/*
 * NOTE: This copyright does *not* cover user programs that use HQ
 * program services by normal system calls through the application
 * program interfaces provided as part of the Hyperic Plug-in Development
 * Kit or the Hyperic Client Development Kit - this is merely considered
 * normal use of the program, and does *not* fall under the heading of
 * "derived work".
 *
 * Copyright (C) [2004, 2005, 2006], Hyperic, Inc.
 * This file is part of HQ.
 *
 * HQ is free software; you can redistribute it and/or modify
 * it under the terms version 2 of the GNU General Public License as
 * published by the Free Software Foundation. This program is distributed
 * in the hope that it will be useful, but WITHOUT ANY WARRANTY; without
 * even the implied warranty of MERCHANTABILITY or FITNESS FOR A
 * PARTICULAR PURPOSE. See the GNU General Public License for more
 * details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
 * USA.
 */

package org.hyperic.hq.common;

import java.util.ArrayList;
import java.util.Collection;
import java.util.Date;
import java.util.List;

import javax.annotation.PostConstruct;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.scheduling.TaskScheduler;
import org.springframework.stereotype.Component;

/**
 * The DiagnosticThread is a simple object running within the server that prints
 * diagnostic information to the server log for objects that have been
 * registered via addDiagnosticObject().
 * 
 * 
 */
@Component
public class DiagnosticsLogger implements Runnable {

    private final Log log = LogFactory.getLog(DiagnosticsLogger.class);

   
    private final TaskScheduler taskScheduler;

    // List of DiagnosticObjects, may want to convert to a Map if we ever
    // want to allow objects to be removed from the DiagnosticThread at
    // runtime.
    private final List<DiagnosticObject> diagnosticObjects = new ArrayList<DiagnosticObject>();

    // How often the thread prints info
    private final long interval = Long.getLong("org.hq.diagnostic.interval", 1000 * 60 * 10).longValue(); // 10 minutes
    
    @Autowired
    public DiagnosticsLogger(@Value("#{scheduler}")TaskScheduler taskScheduler) {
        this.taskScheduler = taskScheduler; 
    }
    
    public long getInterval() {
        return interval;
    }

    @PostConstruct
    public void startThread() {
        //Run the Diagnostics Logger every interval, starting one interval from now
        taskScheduler.scheduleAtFixedRate(this, new Date(System.currentTimeMillis() + interval),interval);
    }
    
    public void addDiagnosticObject(DiagnosticObject o) {
        synchronized (diagnosticObjects) {
            diagnosticObjects.add(o);
        }
    }
    
    public void removeDiagnosticObject(final DiagnosticObject o) {
        synchronized (diagnosticObjects) {
            diagnosticObjects.remove(o);
        }//EO synchronized block
    }//EOM 

    public Collection<DiagnosticObject> getDiagnosticObjects() {
        synchronized (diagnosticObjects) {
            return new ArrayList<DiagnosticObject>(diagnosticObjects);
        }
    }

    public void run() {
        log.info("Starting Diagnostic Thread (interval=" + interval + " ms)");
        try {
                log.info("--- DIAGNOSTICS ---");
                 synchronized (diagnosticObjects) {
                        for(DiagnosticObject o: diagnosticObjects) {
                            try {
                                log.info("[" + o + "] " + o.getShortStatus());
                            } catch (Throwable e) {
                                log.error("Error in diagnostics: " + e, e);
                            }
                        }
                 }
        } catch (Exception e) {
                log.warn("Error encountered while collecting diagnostics", e);
        }
    }
}