package ie.dcu.segment.options;

/**
 * A boolean segmentation algorithm parameter.
 * 
 * @author Kevin McGuinness
 */
public class ToggleOption extends AbstractOption<Boolean> {

	/**
	 * Create a toggle option with the given name, description, and default
	 * value.
	 * 
	 * @param name
	 *        The option name
	 * @param description
	 *        A description of the option
	 * @param def
	 *        The default value for the option
	 */
	public ToggleOption(String name, String description, boolean def) {
		super(OptionType.Toggle, name, description, def);
	}
	

	public Conversion<Boolean> convert(Object value) {
		if (value instanceof Boolean) {
			return valid((Boolean) value);
		} else if (value != null) {
			Boolean val = convert(value.toString());
			if (val != null) {
				return valid(val);
			}
			return invalid("%s is not a valid boolean, value = %s", getName(), value);
		}
		return invalid("value is null");
	}
	
	
	/**
	 * Performs a conversion from a string to a boolean. If the value is "yes",
	 * "true" or "1", then the result is <code>true</code>. Otherwise if the
	 * value is "no", "false" or "0" the result is <code>false</code>. Any
	 * other value produces <code>null</code>. The string is trimmed and case
	 * is ignored.
	 * 
	 * @param str
	 *          The string to convert.
	 * @return <code>true</code>, <code>false</code> or <code>null</code>.
	 */
	private Boolean convert(String str) {
		String v = str.trim();
		
		if (v.equalsIgnoreCase("true") || 
				v.equalsIgnoreCase("yes") || 
				v.equals("1")) 
		{
			return true;
			
		} else if (v.equalsIgnoreCase("false") || 
				v.equalsIgnoreCase("no") || 
				v.equals("0")) 
		{
			return false;
		}
		
		return null;
	}
}