package edu.harvard.seas.pl.formulog.ast;

/*-
 * #%L
 * Formulog
 * %%
 * Copyright (C) 2018 - 2020 President and Fellows of Harvard College
 * %%
 * Licensed 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.
 * #L%
 */

import java.util.Collections;
import java.util.List;

public class BasicRule extends AbstractRule<UserPredicate, ComplexLiteral> {

	private BasicRule(UserPredicate head, List<ComplexLiteral> body) {
		super(head, body);
		if (!head.getSymbol().isIdbSymbol()) {
			throw new IllegalArgumentException(
					"Cannot create rule with non-IDB predicate for head: " + head.getSymbol());
		}
	}

	public static BasicRule make(UserPredicate head, List<ComplexLiteral> body) {
		if (body.isEmpty()) {
			return make(head);
		}
		return new BasicRule(head, body);
	}

	public static BasicRule make(UserPredicate head) {
		return make(head, Collections.singletonList(ComplexLiterals.trueAtom()));
	}

}
