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/*
 *  This file is part of "TweetyProject", a collection of Java libraries for
 *  logical aspects of artificial intelligence and knowledge representation.
 *
 *  TweetyProject is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU Lesser General Public License version 3 as
 *  published by the Free Software Foundation.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU Lesser General Public License for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public License
 *  along with this program. If not, see .
 *
 *  Copyright 2016 The TweetyProject Team 
 */
package net.sf.tweety.action.description.syntax;

import java.util.Collection;
import java.util.HashSet;
import java.util.Set;

import net.sf.tweety.action.signature.ActionSignature;
import net.sf.tweety.commons.Signature;

/**
 * This class represents an action description for the action language C as a
 * set of causal rules, and provides some basic functionality such as grounding.
 * 
 * @author Sebastian Homann
 */
public class CActionDescription extends ActionDescription {
	/**
	 * Creates a new empty action description.
	 */
	public CActionDescription() {
		super();
	}

	/**
	 * Creates a new belief set with the given collection of formulae.
	 * 
	 * @param c a collection of formulae.
	 */
	public CActionDescription(Collection c) {
		for (CausalLaw r : c) {
			if (r instanceof CLaw) {
				add((CLaw) r);
			} else {
				throw new IllegalArgumentException("The action description given contains laws of a wrong type.");
			}
		}
	}

	/**
	 * Calculates a new action description containing all ground instances of each
	 * law in this action description.
	 * 
	 * @return a new action description containing only ground laws.
	 */
	public CActionDescription ground() {
		Set laws = new HashSet();
		for (CLaw law : this) {
			laws.addAll(law.getAllGrounded());
		}
		return new CActionDescription(laws);
	}

	/**
	 * Calculates a new action description which descibes the same transition system
	 * and contains only definite causal laws.
	 * 
	 * @return a new definite action description.
	 * @throws IllegalStateException when there is no equivalent definite action
	 *                               description
	 */
	public CActionDescription toDefinite() throws IllegalStateException {
		Set laws = new HashSet();
		for (CLaw law : this) {
			laws.addAll(law.toDefinite());
		}
		return new CActionDescription(laws);
	}

	/**
	 * Checks whether this action description contains any non-ground laws.
	 * 
	 * @return true iff each law in this action description is grounded.
	 */
	public boolean isGround() {
		for (CLaw law : this)
			if (!law.isGround())
				return false;
		return true;
	}

	/**
	 * Checks whether this action description contains any non-definite laws.
	 * 
	 * @return ture iff each law in this action description is definite.
	 */
	public boolean isDefinite() {
		for (CLaw law : this)
			if (!law.isDefinite())
				return false;
		return true;
	}

	/**
	 * Returns a set of all static laws contained in this action description.
	 * 
	 * @return a set of all static laws contained in this action description.
	 */
	public Set getStaticLaws() {
		Set result = new HashSet();
		for (CLaw r : this) {
			if (r instanceof StaticLaw)
				result.add((StaticLaw) r);
		}
		return result;
	}

	/**
	 * Returns a set of all dynamic laws contained in this action description.
	 * 
	 * @return a set of all dynamic laws contained in this action description.
	 */
	public Set getDynamicLaws() {
		Set result = new HashSet();
		for (CLaw r : this) {
			if (r instanceof DynamicLaw)
				result.add((DynamicLaw) r);
		}
		return result;
	}

	/**
	 * Returns a string representation of this action description in human readable
	 * form, which may be written to a file or printed on screen.
	 * 
	 * @return a string representation of this action description.
	 */
	public String toOutputString() {
		String result = ":- laws\n";
		// static laws first
		for (CLaw r : this.getStaticLaws()) {
			result += r.toString() + "\n";
		}
		for (CLaw r : this.getDynamicLaws()) {
			result += r.toString() + "\n";
		}
		return result;
	}

	@Override
	public Signature getMinimalSignature() {
		ActionSignature sig = new ActionSignature();
		for (CLaw r : this)
			sig.addAll(r.getFormulas());
		return sig;
	}
}