/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 */

package org.apache.streampipes.units;

import com.github.jqudt.Unit;
import com.github.jqudt.onto.UnitFactory;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.net.URI;
import java.util.ArrayList;
import java.util.List;
import java.util.NoSuchElementException;
import java.util.stream.Collectors;

public enum UnitProvider {

	INSTANCE;

	static Logger LOG = LoggerFactory.getLogger(UnitCollector.class);

	private List<Unit> availableUnitTypes = new ArrayList<>();
	private List<Unit> availableUnits = new ArrayList<>();
	
	private UnitFactory factory;
	
	UnitProvider() {
		factory = UnitFactory.getInstance();
		UnitCollector collector = new UnitCollector();
		this.availableUnits.addAll(collector.getAvailableUnits());
		this.availableUnitTypes.addAll(collector.getAvailableUnitTypes());
	}
	
	public List<Unit> getAvailableUnitTypes() {
		return availableUnitTypes;
	}
	
	public List<Unit> getAvailableUnits() {
		return availableUnits;
	}
	
	public Unit getUnit(String resourceUri) {
		return factory.getUnit(resourceUri);
	}

	public Unit getUnitByLabel(String label) {
		try {
			return availableUnits.stream()
					.filter((Unit unit) -> unit.getLabel().equals(label))
					.findFirst()
					.get();
		} catch (NoSuchElementException e) {
			LOG.error("No unit with label \"" + label + "\" found");
			return null;
		}
	}

	public List<Unit> getUnitsByType(URI type) {
		return availableUnits
						.stream()
						.filter(u -> u.getType().equals(type))
						.collect(Collectors.toList());
	}
}
