AbstractEngine

/*
 * #%L
 * prolobjectlink-jpi
 * %%
 * Copyright (C) 2019 Prolobjectlink Project
 * %%
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 * #L%
 */
package io.github.prolobjectlink.prolog;

import static io.github.prolobjectlink.prolog.PrologLogger.IO;

import java.io.IOException;
import java.io.Writer;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Map;
import java.util.NoSuchElementException;
import java.util.Set;

/**
 * Partial implementation of {@link PrologEngine}.
 *
 * @author Jose Zalacain
 * @since 1.0
 */
public abstract class AbstractEngine implements PrologEngine {

	protected final PrologProvider provider;
	private static final String UNKNOWN = "unknown";

	protected AbstractEngine(PrologProvider provider) {
		this.provider = provider;
	}

	public final PrologProvider getProvider() {
		return provider;
	}

	public final void persist(Writer writer) {
		PrologEngine thisEngine = this;
		for (PrologClause prologClause : thisEngine) {
			try {
				writer.write("" + prologClause + "");
			} catch (IOException e) {
				getLogger().error(getClass(), IO, e);
			}
		}
	}

	public final boolean unify(PrologTerm t1, PrologTerm t2) {
		return t1.unify(t2);
	}

	public Map<String, PrologTerm> match(PrologTerm t1, PrologTerm t2) {
		return queryOne(t1 + "=" + t2);
	}

	public final boolean contains(String goal) {
		return query(goal).hasSolution();
	}

	public final boolean contains(PrologTerm goal) {
		return query(goal).hasSolution();
	}

	public final boolean contains(PrologTerm goal, PrologTerm... goals) {
		return query(goal, goals).hasSolution();
	}

	public final Map<String, PrologTerm> queryOne(String goal) {
		return query(goal).oneVariablesSolution();
	}

	public final Map<String, PrologTerm> queryOne(PrologTerm goal) {
		return query(goal).oneVariablesSolution();
	}

	public final Map<String, PrologTerm> queryOne(PrologTerm goal, PrologTerm... goals) {
		return query(goal, goals).oneVariablesSolution();
	}

	public final List<Map<String, PrologTerm>> queryN(int n, String goal) {
		return Arrays.asList(query(goal).nVariablesSolutions(n));
	}

	public final List<Map<String, PrologTerm>> queryN(int n, PrologTerm term) {
		return Arrays.asList(query(term).nVariablesSolutions(n));
	}

	public final List<Map<String, PrologTerm>> queryN(int n, PrologTerm term, PrologTerm... terms) {
		return Arrays.asList(query(term, terms).nVariablesSolutions(n));
	}

	public final List<Map<String, PrologTerm>> queryAll(String goal) {
		return query(goal).all();
	}

	public final List<Map<String, PrologTerm>> queryAll(PrologTerm goal) {
		return query(goal).all();
	}

	public final List<Map<String, PrologTerm>> queryAll(PrologTerm goal, PrologTerm... goals) {
		return query(goal, goals).all();
	}

	public final Map<String, List<PrologClause>> getProgramMap() {
		Map<String, List<PrologClause>> m = new HashMap<String, List<PrologClause>>();
		for (PrologClause clause : this) {
			String key = clause.getIndicator();
			List<PrologClause> l = m.get(key);
			if (l == null) {
				l = new ArrayList<PrologClause>();
				l.add(clause);
				m.put(key, l);
			} else {
				l.add(clause);
			}
		}
		return m;
	}

	public final Set<PrologClause> getProgramClauses() {
		Set<PrologClause> c = new LinkedHashSet<PrologClause>();
		for (PrologClause prologClause : this) {
			c.add(prologClause);
		}
		return c;
	}

	public final boolean isProgramEmpty() {
		return getProgramSize() == 0;
	}

	public final Set<PrologIndicator> currentPredicates() {
		Set<PrologIndicator> pis = new HashSet<PrologIndicator>();
		pis.addAll(getPredicates());
		pis.addAll(getBuiltIns());
		return pis;
	}

	public final DefaultQueryBuilder newQueryBuilder() {
		return new DefaultQueryBuilder(this);
	}

	public final DefaultClauseBuilder newClauseBuilder() {
		return new DefaultClauseBuilder(this);
	}

	public final boolean runOnOSX() {
		return getOSName().equals("Mac OS X") || getOSName().equals("Darwin");
	}

	public final boolean runOnWindows() {
		return getOSName().startsWith("Windows");
	}

	public final boolean runOnLinux() {
		return getOSName().equals("Linux");
	}

	public final String getOSName() {
		String os = System.getProperty("os.name");
		if (os == null)
			return UNKNOWN;
		return os;
	}

	public final String getOSVersion() {
		return System.getProperty("os.version");
	}

	public final String getOSArch() {
		return System.getProperty("os.arch");
	}

	public final PrologLogger getLogger() {
		return provider.getLogger();
	}

	protected final <K extends PrologTerm> K toTerm(Object o, Class<K> from) {
		return provider.toTerm(o, from);
	}

	protected final <K extends PrologTerm, V extends Object> Map<String, PrologTerm>[] toTermMapArray(
			Map<String, V>[] map, Class<K> from) {
		return provider.toTermMapArray(map, from);
	}

	protected final <K> K fromTerm(PrologTerm term, Class<K> to) {
		return provider.fromTerm(term, to);
	}

	protected final <K> K fromTerm(PrologTerm head, PrologTerm[] body, Class<K> to) {
		return provider.fromTerm(head, body, to);
	}

	protected final String removeQuoted(String functor) {
		if (functor != null && functor.startsWith("\'") && functor.endsWith("\'")) {
			return functor.substring(1, functor.length() - 1);
		}
		return functor;
	}

	@Override
	public final String toString() {
		return getName() + " " + getVersion();
	}

	@Override
	public int hashCode() {
		final int prime = 31;
		int result = 1;
		result = prime * result + ((provider == null) ? 0 : provider.hashCode());
		return result;
	}

	@Override
	public boolean equals(Object object) {
		if (this == object)
			return true;
		if (object == null)
			return false;
		if (getClass() != object.getClass())
			return false;
		AbstractEngine other = (AbstractEngine) object;
		if (provider == null) {
			if (other.provider != null)
				return false;
		} else if (!provider.equals(other.provider)) {
			return false;
		}
		return true;
	}

	protected class PrologProgramIterator extends AbstractIterator<PrologClause> implements Iterator<PrologClause> {

		private PrologClause last;
		private final Iterator<PrologClause> i;

		public PrologProgramIterator(Collection<PrologClause> cls) {
			i = cls.iterator();
		}

		public boolean hasNext() {
			return i.hasNext();
		}

		public PrologClause next() {
			if (!i.hasNext()) {
				throw new NoSuchElementException();
			}
			last = i.next();
			return last;
		}

		@Override
		public void remove() {
			PrologTerm h = last.getHead();
			PrologTerm b = last.getBody();
			retract(h, b);
			i.remove();
		}

	}

}