * @param inWriter writer object
	 * @param inName name, or null if none supplied
	 * @param inDesc description, or null if none supplied
	 * @param inIsVersion1_1 true if gpx version 1.1, false for version 1.0
	 */
	private static void writeNameAndDescription(OutputStreamWriter inWriter,
		String inName, String inDesc, boolean inIsVersion1_1) throws IOException
	{
		String desc = (inDesc != null && !inDesc.equals("")) ? inDesc : "Export from GpsPrune";
		// Position of name and description fields needs to be different for GPX1.0 and GPX1.1
		if (inIsVersion1_1)
		{
			// GPX 1.1 has the name and description inside a metadata tag
			inWriter.write("\t<metadata>\n");
		}
		if (inName != null && !inName.equals(""))
		{
			if (inIsVersion1_1) {inWriter.write('\t');}
			inWriter.write("\t<name>");
			inWriter.write(inName);
			inWriter.write("</name>\n");
		}
		if (inIsVersion1_1) {inWriter.write('\t');}
		inWriter.write("\t<desc>");
		inWriter.write(desc);
		inWriter.write("</desc>\n");
		if (inIsVersion1_1)
		{
			inWriter.write("\t</metadata>\n");
		}
	}

	/**
	 * Loop through the track outputting the relevant track points
	 * @param inWriter writer object for output
	 * @param inInfo track info object containing track
	 * @param inExportSelection true to just output current selection
	 * @param inExportTrackpoints true to output track points
	 * @param inExportPhotos true to output photo points
	 * @param inExportAudios true to output audio points
	 * @param inExportTimestamps true to include timestamps in export
	 * @param inOnlyCopies true to only export if source can be copied
	 * @param inCachers list of GpxCachers
	 * @param inPointTag tag to match for each point
	 * @param inStartTag start tag to output
	 * @param inSegmentTag tag to output between segments (or null)
	 * @param inEndTag end tag to output
	 */
	private static int writeTrackPoints(OutputStreamWriter inWriter,
		TrackInfo inInfo, boolean inExportSelection, boolean inExportTrackpoints,
		boolean inExportPhotos, boolean inExportAudios, boolean exportTimestamps,
		boolean inOnlyCopies, GpxCacherList inCachers, String inPointTag,
		String inStartTag, String inSegmentTag, String inEndTag)
	throws IOException
	{
		// Note: far too many input parameters to this method but avoids duplication
		// of output functionality for writing track points and route points
		int numPoints = inInfo.getTrack().getNumPoints();
		int selStart = inInfo.getSelection().getStart();
		int selEnd = inInfo.getSelection().getEnd();
		int numSaved = 0;
		// Loop over track points
		for (int i=0; i<numPoints; i++)
		{
			DataPoint point = inInfo.getTrack().getPoint(i);
			if ((!inExportSelection || (i>=selStart && i<=selEnd)) && !point.isWaypoint())
			{
				if ((point.getPhoto()==null && inExportTrackpoints) || (point.getPhoto()!=null && inExportPhotos)
					|| (point.getAudio()!=null && inExportAudios))
				{
					// get the source from the point (if any)
					String pointSource = getPointSource(inCachers, point);
					// Clear point source if it's the wrong type of point (eg changed from waypoint or route point)
					if (pointSource != null && !pointSource.trim().toLowerCase().startsWith(inPointTag)) {
						pointSource = null;
					}
					if (pointSource != null || !inOnlyCopies)
					{
						// restart track segment if necessary
						if ((numSaved > 0) && point.getSegmentStart() && (inSegmentTag != null)) {
							inWriter.write(inSegmentTag);
						}
						if (numSaved == 0) {inWriter.write(inStartTag);}
						if (pointSource != null)
						{
							// If timestamps checkbox is off, strip the time
							if (!exportTimestamps) {
								pointSource = stripTime(pointSource);
							}
							inWriter.write(pointSource);
							inWriter.write('\n');
						}
						else {
							if (!inOnlyCopies) {exportTrackpoint(point, inWriter, exportTimestamps, inExportPhotos, inExportAudios);}
						}
						numSaved++;
					}
				}
			}
		}
		if (numSaved > 0) {inWriter.write(inEndTag);}
		return numSaved;
	}


	/**
	 * Get the point source for the specified point
	 * @param inCachers list of GPX cachers to ask for source
	 * @param inPoint point object
	 * @return xml source if available, or null otherwise
	 */
	private static String getPointSource(GpxCacherList inCachers, DataPoint inPoint)
	{
		if (inCachers == null || inPoint == null) {return null;}
		String source = inCachers.getSourceString(inPoint);
		if (source == null || !inPoint.isModified()) {return source;}
		// Point has been modified - maybe it's possible to modify the source
		source = replaceGpxTags(source, "lat=\"", "\"", inPoint.getLatitude().output(Coordinate.FORMAT_DECIMAL_FORCE_POINT));
		source = replaceGpxTags(source, "lon=\"", "\"", inPoint.getLongitude().output(Coordinate.FORMAT_DECIMAL_FORCE_POINT));
		source = replaceGpxTags(source, "<ele>", "</ele>", inPoint.getAltitude().getStringValue(UnitSetLibrary.UNITS_METRES));
		source = replaceGpxTags(source, "<time>", "</time>", inPoint.getTimestamp().getText(Timestamp.Format.ISO8601));
		if (inPoint.isWaypoint())
		{
			source = replaceGpxTags(source, "<name>", "</name>", inPoint.getWaypointName());
			if (source != null)
			{
				source = source.replaceAll("<description>", "<desc>").replaceAll("</description>", "</desc>");
			}
			source = replaceGpxTags(source, "<desc>", "</desc>",
				XmlUtils.fixCdata(inPoint.getFieldValue(Field.DESCRIPTION)));
		}
		// photo / audio links
		if (source != null && (inPoint.hasMedia() || source.indexOf("</link>") > 0)) {
			source = replaceMediaLinks(source, makeMediaLink(inPoint));
		}
		return source;
	}

	/**
	 * Replace the given value into the given XML string
	 * @param inSource source XML for point
	 * @param inStartTag start tag for field
	 * @param inEndTag end tag for field
	 * @param inValue value to replace between start tag and end tag
	 * @return modified String, or null if not possible
	 */
	private static String replaceGpxTags(String inSource, String inStartTag, String inEndTag, String inValue)
	{
		if (inSource == null) {return null;}
		// Look for start and end tags within source
		final int startPos = inSource.indexOf(inStartTag);
		final int endPos = inSource.indexOf(inEndTag, startPos+inStartTag.length());
		if (startPos > 0 && endPos > 0)
		{
			String origValue = inSource.substring(startPos + inStartTag.length(), endPos);
			if (inValue != null && origValue.equals(inValue)) {
				// Value unchanged
				return inSource;
			}
			else if (inValue == null || inValue.equals("")) {
				// Need to delete value
				return inSource.substring(0, startPos) + inSource.substring(endPos + inEndTag.length());
			}
			else {
				// Need to replace value
				return inSource.substring(0, startPos+inStartTag.length()) + inValue + inSource.substring(endPos);
			}
		}
		// Value not found for this field in original source
		if (inValue == null || inValue.equals("")) {return inSource;}
		return null;
	}


	/**
	 * Replace the media tags in the given XML string
	 * @param inSource source XML for point
	 * @param inValue value for the current point
	 * @return modified String, or null if not possible
	 */
	private static String replaceMediaLinks(String inSource, String inValue)
	{
		if (inSource == null) {return null;}
		// Note that this method is very similar to replaceGpxTags except there can be multiple link tags
		// and the tags must have attributes.  So either one heavily parameterized method or two.
		// Look for start and end tags within source
		final String STARTTEXT = "<link";
		final String ENDTEXT = "</link>";
		final int startPos = inSource.indexOf(STARTTEXT);
		final int endPos = inSource.lastIndexOf(ENDTEXT);
		if (startPos > 0 && endPos > 0)
		{
			String origValue = inSource.substring(startPos, endPos + ENDTEXT.length());
			if (inValue != null && origValue.equals(inValue)) {
				// Value unchanged
				return inSource;
			}
			else if (inValue == null || inValue.equals("")) {
				// Need to delete value
				return inSource.substring(0, startPos) + inSource.substring(endPos + ENDTEXT.length());
			}
			else {
				// Need to replace value
				return inSource.substring(0, startPos) + inValue + inSource.substring(endPos + ENDTEXT.length());
			}
		}
		// Value not found for this field in original source
		if (inValue == null || inValue.equals("")) {return inSource;}
		return null;
	}


	/**
	 * Get the header string for the xml document including encoding
	 * @param inWriter writer object
	 * @return header string defining encoding
	 */
	private static String getXmlHeaderString(OutputStreamWriter inWriter)
	{
		return "<?xml version=\"1.0\" encoding=\"" + XmlUtils.getEncoding(inWriter) + "\"?>\n";
	}


	/**
	 * Get the header string for the gpx tag
	 * @param inCachers cacher list to ask for headers, if available
	 * @return header string from cachers or as default
	 */
	private static String getGpxHeaderString(GpxCacherList inCachers)
	{
		String gpxHeader = null;
		if (inCachers != null) {gpxHeader = inCachers.getFirstHeader();}
		if (gpxHeader == null || gpxHeader.length() < 5)
		{
			// TODO: Consider changing this to default to GPX 1.1
			// Create default (1.0) header
			gpxHeader = "<gpx version=\"1.0\" creator=\"" + GPX_CREATOR
				+ "\"\n xmlns:xsi=\"http://www.w3.org/2001/XMLSchema-instance\"\n"
				+ " xmlns=\"http://www.topografix.com/GPX/1/0\""
				+ " xsi:schemaLocation=\"http://www.topografix.com/GPX/1/0 http://www.topografix.com/GPX/1/0/gpx.xsd\">\n";
		}
		return gpxHeader + "\n";
	}


	/**
	 * Export the specified waypoint into the file
	 * @param inPoint waypoint to export
	 * @param inWriter writer object
	 * @param inTimestamps true to export timestamps too
	 * @param inPhoto true to export link to photo
	 * @param inAudio true to export link to audio
	 * @throws IOException on write failure
	 */
	private static void exportWaypoint(DataPoint inPoint, Writer inWriter, boolean inTimestamps,
		boolean inPhoto, boolean inAudio)
		throws IOException
	{
		inWriter.write("\t<wpt lat=\"");
		inWriter.write(inPoint.getLatitude().output(Coordinate.FORMAT_DECIMAL_FORCE_POINT));
		inWriter.write("\" lon=\"");
		inWriter.write(inPoint.getLongitude().output(Coordinate.FORMAT_DECIMAL_FORCE_POINT));
		inWriter.write("\">\n");
		// altitude if available
		if (inPoint.hasAltitude())
		{
			inWriter.write("\t\t<ele>");
			inWriter.write("" + inPoint.getAltitude().getStringValue(UnitSetLibrary.UNITS_METRES));
			inWriter.write("</ele>\n");
		}
		// timestamp if available (point might have timestamp and then be turned into a waypoint)
		if (inPoint.hasTimestamp() && inTimestamps)
		{
			inWriter.write("\t\t<time>");
			inWriter.write(inPoint.getTimestamp().getText(Timestamp.Format.ISO8601));
			inWriter.write("</time>\n");
		}
		// write waypoint name after elevation and time
		inWriter.write("\t\t<name>");
		inWriter.write(inPoint.getWaypointName().trim());
		inWriter.write("</name>\n");
		// description, if any
		String desc = XmlUtils.fixCdata(inPoint.getFieldValue(Field.DESCRIPTION));
		if (desc != null && !desc.equals(""))
		{
			inWriter.write("\t\t<desc>");
			inWriter.write(desc);
			inWriter.write("</desc>\n");
		}
		// Media links, if any
		if (inPhoto && inPoint.getPhoto() != null)
		{
			inWriter.write("\t\t");
			inWriter.write(makeMediaLink(inPoint.getPhoto()));
			inWriter.write('\n');
		}
		if (inAudio && inPoint.getAudio() != null)
		{
			inWriter.write("\t\t");
			inWriter.write(makeMediaLink(inPoint.getAudio()));
			inWriter.write('\n');
		}
		// write waypoint type if any
		String type = inPoint.getFieldValue(Field.WAYPT_TYPE);
		if (type != null)
		{
			type = type.trim();
			if (!type.equals(""))
			{
				inWriter.write("\t\t<type>");
				inWriter.write(type);
				inWriter.write("</type>\n");
			}
		}
		inWriter.write("\t</wpt>\n");
	}


	/**
	 * Export the specified trackpoint into the file
	 * @param inPoint trackpoint to export
	 * @param inWriter writer object
	 * @param inTimestamps true to export timestamps too
	 * @param inExportPhoto true to export photo link
	 * @param inExportAudio true to export audio link
	 */
	private static void exportTrackpoint(DataPoint inPoint, Writer inWriter, boolean inTimestamps,
		boolean inExportPhoto, boolean inExportAudio)
		throws IOException
	{
		inWriter.write("\t\t\t<trkpt lat=\"");
		inWriter.write(inPoint.getLatitude().output(Coordinate.FORMAT_DECIMAL_FORCE_POINT));
		inWriter.write("\" lon=\"");
		inWriter.write(inPoint.getLongitude().output(Coordinate.FORMAT_DECIMAL_FORCE_POINT));
		inWriter.write("\">\n");
		// altitude
		if (inPoint.hasAltitude())
		{
			inWriter.write("\t\t\t\t<ele>");
			inWriter.write("" + inPoint.getAltitude().getStringValue(UnitSetLibrary.UNITS_METRES));
			inWriter.write("</ele>\n");
		}
		// timestamp if available (and selected)
		if (inPoint.hasTimestamp() && inTimestamps)
		{
			inWriter.write("\t\t\t\t<time>");
			inWriter.write(inPoint.getTimestamp().getText(Timestamp.Format.ISO8601));
			inWriter.write("</time>\n");
		}
		// photo, audio
		if (inPoint.getPhoto() != null && inExportPhoto) {
			inWriter.write(makeMediaLink(inPoint.getPhoto()));
		}
		if (inPoint.getAudio() != null && inExportAudio) {
			inWriter.write(makeMediaLink(inPoint.getAudio()));
		}
		inWriter.write("\t\t\t</trkpt>\n");
	}


	/**
	 * Make the xml for the media link(s)
	 * @param inPoint point to generate text for
	 * @return link tags, or null if no links
	 */
	private static String makeMediaLink(DataPoint inPoint)
	{
		Photo photo = inPoint.getPhoto();
		AudioClip audio = inPoint.getAudio();
		if (photo == null && audio == null) {
			return null;
		}
		String linkText = "";
		if (photo != null) {
			linkText = makeMediaLink(photo);
		}
		if (audio != null) {
			linkText += makeMediaLink(audio);
		}
		return linkText;
	}

	/**
	 * Make the media link for a single media item
	 * @param inMedia media item, either photo or audio
	 * @return link for this media
	 */
	private static String makeMediaLink(MediaObject inMedia)
	{
		if (inMedia.getFile() != null)
			// file link
			return "<link href=\"" + inMedia.getFile().getAbsolutePath() + "\"><text>" + inMedia.getName() + "</text></link>";
		if (inMedia.getUrl() != null)
			// url link
			return "<link href=\"" + inMedia.getUrl() + "\"><text>" + inMedia.getName() + "</text></link>";
		// No link available, must have been loaded from zip file - no link possible
		return "";
	}


	/**
	 * Strip the time from a GPX point source string
	 * @param inPointSource point source to copy
	 * @return point source with timestamp removed
	 */
	private static String stripTime(String inPointSource)
	{
		return inPointSource.replaceAll("[ \t]*<time>.*?</time>", "");
	}
}