package org.gcube.application.cms.implementations;


import lombok.Synchronized;
import org.gcube.application.cms.caches.Cache;
import org.gcube.application.cms.caches.Engine;
import org.gcube.application.geoportal.common.model.rest.ConfigurationException;

import java.util.HashMap;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;

public class ImplementationProvider {

	private static ImplementationProvider instance=null;
	
	@Synchronized
	public static ImplementationProvider get() {
		if(instance==null) {
			instance=new ImplementationProvider();
		}
		return instance;
	}


	public <T> T getEngineByManagedClass(Class<T> clazz) throws ConfigurationException {
		return (T) implementationsRegistry.get(clazz).getObject();
	}


	private ConcurrentHashMap<Class,Engine> implementationsRegistry=new ConcurrentHashMap<>();

	public <T> void setEngine(Engine<T> engine, Class<T> clazz){
		implementationsRegistry.put(clazz,engine);
	}

	private ImplementationProvider(){
		//Defaults
		setEngine(new DefaultISProvider(),ISInterface.class);
	}
	public Map<Class,String> getManagerList(){
		HashMap<Class,String> toReturn=new HashMap<>();
		implementationsRegistry.forEach(
				(aClass, engine) -> {toReturn.put(engine.getClass(),aClass.getCanonicalName());}
		);
		return toReturn;
	}
}