package eu.dnetlib.pace.util;

import java.io.Serializable;
import java.lang.reflect.InvocationTargetException;
import java.util.Map;
import java.util.stream.Collectors;

import org.reflections.Reflections;

import eu.dnetlib.pace.clustering.ClusteringClass;
import eu.dnetlib.pace.clustering.ClusteringFunction;
import eu.dnetlib.pace.tree.support.Comparator;
import eu.dnetlib.pace.tree.support.ComparatorClass;

public class PaceResolver implements Serializable {

	public static final Reflections CLUSTERING_RESOLVER = new Reflections("eu.dnetlib.pace.clustering");
	public static final Reflections COMPARATOR_RESOLVER = new Reflections("eu.dnetlib.pace.tree");

	private final Map<String, Class<ClusteringFunction>> clusteringFunctions;
	private final Map<String, Class<Comparator>> comparators;

	public PaceResolver() {

		this.clusteringFunctions = CLUSTERING_RESOLVER
			.getTypesAnnotatedWith(ClusteringClass.class)
			.stream()
			.filter(ClusteringFunction.class::isAssignableFrom)
			.collect(
				Collectors
					.toMap(
						cl -> cl.getAnnotation(ClusteringClass.class).value(), cl -> (Class<ClusteringFunction>) cl));

		this.comparators = COMPARATOR_RESOLVER
			.getTypesAnnotatedWith(ComparatorClass.class)
			.stream()
			.filter(Comparator.class::isAssignableFrom)
			.collect(
				Collectors.toMap(cl -> cl.getAnnotation(ComparatorClass.class).value(), cl -> (Class<Comparator>) cl));
	}

	public ClusteringFunction getClusteringFunction(String name, Map<String, Object> params) throws PaceException {
		try {
			return clusteringFunctions.get(name).getDeclaredConstructor(Map.class).newInstance(params);
		} catch (InstantiationException | IllegalAccessException | InvocationTargetException
			| NoSuchMethodException e) {
			throw new PaceException(name + " not found ", e);
		}
	}

	public Comparator getComparator(String name, Map<String, String> params) throws PaceException {
		try {
			return comparators.get(name).getDeclaredConstructor(Map.class).newInstance(params);
		} catch (InstantiationException | IllegalAccessException | InvocationTargetException | NoSuchMethodException
			| NullPointerException e) {
			throw new PaceException(name + " not found ", e);
		}
	}

}