package com.framsticks.remote;

import com.framsticks.core.Node;
import com.framsticks.core.Path;
import com.framsticks.params.AccessInterface;
import com.framsticks.params.CompositeParam;
import com.framsticks.params.FramsClass;
import com.framsticks.core.Instance;
import com.framsticks.util.dispatching.Future;
import com.framsticks.util.StateFunctor;
import com.framsticks.util.Stopwatch;
import org.apache.log4j.Logger;
import static com.framsticks.util.lang.Containers.filterInstanceof;
import com.framsticks.util.dispatching.RunAt;

/**
 * @author Piotr Sniegowski
 */
public class RecursiveFetcher {

	private final static Logger log = Logger.getLogger(RecursiveFetcher.class.getName());

	protected final Instance instance;
	protected final StateFunctor stateFunctor;
	protected int dispatched;
	protected final Stopwatch stopwatch = new Stopwatch();

	public RecursiveFetcher(Instance instance, final Path path, StateFunctor stateFunctor) {
		this.instance = instance;
		this.stateFunctor = stateFunctor;
		dispatched = 1;
		process(path);
	}

	protected void finished() {
		assert instance.isActive();
		log.info("recursively fetched in " + stopwatch);
		stateFunctor.call(null);
	}

	protected void process(final Path path) {
		assert instance.isActive();
		if (path == null || !path.isResolved()) {
			log.warn("path " + path + " is not resolved - skipping");
		} else {
			AccessInterface access = instance.bindAccess(path);
			FramsClass framsClass = access.getFramsClass();
			assert framsClass != null;
			for (CompositeParam p : filterInstanceof(access.getParams(), CompositeParam.class)) {
				Object child = access.get(p, Object.class);
				final Path childPath = path.appendNode(new Node(p, child));
				if (childPath.isResolved() && instance.getInfoFromCache(childPath) != null) {
					++dispatched;
					instance.dispatch(new RunAt<Instance>() {
						@Override
						public void run() {
							fetch(childPath);
						}
					});
					continue;
				}
				++dispatched;
				instance.resolve(childPath, new Future<Path>() {
					@Override
					public void result(Path result, Exception e) {
						assert instance.isActive();
						if (e != null) {
							log.error(e);
							return;
						}
						fetch(result);
					}
				});
			}
		}
		--dispatched;
		if (dispatched == 0) {
			finished();
		}
	}

	protected void fetch(final Path path) {
		instance.fetchValues(path, new StateFunctor() {
			@Override
			public void call(Exception e) {
				if (e != null) {
					log.error("failed to fetch values for " + path + ": " + e);
					process(null);
					return;
				}
				process(path);
			}
		});
	}

}