// Copyright 2012 Citrix Systems, Inc. Licensed under the
// Apache License, Version 2.0 (the "License"); you may not use this
// file except in compliance with the License.  Citrix Systems, Inc.
// reserves all rights not expressly granted by the License.
// You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// 
// Automatically generated by addcopyright.py at 04/03/2012
package com.cloud.agent;

import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.ScheduledFuture;
import java.util.concurrent.ScheduledThreadPoolExecutor;
import java.util.concurrent.TimeUnit;

import org.apache.log4j.Logger;

import com.cloud.utils.concurrency.NamedThreadFactory;

public class MetricsCollector {
    private static final Logger s_logger = Logger.getLogger(MetricsCollector.class);
	
	private final Set<String> vmNames = new HashSet<String>();
	private final Set<String> newVMnames = new HashSet<String>();
	private final Map<String, MockVmMetrics> metricsMap = new HashMap<String, MockVmMetrics>();
	
	private final transient ScheduledThreadPoolExecutor executor = new ScheduledThreadPoolExecutor(1, new NamedThreadFactory("Metrics"));

	private Set<String> _currentVms;
	
	public MetricsCollector(Set<String> currentVms) {
		_currentVms = currentVms;
		getAllVMNames();
	}
	
	public MetricsCollector() {
		
	}
	
	public synchronized void getAllVMNames() {
		Set<String> currentVMs = _currentVms;
		
        newVMnames.clear();
        newVMnames.addAll(currentVMs);
        newVMnames.removeAll(vmNames); //leave only new vms
        
        vmNames.removeAll(currentVMs); //old vms - current vms --> leave non-running vms;
        for (String vm: vmNames) {
        	removeVM(vm);
        }
        
        vmNames.clear();
        vmNames.addAll(currentVMs);
	}
	
	public synchronized void submitMetricsJobs() {
		s_logger.debug("Submit Metric Jobs called");
		
		for (String vm : newVMnames) {
			MockVmMetrics task = new MockVmMetrics(vm);
			if (!metricsMap.containsKey(vm)) {
			    metricsMap.put(vm, task);
			    ScheduledFuture<?> sf = executor.scheduleWithFixedDelay(task, 2, 600, TimeUnit.SECONDS);
			    task.setFuture(sf);
			}
		}
		newVMnames.clear();
	}
	
	public synchronized void addVM(String vmName) {
		newVMnames.add(vmName);
		s_logger.debug("Added vm name= " + vmName);
	}
	
	public synchronized void removeVM(String vmName) {
		newVMnames.remove(vmName);
		vmNames.remove(vmName);
		MockVmMetrics task = metricsMap.get(vmName);
    	if (task != null) {
    		task.stop();
    		boolean r1= task.getFuture().cancel(false);
    		metricsMap.remove(vmName);
    		s_logger.debug("removeVM: cancel returned " + r1 + " for VM " + vmName);
    	} else {
    		s_logger.warn("removeVM called for nonexistent VM " + vmName);
    	}
	}
	
	public synchronized Set<String> getVMNames() {
	  return vmNames;
	}
		
	public synchronized Map<String, MockVmMetrics> getMetricsMap() {
		return metricsMap;
	}
}