/*******************************************************************************
 * Copyright (c) 2000, 2003 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.jface.resource;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.MissingResourceException;
import java.util.ResourceBundle;
import java.util.Set;

import org.eclipse.jface.util.Assert;
import org.eclipse.swt.SWT;
import org.eclipse.swt.graphics.Font;
import org.eclipse.swt.graphics.FontData;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Shell;

/**
 * A font registry maintains a mapping between symbolic font names 
 * and SWT fonts.
 * <p>
 * A font registry owns all of the font objects registered
 * with it, and automatically disposes of them when the SWT Display
 * that creates the fonts is disposed. Because of this, clients do 
 * not need to (indeed, must not attempt to) dispose of font 
 * objects themselves.
 * </p>
 * <p>
 * A special constructor is provided for populating a font registry
 * from a property files using the standard Java resource bundle mechanism.
 * </p>
 * <p>
 * Methods are provided for registering listeners that will be kept
 * apprised of changes to list of registed fonts.
 * </p>
 * <p>
 * Clients may instantiate this class (it was not designed to be subclassed).
 * </p>
 * 
 * Since 3.0 this class extends ResourceRegistry.
 */
public class FontRegistry extends ResourceRegistry {
	
	/**
	 * FontRecord is a private helper class that holds onto a font
	 * and can be used to generate its bold and italic version. 
	 */
	private class FontRecord{
		
		Font baseFont;
		Font boldFont;
		Font italicFont;
		
		FontData[] baseData;
		
		/**
		 * Create a new instance of the receiver based on the 
		 * plain font and the data for it.
		 * @param plainFont The base looked up font.
		 * @param data The data used to look it up.
		 */
		FontRecord(Font plainFont, FontData[] data){
			baseFont = plainFont;
			baseData = data;
		}
		
		/**
		 * Dispose any of the fonts created for this record.
		 */
		void dispose(){
			baseFont.dispose();
			if(boldFont != null)
				boldFont.dispose();
			if(italicFont != null)
				italicFont.dispose();
		}
		
		/**
		 * Return the base Font.
		 * @return Font
		 */
		public Font getBaseFont() {
			return baseFont;
		}
		/**
		 * Return the bold Font. Create a bold version
		 * of the base font to get it.
		 * @return Font
		 */
		public Font getBoldFont() {
			if(boldFont != null)
				return boldFont;
			
			FontData[] boldData = getModifiedFontData(SWT.BOLD);
			boldFont = new Font(Display.getCurrent(),boldData);
			return boldFont;
		}
		
		/**
		 * Get a version of the base font data with the specified 
		 * style.
		 * @param style
		 * @return
		 * @todo Generated comment
		 */
		private FontData[] getModifiedFontData(int style){
			FontData[] styleData = new FontData[baseData.length];
			for (int i = 0; i < styleData.length; i++) {
				FontData base = baseData[i];
				styleData[i] = new FontData(base.getName(),base.getHeight(),base.getStyle() | style);
			}
			
			return styleData;
		}
		
		/**
		 * Return the italic Font. Create an italic version of the
		 * base font to get it.
		 * @return Font
		 */
		public Font getItalicFont() {
			if(italicFont != null)
				return italicFont;
			
			FontData[] italicData = getModifiedFontData(SWT.ITALIC);
			italicFont = new Font(Display.getCurrent(),italicData);
			return italicFont;
		}
		
		/**
		 * Add any fonts that were allocated for this record to the
		 * stale fonts. Anything that matches the default font will
		 * be skipped.
		 * @param defaultFont The system default.
		 */
		void addAllocatedFontsToStale(Font defaultFont){
			//Return all of the fonts allocated by the receiver.
			//if any of them are the defaultFont then don't bother.
			if(defaultFont != baseFont)
				staleFonts.add(baseFont);
			if(defaultFont != boldFont)
				staleFonts.add(baseFont);
			if(defaultFont != italicFont)
				staleFonts.add(baseFont);
		}
	}

    /**
	 * Table of known fonts, keyed by symbolic font name
	 * (key type: <code>String</code>, 
	 *  value type: <code>FontRecord</code>.
	 */
	private Map stringToFontRecord = new HashMap(7);
	/**
	 * Table of known font data, keyed by symbolic font name
	 * (key type: <code>String</code>, 
	 *  value type: <code>org.eclipse.swt.graphics.FontData[]</code>).
	 */
	private Map stringToFontData = new HashMap(7);

	/**
	 * Collection of Fonts that are now stale to be disposed
	 * when it is safe to do so (i.e. on shutdown).
	 * @see List
	 */
	private List staleFonts = new ArrayList();
	
	/**
	 * Runnable that cleans up the manager on disposal of the display.
	 */	
	protected Runnable displayRunnable = new Runnable() {
		public void run() {
			clearCaches();
		}
	};

	/**
	 * Creates an empty font registry.
	 * <p>
	 * There must be an SWT Display created in the current 
	 * thread before calling this method.
	 * </p>
	 */
	public FontRegistry() {
		Display display = Display.getCurrent();
		Assert.isNotNull(display);
		hookDisplayDispose(display);
	}
	/**
	 * Creates a font registry and initializes its content from
	 * a property file.
	 * <p>
	 * There must be an SWT Display created in the current 
	 * thread before calling this method.
	 * </p>
	 * <p>
	 * The OS name (retrieved using <code>System.getProperty("os.name")</code>)
	 * is converted to lowercase, purged of whitespace, and appended 
	 * as suffix (separated by an underscore <code>'_'</code>) to the given 
	 * location string to yield the base name of a resource bundle
	 * acceptable to <code>ResourceBundle.getBundle</code>.
	 * The standard Java resource bundle mechanism is then used to locate
	 * and open the appropriate properties file, taking into account
	 * locale specific variations.
	 * </p>
	 * <p>
	 * For example, on the Windows 2000 operating system the location string
	 * <code>"com.example.myapp.Fonts"</code> yields the base name 
	 * <code>"com.example.myapp.Fonts_windows2000"</code>. For the US English locale,
	 * this further elaborates to the resource bundle name
	 * <code>"com.example.myapp.Fonts_windows2000_en_us"</code>.
	 * </p>
	 * <p>
	 * If no appropriate OS-specific resource bundle is found, the
	 * process is repeated using the location as the base bundle name.
	 * </p>
	 * <p>
	 * The property file contains entries that look like this:
	 * <pre>
	 *	textfont.0=MS Sans Serif-regular-10
	 *	textfont.1=Times New Roman-regular-10
	 *	
	 *	titlefont.0=MS Sans Serif-regular-12
	 *	titlefont.1=Times New Roman-regular-12
	 * </pre>
	 * Each entry maps a symbolic font names (the font registry keys) with
	 * a "<code>.<it>n</it></code> suffix to standard font names
	 * on the right. The suffix indicated order of preference: 
	 * "<code>.0</code>" indicates the first choice,
	 * "<code>.1</code>" indicates the second choice, and so on.
	 * </p>
	 * The following example shows how to use the font registry:
	 * <pre>
	 *	FontRegistry registry = new FontRegistry("com.example.myapp.fonts");
	 *  Font font = registry.get("textfont");
	 *  control.setFont(font);
	 *  ...
	 * </pre>
	 *
	 * @param location the name of the resource bundle
	 * @param the ClassLoader to use to find the resource bundle
	 * @exception MissingResourceException if the resource bundle cannot be found
	 * @since 2.1
	 */
	public FontRegistry(String location, ClassLoader loader)
		throws MissingResourceException {
		Display display = Display.getCurrent();
		Assert.isNotNull(display);
		// FIXE: need to respect loader
		//readResourceBundle(location, loader);
		readResourceBundle(location);

		hookDisplayDispose(display);
	}

	/**
	 * Load the FontRegistry using the ClassLoader from the PlatformUI
	 * plug-in
	 */
	public FontRegistry(String location) throws MissingResourceException {
		// FIXE:
		//	this(location, WorkbenchPlugin.getDefault().getDescriptor().getPluginClassLoader());
		this(location, null);
	}

	/**
	 * Read the resource bundle at location. Look for a file with the
	 * extension _os_ws first, then _os then just the name.
	 * @param location - String - the location of the file.
	 */

	private void readResourceBundle(String location) {
		String osname = System.getProperty("os.name").trim(); //$NON-NLS-1$
		String wsname = SWT.getPlatform();
		osname = StringConverter.removeWhiteSpaces(osname).toLowerCase();
		wsname = StringConverter.removeWhiteSpaces(wsname).toLowerCase();
		String OSLocation = location;
		String WSLocation = location;
		ResourceBundle bundle = null;
		if (osname != null) {
			OSLocation = location + "_" + osname; //$NON-NLS-1$
			if (wsname != null)
				WSLocation = OSLocation + "_" + wsname; //$NON-NLS-1$
		}

		try {
			bundle = ResourceBundle.getBundle(WSLocation);
			readResourceBundle(bundle, WSLocation);
		} catch (MissingResourceException wsException) {
			try {
				bundle = ResourceBundle.getBundle(OSLocation);
				readResourceBundle(bundle, WSLocation);
			} catch (MissingResourceException osException) {
				if (location != OSLocation) {
					bundle = ResourceBundle.getBundle(location);
					readResourceBundle(bundle, WSLocation);
				} else
					throw osException;
			}
		}
	}

	/**
	 * Creates an empty font registry.
	 *
	 * @param display the Display
	 */
	public FontRegistry(Display display) {
		Assert.isNotNull(display);
		hookDisplayDispose(display);
	}

	/**
	 * Find the first valid fontData in the provided list. 
	 * If none are valid return the first one regardless.
	 * If the list is empty return null.
	 * Return null if one cannot be found.
	 * @deprecated use bestDataArray in order to support 
	 * Motif multiple entry fonts.
	 */
	public FontData bestData(FontData[] fonts, Display display) {
		for (int i = 0; i < fonts.length; i++) {
			FontData fd = fonts[i];

			if (fd == null)
				break;

			FontData[] fixedFonts = display.getFontList(fd.getName(), false);
			if (isFixedFont(fixedFonts, fd)) {
				return fd;
			}

			FontData[] scalableFonts = display.getFontList(fd.getName(), true);
			if (scalableFonts.length > 0) {
				return fd;
			}
		}

		//None of the provided datas are valid. Return the
		//first one as it is at least the first choice.
		if (fonts.length > 0)
			return fonts[0];
		else
			//Nothing specified 
			return null;
	}

	/**
	 * Find the first valid fontData in the provided list. 
	 * If none are valid return the first one regardless.
	 * If the list is empty return null.
	 */
	public FontData[] bestDataArray(FontData[] fonts, Display display) {

		FontData bestData = bestData(fonts, display);
		if (bestData == null)
			return null;
		else {
			FontData[] datas = new FontData[1];
			datas[0] = bestData;
			return datas;
		}
	}

	/**
	 * Creates a new font with the given font datas or <code>null</code>
	 * if there is no data.
	 * @return FontRecord for the new Font or <code>null</code>.
	 */
	private FontRecord createFont(String symbolicName, FontData[] fonts) {
		Display display = Display.getCurrent();
		if(display == null)
			return null;
			
		FontData[] validData = bestDataArray(fonts, display);
		if (validData == null) {
			//Nothing specified 
			return null;
		} else {
			//Do not fire the update from creation as it is not a property change
			put(symbolicName, validData, false);
			Font newFont = new Font(display, validData);
			return new FontRecord(newFont,validData);
		}
	}
	
	/**
	 * Calculates the default font and returns the result
	 */
	Font calculateDefaultFont() {
		Display current = Display.getCurrent();
		if (current == null) {
			Shell shell = new Shell();
			Font font = new Font(null, shell.getFont().getFontData());
			shell.dispose();
			return font;
		} else
			return new Font(current, current.getSystemFont().getFontData());
	}
	
	/**
	 * Returns the default font data.  Creates it if necessary.
	 * @return Font
	 */
	public Font defaultFont() {
		return defaultFontRecord().getBaseFont();
	}
	
	/**
	 * Returns the default font record.
	 */
	private FontRecord defaultFontRecord() {
		
		FontRecord record = (FontRecord) stringToFontRecord.get(JFaceResources.DEFAULT_FONT);
		if(record == null){
			Font defaultFont = calculateDefaultFont();
			record = createFont(JFaceResources.DEFAULT_FONT,defaultFont.getFontData());
			stringToFontRecord.put(JFaceResources.DEFAULT_FONT,record);
		}
		return record;
	}
	
	/**
	 * Returns the default font data.  Creates it if necessary.
	 */
	private FontData[] defaultFontData() {
		return defaultFontRecord().baseData;
	}
	
	/**
	 * Returns the font data associated with the given symbolic font name.
	 * Returns the default font data if there is no special value associated
	 * with that name.
	 *
	 * @param symbolicName symbolic font name
	 * @return the font
	 */
	public FontData[] getFontData(String symbolicName) {

		Assert.isNotNull(symbolicName);
		Object result = stringToFontData.get(symbolicName);
		if (result == null)
			return defaultFontData();

		return (FontData[]) result;
	}
	
	/**
	 * Returns the font associated with the given symbolic font name.
	 * Returns the default font if there is no special value associated
	 * with that name.
	 *
	 * @param symbolicName symbolic font name
	 * @return the font
	 */
	public Font get(String symbolicName) {

		return getFontRecord(symbolicName).getBaseFont();
	}
	
	/**
	 * Returns the bold font associated with the given symbolic font name.
	 * Returns the bolded default font if there is no special value associated
	 * with that name.
	 *
	 * @param symbolicName symbolic font name
	 * @return the font
	 * @since 3.0
	 */
	public Font getBold(String symbolicName) {

		return getFontRecord(symbolicName).getBoldFont();
	}
	
	/**
	 * Returns the italic font associated with the given symbolic font name.
	 * Returns the italic default font if there is no special value associated
	 * with that name.
	 *
	 * @param symbolicName symbolic font name
	 * @return the font
	 * @since 3.0
	 */
	public Font getItalic(String symbolicName) {

		return getFontRecord(symbolicName).getItalicFont();
	}
	
	/**
	 * Return the font record for the key.
	 * @param symbolicName The key for the record.
	 * @return FontRecird
	 */
	private FontRecord getFontRecord(String symbolicName){
		Assert.isNotNull(symbolicName);
		Object result = stringToFontRecord.get(symbolicName);
		if (result != null)
			return (FontRecord) result;

		result = stringToFontData.get(symbolicName);
		
		FontRecord fontRecord;
		
		if (result == null)
			fontRecord = defaultFontRecord();
		else 
			fontRecord = createFont(symbolicName, (FontData[]) result);
			
		if (fontRecord == null) // create may have failed.  Ensure we have a valid font.
			fontRecord = defaultFontRecord();
		
		stringToFontRecord.put(symbolicName, fontRecord);
		return fontRecord;

	}


	/* (non-Javadoc)
	 * @see org.eclipse.jface.resource.ResourceRegistry#getKeySet()
	 */
	public Set getKeySet() {
	    return Collections.unmodifiableSet(stringToFontData.keySet());
	}	

	/* (non-Javadoc)
	 * @see org.eclipse.jface.resource.ResourceRegistry#hasValueFor(java.lang.String)
	 */
	public boolean hasValueFor(String fontKey){
		return stringToFontData.containsKey(fontKey);
	}

	/* (non-Javadoc)
	 * @see org.eclipse.jface.resource.ResourceRegistry#clearCaches()
	 */
	protected void clearCaches() {

		Iterator iterator = stringToFontRecord.values().iterator();
		while (iterator.hasNext()) {
			Object next = iterator.next();
			((FontRecord) next).dispose();
		}
		
		disposeFonts(staleFonts.iterator());
		stringToFontRecord.clear();
		staleFonts.clear();
	}
	
	/**
	 * Dispose of all of the fonts in this iterator.
	 * @param Iterator over Collection of Font
	 */
	private void disposeFonts(Iterator iterator) {
		while (iterator.hasNext()) {
			Object next = iterator.next();
			((Font) next).dispose();
		}
	}
	
	/**
	 * Hook a dispose listener on the SWT display.
	 */
	private void hookDisplayDispose(Display display) {
		display.disposeExec(displayRunnable);
	}
	
	/**
	 * Checks whether the given font is in the list of fixed fonts.
	 */
	private boolean isFixedFont(FontData[] fixedFonts, FontData fd) {
		// Can't use FontData.equals() since some values aren't
		// set if a fontdata isn't used.
		int height = fd.getHeight();
		String name = fd.getName();
		for (int i = 0; i < fixedFonts.length; i++) {
			FontData fixed = fixedFonts[i];
			if (fixed.getHeight() == height && fixed.getName().equals(name))
				return true;
		}
		return false;
	}
	/**
	 * Converts a String into a FontData object.
	 */
	private FontData makeFontData(String value)
		throws MissingResourceException {
		try {
			return StringConverter.asFontData(value.trim());
		} catch (DataFormatException e) {
			throw new MissingResourceException("Wrong font data format. Value is: \"" + value + "\"", getClass().getName(), value); //$NON-NLS-2$//$NON-NLS-1$
		}
	}

	/**
	 * Adds (or replaces) a font to this font registry under the given
	 * symbolic name.
	 * <p>
	 * A property change event is reported whenever the mapping from
	 * a symbolic name to a font changes. The source of the event is
	 * this registry; the property name is the symbolic font name.
	 * </p>
	 *
	 * @param symbolicName the symbolic font name
	 * @param fontData an Array of FontData
	 * @param update - fire a font mapping changed if true. False
	 * 	if this method is called from the get method as no setting
	 *  has changed.
	 */
	public void put(String symbolicName, FontData[] fontData) {
		put(symbolicName, fontData, true);
	}

	/**
	 * Adds (or replaces) a font to this font registry under the given
	 * symbolic name.
	 * <p>
	 * A property change event is reported whenever the mapping from
	 * a symbolic name to a font changes. The source of the event is
	 * this registry; the property name is the symbolic font name.
	 * </p>
	 *
	 * @param symbolicName the symbolic font name
	 * @param fontData an Array of FontData
	 * @param update - fire a font mapping changed if true. False
	 * 	if this method is called from the get method as no setting
	 *  has changed.
	 */
	private void put(
		String symbolicName,
		FontData[] fontData,
		boolean update) {

		Assert.isNotNull(symbolicName);
		Assert.isNotNull(fontData);

		FontData[] existing = (FontData[]) stringToFontData.get(symbolicName);
		if (Arrays.equals(existing, fontData))
			return;

		FontRecord oldFont = (FontRecord) stringToFontRecord.remove(symbolicName);
		stringToFontData.put(symbolicName, fontData);
		if (update)
			fireMappingChanged(symbolicName,existing,fontData);

		if (oldFont != null)
			oldFont.addAllocatedFontsToStale(defaultFontRecord().getBaseFont());
	}
	/**
	 * Reads the resource bundle.  This puts FontData[] objects
	 * in the mapping table.  These will lazily be turned into
	 * real Font objects when requested.
	 */
	private void readResourceBundle(ResourceBundle bundle, String bundleName)
		throws MissingResourceException {
		Enumeration keys = bundle.getKeys();
		while (keys.hasMoreElements()) {
			String key = (String) keys.nextElement();
			int pos = key.lastIndexOf('.');
			if (pos == -1) {
				stringToFontData.put(
					key,
					new FontData[] { makeFontData(bundle.getString(key))});
			} else {
				String name = key.substring(0, pos);
				int i = 0;
				try {
					i = Integer.parseInt(key.substring(pos + 1));
				} catch (NumberFormatException e) {
					//Panic the file can not be parsed.
					throw new MissingResourceException("Wrong key format ", bundleName, key); //$NON-NLS-1$
				}
				FontData[] elements = (FontData[]) stringToFontData.get(name);
				if (elements == null) {
					elements = new FontData[8];
					stringToFontData.put(name, elements);
				}
				if (i > elements.length) {
					FontData[] na = new FontData[i + 8];
					System.arraycopy(elements, 0, na, 0, elements.length);
					elements = na;
					stringToFontData.put(name, elements);
				}
				elements[i] = makeFontData(bundle.getString(key));
			}
		}
	}
}