package org.hwo.tasklet;

import java.util.LinkedList;
import java.util.List;

public class TaskletManager {
	
	private static TaskletManager _TaskletManager = new TaskletManager();
	public static TaskletManager instance(){
		return _TaskletManager;
	}
	
	List<TaskletListener> taskletListeners;
	List<TaskletThread> taskletThreads;
	
	List<Tasklet> tasklets;
	
	int	threads;
	boolean shuttingDown;
	
	public TaskletManager(){
		taskletListeners = new LinkedList<TaskletListener>();
		taskletThreads = new LinkedList<TaskletThread>();
		tasklets = new LinkedList<Tasklet>();
		threads = 1;
	}
	
	public synchronized void addTaskletListener(TaskletListener listener){
		taskletListeners.add(listener);
	}
	public synchronized void removeTaskletListener(TaskletListener listener){
		taskletListeners.remove(listener);
	}
	
	public synchronized int getThreads() {
		return threads;
	}
	public synchronized void setThreads(int threads) {
		this.threads = threads;
	}
	
	public synchronized void fireTaskletQueued(Tasklet tasklet){
		for (TaskletListener l:taskletListeners)
			l.taskletQueued(this, tasklet);
	}
	public synchronized void fireTaskletStarted(Tasklet tasklet){
		for (TaskletListener l:taskletListeners)
			l.taskletStarted(this, tasklet);
	}
	public synchronized void fireTaskletFinished(Tasklet tasklet){
		for (TaskletListener l:taskletListeners)
			l.taskletFinished(this, tasklet);
	}
	public synchronized void fireTaskletProgressChanged(Tasklet tasklet){
		for (TaskletListener l:taskletListeners)
			l.taskletProgressChanged(this, tasklet);
	}
	
	public synchronized void enqueue(Tasklet tasklet){
		if (taskletThreads.size() < threads){
			taskletThreads.add(new TaskletThread(this));
		}
		
		tasklets.add(tasklet);
		fireTaskletQueued(tasklet);
		
		this.notify();
	}
	
	public synchronized Tasklet pop(){
		if (tasklets.size()>0)
			return tasklets.remove(0);
		return null;
	}
	
	public int getThreadPoolSize(){
		return taskletThreads.size();
	}
	
	public void shutdown(){
		synchronized (this) {
			shuttingDown = true;
			setThreads(0);			
		}
		
		while (taskletThreads.size() > 0){
			try {
				Thread.sleep(50);
				synchronized (this) {
					this.notifyAll();	
				}
				
			} catch (InterruptedException ex){
				ex.printStackTrace();
			}
		}
	}
	
	public boolean isShuttingDown() {
		return shuttingDown;
	}
	
	public synchronized void removeTaskletThread(TaskletThread taskletThread){
		taskletThreads.remove(taskletThread);
	}

	private Tasklet findTasklet(){		
		for (TaskletThread thread: this.taskletThreads){
			if (Thread.currentThread().equals(thread)){
				return thread.getCurrentTasklet();
			}
		}
		return null;
	}
	
	public synchronized void setProgress(double percentage){
		setProgress(String.format("%d%%", new Double(percentage * 100).intValue()));
	}
	
	public synchronized void setProgress(String progress){
		Tasklet c = findTasklet();
		if (c != null){
			c.setProgress(progress);
			fireTaskletProgressChanged(c);
		}
	}
	
}