/*
    * #%L
    * prolobjectlink-jpi-jpl7
    * %%
    * Copyright (C) 2019 Prolobjectlink Project
    * %%
    * Redistribution and use in source and binary forms, with or without
    * modification, are permitted provided that the following conditions are met:
    * 
   * 1. Redistributions of source code must retain the above copyright notice,
   *    this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright notice,
   *    this list of conditions and the following disclaimer in the documentation
   *    and/or other materials provided with the distribution.
   * 
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
   * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR CONTRIBUTORS BE
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   * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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   * #L%
   */
  package io.github.prolobjectlink.prolog.jpl7;
  
  import static io.github.prolobjectlink.prolog.PrologTermType.LIST_TYPE;
  
  import java.util.Iterator;
  import java.util.NoSuchElementException;
  
  import org.jpl7.Compound;
  import org.jpl7.Query;
  import org.jpl7.Term;
  import org.jpl7.Util;
  
  import io.github.prolobjectlink.prolog.AbstractIterator;
  import io.github.prolobjectlink.prolog.PrologList;
  import io.github.prolobjectlink.prolog.PrologProvider;
  import io.github.prolobjectlink.prolog.PrologTerm;
  
  /**
   * 
   * @author Jose Zalacain
   * @since 1.0
   */
  public class JplList extends JplTerm implements PrologList {
  
  	public static final Term EMPTY;
  
  	static {
  
  		Query query = new Query("X=[]");
  		query.open();
  		EMPTY = query.getSolution().get("X");
  		query.close();
  
  	}
  
  	protected JplList(PrologProvider provider) {
  		super(LIST_TYPE, provider, EMPTY);
  	}
  
  	protected JplList(PrologProvider provider, Term[] arguments) {
  		super(LIST_TYPE, provider);
  		value = EMPTY;
  		for (int i = arguments.length - 1; i >= 0; --i) {
  			value = new Compound("[|]", new Term[] { arguments[i], value });
  		}
  	}
  
  	protected JplList(PrologProvider provider, PrologTerm[] arguments) {
  		super(LIST_TYPE, provider);
  		value = EMPTY;
  		for (int i = arguments.length - 1; i >= 0; --i) {
  			value = new Compound("[|]", new Term[] { ((JplTerm) arguments[i]).value, value });
  		}
  	}
  
  	protected JplList(PrologProvider provider, PrologTerm head, PrologTerm tail) {
  		super(LIST_TYPE, provider);
  		Term h = ((JplTerm) head).value;
  		Term t = ((JplTerm) tail).value;
  		value = new Compound("[|]", new Term[] { h, t });
  	}
  
  	protected JplList(PrologProvider provider, PrologTerm[] arguments, PrologTerm tail) {
  		super(LIST_TYPE, provider);
  		value = fromTerm(tail, Term.class);
  		for (int i = arguments.length - 1; i >= 0; --i) {
  			Term[] args = { fromTerm(arguments[i], Term.class), value };
  			value = new Compound("[|]", args);
  		}
  	}
  
 	public int size() {
 		return Util.listToLength(value);
 	}
 
 	public void clear() {
 		value = EMPTY;
 	}
 
 	public boolean isEmpty() {
 		return value.isListNil();
 	}
 
 	public Iterator<PrologTerm> iterator() {
 		return new SwiPrologListIter(value);
 	}
 
 	public PrologTerm getHead() {
 		Compound list = (Compound) value;
 		return provider.toTerm(list.arg(1), PrologTerm.class);
 	}
 
 	public PrologTerm getTail() {
 		Compound list = (Compound) value;
 		return provider.toTerm(list.arg(2), PrologTerm.class);
 	}
 
 	public int getArity() {
 		return value.arity();
 	}
 
 	public String getFunctor() {
 		return ".";
 	}
 
 	public PrologTerm[] getArguments() {
 		return toTermArray(value.toTermArray(), PrologTerm[].class);
 	}
 
 	public String toString() {
 		StringBuilder string = new StringBuilder("[");
 		Iterator<PrologTerm> i = iterator();
 		if (i.hasNext()) {
 			string.append(i.next());
 		}
 		while (i.hasNext()) {
 			string.append(", ");
 			string.append(i.next());
 		}
 		return string.append("]").toString();
 	}
 
 	private class SwiPrologListIter extends AbstractIterator<PrologTerm> implements Iterator<PrologTerm> {
 
 		private Term ptr;
 		private int index;
 		private int length;
 
 		private SwiPrologListIter(Term l) {
 			ptr = l;
 			if (l.isListPair()) {
 				length = Util.listToLength(l);
 			}
 		}
 
 		public boolean hasNext() {
 			return index < length;
 		}
 
 		public PrologTerm next() {
 
 			if (!hasNext()) {
 				throw new NoSuchElementException();
 			}
 
 			PrologTerm term = toTerm(ptr.arg(1), PrologTerm.class);
 			ptr = ptr.arg(2);
 			index++;
 			return term;
 		}
 
 	}
 
 }