/*
 * The Apache Software License, Version 1.1
 *
 * Copyright (c) 2001 The Apache Software Foundation.  All rights
 * reserved.
 *
 * 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.
 *
 * 3. The end-user documentation included with the redistribution, if
 *    any, must include the following acknowlegement:
 *       "This product includes software developed by the
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowlegement may appear in the software itself,
 *    if and wherever such third-party acknowlegements normally appear.
 *
 * 4. The names "The Jakarta Project", "Ant", and "Apache Software
 *    Foundation" must not be used to endorse or promote products derived
 *    from this software without prior written permission. For written
 *    permission, please contact apache@apache.org.
 *
 * 5. Products derived from this software may not be called "Apache"
 *    nor may "Apache" appear in their names without prior written
 *    permission of the Apache Group.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED 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 APACHE SOFTWARE FOUNDATION OR
 * ITS 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.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 */
package org.apache.tools.ant.gui.wizard;
import org.apache.tools.ant.gui.core.ResourceManager;
import java.util.*;

/**
 * A simple state machine based on the defined ordering of steps
 * in the resources.
 * 
 * @version $Revision$ 
 * @author Simeon Fitch 
 */
public class DefaultStateMachine implements StateMachine {

    /** 
     * Get the list of step IDs defined in the resources as a list.
     * 
     * @param data Current wizard state.
     * @return List of step IDs
     */
    protected List getStepList(WizardData data) {
        return Arrays.asList(data.getResources().getStringArray("steps"));
    }

    /** 
     * Get the next step.
     * 
     * @param curr The current step.
     * @param data The current state of the wizard.
     * @return The ID of next step, or null if there currently isn't one.
     */
    public String getNext(WizardStep curr, WizardData data) {
        List steps = getStepList(data);
        int nextIndex = steps.indexOf(curr.getID()) + 1;
        if(nextIndex > 0 && nextIndex < steps.size()) {
            return (String) steps.get(nextIndex);
        }
        return null;
    }

    /** 
     * Get the previous step.
     * 
     * @param curr The current step.
     * @param data The current state of the wizard.
     * @return The ID of previous step, or null if there currently isn't one.
     */
    public String getPrevious(WizardStep curr, WizardData data) {
        List steps = getStepList(data);
        int nextIndex = steps.indexOf(curr.getID()) - 1;
        if(nextIndex > 0 && nextIndex < steps.size()) {
            return (String) steps.get(nextIndex);
        }
        return null;
    }
}