/*
 * Copyright (c) 2003-2004 Christopher Lenz 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:
 *     Christopher Lenz - initial API and implementation
 * 
 * $Id: OverlayPreferenceStore.java,v 1.1 2004-09-02 18:11:51 jsurfer Exp $
 */

package net.sourceforge.phpeclipse.css.ui.internal.preferences;

import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

import org.eclipse.jface.preference.IPreferenceStore;
import org.eclipse.jface.preference.PreferenceStore;
import org.eclipse.jface.util.IPropertyChangeListener;
import org.eclipse.jface.util.PropertyChangeEvent;

public class OverlayPreferenceStore implements IPreferenceStore {

	// Inner Classes -----------------------------------------------------------

	/**
	 * Descriptor used to denote data types.
	 */
	public static final class Type {
		protected Type() {
		}
	}

	/**
	 * Data structure for the overlay key.
	 */
	public static class OverlayKey {

		private Type fType;
		private String fKey;

		public OverlayKey(Type type, String key) {
			this.fType = type;
			this.fKey = key;
		}
	}

	/**
	 * @see IPropertyChangeListener
	 */
	private class PropertyListener implements IPropertyChangeListener {

		/**
		 * @see IPropertyChangeListener#propertyChange(PropertyChangeEvent)
		 */
		public void propertyChange(PropertyChangeEvent event) {
			OverlayKey key = findOverlayKey(event.getProperty());
			if (key != null) {
				propagateProperty(fParent, key, fStore);
			}
		}
	}

	// Constants ---------------------------------------------------------------

	/**
	 * Boolean property type.
	 */
	public static final Type BOOLEAN = new Type();

	/**
	 * Double property type.
	 */
	public static final Type DOUBLE = new Type();

	/**
	 * Floating point property type.
	 */
	public static final Type FLOAT = new Type();

	/**
	 * Integer property type.
	 */
	public static final Type INT = new Type();

	/**
	 * Long integer property type.
	 */
	public static final Type LONG = new Type();

	/**
	 * String property type.
	 */
	public static final Type STRING = new Type();

	// Instance Variables ------------------------------------------------------

	/**
	 * The parent preference store.
	 */
	private IPreferenceStore fParent;

	/**
	 * The underlying preference store.
	 */
	private IPreferenceStore fStore;

	/**
	 * The keys of this store.
	 */
	private List fOverlayKeys = new ArrayList();

	/**
	 * The property listener.
	 */
	private PropertyListener fPropertyListener;

	// Constructors ------------------------------------------------------------

	/**
	 * Creates and returns a new overlay preference store.
	 * 
	 * @param parent the parent preference store
	 */
	public OverlayPreferenceStore(IPreferenceStore parent) {
		this.fParent = parent;
		fStore = new PreferenceStore();
	}

	// Public Methods ----------------------------------------------------------

	public void addKey(Type type, String key) {
		this.fOverlayKeys.add(new OverlayKey(type, key));
	}
	public void addBooleanKey(String key) {
		addKey(BOOLEAN, key);
	}
	public void addDoubleKey(String key) {
		addKey(DOUBLE, key);
	}
	public void addFloatKey(String key) {
		addKey(FLOAT, key);
	}
	public void addIntKey(String key) {
		addKey(INT, key);
	}
	public void addLongKey(String key) {
		addKey(LONG, key);
	}
	public void addStringKey(String key) {
		addKey(STRING, key);
	}

	/**
	 * Propagates all overlay keys from this store to the parent store.
	 */
	public void propagate() {
		for (Iterator i = fOverlayKeys.iterator(); i.hasNext(); ) {
			propagateProperty(fStore, (OverlayKey) i.next(), fParent);
		}
	}

	/**
	 * Loads the values from the parent into this store.
	 */
	public void load() {
		for (Iterator i = fOverlayKeys.iterator(); i.hasNext(); ) {
			loadProperty(fParent, (OverlayKey) i.next(), fStore, true);
		}
	}

	/**
	 * Loads the default values.
	 */
	public void loadDefaults() {
		for (Iterator i = fOverlayKeys.iterator(); i.hasNext(); ) {
			setToDefault(((OverlayKey) i.next()).fKey);
		}
	}

	/**
	 * Starts to listen for changes.
	 */
	public void startListening() {
		if (fPropertyListener == null) {
			fPropertyListener = new PropertyListener();
			fParent.addPropertyChangeListener(fPropertyListener);
		}
	}

	/**
	 * Stops to listen for changes.
	 */
	public void stopListening() {
		if (fPropertyListener != null) {
			fParent.removePropertyChangeListener(fPropertyListener);
			fPropertyListener = null;
		}
	}

	// IPreferenceStore Implementation -----------------------------------------

	/**
	 * @see IPreferenceStore#addPropertyChangeListener(org.eclipse.jface.util.IPropertyChangeListener)
	 */
	public void addPropertyChangeListener(IPropertyChangeListener listener) {
		fStore.addPropertyChangeListener(listener);
	}

	/**
	 * @see IPreferenceStore#removePropertyChangeListener(org.eclipse.jface.util.IPropertyChangeListener)
	 */
	public void removePropertyChangeListener(IPropertyChangeListener listener) {
		fStore.removePropertyChangeListener(listener);
	}

	/**
	 * @see IPreferenceStore#firePropertyChangeEvent(java.lang.String, java.lang.Object, java.lang.Object)
	 */
	public void firePropertyChangeEvent(String name, Object oldValue,
		Object newValue) {
		fStore.firePropertyChangeEvent(name, oldValue, newValue);
	}

	/**
	 * @see IPreferenceStore#contains(java.lang.String)
	 */
	public boolean contains(String name) {
		return fStore.contains(name);
	}

	/**
	 * @see IPreferenceStore#getBoolean(java.lang.String)
	 */
	public boolean getBoolean(String name) {
		return fStore.getBoolean(name);
	}

	/**
	 * @see IPreferenceStore#getDefaultBoolean(java.lang.String)
	 */
	public boolean getDefaultBoolean(String name) {
		return fStore.getDefaultBoolean(name);
	}

	/**
	 * @see IPreferenceStore#getDefaultDouble(java.lang.String)
	 */
	public double getDefaultDouble(String name) {
		return fStore.getDefaultDouble(name);
	}

	/**
	 * @see IPreferenceStore#getDefaultFloat(String)
	 */
	public float getDefaultFloat(String name) {
		return fStore.getDefaultFloat(name);
	}

	/**
	 * @see IPreferenceStore#getDefaultInt(String)
	 */
	public int getDefaultInt(String name) {
		return fStore.getDefaultInt(name);
	}

	/**
	 * @see IPreferenceStore#getDefaultLong(String)
	 */
	public long getDefaultLong(String name) {
		return fStore.getDefaultLong(name);
	}

	/**
	 * @see IPreferenceStore#getDefaultString(String)
	 */
	public String getDefaultString(String name) {
		return fStore.getDefaultString(name);
	}

	/**
	 * @see IPreferenceStore#getDouble(String)
	 */
	public double getDouble(String name) {
		return fStore.getDouble(name);
	}

	/**
	 * @see IPreferenceStore#getFloat(String)
	 */
	public float getFloat(String name) {
		return fStore.getFloat(name);
	}

	/**
	 * @see IPreferenceStore#getInt(String)
	 */
	public int getInt(String name) {
		return fStore.getInt(name);
	}

	/**
	 * @see IPreferenceStore#getLong(String)
	 */
	public long getLong(String name) {
		return fStore.getLong(name);
	}

	/**
	 * @see IPreferenceStore#getString(String)
	 */
	public String getString(String name) {
		return fStore.getString(name);
	}

	/**
	 * @see IPreferenceStore#isDefault(String)
	 */
	public boolean isDefault(String name) {
		return fStore.isDefault(name);
	}

	/**
	 * @see IPreferenceStore#needsSaving()
	 */
	public boolean needsSaving() {
		return fStore.needsSaving();
	}

	/**
	 * @see IPreferenceStore#putValue(String, String)
	 */
	public void putValue(String name, String value) {
		if (covers(name)) {
			fStore.putValue(name, value);
		}
	}

	/**
	 * @see IPreferenceStore#setDefault(String, double)
	 */
	public void setDefault(String name, double value) {
		if (covers(name)) {
			fStore.setDefault(name, value);
		}
	}

	/**
	 * @see IPreferenceStore#setDefault(String, float)
	 */
	public void setDefault(String name, float value) {
		if (covers(name)) {
			fStore.setDefault(name, value);
		}
	}

	/**
	 * @see IPreferenceStore#setDefault(String, int)
	 */
	public void setDefault(String name, int value) {
		if (covers(name)) {
			fStore.setDefault(name, value);
		}
	}

	/**
	 * @see IPreferenceStore#setDefault(String, long)
	 */
	public void setDefault(String name, long value) {
		if (covers(name)) {
			fStore.setDefault(name, value);
		}
	}

	/**
	 * @see IPreferenceStore#setDefault(String, String)
	 */
	public void setDefault(String name, String value) {
		if (covers(name)) {
			fStore.setDefault(name, value);
		}
	}

	/**
	 * @see IPreferenceStore#setDefault(String, boolean)
	 */
	public void setDefault(String name, boolean value) {
		if (covers(name)) {
			fStore.setDefault(name, value);
		}
	}

	/**
	 * @see IPreferenceStore#setToDefault(String)
	 */
	public void setToDefault(String name) {
		fStore.setToDefault(name);
	}

	/**
	 * @see IPreferenceStore#setValue(String, double)
	 */
	public void setValue(String name, double value) {
		if (covers(name)) {
			fStore.setValue(name, value);
		}
	}

	/**
	 * @see IPreferenceStore#setValue(String, float)
	 */
	public void setValue(String name, float value) {
		if (covers(name)) {
			fStore.setValue(name, value);
		}
	}

	/**
	 * @see IPreferenceStore#setValue(String, int)
	 */
	public void setValue(String name, int value) {
		if (covers(name)) {
			fStore.setValue(name, value);
		}
	}

	/**
	 * @see IPreferenceStore#setValue(String, long)
	 */
	public void setValue(String name, long value) {
		if (covers(name)) {
			fStore.setValue(name, value);
		}
	}

	/**
	 * @see IPreferenceStore#setValue(String, String)
	 */
	public void setValue(String name, String value) {
		if (covers(name)) {
			fStore.setValue(name, value);
		}
	}

	/**
	 * @see IPreferenceStore#setValue(String, boolean)
	 */
	public void setValue(String name, boolean value) {
		if (covers(name)) {
			fStore.setValue(name, value);
		}
	}

	// Protected Methods -------------------------------------------------------

	/**
	 * Tries to find and return the overlay key for the given preference key
	 * string.
	 * 
	 * @param key the preference key string
	 * @return the overlay key or <code>null</code> if none can be found
	 */
	protected final OverlayKey findOverlayKey(String key) {
		for (Iterator i = fOverlayKeys.iterator(); i.hasNext(); ) {
			OverlayKey k = (OverlayKey) i.next();
			if (k.fKey.equals(key)) {
				return k;
			}
		}
		return null;
	}

	/**
	 * Propagates the given overlay key from the orgin to the target preference
	 * store.
	 * 
	 * @param origin the source preference store
	 * @param key the overlay key
	 * @param target the preference store to which the key is propagated
	 */
	protected final void propagateProperty(IPreferenceStore origin,
		OverlayKey key, IPreferenceStore target) {
		if (origin.isDefault(key.fKey)) {
			if (!target.isDefault(key.fKey)) {
				target.setToDefault(key.fKey);
			}
			return;
		}
		Type d = key.fType;
		if (BOOLEAN == d) {
			boolean originValue = origin.getBoolean(key.fKey);
			boolean targetValue = target.getBoolean(key.fKey);
			if (targetValue != originValue) {
				target.setValue(key.fKey, originValue);
			}
		} else if (DOUBLE == d) {
			double originValue = origin.getDouble(key.fKey);
			double targetValue = target.getDouble(key.fKey);
			if (targetValue != originValue) {
				target.setValue(key.fKey, originValue);
			}
		} else if (FLOAT == d) {
			float originValue = origin.getFloat(key.fKey);
			float targetValue = target.getFloat(key.fKey);
			if (targetValue != originValue) {
				target.setValue(key.fKey, originValue);
			}
		} else if (INT == d) {
			int originValue = origin.getInt(key.fKey);
			int targetValue = target.getInt(key.fKey);
			if (targetValue != originValue) {
				target.setValue(key.fKey, originValue);
			}
		} else if (LONG == d) {
			long originValue = origin.getLong(key.fKey);
			long targetValue = target.getLong(key.fKey);
			if (targetValue != originValue) {
				target.setValue(key.fKey, originValue);
			}
		} else if (STRING == d) {
			String originValue = origin.getString(key.fKey);
			String targetValue = target.getString(key.fKey);
			if ((targetValue != null) && (originValue != null)
			 && !targetValue.equals(originValue)) {
				target.setValue(key.fKey, originValue);
			}
		}
	}

	// Private Methods ---------------------------------------------------------

	/**
	 * Tells whether the given preference key string is
	 * covered by this overlay store.
	 * 
	 * @param key the preference key string
	 * @return <code>true</code> if this overlay store covers the given key
	 */
	private boolean covers(String key) {
		return (findOverlayKey(key) != null);
	}

	/**
	 * Loads the given key from the orgin into the target.
	 * 
	 * @param orgin the source preference store
	 * @param key the overlay key
	 * @param target the preference store to which the key is propagated
	 * @param forceInitialization if <code>true</code> the value in the target
	 *        gets initialized before loading
	 */
	private void loadProperty(IPreferenceStore orgin, OverlayKey key,
		IPreferenceStore target, boolean forceInitialization) {
		Type d = key.fType;
		if (BOOLEAN == d) {
			if (forceInitialization) {
				target.setValue(key.fKey, true);
			}
			target.setValue(key.fKey, orgin.getBoolean(key.fKey));
			target.setDefault(key.fKey, orgin.getDefaultBoolean(key.fKey));
		} else if (DOUBLE == d) {
			if (forceInitialization) {
				target.setValue(key.fKey, 1.0D);
			}
			target.setValue(key.fKey, orgin.getDouble(key.fKey));
			target.setDefault(key.fKey, orgin.getDefaultDouble(key.fKey));
		} else if (FLOAT == d) {
			if (forceInitialization) {
				target.setValue(key.fKey, 1.0F);
			}
			target.setValue(key.fKey, orgin.getFloat(key.fKey));
			target.setDefault(key.fKey, orgin.getDefaultFloat(key.fKey));
		} else if (INT == d) {
			if (forceInitialization) {
				target.setValue(key.fKey, 1);
			}
			target.setValue(key.fKey, orgin.getInt(key.fKey));
			target.setDefault(key.fKey, orgin.getDefaultInt(key.fKey));
		} else if (LONG == d) {
			if (forceInitialization) {
				target.setValue(key.fKey, 1L);
			}
			target.setValue(key.fKey, orgin.getLong(key.fKey));
			target.setDefault(key.fKey, orgin.getDefaultLong(key.fKey));
		} else if (STRING == d) {
			if (forceInitialization) {
				target.setValue(key.fKey, "1"); //$NON-NLS-1$
			}
			target.setValue(key.fKey, orgin.getString(key.fKey));
			target.setDefault(key.fKey, orgin.getDefaultString(key.fKey));
		}
	}

}