package models.dataConstraintModel;

import models.algebra.Expression;
import models.algebra.Symbol;
import models.algebra.Term;

public class ListTerm extends Term {

	public ListTerm() {
		super(new Symbol("list", -1));
		setType(DataConstraintModel.typeList);
	}

	public void append(Expression value) {
		addChild(value);
	}

	public Expression get(int index) {
		return getChild(index);
	}
	
	public int size() {
		return children.size();
	}
	
	@Override
	public Expression unify(Expression another) {
		if (another instanceof ListTerm) {
			ListTerm anotherTerm = (ListTerm) another;
			if (children.size() != anotherTerm.children.size()) return null;
			ListTerm unifiedTerm = new ListTerm();
			for (int i = 0; i < children.size(); i++) {
				unifiedTerm.addChild(children.get(i).unify(anotherTerm.children.get(i)));
			}
			return unifiedTerm;
		}
		return this;
	}
	
	@Override
	public Object clone() {
		ListTerm newTerm = new ListTerm();
		for (Expression e: children) {
			newTerm.addChild((Expression) e.clone());
		}
		return newTerm;
	}
	
	public String toString() {
		String listStr = "[";
		String delim = "";
		for (Expression child: getChildren()) {
			listStr += delim + child.toString();
			delim = ", ";
		}
		return listStr + "]";
	}
}