/**
 * File: Algorithm.java
 * Author: Brian Borowski
 * Date created: December 26, 2010
 * Date last modified: May 7, 2011
 */
public abstract class Algorithm {
    public static final int NOT_APPLICABLE = -1;

    public volatile static long numberVisited, numberExpanded;
    private static long startTime, endTime;

    public static int initialMovesEstimate, movesRequired;
    public static boolean running, solved;
    public static String shortestPath;

    public static float getRunningTimeInSeconds() {
        final long diff = endTime - startTime;
        // Have seen negative numbers on systems with multiple processors.
        if (diff < 0) return 0.0f;
        return diff / 1000f;
    }

    public static float getElapsedTimeInSeconds() {
        final long diff = System.currentTimeMillis() - startTime;
        // Have seen negative numbers on systems with multiple processors.
        if (diff < 0) return 0.0f;
        return diff / 1000f;
    }

    abstract void solvePuzzle(final long currentState, final int numOfThreads);

    public void solve(final long currentState, final int numOfThreads) {
        Node.initialize();
        initialize();

        solvePuzzle(currentState, numOfThreads);

        markEndTime();
        running = false;
    }

    public abstract void cleanup();

    public void start() {
        running = true;
        solved = false;
    }

    public void stop() {
        running = false;
    }

    private static void initialize() {
        startTime = System.currentTimeMillis();
        solved = false;
        running = true;
        numberVisited = 0;
        numberExpanded = 0;
    }

    private static void markEndTime() {
        endTime = System.currentTimeMillis();
    }
}