package com.onaro.util.jfc.date;

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Component;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
import java.util.GregorianCalendar;

import javax.swing.DefaultListCellRenderer;
import javax.swing.JList;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JSpinner;
import javax.swing.ListSelectionModel;
import javax.swing.SpinnerDateModel;
import javax.swing.event.ChangeEvent;
import javax.swing.event.ChangeListener;
import javax.swing.event.ListSelectionEvent;
import javax.swing.event.ListSelectionListener;

import com.onaro.client.DateFormats;

/**
 * A three way time selection component. To select time, the user may type it in an input field, use a spinner or select
 * from a list.
 * <p>
 * The current selected date can be traced using <code>PropertyChangeEvent</code>s.
 */
public class TimeSelector extends JPanel {

    private static final long serialVersionUID = 1L;

    /**
     * Property name for the current selected time.
     */
    public static final String PROPERTY_TIME = "selectedTime"; //$NON-NLS-1$

    /**
     * The current time.
     */
    private Date time;

    /**
     * A spinner allowing the user to roll the time back and forwards in steps of one minute.
     */
    private JSpinner timeSpinner;

    /**
     * Pattern for time display.
     */
    private String timePattern = DateFormats.getHourPattern();

    /**
     * The list of hours the user may select from.
     */
    private JList<Object> quickSelectionList;

    /**
     * The number of entries in the quick time selection list
     */
    public static final int QUICK_SELECT_ENTRIES = 48;

    /**
     * The time interval in minutes between the options of the quick time selection list.
     */
    public static final int QUICK_SELECT_INTERVAL = 30;

    /**
     * Constructs a time selector that uses the current time and is using the default time format.
     */
    public TimeSelector() {
        this(new Date());
    }

    /**
     * Constructs a time selector that is using the default time format.
     * 
     * @param initialTime
     *            the time selected initially
     */
    public TimeSelector(Date initialTime) {
        this(initialTime, null);
    }

    /**
     * Constructs a time selector.
     * 
     * @param initialTime
     *            the time selected initially
     * @param timePattern
     *            time display format
     */
    public TimeSelector(Date initialTime, String timePattern) {
        super(new BorderLayout());

        this.time = initialTime;
        if (timePattern != null) {
            this.timePattern = timePattern;
        }

        /**
         * Setup the minutes and hours spinner.
         */
        timeSpinner = new JSpinner(new SpinnerDateModel(time, null, null, Calendar.MINUTE));
        timeSpinner.setEditor(new JSpinner.DateEditor(timeSpinner, this.timePattern));
        timeSpinner.addChangeListener(new ChangeListener() {
            public void stateChanged(ChangeEvent e) {
                setTime((Date) timeSpinner.getValue());
            }
        });
        add(timeSpinner, BorderLayout.NORTH);

        /**
         * Setup the quick select hours list
         */
        initQuickSelection();
        quickSelectionList.setBackground(Color.WHITE);
        add(new JScrollPane(quickSelectionList), BorderLayout.CENTER);
    }
    
    @Override
    public void setEnabled(boolean enabled) {
        super.setEnabled(enabled);

        timeSpinner.setEnabled(enabled);
        quickSelectionList.setEnabled(enabled);
    }

    /**
     * Initializes the quick time selection list.
     */
    private void initQuickSelection() {
        Calendar timeIterator = new GregorianCalendar();
        timeIterator.clear();
        timeIterator.set(Calendar.HOUR_OF_DAY, 0);
        timeIterator.set(Calendar.MINUTE, 0);

        Date quickSelectableTime[] = new Date[QUICK_SELECT_ENTRIES];
        for (int i = 0; i < QUICK_SELECT_ENTRIES; ++i) {
            quickSelectableTime[i] = timeIterator.getTime();
            timeIterator.add(Calendar.MINUTE, QUICK_SELECT_INTERVAL);
        }

        quickSelectionList = new JList<Object>(quickSelectableTime);
        quickSelectionList.setCellRenderer(new DefaultListCellRenderer() {
            private static final long serialVersionUID = 1L;
            SimpleDateFormat timeFormatter = new SimpleDateFormat(TimeSelector.this.timePattern);

            public Component getListCellRendererComponent(JList<?> list, Object value, int index, boolean isSelected,
                    boolean cellHasFocus) {
                return super.getListCellRendererComponent(list, timeFormatter.format(value), index, isSelected,
                        cellHasFocus);
            }
        });
        quickSelectionList.getSelectionModel().addListSelectionListener(new ListSelectionListener() {
            public void valueChanged(ListSelectionEvent e) {
                if (!e.getValueIsAdjusting()) {
                    setTime((Date) quickSelectionList.getSelectedValue());
                }
            }
        });
        quickSelectionList.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
    }

    /**
     * Sets the current selected time.
     * 
     * @param newTime
     *            the new selected time
     */
    public void setTime(Date newTime) {
        if (newTime != null) {
            Date oldTime = time;

            if (!newTime.equals(oldTime)) {
                time = newTime;

                timeSpinner.setValue(newTime);

                Calendar newTimeCal = new GregorianCalendar();
                newTimeCal.setTime(newTime);
                Calendar timeCal = new GregorianCalendar();
                timeCal.clear();
                timeCal.set(Calendar.HOUR_OF_DAY, newTimeCal.get(Calendar.HOUR_OF_DAY));
                timeCal.set(Calendar.MINUTE, newTimeCal.get(Calendar.MINUTE));
                Date selectTime = timeCal.getTime();
                quickSelectionList.setSelectedValue(selectTime, true);
                if (!selectTime.equals(quickSelectionList.getSelectedValue())) {
                    quickSelectionList.clearSelection();
                }

                firePropertyChange(PROPERTY_TIME, oldTime, newTime);
            }
        }
    }

    /**
     * Gets the current selected time.
     * 
     * @return the current selected time
     */
    public Date getTime() {
        return time;
    }

}