Copyright (c) 2012 Contributors.
All rights reserved.
This program and the accompanying materials are made available
under the terms of the Eclipse Public License v1.0
which accompanies this distribution and is available at
http://eclipse.org/legal/epl-v10.html
Contributors:
  Abraham Nevado (lucierna) initial implementation
/*******************************************************************************
 * Copyright (c) 2012 Contributors.
 * All rights reserved.
 * This program and the accompanying materials are made available
 * under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution and is available at
 * http://eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *   Abraham Nevado (lucierna) initial implementation
 ********************************************************************************/

package org.aspectj.weaver.tools.cache;

import java.io.File;

import org.aspectj.weaver.Dump;

public class SimpleCacheFactory {
	
	public static final String CACHE_ENABLED_PROPERTY = "aj.weaving.cache.enabled";
	public static final String CACHE_DIR = "aj.weaving.cache.dir";
	public static final String CACHE_IMPL = "aj.weaving.cache.impl";
	
	public static final String PATH_DEFAULT= "/tmp/"; // TODO windows default...?
	public static final boolean BYDEFAULT= false;	
		
		
	public static String path = PATH_DEFAULT;
	public static Boolean enabled = false;
	private static boolean determinedIfEnabled = false;
	private static SimpleCache lacache=null;
	
	public static synchronized SimpleCache createSimpleCache(){
		if (lacache==null){
		 	if (!determinedIfEnabled) {
		 		determineIfEnabled();
		 	}

			if (!enabled) {
				return null;
			}

			try {
				path = System.getProperty(CACHE_DIR);
				if (path == null){
					path = PATH_DEFAULT;
				}
				
			} catch (Throwable t) {
				path=PATH_DEFAULT;
				t.printStackTrace();
				Dump.dumpWithException(t);
			}
			File f = new File(path);
			if (!f.exists()){
				f.mkdir();
			}
			lacache= new SimpleCache(path, enabled);
		}
		return lacache;
		
	}

	private static void determineIfEnabled() {
		try {
			String property = System.getProperty(CACHE_ENABLED_PROPERTY);
			if (property == null ){
				enabled = BYDEFAULT;
			}
			else if (property.equalsIgnoreCase("true")){
				
					String impl = System.getProperty(CACHE_IMPL);
					if (SimpleCache.IMPL_NAME.equals(impl)){
						enabled = true;
					}
					else{
						enabled = BYDEFAULT;
					}
			}
			else{
				enabled = BYDEFAULT;
			}
			
		} catch (Throwable t) {
			enabled=BYDEFAULT;
			System.err.println("Error creating cache");
			t.printStackTrace();
			Dump.dumpWithException(t);
		}
		determinedIfEnabled = true;
	}
	
	// Should behave ok with two threads going through here, well whoever gets there first will set determinedIfEnabled but only after
	// it has set 'enabled' to the right value.
	public static boolean isEnabled() {
		if (!determinedIfEnabled) {
			determineIfEnabled();
		}
		return enabled;
	} 
	

}