content: package tim.prune.function.settings;
  
  import java.awt.BorderLayout;
  import java.awt.Component;
  import java.awt.FlowLayout;
  import java.io.BufferedReader;
  import java.io.File;
  import java.io.FileReader;
  import java.io.IOException;
  import java.util.Locale;
  
  import javax.swing.BorderFactory;
  import javax.swing.Box;
  import javax.swing.BoxLayout;
  import javax.swing.JButton;
  import javax.swing.JComboBox;
  import javax.swing.JDialog;
  import javax.swing.JFileChooser;
  import javax.swing.JLabel;
  import javax.swing.JOptionPane;
  import javax.swing.JPanel;
  import javax.swing.JTextField;
  import javax.swing.SwingConstants;
  import javax.swing.border.EtchedBorder;
  
  import tim.prune.App;
  import tim.prune.GenericFunction;
  import tim.prune.I18nManager;
  import tim.prune.config.Config;
  import tim.prune.load.GenericFileFilter;
  
  /**
   * Class to show the popup window for setting the language code / file
   */
  public class SetLanguage extends GenericFunction
  {
  	private JDialog _dialog = null;
  	private JComboBox<String> _languageDropDown = null;
  	private JTextField _langFileBox = null;
  	private int _startIndex = 0;
  
  	/** Names of languages for display in dropdown (not translated) */
  	private static final String[] LANGUAGE_NAMES = {"afrikaans", "catal\u00e0", "\u010de\u0161tina", "deutsch",
  		"english", "american english", "espa\u00f1ol", "fran\u00e7ais", "italiano", "magyar", "nederlands",
  		"norsk bokm\u00e5l", "polski", "portugu\u00eas", "rom\u00e2n\u0103", "suomi", "svenska",
  		"\u0440\u0443\u0441\u0441\u043a\u0438\u0439 (russian)", "\u4e2d\u6587 (chinese)",
  		"schwiizerd\u00fc\u00fctsch"
  	};
  	/** Associated language codes (must be in same order as names!) */
  	private static final String[] LANGUAGE_CODES = {"af", "ca", "cz", "de", "en", "en_us", "es", "fr", "it", "hu",
  		"nl", "no", "pl", "pt", "ro", "fi", "sv", "ru", "zh", "de_ch"
  	};
  
  
  	/**
  	 * Constructor
  	 * @param inApp app object
  	 */
  	public SetLanguage(App inApp) {
  		super(inApp);
  	}
  
  	/**
  	 * Return the name key for this function
  	 */
  	public String getNameKey() {
  		return "function.setlanguage";
  	}
  
  	/**
  	 * @return the contents of the window as a Component
  	 */
  	private Component makeContents()
  	{
  		JPanel mainPanel = new JPanel();
  		mainPanel.setLayout(new BorderLayout(0, 5));
  		JPanel midPanel = new JPanel();
  		midPanel.setLayout(new BoxLayout(midPanel, BoxLayout.Y_AXIS));
  		midPanel.setBorder(BorderFactory.createEmptyBorder(3, 3, 3, 3));
  		// description labels
  		JLabel label1 = new JLabel("<html>" + I18nManager.getText("dialog.setlanguage.firstintro") + "</html>");
  		label1.setAlignmentX(Component.LEFT_ALIGNMENT);
  		label1.setHorizontalAlignment(SwingConstants.LEFT);
  		midPanel.add(label1);
  		JLabel label2 = new JLabel("<html>" + I18nManager.getText("dialog.setlanguage.secondintro") + "</html>");
  		label2.setAlignmentX(Component.LEFT_ALIGNMENT);
  		label2.setHorizontalAlignment(SwingConstants.LEFT);
  		midPanel.add(label2);
  		midPanel.add(Box.createVerticalStrut(10));
  
  		// built-in languages
  		JPanel builtinPanel = new JPanel();
  		builtinPanel.setBorder(BorderFactory.createCompoundBorder(
  			BorderFactory.createEtchedBorder(EtchedBorder.LOWERED), BorderFactory.createEmptyBorder(3, 3, 3, 3))
  		);
  		builtinPanel.setLayout(new BoxLayout(builtinPanel, BoxLayout.X_AXIS));
  		builtinPanel.add(new JLabel(I18nManager.getText("dialog.setlanguage.language") + " : "));
  		// Language dropdown
  		_languageDropDown = new JComboBox<String>(LANGUAGE_NAMES);
  		builtinPanel.add(_languageDropDown);
  		builtinPanel.add(Box.createHorizontalGlue());
  		JButton selectLangButton = new JButton(I18nManager.getText("button.select"));
  		selectLangButton.addActionListener(e -> selectLanguage());
  		builtinPanel.add(selectLangButton);
  		builtinPanel.setAlignmentX(Component.LEFT_ALIGNMENT);
  		midPanel.add(builtinPanel);
  		midPanel.add(Box.createVerticalStrut(4));
  
  		// external language file
  		JPanel extraPanel = new JPanel();
  		extraPanel.setBorder(BorderFactory.createCompoundBorder(
  			BorderFactory.createEtchedBorder(EtchedBorder.LOWERED), BorderFactory.createEmptyBorder(3, 3, 3, 3))
  		);
  		extraPanel.setLayout(new BoxLayout(extraPanel, BoxLayout.X_AXIS));
  		extraPanel.add(new JLabel(I18nManager.getText("dialog.setlanguage.languagefile") + " : "));
  		_langFileBox = new JTextField("some_long_example_file_path.txt");
  		extraPanel.add(_langFileBox);
  		// browse button
  		JButton browseButton = new JButton(I18nManager.getText("button.browse"));
  		extraPanel.add(browseButton);
  		browseButton.addActionListener(e -> chooseFile());
  		extraPanel.add(Box.createHorizontalStrut(5));
  		JButton selectFileButton = new JButton(I18nManager.getText("button.select"));
  		selectFileButton.addActionListener(e -> selectLanguageFile());
  		extraPanel.add(selectFileButton);
  		extraPanel.setAlignmentX(Component.LEFT_ALIGNMENT);
  		midPanel.add(Box.createVerticalStrut(5));
  		midPanel.add(extraPanel);
  		midPanel.add(Box.createVerticalGlue());
  		mainPanel.add(midPanel, BorderLayout.CENTER);
  
  		// Cancel button at the bottom
  		JPanel buttonPanel = new JPanel();
  		buttonPanel.setLayout(new FlowLayout(FlowLayout.RIGHT));
  		JButton cancelButton = new JButton(I18nManager.getText("button.cancel"));
  		cancelButton.addActionListener(e -> _dialog.dispose());
  		buttonPanel.add(cancelButton);
  		mainPanel.add(buttonPanel, BorderLayout.SOUTH);
  		return mainPanel;
  	}
  
  
  	/**
  	 * Show window
  	 */
  	public void begin()
  	{
  		if (_dialog == null)
  		{
  			_dialog = new JDialog(_parentFrame, getName());
  			_dialog.setLocationRelativeTo(_parentFrame);
  			_dialog.getContentPane().add(makeContents());
  			_dialog.pack();
  		}
  		// Try to use code from config
  		String code = getConfig().getConfigString(Config.KEY_LANGUAGE_CODE);
  		int index = getLanguageIndex(code);
  		// If it's not present, then use system locale settings
  		if (index < 0)
  		{
  			Locale locale = Locale.getDefault();
  			index = getLanguageIndex(locale.getLanguage() + "_" + locale.getCountry());
  			if (index < 0) {
  				index = getLanguageIndex(locale.getLanguage());
  			}
  		}
  		// Select appropriate language from dropdown
  		if (index >= 0) {
  			_languageDropDown.setSelectedIndex(index);
  		}
  		_startIndex = _languageDropDown.getSelectedIndex();
  		// Get language file from config
  		String langfile = getConfig().getConfigString(Config.KEY_LANGUAGE_FILE);
  		_langFileBox.setText(langfile == null ? "" : langfile);
  		_dialog.setVisible(true);
  	}
  
  	/**
  	 * Find the index of the given language code
  	 * @param inCode code to look for
  	 * @return index if found or -1
  	 */
  	private static int getLanguageIndex(String inCode)
  	{
  		int idx = -1;
  		if (inCode != null && !inCode.equals(""))
  		{
  			for (int i=0; i<LANGUAGE_CODES.length; i++)
  			{
  				if (LANGUAGE_CODES[i].equalsIgnoreCase(inCode)) {
  					idx = i;
  				}
  			}
  		}
  		return idx;
  	}
  
  	/**
  	 * Set the currently selected language in the Config
  	 */
  	private void selectLanguage()
  	{
  		int index = _languageDropDown.getSelectedIndex();
  		// If index hasn't changed then don't dismiss dialog
  		if (index >= 0 && index != _startIndex)
  		{
  			String code = LANGUAGE_CODES[index];
  			// Set code and langfile in config
  			getConfig().setConfigString(Config.KEY_LANGUAGE_CODE, code);
  			getConfig().setConfigString(Config.KEY_LANGUAGE_FILE, null);
  			_dialog.dispose();
  			showEndMessage();
  		}
  	}
  
  	/**
  	 * Select the currently selected language file to use for texts
  	 */
  	private void selectLanguageFile()
  	{
  		final String oldPath = getConfig().getConfigString(Config.KEY_LANGUAGE_FILE);
  		String filename = _langFileBox.getText();
  		// Check there is an entry in the box
  		if (filename != null && !filename.equals(""))
  		{
  			// Check the file exists and is readable
  			File textsFile = new File(filename);
  			if (!textsFile.exists() || !textsFile.canRead())
  			{
  				_app.showErrorMessage(getNameKey(), "error.load.noread");
  			}
  			else if (!languageFileLooksOk(textsFile))
  			{
  				_app.showErrorMessage(getNameKey(), "error.language.wrongfile");
  			}
  			else if (oldPath == null || !textsFile.getAbsolutePath().equalsIgnoreCase(oldPath))
  			{
  				// Set in Config
  				getConfig().setConfigString(Config.KEY_LANGUAGE_FILE, textsFile.getAbsolutePath());
  				_dialog.dispose();
  				showEndMessage();
  			}
  		}
  		else
  		{
  			// if file was previously selected, and now it's blank, then reset Config
  			if (oldPath != null && oldPath.length() > 0)
  			{
  				getConfig().setConfigString(Config.KEY_LANGUAGE_FILE, null);
  				_dialog.dispose();
  				showEndMessage();
  			}
  		}
  	}
  
  	/**
  	 * Check the given file to see if it looks like a language file
  	 * @param inFile File object to load
  	 * @return true if file looks ok
  	 */
  	private static boolean languageFileLooksOk(File inFile)
  	{
  		boolean ok = false;
  		boolean wrong = false;
  		try (BufferedReader reader = new BufferedReader(new FileReader(inFile)))
  		{
  			// Read through text file looking for lines with the right start
  			String currLine = reader.readLine();
  			while (currLine != null && !ok && !wrong)
  			{
  				if (currLine.trim().length() > 0 && currLine.matches("[a-z.]+=.+")) {
  					ok = true;
  				}
  				if (currLine.indexOf('\0') >= 0) {
  					wrong = true;
  				}
  				currLine = reader.readLine();
  			}
  		} catch (IOException e) {
  			wrong = true;
  		}
  		return ok && !wrong;
  	}
  
  	/**
  	 * Function activated by the "Browse..." button to select a file
  	 */
  	private void chooseFile()
  	{
  		JFileChooser chooser = new JFileChooser();
  		chooser.addChoosableFileFilter(
  			new GenericFileFilter("filetypefilter.txt", new String[] {"txt", "text"}));
  		chooser.setAcceptAllFileFilterUsed(true);
  		// Set start path from currently selected file
  		String currPath = _langFileBox.getText();
  		if (currPath != null && currPath.length() > 1) {
  			chooser.setSelectedFile(new File(currPath));
  		}
  		if (chooser.showOpenDialog(_parentFrame) == JFileChooser.APPROVE_OPTION)
  		{
  			_langFileBox.setText(chooser.getSelectedFile().getAbsolutePath());
  		}
  	}
  
  	/**
  	 * Show message to remind about saving settings and restarting
  	 */
  	private void showEndMessage()
  	{
  		final boolean autoSave = getConfig().getConfigBoolean(Config.KEY_AUTOSAVE_SETTINGS);
  		final String messageKey = autoSave ?
  			"dialog.setlanguage.endmessagewithautosave" : "dialog.setlanguage.endmessage";
  		JOptionPane.showMessageDialog(_parentFrame, I18nManager.getText(messageKey),
  			getName(), JOptionPane.INFORMATION_MESSAGE);
  	}
  }
  