package org.greenstone.gsdl3.gs3build.metadata;

public class METSDate
{
	String era;
	String year;
	String month;
	String day;
	String hour;
	String minute;
	String second;
	String timezone;

	public void METSDate(String string)
	{	String date;

		int timeAt = string.indexOf('T');

		// if we've got a time signature, get it
		if (timeAt >= 0) {
		  // get the date for later use
			date = string.substring(0, timeAt);

			// extract the time string
			String time = string.substring(timeAt+1);

			// check for time zone usage - currently '+' and '-' only...
			int zoneAt = time.indexOf('+');
			if (zoneAt == -1) {	
				zoneAt = time.indexOf('-');
			}
			if (zoneAt >= 0) {
				this.timezone = time.substring(zoneAt);
				time = time.substring(0, zoneAt);
			}

			// finally, divide into hours, minutes etc.
			int hourAt = time.indexOf(':');
			if (hourAt >= 0) {
				this.hour = time.substring(0, hourAt);

				time = time.substring(hourAt+1);
				int minuteAt = time.indexOf(':');
				if (minuteAt >= 0)
				{	this.minute = time.substring(0, minuteAt);
					this.second = time.substring(minuteAt+1);
				}
				else
				{ this.minute = time;
					this.second = null;
				}
			}
		}
		else 
		{ this.timezone = null;
			this.hour     = null;
			this.minute   = null;
			this.second   = null;

			date = string;
		}

		// get the era
		int prefixEnds = 0;
		while (!Character.isDigit(date.charAt(prefixEnds)))
		{ prefixEnds ++;
		}

		if (prefixEnds != 0) {
			this.era = date.substring(0, prefixEnds);
			date = date.substring(prefixEnds);
		}
		else {
			this.era = null;
		}

		// finally, get the date
		
		// now try dividing up by '-'
		int yearAt = date.indexOf('-');
		if (yearAt >= 0) {
			this.year = date.substring(0, yearAt);
			date = date.substring(yearAt+1);

			int monthAt = date.indexOf('-');
			if (monthAt >= 0) {
				this.month = date.substring(0, monthAt);
				this.day = date.substring(monthAt+1);
			}
			else {
				this.month = date;
				this.day   = null;
			}
		}
		else {
			// try dividing by YYYYMMDD - any part of which may be missing...
			if (date.length() >= 4) {
				this.year = date.substring(0, 4);
				if (date.length() >= 6) {
					this.month = date.substring(4, 6);
					this.day = date.substring(6);
				}
				else {
					this.month = date.substring(4);
					this.day   = null;
				}
			}
			// we just have a day in this case...
			else {
				this.year = date;
				this.month = null;
				this.day = null;
			}
		}
	}

	public String toString()
	{	if (this.year == null) {
			return "";
		}

		StringBuffer buffer = new StringBuffer();

		if (this.era != null) {
			buffer.append(era);
		}
		buffer.append(year);
		if (this.month != null) {
			buffer.append("-");
			buffer.append(this.month);
			if (this.day != null) {
				buffer.append("-");
				buffer.append(this.day);

				if (this.hour != null) {
					buffer.append("T");
					buffer.append(this.hour);
					buffer.append(":");
					buffer.append(this.minute);
					if (this.second != null) {
						buffer.append(":");
						buffer.append(this.second);

						if (this.timezone != null) {
							buffer.append(this.timezone);
						}
					}
				}
			}
		}
		return buffer.toString();
	}
}