/* 
@ITMillApache2LicenseForJavaFiles@
 */

package com.itmill.toolkit.ui;

import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
import java.util.Locale;
import java.util.Map;

import com.itmill.toolkit.data.Property;
import com.itmill.toolkit.terminal.PaintException;
import com.itmill.toolkit.terminal.PaintTarget;

/**
 * <p>
 * A date editor component that can be bound to any bindable Property. that is
 * compatible with <code>java.util.Date</code>.
 * </p>
 * <p>
 * Since <code>DateField</code> extends <code>AbstractField</code> it implements
 * the {@link com.itmill.toolkit.data.Buffered}interface. A
 * <code>DateField</code> is in write-through mode by default, so
 * {@link com.itmill.toolkit.ui.AbstractField#setWriteThrough(boolean)}must be
 * called to enable buffering.
 * </p>
 * 
 * @author IT Mill Ltd.
 * @version
 * @VERSION@
 * @since 3.0
 */
public class DateField extends AbstractField {

    /* Private members */

    /**
     * Resolution identifier: milliseconds.
     */
    public static final int RESOLUTION_MSEC = 0;

    /**
     * Resolution identifier: seconds.
     */
    public static final int RESOLUTION_SEC = 1;

    /**
     * Resolution identifier: minutes.
     */
    public static final int RESOLUTION_MIN = 2;

    /**
     * Resolution identifier: hours.
     */
    public static final int RESOLUTION_HOUR = 3;

    /**
     * Resolution identifier: days.
     */
    public static final int RESOLUTION_DAY = 4;

    /**
     * Resolution identifier: months.
     */
    public static final int RESOLUTION_MONTH = 5;

    /**
     * Resolution identifier: years.
     */
    public static final int RESOLUTION_YEAR = 6;

    /**
     * Popup date selector (calendar).
     */
    protected static final String TYPE_POPUP = "popup";

    /**
     * Inline date selector (calendar).
     */
    protected static final String TYPE_INLINE = "inline";

    /**
     * Specified widget type.
     */
    protected String type = TYPE_POPUP;

    /**
     * Specified smallest modifiable unit.
     */
    private int resolution = RESOLUTION_MSEC;

    /**
     * Specified largest modifiable unit.
     */
    private static final int largestModifiable = RESOLUTION_YEAR;

    /**
     * The internal calendar to be used in java.utl.Date conversions.
     */
    private Calendar calendar;

    /**
     * Overridden format string
     */
    private String dateFormat;

    /* Constructors */

    /**
     * Constructs an empty <code>DateField</code> with no caption.
     */
    public DateField() {
    }

    /**
     * Constructs an empty <code>DateField</code> with caption.
     * 
     * @param caption
     *            the caption of the datefield.
     */
    public DateField(String caption) {
        setCaption(caption);
    }

    /**
     * Constructs a new <code>DateField</code> that's bound to the specified
     * <code>Property</code> and has the given caption <code>String</code>.
     * 
     * @param caption
     *            the caption <code>String</code> for the editor.
     * @param dataSource
     *            the Property to be edited with this editor.
     */
    public DateField(String caption, Property dataSource) {
        this(dataSource);
        setCaption(caption);
    }

    /**
     * Constructs a new <code>DateField</code> that's bound to the specified
     * <code>Property</code> and has no caption.
     * 
     * @param dataSource
     *            the Property to be edited with this editor.
     */
    public DateField(Property dataSource) throws IllegalArgumentException {
        if (!Date.class.isAssignableFrom(dataSource.getType())) {
            throw new IllegalArgumentException("Can't use "
                    + dataSource.getType().getName()
                    + " typed property as datasource");
        }

        setPropertyDataSource(dataSource);
    }

    /**
     * Constructs a new <code>DateField</code> with the given caption and
     * initial text contents. The editor constructed this way will not be bound
     * to a Property unless
     * {@link com.itmill.toolkit.data.Property.Viewer#setPropertyDataSource(Property)}
     * is called to bind it.
     * 
     * @param caption
     *            the caption <code>String</code> for the editor.
     * @param value
     *            the Date value.
     */
    public DateField(String caption, Date value) {
        setValue(value);
        setCaption(caption);
    }

    /* Component basic features */

    /*
     * Paints this component. Don't add a JavaDoc comment here, we use the
     * default documentation from implemented interface.
     */
    @Override
    public void paintContent(PaintTarget target) throws PaintException {
        super.paintContent(target);

        // Adds the locale as attribute
        final Locale l = getLocale();
        if (l != null) {
            target.addAttribute("locale", l.toString());
        }

        if (getDateFormat() != null) {
            target.addAttribute("format", dateFormat);
        }

        target.addAttribute("type", type);

        // Gets the calendar
        final Calendar calendar = getCalendar();
        final Date currentDate = (Date) getValue();

        for (int r = resolution; r <= largestModifiable; r++) {
            switch (r) {
            case RESOLUTION_MSEC:
                target.addVariable(this, "msec", currentDate != null ? calendar
                        .get(Calendar.MILLISECOND) : -1);
                break;
            case RESOLUTION_SEC:
                target.addVariable(this, "sec", currentDate != null ? calendar
                        .get(Calendar.SECOND) : -1);
                break;
            case RESOLUTION_MIN:
                target.addVariable(this, "min", currentDate != null ? calendar
                        .get(Calendar.MINUTE) : -1);
                break;
            case RESOLUTION_HOUR:
                target.addVariable(this, "hour", currentDate != null ? calendar
                        .get(Calendar.HOUR_OF_DAY) : -1);
                break;
            case RESOLUTION_DAY:
                target.addVariable(this, "day", currentDate != null ? calendar
                        .get(Calendar.DAY_OF_MONTH) : -1);
                break;
            case RESOLUTION_MONTH:
                target.addVariable(this, "month",
                        currentDate != null ? calendar.get(Calendar.MONTH) + 1
                                : -1);
                break;
            case RESOLUTION_YEAR:
                target.addVariable(this, "year", currentDate != null ? calendar
                        .get(Calendar.YEAR) : -1);
                break;
            }
        }
    }

    /*
     * Gets the components UIDL tag string. Don't add a JavaDoc comment here, we
     * use the default documentation from implemented interface.
     */
    @Override
    public String getTag() {
        return "datefield";
    }

    /*
     * Invoked when a variable of the component changes. Don't add a JavaDoc
     * comment here, we use the default documentation from implemented
     * interface.
     */
    @Override
    public void changeVariables(Object source, Map variables) {
        super.changeVariables(source, variables);

        if (!isReadOnly()
                && (variables.containsKey("year")
                        || variables.containsKey("month")
                        || variables.containsKey("day")
                        || variables.containsKey("hour")
                        || variables.containsKey("min")
                        || variables.containsKey("sec") || variables
                        .containsKey("msec"))) {

            // Old and new dates
            final Date oldDate = (Date) getValue();
            Date newDate = null;

            // Gets the new date in parts
            // Null values are converted to negative values.
            int year = variables.containsKey("year") ? (variables.get("year") == null ? -1
                    : ((Integer) variables.get("year")).intValue())
                    : -1;
            int month = variables.containsKey("month") ? (variables
                    .get("month") == null ? -1 : ((Integer) variables
                    .get("month")).intValue() - 1) : -1;
            int day = variables.containsKey("day") ? (variables.get("day") == null ? -1
                    : ((Integer) variables.get("day")).intValue())
                    : -1;
            int hour = variables.containsKey("hour") ? (variables.get("hour") == null ? -1
                    : ((Integer) variables.get("hour")).intValue())
                    : -1;
            int min = variables.containsKey("min") ? (variables.get("min") == null ? -1
                    : ((Integer) variables.get("min")).intValue())
                    : -1;
            int sec = variables.containsKey("sec") ? (variables.get("sec") == null ? -1
                    : ((Integer) variables.get("sec")).intValue())
                    : -1;
            int msec = variables.containsKey("msec") ? (variables.get("msec") == null ? -1
                    : ((Integer) variables.get("msec")).intValue())
                    : -1;

            // If all of the components is < 0 use the previous value
            if (year < 0 && month < 0 && day < 0 && hour < 0 && min < 0
                    && sec < 0 && msec < 0) {
                newDate = null;
            } else {

                // Clone the calendar for date operation
                final Calendar cal = getCalendar();

                // Make sure that meaningful values exists
                // Use the previous value if some of the variables
                // have not been changed.
                year = year < 0 ? cal.get(Calendar.YEAR) : year;
                month = month < 0 ? cal.get(Calendar.MONTH) : month;
                day = day < 0 ? cal.get(Calendar.DAY_OF_MONTH) : day;
                hour = hour < 0 ? cal.get(Calendar.HOUR_OF_DAY) : hour;
                min = min < 0 ? cal.get(Calendar.MINUTE) : min;
                sec = sec < 0 ? cal.get(Calendar.SECOND) : sec;
                msec = msec < 0 ? cal.get(Calendar.MILLISECOND) : msec;

                // Sets the calendar fields
                cal.set(Calendar.YEAR, year);
                cal.set(Calendar.MONTH, month);
                cal.set(Calendar.DAY_OF_MONTH, day);
                cal.set(Calendar.HOUR_OF_DAY, hour);
                cal.set(Calendar.MINUTE, min);
                cal.set(Calendar.SECOND, sec);
                cal.set(Calendar.MILLISECOND, msec);

                // Assigns the date
                newDate = cal.getTime();
            }

            if (newDate != oldDate
                    && (newDate == null || !newDate.equals(oldDate))) {
                setValue(newDate, true); // Don't require a repaint, client
                // updates itself
            }
        }
    }

    /* Property features */

    /*
     * Gets the edited property's type. Don't add a JavaDoc comment here, we use
     * the default documentation from implemented interface.
     */
    @Override
    public Class getType() {
        return Date.class;
    }

    /*
     * Returns the value of the property in human readable textual format. Don't
     * add a JavaDoc comment here, we use the default documentation from
     * implemented interface.
     */
    @Override
    public String toString() {
        final Date value = (Date) getValue();
        if (value != null) {
            return value.toString();
        }
        return null;
    }

    /*
     * Sets the value of the property. Don't add a JavaDoc comment here, we use
     * the default documentation from implemented interface.
     */
    @Override
    public void setValue(Object newValue) throws Property.ReadOnlyException,
            Property.ConversionException {
        setValue(newValue, false);
    }

    @Override
    public void setValue(Object newValue, boolean repaintIsNotNeeded)
            throws Property.ReadOnlyException, Property.ConversionException {

        // Allows setting dates directly
        if (newValue == null || newValue instanceof Date) {
            super.setValue(newValue, repaintIsNotNeeded);
        } else {

            // Try to parse as string
            try {
                final SimpleDateFormat parser = new SimpleDateFormat();
                final Date val = parser.parse(newValue.toString());
                super.setValue(val, repaintIsNotNeeded);
            } catch (final ParseException e) {
                throw new Property.ConversionException(e.getMessage());
            }
        }
    }

    /**
     * Sets the DateField datasource. Datasource type must assignable to Date.
     * 
     * @see com.itmill.toolkit.data.Property.Viewer#setPropertyDataSource(Property)
     */
    @Override
    public void setPropertyDataSource(Property newDataSource) {
        if (newDataSource == null
                || Date.class.isAssignableFrom(newDataSource.getType())) {
            super.setPropertyDataSource(newDataSource);
        } else {
            throw new IllegalArgumentException(
                    "DateField only supports Date properties");
        }
    }

    /**
     * Gets the resolution.
     * 
     * @return int
     */
    public int getResolution() {
        return resolution;
    }

    /**
     * Sets the resolution of the DateField.
     * 
     * @param resolution
     *            the resolution to set.
     */
    public void setResolution(int resolution) {
        this.resolution = resolution;
    }

    /**
     * Returns new instance calendar used in Date conversions.
     * 
     * Returns new clone of the calendar object initialized using the the
     * current date (if available)
     * 
     * If this is no calendar is assigned the <code>Calendar.getInstance</code>
     * is used.
     * 
     * @return the Calendar.
     * @see #setCalendar(Calendar)
     */
    private Calendar getCalendar() {

        // Makes sure we have an calendar instance
        if (calendar == null) {
            calendar = Calendar.getInstance();
        }

        // Clone the instance
        final Calendar newCal = (Calendar) calendar.clone();

        // Assigns the current time tom calendar.
        final Date currentDate = (Date) getValue();
        if (currentDate != null) {
            newCal.setTime(currentDate);
        }

        return newCal;
    }

    /**
     * Sets formatting used by some component implementations. See
     * {@link SimpleDateFormat} for format details.
     * 
     * By default it is encouraged to used default formatting defined by Locale,
     * but due some JVM bugs it is sometimes necessary to use this method to
     * override formatting. See Toolkit issue #2200.
     * 
     * @param dateFormat
     *            the dateFormat to set
     * 
     * @see com.itmill.toolkit.ui.AbstractComponent#setLocale(Locale))
     */
    public void setDateFormat(String dateFormat) {
        this.dateFormat = dateFormat;
    }

    /**
     * Reterns a format string used to format date value on client side or null
     * if default formatting from {@link Component#getLocale()} is used.
     * 
     * @return the dateFormat
     */
    public String getDateFormat() {
        return dateFormat;
    }

}