/*******************************************************************************
 * Copyright (c) 2000, 2006 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.jface.preference;

import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.PrintStream;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.Enumeration;
import java.util.Properties;

import org.eclipse.core.commands.common.EventManager;
import org.eclipse.jface.resource.JFaceResources;
import org.eclipse.core.runtime.Assert;
import org.eclipse.jface.util.IPropertyChangeListener;
import org.eclipse.jface.util.PropertyChangeEvent;
import org.eclipse.jface.util.SafeRunnable;

/**
 * A concrete preference store implementation based on an internal
 * <code>java.util.Properties</code> object, with support for persisting the
 * non-default preference values to files or streams.
 * <p>
 * This class was not designed to be subclassed.
 * </p>
 * 
 * @see IPreferenceStore
 */
public class PreferenceStore extends EventManager implements
		IPersistentPreferenceStore {

	/**
	 * The mapping from preference name to preference value (represented as
	 * strings).
	 */
	private Properties properties;

	/**
	 * The mapping from preference name to default preference value (represented
	 * as strings); <code>null</code> if none.
	 */
	private Properties defaultProperties;

	/**
	 * Indicates whether a value as been changed by <code>setToDefault</code>
	 * or <code>setValue</code>; initially <code>false</code>.
	 */
	private boolean dirty = false;

	/**
	 * The file name used by the <code>load</code> method to load a property
	 * file. This filename is used to save the properties file when
	 * <code>save</code> is called.
	 */
	private String filename;

	/**
	 * Creates an empty preference store.
	 * <p>
	 * Use the methods <code>load(InputStream)</code> and
	 * <code>save(InputStream)</code> to load and store this preference store.
	 * </p>
	 * 
	 * @see #load(InputStream)
	 * @see #save(OutputStream, String)
	 */
	public PreferenceStore() {
		defaultProperties = new Properties();
		properties = new Properties(defaultProperties);
	}

	/**
	 * Creates an empty preference store that loads from and saves to the a
	 * file.
	 * <p>
	 * Use the methods <code>load()</code> and <code>save()</code> to load
	 * and store this preference store.
	 * </p>
	 * 
	 * @param filename
	 *            the file name
	 * @see #load()
	 * @see #save()
	 */
	public PreferenceStore(String filename) {
		this();
		Assert.isNotNull(filename);
		this.filename = filename;
	}

	/*
	 * (non-Javadoc) Method declared on IPreferenceStore.
	 */
	public void addPropertyChangeListener(IPropertyChangeListener listener) {
		addListenerObject(listener);
	}

	/*
	 * (non-Javadoc) Method declared on IPreferenceStore.
	 */
	public boolean contains(String name) {
		return (properties.containsKey(name) || defaultProperties
				.containsKey(name));
	}

	/*
	 * (non-Javadoc) Method declared on IPreferenceStore.
	 */
	public void firePropertyChangeEvent(String name, Object oldValue,
			Object newValue) {
		final Object[] finalListeners = getListeners();
		// Do we need to fire an event.
		if (finalListeners.length > 0
				&& (oldValue == null || !oldValue.equals(newValue))) {
			final PropertyChangeEvent pe = new PropertyChangeEvent(this, name,
					oldValue, newValue);
			for (int i = 0; i < finalListeners.length; ++i) {
				final IPropertyChangeListener l = (IPropertyChangeListener) finalListeners[i];
				SafeRunnable.run(new SafeRunnable(JFaceResources
						.getString("PreferenceStore.changeError")) { //$NON-NLS-1$
							public void run() {
								l.propertyChange(pe);
							}
						});
			}
		}
	}

	/*
	 * (non-Javadoc) Method declared on IPreferenceStore.
	 */
	public boolean getBoolean(String name) {
		return getBoolean(properties, name);
	}

	/**
	 * Helper function: gets boolean for a given name.
	 * 
	 * @param p
	 * @param name
	 * @return boolean
	 */
	private boolean getBoolean(Properties p, String name) {
		String value = p != null ? p.getProperty(name) : null;
		if (value == null) {
			return BOOLEAN_DEFAULT_DEFAULT;
		}
		if (value.equals(IPreferenceStore.TRUE)) {
			return true;
		}
		return false;
	}

	/*
	 * (non-Javadoc) Method declared on IPreferenceStore.
	 */
	public boolean getDefaultBoolean(String name) {
		return getBoolean(defaultProperties, name);
	}

	/*
	 * (non-Javadoc) Method declared on IPreferenceStore.
	 */
	public double getDefaultDouble(String name) {
		return getDouble(defaultProperties, name);
	}

	/*
	 * (non-Javadoc) Method declared on IPreferenceStore.
	 */
	public float getDefaultFloat(String name) {
		return getFloat(defaultProperties, name);
	}

	/*
	 * (non-Javadoc) Method declared on IPreferenceStore.
	 */
	public int getDefaultInt(String name) {
		return getInt(defaultProperties, name);
	}

	/*
	 * (non-Javadoc) Method declared on IPreferenceStore.
	 */
	public long getDefaultLong(String name) {
		return getLong(defaultProperties, name);
	}

	/*
	 * (non-Javadoc) Method declared on IPreferenceStore.
	 */
	public String getDefaultString(String name) {
		return getString(defaultProperties, name);
	}

	/*
	 * (non-Javadoc) Method declared on IPreferenceStore.
	 */
	public double getDouble(String name) {
		return getDouble(properties, name);
	}

	/**
	 * Helper function: gets double for a given name.
	 * 
	 * @param p
	 * @param name
	 * @return double
	 */
	private double getDouble(Properties p, String name) {
		String value = p != null ? p.getProperty(name) : null;
		if (value == null) {
			return DOUBLE_DEFAULT_DEFAULT;
		}
		double ival = DOUBLE_DEFAULT_DEFAULT;
		try {
			ival = new Double(value).doubleValue();
		} catch (NumberFormatException e) {
		}
		return ival;
	}

	/*
	 * (non-Javadoc) Method declared on IPreferenceStore.
	 */
	public float getFloat(String name) {
		return getFloat(properties, name);
	}

	/**
	 * Helper function: gets float for a given name.
	 * 
	 * @param p
	 * @param name
	 * @return float
	 */
	private float getFloat(Properties p, String name) {
		String value = p != null ? p.getProperty(name) : null;
		if (value == null) {
			return FLOAT_DEFAULT_DEFAULT;
		}
		float ival = FLOAT_DEFAULT_DEFAULT;
		try {
			ival = new Float(value).floatValue();
		} catch (NumberFormatException e) {
		}
		return ival;
	}

	/*
	 * (non-Javadoc) Method declared on IPreferenceStore.
	 */
	public int getInt(String name) {
		return getInt(properties, name);
	}

	/**
	 * Helper function: gets int for a given name.
	 * 
	 * @param p
	 * @param name
	 * @return int
	 */
	private int getInt(Properties p, String name) {
		String value = p != null ? p.getProperty(name) : null;
		if (value == null) {
			return INT_DEFAULT_DEFAULT;
		}
		int ival = 0;
		try {
			ival = Integer.parseInt(value);
		} catch (NumberFormatException e) {
		}
		return ival;
	}

	/*
	 * (non-Javadoc) Method declared on IPreferenceStore.
	 */
	public long getLong(String name) {
		return getLong(properties, name);
	}

	/**
	 * Helper function: gets long for a given name.
	 * 
	 * @param p
	 *            the properties storage (may be <code>null</code>)
	 * @param name
	 *            the name of the property
	 * @return the long or a default value of if:
	 *         <ul>
	 *         <li>properties storage is <code>null</code></li>
	 *         <li>property is not found</li>
	 *         <li>property value is not a number</li>
	 *         </ul>
	 * @see IPreferenceStore#LONG_DEFAULT_DEFAULT
	 */
	private long getLong(Properties p, String name) {
		String value = p != null ? p.getProperty(name) : null;
		if (value == null) {
			return LONG_DEFAULT_DEFAULT;
		}
		long ival = LONG_DEFAULT_DEFAULT;
		try {
			ival = Long.parseLong(value);
		} catch (NumberFormatException e) {
		}
		return ival;
	}

	/*
	 * (non-Javadoc) Method declared on IPreferenceStore.
	 */
	public String getString(String name) {
		return getString(properties, name);
	}

	/**
	 * Helper function: gets string for a given name.
	 * 
	 * @param p
	 *            the properties storage (may be <code>null</code>)
	 * @param name
	 *            the name of the property
	 * @return the value or a default value of if:
	 *         <ul>
	 *         <li>properties storage is <code>null</code></li>
	 *         <li>property is not found</li>
	 *         <li>property value is not a number</li>
	 *         </ul>
	 * @see IPreferenceStore#STRING_DEFAULT_DEFAULT
	 */
	private String getString(Properties p, String name) {
		String value = p != null ? p.getProperty(name) : null;
		if (value == null) {
			return STRING_DEFAULT_DEFAULT;
		}
		return value;
	}

	/*
	 * (non-Javadoc) Method declared on IPreferenceStore.
	 */
	public boolean isDefault(String name) {
		return (!properties.containsKey(name) && defaultProperties
				.containsKey(name));
	}

	/**
	 * Prints the contents of this preference store to the given print stream.
	 * 
	 * @param out
	 *            the print stream
	 */
	public void list(PrintStream out) {
		properties.list(out);
	}

	/**
	 * Prints the contents of this preference store to the given print writer.
	 * 
	 * @param out
	 *            the print writer
	 */
	public void list(PrintWriter out) {
		properties.list(out);
	}

	/**
	 * Loads this preference store from the file established in the constructor
	 * <code>PreferenceStore(java.lang.String)</code> (or by
	 * <code>setFileName</code>). Default preference values are not affected.
	 * 
	 * @exception java.io.IOException
	 *                if there is a problem loading this store
	 */
	public void load() throws IOException {
		if (filename == null) {
			throw new IOException("File name not specified");//$NON-NLS-1$
		}
		FileInputStream in = new FileInputStream(filename);
		load(in);
		in.close();
	}

	/**
	 * Loads this preference store from the given input stream. Default
	 * preference values are not affected.
	 * 
	 * @param in
	 *            the input stream
	 * @exception java.io.IOException
	 *                if there is a problem loading this store
	 */
	public void load(InputStream in) throws IOException {
		properties.load(in);
		dirty = false;
	}

	/*
	 * (non-Javadoc) Method declared on IPreferenceStore.
	 */
	public boolean needsSaving() {
		return dirty;
	}

	/**
	 * Returns an enumeration of all preferences known to this store which have
	 * current values other than their default value.
	 * 
	 * @return an array of preference names
	 */
	public String[] preferenceNames() {
		ArrayList list = new ArrayList();
		Enumeration it = properties.propertyNames();
		while (it.hasMoreElements()) {
			list.add(it.nextElement());
		}
		return (String[]) list.toArray(new String[list.size()]);
	}

	/*
	 * (non-Javadoc) Method declared on IPreferenceStore.
	 */
	public void putValue(String name, String value) {
		String oldValue = getString(name);
		if (oldValue == null || !oldValue.equals(value)) {
			setValue(properties, name, value);
			dirty = true;
		}
	}

	/*
	 * (non-Javadoc) Method declared on IPreferenceStore.
	 */
	public void removePropertyChangeListener(IPropertyChangeListener listener) {
		removeListenerObject(listener);
	}

	/**
	 * Saves the non-default-valued preferences known to this preference store
	 * to the file from which they were originally loaded.
	 * 
	 * @exception java.io.IOException
	 *                if there is a problem saving this store
	 */
	public void save() throws IOException {
		if (filename == null) {
			throw new IOException("File name not specified");//$NON-NLS-1$
		}
		FileOutputStream out = null;
		try {
			out = new FileOutputStream(filename);
			save(out, null);
		} finally {
			if (out != null) {
				out.close();
			}
		}
	}

	/**
	 * Saves this preference store to the given output stream. The given string
	 * is inserted as header information.
	 * 
	 * @param out
	 *            the output stream
	 * @param header
	 *            the header
	 * @exception java.io.IOException
	 *                if there is a problem saving this store
	 */
	public void save(OutputStream out, String header) throws IOException {
		properties.store(out, header);
		dirty = false;
	}

	/*
	 * (non-Javadoc) Method declared on IPreferenceStore.
	 */
	public void setDefault(String name, double value) {
		setValue(defaultProperties, name, value);
	}

	/*
	 * (non-Javadoc) Method declared on IPreferenceStore.
	 */
	public void setDefault(String name, float value) {
		setValue(defaultProperties, name, value);
	}

	/*
	 * (non-Javadoc) Method declared on IPreferenceStore.
	 */
	public void setDefault(String name, int value) {
		setValue(defaultProperties, name, value);
	}

	/*
	 * (non-Javadoc) Method declared on IPreferenceStore.
	 */
	public void setDefault(String name, long value) {
		setValue(defaultProperties, name, value);
	}

	/*
	 * (non-Javadoc) Method declared on IPreferenceStore.
	 */
	public void setDefault(String name, String value) {
		setValue(defaultProperties, name, value);
	}

	/*
	 * (non-Javadoc) Method declared on IPreferenceStore.
	 */
	public void setDefault(String name, boolean value) {
		setValue(defaultProperties, name, value);
	}

	/**
	 * Sets the name of the file used when loading and storing this preference
	 * store.
	 * <p>
	 * Afterward, the methods <code>load()</code> and <code>save()</code>
	 * can be used to load and store this preference store.
	 * </p>
	 * 
	 * @param name
	 *            the file name
	 * @see #load()
	 * @see #save()
	 */
	public void setFilename(String name) {
		filename = name;
	}

	/*
	 * (non-Javadoc) Method declared on IPreferenceStore.
	 */
	public void setToDefault(String name) {
		Object oldValue = properties.get(name);
		properties.remove(name);
		dirty = true;
		Object newValue = null;
		if (defaultProperties != null) {
			newValue = defaultProperties.get(name);
		}
		firePropertyChangeEvent(name, oldValue, newValue);
	}

	/*
	 * (non-Javadoc) Method declared on IPreferenceStore.
	 */
	public void setValue(String name, double value) {
		double oldValue = getDouble(name);
		if (oldValue != value) {
			setValue(properties, name, value);
			dirty = true;
			firePropertyChangeEvent(name, new Double(oldValue), new Double(
					value));
		}
	}

	/*
	 * (non-Javadoc) Method declared on IPreferenceStore.
	 */
	public void setValue(String name, float value) {
		float oldValue = getFloat(name);
		if (oldValue != value) {
			setValue(properties, name, value);
			dirty = true;
			firePropertyChangeEvent(name, new Float(oldValue), new Float(value));
		}
	}

	/*
	 * (non-Javadoc) Method declared on IPreferenceStore.
	 */
	public void setValue(String name, int value) {
		int oldValue = getInt(name);
		if (oldValue != value) {
			setValue(properties, name, value);
			dirty = true;
			firePropertyChangeEvent(name, new Integer(oldValue), new Integer(
					value));
		}
	}

	/*
	 * (non-Javadoc) Method declared on IPreferenceStore.
	 */
	public void setValue(String name, long value) {
		long oldValue = getLong(name);
		if (oldValue != value) {
			setValue(properties, name, value);
			dirty = true;
			firePropertyChangeEvent(name, new Long(oldValue), new Long(value));
		}
	}

	/*
	 * (non-Javadoc) Method declared on IPreferenceStore.
	 */
	public void setValue(String name, String value) {
		String oldValue = getString(name);
		if (oldValue == null || !oldValue.equals(value)) {
			setValue(properties, name, value);
			dirty = true;
			firePropertyChangeEvent(name, oldValue, value);
		}
	}

	/*
	 * (non-Javadoc) Method declared on IPreferenceStore.
	 */
	public void setValue(String name, boolean value) {
		boolean oldValue = getBoolean(name);
		if (oldValue != value) {
			setValue(properties, name, value);
			dirty = true;
			firePropertyChangeEvent(name, oldValue ? Boolean.TRUE
					: Boolean.FALSE, value ? Boolean.TRUE : Boolean.FALSE);
		}
	}

	/**
	 * Helper method: sets value for a given name.
	 * 
	 * @param p
	 * @param name
	 * @param value
	 */
	private void setValue(Properties p, String name, double value) {
		Assert.isTrue(p != null);
		p.put(name, Double.toString(value));
	}

	/**
	 * Helper method: sets value for a given name.
	 * 
	 * @param p
	 * @param name
	 * @param value
	 */
	private void setValue(Properties p, String name, float value) {
		Assert.isTrue(p != null);
		p.put(name, Float.toString(value));
	}

	/**
	 * Helper method: sets value for a given name.
	 * 
	 * @param p
	 * @param name
	 * @param value
	 */
	private void setValue(Properties p, String name, int value) {
		Assert.isTrue(p != null);
		p.put(name, Integer.toString(value));
	}

	/**
	 * Helper method: sets the value for a given name.
	 * 
	 * @param p
	 * @param name
	 * @param value
	 */
	private void setValue(Properties p, String name, long value) {
		Assert.isTrue(p != null);
		p.put(name, Long.toString(value));
	}

	/**
	 * Helper method: sets the value for a given name.
	 * 
	 * @param p
	 * @param name
	 * @param value
	 */
	private void setValue(Properties p, String name, String value) {
		Assert.isTrue(p != null && value != null);
		p.put(name, value);
	}

	/**
	 * Helper method: sets the value for a given name.
	 * 
	 * @param p
	 * @param name
	 * @param value
	 */
	private void setValue(Properties p, String name, boolean value) {
		Assert.isTrue(p != null);
		p.put(name, value == true ? IPreferenceStore.TRUE
				: IPreferenceStore.FALSE);
	}
}