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/*
 * Copyright (c) 2013, SRI International
 * All rights reserved.
 * Licensed under the The BSD 3-Clause License;
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at:
 * 
 * http://opensource.org/licenses/BSD-3-Clause
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 
 * Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 * 
 * 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.
 * 
 * Neither the name of the aic-expresso nor the names of its
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 * 
 * 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 HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, 
 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES 
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, 
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE.
 */
package com.sri.ai.expresso.core;

import static com.sri.ai.util.Util.castOrThrowError;
import static com.sri.ai.util.Util.list;

import java.util.ArrayList;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;

import com.google.common.annotations.Beta;
import com.sri.ai.expresso.api.Expression;
import com.sri.ai.expresso.api.ExpressionAndSyntacticContext;
import com.sri.ai.expresso.api.SubExpressionAddress;
import com.sri.ai.expresso.api.SyntaxTree;
import com.sri.ai.expresso.api.Tuple;
import com.sri.ai.expresso.helper.SyntaxTrees;
import com.sri.ai.grinder.api.Registry;
import com.sri.ai.grinder.core.AbstractNonQuantifiedExpression;
import com.sri.ai.util.Util;

/**
 * A default implementation of a {@link Tuple}.
 * 
 * @author braz
 */
@Beta
public class DefaultTuple extends AbstractNonQuantifiedExpression implements Tuple {

	private static final long serialVersionUID = 1L;
	
	private ArrayList      arguments;
	private SyntaxTree                 syntaxTree;
	private List expressionAndSyntacticContexts;
	
	public DefaultTuple() {
		this(list());
	}
	
	public DefaultTuple(List arguments) {
		super();
		this.arguments = new ArrayList<>(arguments);
		
		this.syntaxTree = makeSyntaxTree();
		
		expressionAndSyntacticContexts = new LinkedList();
		int i = 0;
		for (Expression argument : arguments) {
			expressionAndSyntacticContexts.add(new DefaultExpressionAndSyntacticContext(argument, new IndexAddress(i++)));
		}
	}

	private DefaultCompoundSyntaxTree makeSyntaxTree() {
		DefaultCompoundSyntaxTree result;
		if (arguments.size() == 1) {
			result = new DefaultCompoundSyntaxTree("tuple", arguments.get(0));
		}
		else {
			ArrayList argumentsSyntaxTrees = Util.mapIntoArrayList(arguments, e -> e == null? null : e.getSyntaxTree());
			SyntaxTree kleeneList = SyntaxTrees.makeKleeneListIfNeeded(argumentsSyntaxTrees);
			result = new DefaultCompoundSyntaxTree(Tuple.TUPLE_LABEL, kleeneList);
		}
		return result;
	}

	@Override
	public List getArguments() {
		return arguments;
	}

	@Override
	public int numberOfArguments() {
		return arguments.size();
	}

	@Override
	public Expression get(int index) {
		return arguments.get(index);
	}

	@Override
	public Expression set(int i, Expression newIthArgument) {
		Tuple result;
		
		if (get(i) == newIthArgument) {
			result = this;
		}
		else {
			ArrayList newArguments = new ArrayList(arguments);
			newArguments.set(i, newIthArgument);
			result = new DefaultTuple(newArguments);
		}
		
		return result;
	}

	@Override
	public Iterator getImmediateSubExpressionsAndContextsIterator() {
		return expressionAndSyntacticContexts.iterator();
	}

	@Override
	public Object getSyntacticFormType() {
		return "Tuple";
	}

	@Override
	public SyntaxTree getSyntaxTree() {
		return syntaxTree;
	}

	@Override
	public Expression replaceSymbol(Expression symbol, Expression newSymbol, Registry registry) {
		// TODO: incorrect! Must replace quantified symbols in sub-expressions too, this won't do it.
		Expression result = replaceAllOccurrences(symbol, newSymbol, registry);
		return result;
	}

	@Override
	public Expression clone() {
		return new DefaultTuple((ArrayList) getArguments());
	}
	
	private static class IndexAddress implements SubExpressionAddress {

		private int index;
		
		public IndexAddress(int index) {
			super();
			this.index = index;
		}

		@Override
		public Expression replace(Expression expression, Expression newSubExpression) {
			Util.myAssert(() -> expression instanceof DefaultTuple, () -> DefaultTuple.class.getSimpleName() + ".IndexAddress applied to expression " + expression + " of class " + expression.getClass());
			Expression result = expression.set(this.index, newSubExpression);
			return result;
		}

		@Override
		public Expression getSubExpressionOf(Expression expression) {
			Tuple tuple = castOrThrowError(Tuple.class, expression, "Attempt at obtaining " + index + "-th component expression of %s which should be an instance of %s but is an instance of %s");
			Expression result = tuple.get(index);
			return result;
		}
	}

	@Override
	public String makeToString() {
		String result;
		if (numberOfArguments() == 1) {
			result = "tuple(" + get(0) + ")";
		}
		else {
			result = "(" + Util.join(", ", getArguments()) + ")";
		}
		return result;
	}

	@Override
	public Expression getFunctor() {
		return null;
	}
}