/*

* Copyright (c) 2009 Nokia Corporation and/or its subsidiary(-ies).

* All rights reserved.

* This component and the accompanying materials are made available

* under the terms of "Eclipse Public License v1.0"

* which accompanies this distribution, and is available

* at the URL "http://www.eclipse.org/legal/epl-v10.html".

*

* Initial Contributors:

* Nokia Corporation - initial contribution.

*

* Contributors:

*

* Description:

*

*/

package javax.microedition.lcdui;

import java.util.Enumeration;

import java.util.Hashtable;

import org.eclipse.swt.events.SelectionListener;

import org.eclipse.swt.widgets.Control;

/**

 * Implementation of LCDUI <code>Command</code> class.

 */

public class Command

{

    /**

     * Command type SCREEN.

     */

    public static final int SCREEN = 1;

    /**

     * Command type BACK.

     */

    public static final int BACK = 2;

    /**

     * Command type CANCEL.

     */

    public static final int CANCEL = 3;

    /**

     * Command type OK.

     */

    public static final int OK = 4;

    /**

     * Command type HELP.

     */

    public static final int HELP = 5;

    /**

     * Command type STOP.

     */

    public static final int STOP = 6;

    /**

     * Command type EXIT.

     */

    public static final int EXIT = 7;

    /**

     * Command type ITEM.

     */

    public static final int ITEM = 8;

    private static final String EMPTY_STRING = "";

    private String shortLabel;

    private String longLabel;

    private int type;

    private int priority;

    // List of eSWT's Commands associated with this Command.

    // There must be one eSWT Command per Control.

    private Hashtable eswtCommands = new Hashtable();

    // List of priorities created. This is used when LCDUI priorities

    // are mapped to eSWT priorities.

    private static Hashtable priorities;

    static

    {

        priorities = new Hashtable();

        priorities.put(new Integer(Integer.MIN_VALUE),

                       new Integer(0));

        priorities.put(new Integer(Integer.MAX_VALUE),

                       new Integer(Integer.MAX_VALUE));

    }

    /**

     * Creates new Command.

     *

     * @param shortLabel Label of Command.

     * @param type Type of command.

     * @param priority Priority of command.

     */

    public Command(String shortLabel, int type, int priority)

    {

        this(shortLabel, null, type, priority);

    }

    /**

     * Creates new Command.

     *

     * @param shortLabel Label of command.

     * @param longLabel Long label of command.

     * @param type Type of command.

     * @param priority Priority of command.

     */

    public Command(String shortLabel,

                   String longLabel,

                   int type,

                   int priority)

    {

        if(shortLabel == null)

        {

            throw new NullPointerException(

                MsgRepository.COMMAND_EXCEPTION_LABEL_IS_NULL);

        }

        if(type < SCREEN || type > ITEM)

        {

            throw new IllegalArgumentException(

                MsgRepository.COMMAND_EXCEPTION_INVALID_TYPE);

        }

        this.type = type;

        this.shortLabel = shortLabel;

        this.longLabel = longLabel;

        this.priority = priority;

    }

    /**

     * Gets the label of the command.

     *

     * @return Label of this command.

     */

    public String getLabel()

    {

        return shortLabel;

    }

    /**

     * Get the long label of the command.

     *

     * @return Long label of this command.

     */

    public String getLongLabel()

    {

        return longLabel;

    }

    /**

     * Gets the command type.

     *

     * @return Type of this command.

     */

    public int getCommandType()

    {

        return type;

    }

    /**

     * Gets the priority of the command.

     *

     * @return Priority of this command.

     */

    public int getPriority()

    {

        return priority;

    }

    /**

     * Gets eSWT Command associated with this command on the queried Control.

     *

     * @param control the queried Control.

     * @return eSWT Command.

     */

    org.eclipse.ercp.swt.mobile.Command getESWTCommand(Control control)

    {

        if(control != null)

        {

            return (org.eclipse.ercp.swt.mobile.Command)

                   eswtCommands.get(control);

        }

        return null;

    }

    /**

     * Add a SelectionListener to this command's eSWT command widget on the

     * specified control.

     *

     * @param control

     * @param listener

     */

    void eswtAddCommandSelectionListener(Control control,

                                         SelectionListener listener)

    {

        if(listener != null)

        {

            org.eclipse.ercp.swt.mobile.Command cmd = getESWTCommand(control);

            if(cmd != null && !cmd.isDisposed())

            {

                // Remove listener if it is already added. Same listener

                // should be in same command only once:

                cmd.removeSelectionListener(listener);

                cmd.addSelectionListener(listener);

            }

        }

    }

    /**

     * Removes the SelectionListener from this command's eSWT command widget on

     * the specified control.

     *

     * @param control

     * @param listener

     */

    void eswtRemoveCommandSelectionListener(Control control,

                                            SelectionListener listener)

    {

        if(listener != null)

        {

            org.eclipse.ercp.swt.mobile.Command cmd = getESWTCommand(control);

            if(cmd != null && !cmd.isDisposed())

            {

                cmd.removeSelectionListener(listener);

            }

        }

    }

    /**

     * Adds eSWT Command to this command.

     *

     * @param control The Control where eSWT Command is added. For example

     *            Shell.

     * @param isDefault If true, created eSWT command is set to be default one.

     */

    void addESWTCommand(Control control, final boolean isDefault)

    {

        final Control finalControl = control;

        ESWTUIThreadRunner.syncExec(new Runnable()

        {

            public void run()

            {

                eswtAddESWTCommand(finalControl, isDefault);

            }

        });

    }

    /**

     * eSWT callback to add an eSWT Command to vector of eSWT Commands.

     *

     * @param control eSWT control on which the command is created.

     * @param isDefault If true, created eSWT command is set to be default one.

     */

    void eswtAddESWTCommand(Control control, boolean isDefault)

    {

        if(!eswtCommands.containsKey(control))

        {

            int eswtType = getEswtType(type);

            int eswtPriority = getESWTPriority(priority);

            org.eclipse.ercp.swt.mobile.Command eswtCommand =

                new org.eclipse.ercp.swt.mobile.Command(

                control, eswtType, eswtPriority);

            eswtCommand.setText(shortLabel);

            if(longLabel != null)

            {

                eswtCommand.setLongLabel(longLabel);

            }

            if(isDefault)

            {

                eswtCommand.setDefaultCommand();

            }

            eswtCommands.put(control, eswtCommand);

        }

    }

    /**

     * Removes eSWT Command from this command.

     *

     * @param control The Control where eSWT Command is located.

     */

    void removeESWTCommand(Control control)

    {

        final Control finalControl = control;

        ESWTUIThreadRunner.syncExec(new Runnable()

        {

            public void run()

            {

                eswtRemoveESWTCommand(finalControl);

            }

        });

    }

    /**

     * eSWT callback to remove an eSWT Command to vector of eSWT Commands.

     */

    void eswtRemoveESWTCommand(Control control)

    {

        if(eswtCommands.containsKey(control))

        {

            if(getESWTCommand(control) != null)

            {

                getESWTCommand(control).dispose();

            }

            eswtCommands.remove(control);

        }

    }

    /**

     * Get eSWT command type.

     *

     * @param cmdType LCDUI type

     * @return mapped eSWT command type.

     */

    private int getEswtType(int cmdType)

    {

        int eswtType = 0;

        // There are no Command types SCREEN and ITEM in eSWT so

        // the eSWT type GENERAL is used for those types.

        switch(cmdType)

        {

        case SCREEN:

            eswtType = org.eclipse.ercp.swt.mobile.Command.GENERAL;

            break;

        case BACK:

            eswtType = org.eclipse.ercp.swt.mobile.Command.BACK;

            break;

        case CANCEL:

            eswtType = org.eclipse.ercp.swt.mobile.Command.CANCEL;

            break;

        case OK:

            eswtType = org.eclipse.ercp.swt.mobile.Command.OK;

            break;

        case HELP:

            eswtType = org.eclipse.ercp.swt.mobile.Command.HELP;

            break;

        case STOP:

            eswtType = org.eclipse.ercp.swt.mobile.Command.STOP;

            break;

        case EXIT:

            eswtType = org.eclipse.ercp.swt.mobile.Command.EXIT;

            break;

        case ITEM:

            eswtType = org.eclipse.ercp.swt.mobile.Command.GENERAL;

            break;

        default:

            break;

        }

        return eswtType;

    }

    /**

     * If Command is created with empty label ("") then system should use

     * default label depending of Command type. This method will return the

     * default label. Method assumes that the type-field is initialized before

     * this method is called.

     *

     * @return Default label.

     */

    static String getDefaultLabel(int type)

    {

        String rValue;

        switch(type)

        {

        case SCREEN:

            rValue = MsgRepository.COMMAND_LABEL_SCREEN;

            break;

        case BACK:

            rValue = MsgRepository.COMMAND_LABEL_BACK;

            break;

        case CANCEL:

            rValue = MsgRepository.COMMAND_LABEL_CANCEL;

            break;

        case OK:

            rValue = MsgRepository.COMMAND_LABEL_OK;

            break;

        case HELP:

            rValue = MsgRepository.COMMAND_LABEL_HELP;

            break;

        case STOP:

            rValue = MsgRepository.COMMAND_LABEL_STOP;

            break;

        case EXIT:

            rValue = MsgRepository.COMMAND_LABEL_EXIT;

            break;

        case ITEM:

            rValue = MsgRepository.COMMAND_LABEL_ITEM;

            break;

        default:

            rValue = EMPTY_STRING;

            break;

        }

        return rValue;

    }

    /**

     * In eSWT lowest possible priority value is 0, but in LCDUI it's ok to have

     * negative priority values. This method converts LCDUI priority to eSWT

     * priority. In practise the method provides acceptable priorities for all

     * kind of applications, but in theory, in worst case scenario, if using

     * very uncommon priority numbering scheme and if there are more than 31

     * commands and every command has different priority than other commands,

     * then same priority might be returned more than once.

     *

     * The meaning of variables:

     * <li>a = nearest smaller lcdui priority.

     * <li>b = nearest larger lcdui priority.

     * <li>c = lcdui priority to be converted.

     * <li>a1 = eswt priority value associated with a.

     * <li>b1 = eswt priority value associated with b.

     * <li>c1 = eswt priority value associated with c.

     * <li>x = value in the middle of a1 and b1.

     * <li>ac = distance from a to c.

     * <li>cb = distance from c to b.

     * <li>a1x = distance from a1 to x.

     *

     * @param c Lcdui priority to be converted.

     * @see OpenLCDUI design document for more detailed description of the

     *      algorithm.

     */

    private int getESWTPriority(int c)

    {

        // Find out nearest values from keys (LCDUI priorities). "a" will

        // be nearest smaller value and "b" will be nearest larger value.

        Integer a = new Integer(Integer.MIN_VALUE);

        Integer b = new Integer(Integer.MAX_VALUE);

        for(Enumeration e = priorities.keys(); e.hasMoreElements();)

        {

            Integer i = (Integer) e.nextElement();

            if((i.intValue() >= a.intValue()) && (i.intValue() <= c))

            {

                a = i;

            }

            if((i.intValue() <= b.intValue()) && (i.intValue() >= c))

            {

                b = i;

            }

        }

        // Calculate eSWT priority candidate. "a1" is nearest

        // smaller value in eSWT priorities and "b1" is nearest

        // larger value and x is the candidate:

        int a1 = ((Integer) priorities.get(a)).intValue();

        int b1 = ((Integer) priorities.get(b)).intValue();

        int a1x = ((b1 - a1) / 2);

        int x = a1x + a1;

        // Calculate distances from new LCDUI priority to nearest

        // LCDUI priorities already saved:

        long ac = Math.abs((long) a.intValue() - (long) c);

        long cb = Math.abs((long) b.intValue() - (long) c);

        // Decide whether to use candidate or one of the nearest values:

        int c1 = 0;

        if(ac > cb)

        {

            if(cb < a1x)

            {

                // Use nearest larger value:

                c1 = (int)(b1 - cb);

            }

            else

            {

                // Use candidate:

                c1 = x;

            }

        }

        else

        {

            if(ac < a1x)

            {

                // Use nearest smaller value:

                c1 = (int)(a1 + ac);

            }

            else

            {

                // Use candidate:

                c1 = x;

            }

        }

        // Save new priority to the HashTable if not already exists.

        if(!priorities.contains(new Integer(c1)))

        {

            priorities.put(new Integer(c), new Integer(c1));

        }

        // Return flipped priority because in LCDUI lower priority

        // means higher importance, but in eSWT lower priority means

        // lower importance:

        return Integer.MAX_VALUE - c1;

    }

}