package org.apache.tuscany.sca.binding.erlang.impl;

import java.util.HashMap;
import java.util.Map;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

import org.apache.tuscany.sca.binding.erlang.ErlangBinding;
import org.apache.tuscany.sca.binding.erlang.impl.exceptions.ErlangException;
import org.apache.tuscany.sca.runtime.RuntimeComponentService;

import com.ericsson.otp.erlang.OtpConnection;
import com.ericsson.otp.erlang.OtpSelf;

public class ErlangNode implements Runnable {

	private Map<String, RuntimeComponentService> services = new HashMap<String, RuntimeComponentService>();
	private Map<String, ErlangBinding> bindings = new HashMap<String, ErlangBinding>();
	private String name;
	private OtpSelf self;
	private ExecutorService executors;
	private boolean stopRequested;

	public ErlangNode(String name) throws Exception {
		this.name = name;
		self = new OtpSelf(name);
		boolean registered = self.publishPort();
		if (!registered) {
			// TODO: externalize messages?
			throw new ErlangException(
					"Problem with publishing service under epmd server.");
		}
	}

	private void stop() {
		stopRequested = true;
		executors.shutdownNow();
	}

	public void run() {
		executors = Executors.newFixedThreadPool(10);
		while (!stopRequested) {
			try {
				OtpConnection connection = self.accept();
				executors.execute(new RpcExecutor(services, bindings,
						connection));
			} catch (Exception e) {
				// TODO: handle exception
				e.printStackTrace();
			}
		}
	}

	public void registerModule(ErlangBinding binding,
			RuntimeComponentService service) throws ErlangException {
		if (services.containsKey(binding.getModule())) {
			// TODO: externalize message
			// TODO: really want to throw exception? Log only?
			throw new ErlangException("Module " + binding.getModule()
					+ " already defined under " + name
					+ " node. Duplicate module won't be started");
		} else {
			if (services.size() == 0) {
				// TODO: should ErlangNode manage its thread?
				Thread selfThread = new Thread(this);
				selfThread.start();
			}
			services.put(binding.getModule(), service);
			bindings.put(binding.getModule(), binding);
		}
	}

	public void unregisterModule(ErlangBinding binding) throws ErlangException {
		if (services.containsKey(binding.getModule())) {
			services.remove(binding.getModule());
			bindings.remove(binding.getModule());
			if (services.size() == 0) {
				stop();
			}
		}
	}

}