/*******************************************************************************
 * Copyright (c) 2000, 2008 IBM Corporation and others.
 * 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
 *******************************************************************************/
package org.eclipse.swt.graphics;


import org.eclipse.swt.internal.*;
import org.eclipse.swt.internal.photon.*;
import org.eclipse.swt.*;

/**
 * Instances of this class manage operating system resources that
 * define how text looks when it is displayed. Fonts may be constructed
 * by providing a device and either name, size and style information
 * or a <code>FontData</code> object which encapsulates this data.
 * <p>
 * Application code must explicitly invoke the <code>Font.dispose()</code> 
 * method to release the operating system resources managed by each instance
 * when those instances are no longer required.
 * </p>
 *
 * @see FontData
 * @see <a href="http://www.eclipse.org/swt/snippets/#font">Font snippets</a>
 * @see <a href="http://www.eclipse.org/swt/examples.php">SWT Examples: GraphicsExample, PaintExample</a>
 * @see <a href="http://www.eclipse.org/swt/">Sample code and further information</a>
 */
public final class Font extends Resource {

	/**
	 * the handle to the OS font resource
	 * (Warning: This field is platform dependent)
	 * <p>
	 * <b>IMPORTANT:</b> This field is <em>not</em> part of the SWT
	 * public API. It is marked public only so that it can be shared
	 * within the packages provided by SWT. It is not available on all
	 * platforms and should never be accessed from application code.
	 * </p>
	 * 
	 * @noreference This field is not intended to be referenced by clients.
	 */
	public byte[] handle;

Font(Device device) {
	super(device);
}

/**	 
 * Constructs a new font given a device and font data
 * which describes the desired font's appearance.
 * <p>
 * You must dispose the font when it is no longer required. 
 * </p>
 *
 * @param device the device to create the font on
 * @param fd the FontData that describes the desired font (must not be null)
 * 
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT - if device is null and there is no current device</li>
 *    <li>ERROR_NULL_ARGUMENT - if the fd argument is null</li>
 * </ul>
 * @exception SWTError <ul>
 *    <li>ERROR_NO_HANDLES - if a font could not be created from the given font data</li>
 * </ul>
 */
public Font(Device device, FontData fd) {
	super(device);
	if (fd == null) SWT.error(SWT.ERROR_NULL_ARGUMENT);
	init(fd.getName(), fd.getHeight(), fd.getStyle(), fd.stem);
	init();
}

/**	 
 * Constructs a new font given a device and an array
 * of font data which describes the desired font's
 * appearance.
 * <p>
 * You must dispose the font when it is no longer required. 
 * </p>
 *
 * @param device the device to create the font on
 * @param fds the array of FontData that describes the desired font (must not be null)
 * 
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT - if device is null and there is no current device</li>
 *    <li>ERROR_NULL_ARGUMENT - if the fds argument is null</li>
 *    <li>ERROR_INVALID_ARGUMENT - if the length of fds is zero</li>
 *    <li>ERROR_NULL_ARGUMENT - if any fd in the array is null</li>
 * </ul>
 * @exception SWTError <ul>
 *    <li>ERROR_NO_HANDLES - if a font could not be created from the given font data</li>
 * </ul>
 * 
 * @since 2.1
 */
public Font(Device device, FontData[] fds) {
	super(device);
	if (fds == null) SWT.error(SWT.ERROR_NULL_ARGUMENT);
	if (fds.length == 0) SWT.error(SWT.ERROR_INVALID_ARGUMENT);
	for (int i=0; i<fds.length; i++) {
		if (fds[i] == null) SWT.error(SWT.ERROR_INVALID_ARGUMENT);
	}
	FontData fd = fds[0];
	init(fd.getName(), fd.getHeight(), fd.getStyle(), fd.stem);
	init();
}
/**	 
 * Constructs a new font given a device, a font name,
 * the height of the desired font in points, and a font
 * style.
 * <p>
 * You must dispose the font when it is no longer required. 
 * </p>
 *
 * @param device the device to create the font on
 * @param name the name of the font (must not be null)
 * @param height the font height in points
 * @param style a bit or combination of NORMAL, BOLD, ITALIC
 * 
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT - if device is null and there is no current device</li>
 *    <li>ERROR_NULL_ARGUMENT - if the name argument is null</li>
 *    <li>ERROR_INVALID_ARGUMENT - if the height is negative</li>
 * </ul>
 * @exception SWTError <ul>
 *    <li>ERROR_NO_HANDLES - if a font could not be created from the given arguments</li>
 * </ul>
 */
public Font(Device device, String name, int height, int style) {
	super(device);
	if (name == null) SWT.error(SWT.ERROR_NULL_ARGUMENT);
	init(name, height, style, null);
	init();
}

void destroy() {
	handle = null;
}

/**
 * Compares the argument to the receiver, and returns true
 * if they represent the <em>same</em> object using a class
 * specific comparison.
 *
 * @param object the object to compare with this object
 * @return <code>true</code> if the object is the same as this object and <code>false</code> otherwise
 *
 * @see #hashCode
 */
public boolean equals(Object object) {
	if (object == this) return true;
	if (!(object instanceof Font)) return false;
	byte[] h = ((Font)object).handle;
	if (h == handle) return true;
	if (h == null || handle == null) return false;
	if (h.length != handle.length) return false;
	for (int i=0; i<h.length; i++) {
		if (handle[i] != h[i]) return false;
		if (handle[i] == 0) break;
	}
	return true;
}

/**
 * Returns an array of <code>FontData</code>s representing the receiver.
 * On Windows, only one FontData will be returned per font. On X however, 
 * a <code>Font</code> object <em>may</em> be composed of multiple X 
 * fonts. To support this case, we return an array of font data objects.
 *
 * @return an array of font data objects describing the receiver
 *
 * @exception SWTException <ul>
 *    <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 */
public FontData[] getFontData() {
	if (isDisposed()) SWT.error(SWT.ERROR_GRAPHIC_DISPOSED);
	return new FontData[]{new FontData(handle)};
}

/**
 * Returns an integer hash code for the receiver. Any two 
 * objects that return <code>true</code> when passed to 
 * <code>equals</code> must return the same value for this
 * method.
 *
 * @return the receiver's hash
 *
 * @see #equals
 */
public int hashCode () {
	if (handle == null) return 0;
	return handle.hashCode();
}

/**
 * Returns <code>true</code> if the font has been disposed,
 * and <code>false</code> otherwise.
 * <p>
 * This method gets the dispose state for the font.
 * When a font has been disposed, it is an error to
 * invoke any other method (except {@link #dispose()}) using the font.
 *
 * @return <code>true</code> when the font is disposed and <code>false</code> otherwise
 */
public boolean isDisposed() {
	return handle == null;
}

void init(String name, int height, int style, byte[] stem) {
	if (height < 0) SWT.error(SWT.ERROR_INVALID_ARGUMENT);
	if (stem != null) {
		handle = stem;
	} else {
		byte[] description = Converter.wcsToMbcs(null, name, true);
		int osStyle = 0;
		if ((style & SWT.BOLD) != 0) osStyle |= OS.PF_STYLE_BOLD;
		if ((style & SWT.ITALIC) != 0) osStyle |= OS.PF_STYLE_ITALIC;
		byte[] buffer = new byte[OS.MAX_FONT_TAG];
		if (OS.PfGenerateFontName(description, osStyle, height, buffer) != 0) handle = buffer;
		if (handle == null) {
			byte[] defaultFont = device.systemFont.handle;
			int fontID = OS.PfDecomposeStemToID(defaultFont);
			if (fontID != 0) {
				int desc = OS.PfFontDescription(fontID);
				int length = OS.strlen(desc);
				byte[] defaultFontName = new byte[length + 1];
				OS.memmove(defaultFontName, desc, length);
				OS.PfFreeFont(fontID);
				if (OS.PfGenerateFontName(defaultFontName, osStyle, height, buffer) != 0) handle = buffer;
			}
			if (handle == null) handle = defaultFont;
		}
	}
	if (handle == null)SWT.error(SWT.ERROR_NO_HANDLES);
}

public static Font photon_new(Device device, byte[] stem) {
	Font font = new Font(device);
	font.init(null, 0, 0, stem);
	return font;
}

/**
 * Returns a string containing a concise, human-readable
 * description of the receiver.
 *
 * @return a string representation of the receiver
 */
public String toString () {
	if (isDisposed()) return "Font {*DISPOSED*}";
	int index = 0;
	while (index < handle.length) {
		if (handle[index] == 0) break;
		index++;
	}
	String text = new String(handle, 0, index);
	return "Font {" + text + "}";
}

}