package com.onaro.sanscreen.client.view.tabular.value;

import java.io.Serializable;
import java.text.DateFormat;
import java.util.Calendar;
import java.util.Date;

import org.apache.commons.lang3.StringUtils;
import org.apache.commons.lang3.time.DateUtils;

import com.onaro.client.DateFormats;

/**
 * Table column value representing a Date value. The date value is rounded to minute
 * precision (to match the default format). This value responds to sorting and toString() 
 * properly, using the format by {@link #formatDate(Date, DateFormat)} (overridable).
 * 
 * @author jmyers
 *
 */
public class DateValue implements Comparable<DateValue>, Serializable {
 
    private static final long serialVersionUID = 1L;
    
    protected final Date date;
    protected final DateFormat format;
    protected final String display;
    
    /**
     * Construct a date value, using the formatter specified in {@link #getDefaultDateFormat()}.
     * @param date the value's date
     */
    public DateValue(final Date date) {
        this(date, getDefaultDateFormat());
    }
    
    /**
     * Construct a date value, using a custom format.
     * @param date
     * @param format
     */
    public DateValue(final Date date, final DateFormat format) {
        // Round the date value to minute precision
        this.date = date == null ? null : DateUtils.round(date, getDefaultDatePrecision());
        this.format = format == null ? getDefaultDateFormat() : format;
        this.display = formatDate(this.date, this.format);
    }
    
    /**
     * Get the default date format to use for DateValue instances.
     * @return the default format
     */
    protected static DateFormat getDefaultDateFormat() {
        return DateFormats.getDayShortDateTimeFormat();
    }
    
    /**
     * Get the default date rounding precision. All dates will be rounded
     * to this precision. Normally, this precision should match the most significant
     * portion of the date format used. The returned value should be constants from the
     * {@link java.util.Calendar} class.
     * 
     * @return the precision to use for the date values
     */
    protected static int getDefaultDatePrecision() {
        return Calendar.MINUTE;
    }
    
    /**
     * Format the date value. If the date is null, an empty string is returned.
     * Otherwise the passed in formatter is used to format the date.
     * @param date the date value
     * @param format the format used to format the date
     * @return the formatted date string
     */
    protected String formatDate(final Date date, final DateFormat format) {
        if (date == null) {
            return StringUtils.EMPTY;
        }  
        
        return format.format(date);
    }
    
    public Date getDate() {
        return new Date(this.date.getTime());
    }
    
    public DateFormat getFormat() {
        return this.format;
    }
    
    @Override
    public String toString() {
        return display;
    }

    @Override
    public int compareTo(DateValue o) {
        if (date == null) {
            if (o.date == null) return 0;
            else return 1;
        }
        if (o.date == null) return -1;
        
        return date.compareTo(o.date);
    }

    @Override
    public int hashCode() {
        final int prime = 31;
        int result = 1;
        result = prime * result + ((date == null) ? 0 : date.hashCode());
        return result;
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj) return true;
        if (obj == null) return false;
        if (getClass() != obj.getClass()) return false;
        DateValue other = (DateValue) obj;
        if (date == null) {
            if (other.date != null) return false;
        }
        else if (!date.equals(other.date)) return false;
        return true;
    }
}