/*
 *  JFLAP - Formal Languages and Automata Package
 * 
 * 
 *  Susan H. Rodger
 *  Computer Science Department
 *  Duke University
 *  August 27, 2009

 *  Copyright (c) 2002-2009
 *  All rights reserved.

 *  JFLAP is open source software. Please see the LICENSE for terms.
 *
 */





package gui.action;

import gui.environment.AutomatonEnvironment;
import gui.environment.EnvironmentFrame;
import gui.environment.Universe;
import gui.grammar.automata.ConvertController;
import gui.grammar.automata.ConvertPane;
import gui.grammar.automata.PDAConvertController;
import gui.viewer.SelectionDrawer;
import gui.viewer.ZoomPane;

import java.awt.BorderLayout;
import java.util.HashSet;
import java.util.Iterator;

import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.border.BevelBorder;

import automata.Automaton;
import automata.State;
import automata.Transition;
import automata.pda.PDAToCFGConverter;
import automata.pda.PDATransition;
import automata.pda.PushdownAutomaton;

/**
 * This action handles the conversion of an PDA to a context free grammar.
 * 
 * @author Thomas Finley
 */

public class ConvertPDAToGrammarAction extends ConvertAutomatonToGrammarAction {
	/**
	 * Instantiates a new <CODE>ConvertFSAToGrammarAction</CODE>.
	 * 
	 * @param environment
	 *            the environment
	 */
	public ConvertPDAToGrammarAction(AutomatonEnvironment environment) {
		super(environment);
	}

	/**
	 * Checks the PDA to make sure it's ready to be converted.
	 */
	protected boolean checkAutomaton() {
		EnvironmentFrame frame = Universe.frameForEnvironment(getEnvironment());
		JPanel messagePanel = new JPanel(new BorderLayout());
		SelectionDrawer drawer = new SelectionDrawer(getAutomaton());
		JLabel messageLabel = new JLabel();
		ZoomPane zoom = new ZoomPane(drawer);
		JPanel tempPanel = new JPanel(new BorderLayout());
		tempPanel.setBorder(new BevelBorder(BevelBorder.LOWERED));
		zoom.setPreferredSize(new java.awt.Dimension(300, 200));
		tempPanel.add(zoom, BorderLayout.CENTER);
		messagePanel.add(tempPanel, BorderLayout.CENTER);
		messagePanel.add(messageLabel, BorderLayout.SOUTH);
		// Check the final states.
		State[] finalStates = getAutomaton().getFinalStates();
		if (finalStates.length != 1) {
			JOptionPane.showMessageDialog(frame,
					"There must be exactly one final state!",
					"Final State Error", JOptionPane.ERROR_MESSAGE);
			return false;
		}
		// Are all transitions to the final state okay?
		Transition[] toFinal = getAutomaton().getTransitionsToState(
				finalStates[0]);
		HashSet bad = new HashSet();
		for (int i = 0; i < toFinal.length; i++) {
			PDATransition t = (PDATransition) toFinal[i];
			if (!t.getStringToPop().equals("Z"))
				bad.add(t);
		}
		if (bad.size() != 0) {
			drawer.clearSelected();
			Iterator it = bad.iterator();
			while (it.hasNext())
				drawer.addSelected((Transition) it.next());
			messageLabel.setText("Transitions to final must pop only 'Z'.");
			JOptionPane.showMessageDialog(frame, messagePanel,
					"Final Transitions Error", JOptionPane.ERROR_MESSAGE);
			return false;
		}
		// Are the transitions okay?
		Transition[] transitions = getAutomaton().getTransitions();
		bad.clear();
		for (int i = 0; i < transitions.length; i++) {
			PDATransition t = (PDATransition) transitions[i];
			if (// t.getInputToRead().length() != 1 ||
			t.getStringToPop().length() != 1
					|| (t.getStringToPush().length() != 2 && t
							.getStringToPush().length() != 0))
				bad.add(t);
		}
		if (bad.size() != 0) {
			drawer.clearSelected();
			Iterator it = bad.iterator();
			while (it.hasNext())
				drawer.addSelected((Transition) it.next());
			messageLabel.setText("Transitions must pop 1 and push 0 or 2.");
			JOptionPane.showMessageDialog(frame, messagePanel,
					"Transitions Error", JOptionPane.ERROR_MESSAGE);
			return false;
		}
		return true;
	}

	/**
	 * This object is only applicable to pushdown automatons.
	 * 
	 * @param object
	 *            the object to test
	 * @return <CODE>true</CODE> if the object is a pushdown automaton, <CODE>false</CODE>
	 *         otherwise
	 */
	public static boolean isApplicable(Object object) {
		return object instanceof PushdownAutomaton;
	}

	/**
	 * Initializes the convert controller.
	 * 
	 * @param pane
	 *            the convert pane that holds the automaton pane and the grammar
	 *            table
	 * @param drawer
	 *            the selection drawer of the new view
	 * @param automaton
	 *            the automaton that's being converted; note that this will not
	 *            be the exact object returned by <CODE>getAutomaton</CODE>
	 *            since a clone is made
	 * @return the convert controller to handle the conversion of the automaton
	 *         to a grammar
	 */
	protected ConvertController initializeController(ConvertPane pane,
			SelectionDrawer drawer, Automaton automaton) {
		return new PDAConvertController(pane, drawer,
				(PushdownAutomaton) automaton);
	}

	/** The environment this action is part of. */
	private AutomatonEnvironment environment;

	/** The automaton to convert. */
	private PushdownAutomaton automaton;

	/** The grammar converter. */
	private PDAToCFGConverter converter = new PDAToCFGConverter();
}