package foundation.action;

public enum Moment {

	Before, After, On;
	
	public static Moment parse(String value) {
		if (value == null) {
			return On;
		}
		
		value = value.toLowerCase();
		
		if ("before".equals(value)) {
			return Before;
		}
		else if ("after".equals(value)) {
			return After;
		}
		
		return On;
	}

	public static int subtract(Moment one, Moment another) {
		if (one == null) {
			if (another == null) {
				return 0;
			}
			else if (Moment.Before == another) {
				return 1;
			}
			else if (Moment.After == another) {
				return -1;
			}
		}
		else if (Moment.Before == one) {
			if (another == null) {
				return -1;
			}
			else if (Moment.Before == another) {
				return 0;
			}
			else if (Moment.After == another) {
				return -1;
			}
		}
		else if (Moment.After == one) {
			if (another == null) {
				return 1;
			}
			else if (Moment.Before == another) {
				return 1;
			}
			else if (Moment.After == another) {
				return 0;
			}			
		}
		
		return 0;
	}
	
}