/*******************************************************************************

 * Copyright (c) 2000, 2007 IBM Corporation and others.

 * Portion Copyright (c) 2008 Nokia Corporation and/or its subsidiary(-ies).

 * All rights reserved. This program and the accompanying materials

 * are made available under the terms of the Eclipse Public License v1.0

 * which accompanies this distribution, and is available at

 * http://www.eclipse.org/legal/epl-v10.html

 *

 * Contributors:

 *     IBM Corporation - initial API and implementation

 *     Nokia Corporation - S60 implementation

 *     Nokia Corporation - QT implementation

 *******************************************************************************/

package org.eclipse.swt.widgets;

import org.eclipse.swt.SWT;

import org.eclipse.swt.SWTException;

import org.eclipse.swt.widgets.Composite;

import org.eclipse.swt.events.SelectionEvent;

import org.eclipse.swt.widgets.TypedListener;

import org.eclipse.swt.events.SelectionListener;

import org.eclipse.swt.internal.qt.OS;

import org.eclipse.swt.internal.qt.WidgetState;

/**

 * 

 * Instances of this class represent a selectable user interface object that

 * launchs other applications when activated by the end-user.

 * 

 * <p>

 * This class represents several types of hyperlinks associated with certain

 * functionalities. The end-user can activate the associated program determined

 * by the style. The concrete visual effect and activation behaviour vary from

 * platform to platform.

 * </p>

 * <p>

 * A HyperLink instance accepts general characters as other controls do, but the

 * appearance is implementation and locale dependent, for example, a HyperLink

 * object with the PHONE style might display as follows: <br>

 * (416) 123-4567 <br>

 * but the actual contents of the object visible to the application through the

 * APIs, e.g. <code>getText()</code>, can be the string "4161234567".

 * </p>

 * <p>

 * <b>Example </b>

 * 

 * <pre>

 * HyperLink email = new HyperLink(composite, SWT.NONE, HyperLink.EMAIL);

 * email.setText("firstname.lastname@foo.com");

 * HyperLink dialler = new HyperLink(composite, SWT.BORDER | SWT.LEFT,

 *         HyperLink.PHONE);

 * dialler.setText("3581234567");

 * </pre>

 * 

 * </p>

 * <dl>

 * <dt><b>Styles: </b></dt>

 * <dd>BORDER, CENTER, LEFT, RIGHT</dd>

 * <dt><b>Format Styles: </b></dt>

 * <dd>URL: launches a platform specific web browser when activated</dd>

 * <dd>EMAIL: opens the platform specific e-mail client when activated</dd>

 * <dd>PHONE: shows a platform specific dialler interface when activated</dt>

 * <dt><b>Events: </b></dt>

 * <dd>(none)</dd>

 * </dl>

 * <p>

 * Note: Since the style provides hint for the implementation, there is no event

 * that applications need to listen to.

 * </p>

 * <p>

 * IMPORTANT: This class is <em>not</em> intended to be subclassed.

 * </p>

 */

public class Link extends org.eclipse.swt.widgets.Control {

    String text;

    /*

     * This flag is set to true when the control gains focus because of 

     * keyboard event. In such a case user needs to press tab again to 

     * get the link highlighted, so we cannot traverse.

     */

    boolean keyFocusIn;

    static final String LINK_START = "<a>";

    static final String LINK_END = "</a>";

    /**

     * Constructs a new instance of this class given its parent, a style value

     * describing its behavior and appearance.

     * <p>

     * The style value is either one of the style constants defined in class

     * <code>SWT</code> which is applicable to instances of this class, or must

     * be built by <em>bitwise OR</em> 'ing together (that is, using the

     * <code>int</code> "|" operator) two or more of those <code>SWT</code>

     * style constants. The class description lists the style constants that are

     * applicable to the class. Style bits are also inherited from superclasses.

     * </p>

     * 

     * @param parent

     *            a composite control which will be the parent of the new

     *            instance (cannot be null)

     * @param style

     *            the style of control to construct

     * 

     * @exception IllegalArgumentException

     *                <ul>

     *                <li>ERROR_NULL_ARGUMENT - if the parent is null</li>

     *                </ul>

     * @exception SWTException

     *                <ul>

     *                <li>ERROR_THREAD_INVALID_ACCESS - if not called from the

     *                thread that created the parent</li>

     *                <li>ERROR_INVALID_SUBCLASS - if this class is not an

     *                allowed subclass</li>

     *                </ul>

     * 

     * @see SWT#BORDER

     * @see SWT#CENTER

     * @see SWT#LEFT

     * @see SWT#RIGHT

     */

    public Link(Composite parent, int style) {

        this(parent, style, 0, null);

    }

    /**

     * <p>

     * <b>IMPORTANT:</b> This constructor is <em>not</em> part of the SWT

     * public API. It should never be referenced from application code. 

     * </p>

     */

    protected Link(Composite parent, int style, int format, Object packageProxy) {

        super(parent,

              checkBits(style, SWT.LEFT, SWT.CENTER, SWT.RIGHT, 0, 0, 0),

              format, packageProxy, false);

        setAlignment(style);

        OS.QLabel_setTextInteractionFlags(handle, OS.QT_TEXTBROWSERINTERACTION);

        OS.QLabel_setOpenExternalLinks(handle, false);

        text = "";

    }

    /**

     * Adds the listener to the collection of listeners who will

     * be notified when the control is selected by the user, by sending

     * it one of the messages defined in the <code>SelectionListener</code>

     * interface.

     * <p>

     * <code>widgetSelected</code> is called when the control is selected.

     * <code>widgetDefaultSelected</code> is not called.

     * </p>

     *

     * @param listener the listener which should be notified

     *

     * @exception IllegalArgumentException <ul>

     *    <li>ERROR_NULL_ARGUMENT - if the listener is null</li>

     * </ul>

     * @exception SWTException <ul>

     *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>

     *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>

     * </ul>

     *

     * @see SelectionListener

     * @see #removeSelectionListener

     * @see SelectionEvent

     */

    public void addSelectionListener (SelectionListener listener) {

        checkWidget ();

        if (listener == null) SWT.error (SWT.ERROR_NULL_ARGUMENT);

        TypedListener typedListener = new TypedListener (listener);

        addListener(SWT.Selection,typedListener);

        addListener(SWT.DefaultSelection, typedListener);

    }

    void createHandle_pp(int index) {

        frameHandle = topHandle = handle = OS.QLabel_new();

        state |= WidgetState.HANDLE;

    }

    /**

     * Returns the receiver's text, which will be an empty string if it has

     * never been set.

     * 

     * @return the receiver's text

     * 

     * @exception SWTException

     *                <ul>

     *                <li>ERROR_WIDGET_DISPOSED - if the receiver has been

     *                disposed</li>

     *                <li>ERROR_THREAD_INVALID_ACCESS - if not called from the

     *                thread that created the receiver</li>

     *                </ul>

     * @see #setText(String)

     */

    public String getText() {

        checkWidget();

        return text;

    }

    void hookEvents_pp() {

        super.hookEvents_pp();

        int signalProxy = OS.SignalHandler_new(handle, 

                OS.QSIGNAL_LINKACTIVATED);

        OS.QObject_connectOrThrow(handle, "linkActivated(const QString&)",

                signalProxy, "widgetSignal(const QString&)",

                OS.QT_AUTOCONNECTION);

    }

    boolean qt_event_focusIn(int reason) {

        if (reason != OS.QT_MOUSEFOCUSREASON) {

            keyFocusIn = true;

        }

        return super.qt_event_focusIn(reason);

    }

    boolean qt_event_focusOut(int reason) {

        keyFocusIn = false;

        return super.qt_event_focusOut(reason);

    }

    void qt_signal_linkActivated_pp(String link) {

        Event event = new Event ();

        event.text = link;

        sendEvent (SWT.Selection, event);

    }

    /**

     * Removes the listener from the collection of listeners who will

     * be notified when the control is selected by the user.

     *

     * @param listener the listener which should no longer be notified

     *

     * @exception IllegalArgumentException <ul>

     *    <li>ERROR_NULL_ARGUMENT - if the listener is null</li>

     * </ul>

     * @exception SWTException <ul>

     *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>

     *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>

     * </ul>

     *

     * @see SelectionListener

     * @see #addSelectionListener

     */

    public void removeSelectionListener (SelectionListener listener) {

        checkWidget();

        if (listener == null) SWT.error(SWT.ERROR_NULL_ARGUMENT);

        removeListener(SWT.Selection, listener);

        removeListener(SWT.DefaultSelection, listener);    

    }

    void setAlignment(int style) {

        int qAlign = OS.QT_ALIGNVCENTER;

        if ((style & SWT.LEFT) != 0) {

            qAlign |= OS.QT_ALIGNLEFT;

        } else if ((style & SWT.CENTER) != 0) {

            qAlign |= OS.QT_ALIGNHCENTER;

        } else if ((style & SWT.RIGHT) != 0) {

            qAlign |= OS.QT_ALIGNRIGHT;

        }

        OS.QLabel_setAlignment(handle, qAlign);

    }

    public void setEnabled(boolean enabled) {

        /**

         * To disable/enable user interaction for a QLabel,

         * we need to set the text interaction flags.

         */

        if (enabled != getEnabled()) {

            OS.QLabel_setTextInteractionFlags(handle, 

                    enabled ? OS.QT_TEXTBROWSERINTERACTION : 

                              OS.QT_NOTEXTINTERACTION);

        }

        super.setEnabled(enabled);

    }

    /**

     * Sets the receiver's text.

     * <p>

     * This method sets the link text.

     * </p>

     * 

     * @param string

     *            the new text

     * 

     * @exception IllegalArgumentException

     *                <ul>

     *                <li>ERROR_NULL_ARGUMENT - if the text is null</li>

     *                </ul>

     * @exception SWTException

     *                <ul>

     *                <li>ERROR_WIDGET_DISPOSED - if the receiver has been

     *                disposed</li>

     *                <li>ERROR_THREAD_INVALID_ACCESS - if not called from the

     *                thread that created the receiver</li>

     *                </ul>

     * @see #getText()

     */

    public void setText(String string) {

        checkWidget();

        if (string == null)

            SWT.error(SWT.ERROR_NULL_ARGUMENT);

        text = string;

        OS.QLabel_setText(handle, adjustTags(text));

    }

    /*

     * QLabel does not render a link as a link if it is created like this:

     *   Text and <a>link</a> and another <a>link</a>

     * QLabel requires the href part to be there also. This function changes

     * the string above to this:

     *   Text and <a href="link">link</a> and another <a href="link">link</a>

     */

    static String adjustTags(String str) {

        int pos = str.indexOf(LINK_START);

        if (pos == -1) {

            return str;

        }

        int start = 0;

        int endPos = pos;

        StringBuffer sb = new StringBuffer();

        String clean = "";

        while (pos != -1) {

            sb.append(str.substring(start, pos)).append("<a href=\"");

            start = pos + LINK_START.length();

            endPos = str.indexOf(LINK_END, start);           

            if (endPos != -1) {

                clean = str.substring(start, endPos);

                sb.append(clean);

            } else {

                // If the link format is invalid in any way, just use 

                // original string and try not to be too clever.

                return str;

            }

            sb.append("\">"+clean+LINK_END);

            start = endPos + LINK_END.length();     

            pos = str.indexOf(LINK_START, start);            

        }

        sb.append(str.substring(endPos));

        return sb.toString();

    }

    void setTraversalFlags_pp(int type, int key, int modifier,

            int character) {

        if (type == SWT.TRAVERSE_RETURN) {

            // use RETURN key to activate link,

            // which should be delivered to QLabel instance

            traverseDoit = false;

            traverseCancel = false;

            return;

        }

        super.setTraversalFlags_pp(type, key, modifier, character);

        switch (key) {

            case OS.QT_KEY_ENTER:  // By default, enter key is used for 

            case OS.QT_KEY_RETURN: // default selection, not traversing.

                traverseDoit = false;

                traverseCancel = false;

                break;

            case OS.QT_KEY_TAB:

                if (isFocusControl() && keyFocusIn) {

                    traverseDoit = false;

                    traverseCancel = false;

                    keyFocusIn = false;

                }

                break;

            default:

                break;

        }

    }

}