package tim.prune.function;

import java.awt.BorderLayout;
import java.awt.Component;
import java.awt.FlowLayout;
import java.awt.event.ItemEvent;
import java.awt.event.ItemListener;
import java.awt.event.KeyAdapter;
import java.awt.event.KeyEvent;

import javax.swing.BorderFactory;
import javax.swing.ButtonGroup;
import javax.swing.JButton;
import javax.swing.JComboBox;
import javax.swing.JDialog;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JRadioButton;
import javax.swing.SwingUtilities;

import tim.prune.App;
import tim.prune.GenericFunction;
import tim.prune.I18nManager;
import tim.prune.data.Distance;
import tim.prune.data.Field;
import tim.prune.data.TimeDifference;
import tim.prune.data.Unit;
import tim.prune.data.UnitSetLibrary;
import tim.prune.gui.GuiGridLayout;
import tim.prune.gui.WholeNumberField;

/**
 * Superclass for functions which act on a defined
 * distance limit or time limit
 */
public abstract class DistanceTimeLimitFunction extends GenericFunction
{
	/** Dialog */
	protected JDialog _dialog = null;
	/** Radio buttons for splitting by distance and time */
	private JRadioButton _distLimitRadio = null, _timeLimitRadio = null;
	/** Radio button for splitting by fraction (such as half-distance) */
	private JRadioButton _halvesRadio = null;
	/** Flag for whether to offer halves or not */
	private final boolean _showHalves;
	/** Dropdown for selecting distance units */
	private JComboBox<String> _distUnitsDropdown = null;
	/** Text field for entering distance */
	private WholeNumberField _distanceField = null;
	/** Text fields for entering distance */
	private WholeNumberField _limitHourField = null, _limitMinField = null;
	/** Ok and cancel buttons */
	private JButton _okButton = null;


	/**
	 * React to item changes and key presses by enabling / disabling ok button
	 */
	private class ChangeListener extends KeyAdapter implements ItemListener
	{
		/** Item changed in ItemListener */
		public void itemStateChanged(ItemEvent event) {
			enableOkButton();
		}

		/** Key released in KeyListener */
		public void keyReleased(KeyEvent event) {
			enableOkButton();
			if (event.getKeyCode() == KeyEvent.VK_ESCAPE) {
				_dialog.dispose();
			}
		}
	}

	/**
	 * Constructor
	 */
	public DistanceTimeLimitFunction(App inApp, boolean inShowHalves)
	{
		super(inApp);
		_showHalves = inShowHalves;
	}

	/**
	 * Begin the function
	 */
	public void begin()
	{
		if (_dialog == null)
		{
			_dialog = new JDialog(_parentFrame, getName(), true);
			_dialog.setLocationRelativeTo(_parentFrame);
			_dialog.setDefaultCloseOperation(JDialog.DISPOSE_ON_CLOSE);
			_dialog.getContentPane().add(makeDialogComponents());
			_dialog.pack();
		}
		enableOkButton();
		// TODO: Maybe set distance units according to current Config setting?
		final boolean hasTimestamps = _app.getTrackInfo().getTrack().hasData(Field.TIMESTAMP);
		_timeLimitRadio.setEnabled(hasTimestamps);
		if (!hasTimestamps) {
			_distLimitRadio.setSelected(true);
		}
		SwingUtilities.invokeLater(() -> _distanceField.requestFocus());
		_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(5, 5));

		// Make radio buttons for the options
		_distLimitRadio = new JRadioButton(I18nManager.getText("dialog.correlate.options.distancelimit") + ": ");
		_timeLimitRadio = new JRadioButton(I18nManager.getText("dialog.correlate.options.timelimit") + ": ");
		if (_showHalves) {
			_halvesRadio = new JRadioButton(I18nManager.getText("dialog.markers.halves"));
		}
		ButtonGroup radioGroup = new ButtonGroup();
		radioGroup.add(_distLimitRadio);
		radioGroup.add(_timeLimitRadio);
		if (_showHalves) {
			radioGroup.add(_halvesRadio);
		}

		// central panel for limits
		JPanel limitsPanel = new JPanel();
		limitsPanel.setBorder(BorderFactory.createEmptyBorder(8, 8, 8, 8));
		GuiGridLayout grid = new GuiGridLayout(limitsPanel, new double[] {0.5, 1.0},
			new boolean[] {false, false});
		ChangeListener optionsChangedListener = new ChangeListener();
		// distance limits
		grid.add(_distLimitRadio);
		_distLimitRadio.setSelected(true);
		_distLimitRadio.addItemListener(optionsChangedListener);
		JPanel distLimitPanel = new JPanel();
		distLimitPanel.setLayout(new FlowLayout());
		_distanceField = new WholeNumberField(3);
		_distanceField.addKeyListener(optionsChangedListener);
		distLimitPanel.add(_distanceField);
		String[] distUnitsOptions = {I18nManager.getText("units.kilometres"), I18nManager.getText("units.metres"),
			I18nManager.getText("units.miles")};
		_distUnitsDropdown = new JComboBox<String>(distUnitsOptions);
		_distUnitsDropdown.addItemListener(optionsChangedListener);
		distLimitPanel.add(_distUnitsDropdown);
		distLimitPanel.setAlignmentX(Component.LEFT_ALIGNMENT);
		grid.add(distLimitPanel);

		// time limit panel
		grid.add(_timeLimitRadio);
		_timeLimitRadio.addItemListener(optionsChangedListener);
		JPanel timeLimitPanel = new JPanel();
		timeLimitPanel.setLayout(new FlowLayout());
		_limitHourField = new WholeNumberField(2);
		_limitHourField.addKeyListener(optionsChangedListener);
		timeLimitPanel.add(_limitHourField);
		timeLimitPanel.add(new JLabel(I18nManager.getText("dialog.correlate.options.offset.hours")));
		_limitMinField = new WholeNumberField(3);
		_limitMinField.addKeyListener(optionsChangedListener);
		timeLimitPanel.add(_limitMinField);
		timeLimitPanel.add(new JLabel(I18nManager.getText("units.minutes")));
		timeLimitPanel.setAlignmentX(Component.LEFT_ALIGNMENT);
		grid.add(timeLimitPanel);

		// halves
		if (_showHalves)
		{
			grid.add(_halvesRadio);
			_halvesRadio.addItemListener(optionsChangedListener);
		}

		dialogPanel.add(limitsPanel, BorderLayout.NORTH);

		// button panel at bottom
		JPanel buttonPanel = new JPanel();
		buttonPanel.setLayout(new FlowLayout(FlowLayout.RIGHT));
		// OK button
		_okButton = new JButton(I18nManager.getText("button.ok"));
		_okButton.addActionListener(e -> performFunction());
		buttonPanel.add(_okButton);
		// Cancel button
		JButton cancelButton = new JButton(I18nManager.getText("button.cancel"));
		cancelButton.addActionListener(e -> _dialog.dispose());
		cancelButton.addKeyListener(new KeyAdapter() {
			public void keyPressed(KeyEvent inE) {
				if (inE.getKeyCode() == KeyEvent.VK_ESCAPE) {_dialog.dispose();}
			}
		});
		buttonPanel.add(cancelButton);
		dialogPanel.add(buttonPanel, BorderLayout.SOUTH);
		return dialogPanel;
	}

	/**
	 * Enable or disable the OK button according to the inputs
	 */
	private void enableOkButton()
	{
		boolean enabled = false;
		if (_distLimitRadio.isSelected()) {
			enabled = _distanceField.getValue() > 0;
		}
		else if (_timeLimitRadio.isSelected()) {
			enabled = _limitHourField.getValue() > 0 || _limitMinField.getValue() > 0;
		}
		else if (_halvesRadio != null && _halvesRadio.isSelected()) {
			enabled = true;
		}
		_okButton.setEnabled(enabled);

		// Also enable/disable the other fields
		_distanceField.setEnabled(_distLimitRadio.isSelected());
		_distUnitsDropdown.setEnabled(_distLimitRadio.isSelected());
		_limitHourField.setEnabled(_timeLimitRadio.isSelected());
		_limitMinField.setEnabled(_timeLimitRadio.isSelected());
	}

	/**
	 * @return selected time limit in seconds, or 0
	 */
	protected int getTimeLimitInSeconds()
	{
		if (_timeLimitRadio.isSelected()
			&& (_limitHourField.getValue() > 0 || _limitMinField.getValue() > 0))
		{
			int timeLimitSeconds = _limitHourField.getValue() * 60 * 60
				+ _limitMinField.getValue() * 60;
			if (timeLimitSeconds > 0) {
				return timeLimitSeconds;
			}
		}
		return 0;
	}

	/**
	 * @return selected distance limit in radians, or 0.0
	 */
	protected double getDistanceLimitRadians()
	{
		if (_distLimitRadio.isSelected()
			&& _distanceField.getValue() > 0)
		{
			final Unit[] distUnits = {UnitSetLibrary.UNITS_KILOMETRES,
				UnitSetLibrary.UNITS_METRES, UnitSetLibrary.UNITS_MILES};
			Unit distUnit = distUnits[_distUnitsDropdown.getSelectedIndex()];
			double distLimitRadians = Distance.convertDistanceToRadians(_distanceField.getValue(), distUnit);
			return distLimitRadians;
		}
		return 0.0;
	}

	/**
	 * @return selected distance limit in km, or 0.0
	 */
	protected double getDistanceLimitKilometres()
	{
		return Distance.convertRadiansToDistance(getDistanceLimitRadians(), UnitSetLibrary.UNITS_KILOMETRES);
	}

	/**
	 * @return true if "halves" option was selected
	 */
	protected boolean isHalvesSelected() {
		return _halvesRadio != null && _halvesRadio.isSelected();
	}

	/**
	 * The dialog has been completed and OK pressed, so do the corresponding function
	 */
	protected abstract void performFunction();

	/**
	 * Create a description for the given multiple of the configured limit
	 * @param inMultiple multiple of selected limit
	 * @return language-specific String description for waypoint names
	 */
	protected String createLimitDescription(int inMultiple)
	{
		if (_distLimitRadio.isSelected()
			&& _distanceField.getValue() > 0)
		{
			final int distLimit = inMultiple * _distanceField.getValue();
			final String[] distUnits = {"kilometres", "metres", "miles"};
			final String unitKey = "units." + distUnits[_distUnitsDropdown.getSelectedIndex()] + ".short";
			return "" + distLimit + " " + I18nManager.getText(unitKey);
		}
		else if (_timeLimitRadio.isSelected())
		{
			final long timeLimitSecs = (long) getTimeLimitInSeconds() * inMultiple;
			return new TimeDifference(timeLimitSecs).getDescription();
		}
		return null;
	}
}