package edu.osu.cse421;

import java.util.Arrays;
import java.util.logging.Logger;
import java.util.logging.Handler;
import java.util.logging.Level;

/**
 * Utility class for diagnosing Logging configuration. The class provides
 * methods for displaying information relevant to the behavior of a logger.
 * 
 * @author paolo
 */
public final class Loggers {

	/**
	 * Private constructor to prevent this class from being instantiated.
	 */
	private Loggers() {
	}

	/**
	 * Calculates the levels of all the handlers in an array of handlers.
	 * 
	 * @param h
	 *            an array of handlers
	 * @return x[] such that x.length = h.length for all i in 0 <= i < h.length,
	 *         x[i] = level of h[i]
	 */
	private static Level[] handlerLevels(final Handler[] h) {
		Level[] hlevels = new Level[h.length];
		for (int i = 0; i < h.length; i++) {
			hlevels[i] = h[i].getLevel();
		}
		return hlevels;
	}

	/**
	 * Displays relevant information for a single logger.
	 *
	 * @param logger the logger to be displayed
	 */
	public static void showLoggerInfo(final Logger logger) {
		if (logger.getParent() == null) {
			System.out.println("Root Logger");
		} else {
			System.out.println("Child Logger (Parent is \""
					+ logger.getParent().getName() + "\")");
		}
		System.out.println("  Name:     " + "\"" + logger.getName() + "\"");
		System.out.println("  Level:    " + logger.getLevel());
		System.out.println("  Handlers: "
				+ Arrays.toString(logger.getHandlers()));
		System.out.println("  Handler levels: "
				+ Arrays.toString(handlerLevels(logger.getHandlers())));
	}

	/**
	 * Displays relevant information for the hierarchy of loggers
	 * above (by the parent relationship) of a  single logger.
	 *
	 * @param logger the leaf of the path of loggers to be displayed
	 */
	public static void showLoggerTreeInfo(final Logger logger) {
		if (logger.getParent() == null) {
			showLoggerInfo(logger);
		} else {
			showLoggerTreeInfo(logger.getParent());
			showLoggerInfo(logger);
		}
	}
}