/*******************************************************************************
 * Copyright (c) 2000, 2004 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Common Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/cpl-v10.html
 * 
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.swt.widgets;


import org.eclipse.swt.internal.win32.*;
import org.eclipse.swt.*;
import org.eclipse.swt.graphics.*;

/**
 * Instances of this class represent a selectable user interface object
 * corresponding to a tab for a page in a tab folder.
 * <dl>
 * <dt><b>Styles:</b></dt>
 * <dd>(none)</dd>
 * <dt><b>Events:</b></dt>
 * <dd>(none)</dd>
 * </dl>
 * <p>
 * IMPORTANT: This class is <em>not</em> intended to be subclassed.
 * </p>
 */

public class TabItem extends Item {
	TabFolder parent;
	Control control;
	String toolTipText;

/**
 * Constructs a new instance of this class given its parent
 * (which must be a <code>TabFolder</code>) and a style value
 * describing its behavior and appearance. The item is added
 * to the end of the items maintained by its parent.
 * <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
 * @see Widget#checkSubclass
 * @see Widget#getStyle
 */
public TabItem (TabFolder parent, int style) {
	super (parent, style);
	this.parent = parent;
	parent.createItem (this, parent.getItemCount ());
}

/**
 * Constructs a new instance of this class given its parent
 * (which must be a <code>TabFolder</code>), a style value
 * describing its behavior and appearance, and the index
 * at which to place it in the items maintained by its parent.
 * <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
 * @param index the index to store the receiver in its parent
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT - if the parent is null</li>
 *    <li>ERROR_INVALID_RANGE - if the index is either negative or greater than the parent's current tab count</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
 * @see Widget#checkSubclass
 * @see Widget#getStyle
 */
public TabItem (TabFolder parent, int style, int index) {
	super (parent, style);
	this.parent = parent;
	parent.createItem (this, index);
}

protected void checkSubclass () {
	if (!isValidSubclass ()) error (SWT.ERROR_INVALID_SUBCLASS);
}

/**
 * Returns the control that is used to fill the client area of
 * the tab folder when the user selects the tab item.  If no
 * control has been set, return <code>null</code>.
 * <p>
 * @return the control
 *
 * @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>
 */
public Control getControl () {
	checkWidget();
	return control;
}

/**
 * Returns the receiver's parent, which must be a <code>TabFolder</code>.
 *
 * @return the receiver's parent
 *
 * @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>
 */
public TabFolder getParent () {
	checkWidget();
	return parent;
}

/**
 * Returns the receiver's tool tip text, or null if it has
 * not been set.
 *
 * @return the receiver's tool tip 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>
 */
public String getToolTipText () {
	checkWidget();
	return toolTipText;
}

void releaseChild () {
	super.releaseChild ();
	int index = parent.indexOf (this);
	if (index == parent.getSelectionIndex ()) {
		if (control != null) control.setVisible (false);
	}
	parent.destroyItem (this);
}

void releaseWidget () {
	super.releaseWidget ();
	control = null;
	parent = null;
}

/**
 * Sets the control that is used to fill the client area of
 * the tab folder when the user selects the tab item.
 * <p>
 * @param control the new control (or null)
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_INVALID_ARGUMENT - if the control has been disposed</li> 
 *    <li>ERROR_INVALID_PARENT - if the control is not in the same widget tree</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>
 */
public void setControl (Control control) {
	checkWidget();
	if (control != null) {
		if (control.isDisposed()) error (SWT.ERROR_INVALID_ARGUMENT);
		if (control.parent != parent) error (SWT.ERROR_INVALID_PARENT);
	}
	if (this.control != null && this.control.isDisposed ()) {
		this.control = null;
	}
	Control oldControl = this.control, newControl = control;
	this.control = control;
	int index = parent.indexOf (this);
	if (index != parent.getSelectionIndex ()) {
		if (newControl != null) newControl.setVisible (false);
		return;
	}
	if (newControl != null) {
		newControl.setBounds (parent.getClientArea ());
		newControl.setVisible (true);
	}
	if (oldControl != null) oldControl.setVisible (false);
}

public void setImage (Image image) {
	checkWidget();
	int index = parent.indexOf (this);
	if (index == -1) return;
	super.setImage (image);
	/*
	* Bug in Windows.  In version 6.00 of COMCTL32.DLL, tab
	* items with an image and a label that includes '&' cause
	* the tab to draw incorrectly (even when doubled '&&').
	* The image  overlaps the label.  The fix is to remove
	* all '&' characters from the string. 
	*/
	if (OS.COMCTL32_MAJOR >= 6) {
		if (text.indexOf ('&') != -1) setText (text);
	}
	int hwnd = parent.handle;
	TCITEM tcItem = new TCITEM ();
	tcItem.mask = OS.TCIF_IMAGE;
	tcItem.iImage = parent.imageIndex (image);
	OS.SendMessage (hwnd, OS.TCM_SETITEM, index, tcItem);
}
/**
 * Sets the receiver's text.  The string may include
 * the mnemonic character.
 * </p>
 * <p>
 * Mnemonics are indicated by an '&amp' that causes the next
 * character to be the mnemonic.  When the user presses a
 * key sequence that matches the mnemonic, a selection
 * event occurs. On most platforms, the mnemonic appears
 * underlined but may be emphasised in a platform specific
 * manner.  The mnemonic indicator character '&amp' can be
 * escaped by doubling it in the string, causing a single
 *'&amp' to be displayed.
 * </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>
 * 
 */
public void setText (String string) {
	checkWidget();
	if (string == null) error (SWT.ERROR_NULL_ARGUMENT);
	int index = parent.indexOf (this);
	if (index == -1) return;
	super.setText (string);
	/*
	* Bug in Windows.  In version 6.00 of COMCTL32.DLL, tab
	* items with an image and a label that includes '&' cause
	* the tab to draw incorrectly (even when doubled '&&').
	* The image  overlaps the label.  The fix is to remove
	* all '&' characters from the string. 
	*/
	if (OS.COMCTL32_MAJOR >= 6 && image != null) {
		if (text.indexOf ('&') != -1) {
			int length = string.length ();
			char[] text = new char [length];
			string.getChars ( 0, length, text, 0);
			int i = 0, j = 0;
			for (i=0; i<length; i++) {
				if (text[i] != '&') text [j++] = text [i];
			}
			if (j < i) string = new String (text, 0, j);
		}
	}
	int hwnd = parent.handle;
	int hHeap = OS.GetProcessHeap ();
	TCHAR buffer = new TCHAR (parent.getCodePage (), string, true);
	int byteCount = buffer.length () * TCHAR.sizeof;
	int pszText = OS.HeapAlloc (hHeap, OS.HEAP_ZERO_MEMORY, byteCount);
	OS.MoveMemory (pszText, buffer, byteCount); 
	TCITEM tcItem = new TCITEM ();
	tcItem.mask = OS.TCIF_TEXT;
	tcItem.pszText = pszText;
	OS.SendMessage (hwnd, OS.TCM_SETITEM, index, tcItem);
	OS.HeapFree (hHeap, 0, pszText);
}

/**
 * Sets the receiver's tool tip text to the argument, which
 * may be null indicating that no tool tip text should be shown.
 *
 * @param string the new tool tip text (or null)
 *
 * @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>
 */
public void setToolTipText (String string) {
	checkWidget();
	toolTipText = string;
}

}