/*
 * $Id$
 *
 * Copyright (c) 2001, 2011, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */
package com.sun.javatest.tool;

import java.awt.BorderLayout;
import java.awt.CardLayout;
import java.awt.Component;
import java.awt.Dimension;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.WindowEvent;
import java.awt.event.WindowListener;
import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.FileNotFoundException;
import java.io.InputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.util.Collection;
import java.util.Enumeration;
import java.util.Hashtable;
import java.util.Map;
import java.util.Properties;
import java.util.Set;

import javax.help.CSH;
import javax.help.HelpBroker;
import javax.swing.BorderFactory;
import javax.swing.JButton;
import javax.swing.JComponent;
import javax.swing.JDialog;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTree;
import javax.swing.event.TreeModelListener;
import javax.swing.event.TreeSelectionEvent;
import javax.swing.event.TreeSelectionListener;
import javax.swing.tree.DefaultTreeCellRenderer;
import javax.swing.tree.TreeModel;
import javax.swing.tree.TreeSelectionModel;
import javax.swing.tree.TreePath;
import com.sun.javatest.util.DynamicArray;
import com.sun.javatest.util.I18NResourceBundle;
import com.sun.javatest.util.SortedProperties;
import java.awt.event.KeyEvent;
import javax.swing.AbstractAction;
import javax.swing.ActionMap;
import javax.swing.InputMap;
import javax.swing.KeyStroke;

/**
 * A class which provides a collection of user preferences,
 * and a GUI interface to edit them. Preferences are represented
 * as named string values.
 * For now, the data is stored in a standard Java properties file 
 * in the user's home directory; eventually, it will be converted to
 * use the J2SE support for user preferences.
 */
public class Preferences
{
    /**
     * An observer interface for use by those that wishing to monitor changes 
     * to user preferences.
     */
    public static interface Observer {
	/**
	 * A preference has been changed.
	 * @param name the name of the preference that has been changed
	 * @param newValue the new value for the named preference
	 */
	public void updated(String name, String newValue);
    }

    /**
     * Access the single Preferences object.
     * @return the single Preferences object
     */
    public static Preferences access() {
	if (theOne == null) 
	    theOne = new Preferences(getDefaultPrefsFile());
	return theOne;
    }

    static File getPrefsDir() {
        File userDir = new File(System.getProperty("user.home"));
        String prefDir = System.getProperty("javatest.preferences.dir", ".javatest");
        return new File(userDir, prefDir);
    }

    private static File getDefaultPrefsFile() {
	String s = System.getProperty("javatest.preferences.file");
	if (s == null) {
	    File jtDir = getPrefsDir();
	    return new File(jtDir, "preferences");
	}
	else if (!s.equals("NONE"))
	    return new File(s);
	else
	    return null;
    }

    private static Preferences theOne;

    private Preferences(File file) {
	prefsFile = file;
	isUpToDate = true;
	Properties p = new SortedProperties();

	try {
	    if (prefsFile != null) {
		InputStream in = new BufferedInputStream(new FileInputStream(prefsFile));
		p.load(in);
		in.close();
        fileModifiedTime = prefsFile.lastModified();
	    }
	}
	catch (FileNotFoundException ignore) {
	}
	catch (IOException ignore) {
	    // ??
	}
	props = p;
    }

    /**
     * Save the current set of user preferences.
     * For now, the data is stored in a standard Java properties file 
     * in the user's home directory; eventually, it will be converted to
     * use the J2SE support for user preferences.
     */
    public synchronized void save() {
	if (prefsFile != null && (!isUpToDate || fileModifiedTime != prefsFile.lastModified())) {
	    try {
		File parentDir = new File(prefsFile.getParent());
		if (!parentDir.exists())
		    parentDir.mkdirs();
		OutputStream out = new BufferedOutputStream(new FileOutputStream(prefsFile));
		props.store(out, "JT Harness Preferences");
		out.close();
		isUpToDate = true;
                fileModifiedTime = prefsFile.lastModified();
	    }
	    catch (IOException e) {
		System.err.println(i18n.getString("prefs.cannotSave", e));
	    }
	}
    }

    /**
     * Get a named preference value.
     * @param name the name of the desired preference
     * @return the value of the named preference, or null if no such preference found
     * @see #setPreference
     */
    public String getPreference(String name) {
	return getPreference(name, null);
    }

    /**
     * Get a named preference value, using a default if the named preference
     * is not found.
     * @param name the name of the desired preference
     * @param defaultValue the default value to be returned if no such preference
     * is found
     * @return the value of the named preference, or the default value if no such preference found
     * @see #setPreference
     */
    public String getPreference(String name, String defaultValue) {
	String v = (String) (props.get(name));
	if (v == null)
	    v = defaultValue;
	return v;
    }

    /**
     * Set the value of a named preference. Any interested observers will
     * be notified.
     * @param name the name of the preference to be set
     * @param newValue the new value for the preference
     * @see #getPreference
     */
    public void setPreference(String name, String newValue) {
	isUpToDate = false;
	props.put(name, newValue);
	// notify observers
	for (Enumeration e = observers.keys(); e.hasMoreElements(); ) {
	    String prefix = (String)(e.nextElement());
	    if (name.startsWith(prefix)) {
		Observer[] obs = (Observer[])observers.get(prefix);
		for (int i = 0; i < obs.length; i++) {
		    obs[i].updated(name, newValue);
		}
	    }
	}
    }

    /**
     * Add an observer to be notified of changes to all preferences
     * whose name begins with a given prefix. This allows an observer
     * to monitor a single preference or a group of preferences.
     * @param prefix the prefix to determine which preferences will
     * 		be observed
     * @param o the observer to be added
     * @see #removeObserver
     */
    public void addObserver(String prefix, Observer o) {
	// very crude observer storage for now; results in o(n) per preference
	// cost when updating preferences
	Observer[] obs = (Observer[])observers.get(prefix);
	if (obs == null)
	    obs = new Observer[] { o };
	else
	    obs = (Observer[])DynamicArray.append(obs, o);
	observers.put(prefix, obs);
    }

    /**
     * Add an observer to be notified of changes to all preferences
     * whose name begins with any of a set of given prefixes. 
     * This allows an observer to monitor a single preference 
     * or a group of preferences.
     * @param prefixes the prefix to determine which preferences will
     * 		be observed
     * @param o the observer to be added
     * @see #removeObserver
     */
    public void addObserver(String[] prefixes, Observer o) {
	for (int i = 0; i < prefixes.length; i++) {
	    addObserver(prefixes[i], o);
	}
    }

    /**
     * Remove an observer which was previously registered to be 
     * notified of changes to all preferences whose name begins 
     * with a given prefix. The prefix must exactly match the
     * prefix with which it was previously registered.
     * @param prefix the prefix to identify which instance of the
     * observer to be removed
     * @param o the observer to be removed
     * @see #addObserver
     */
    public void removeObserver(String prefix, Observer o) {
	Observer[] obs = (Observer[])observers.get(prefix);
	if (obs != null) {
	    obs = (Observer[])DynamicArray.remove(obs, o);
	    observers.put(prefix, obs);
	}
    }

    /**
     * Remove an observer which was previously registered to be 
     * notified of changes to all preferences whose name begins 
     * with any of a set of prefixed. Each prefix must exactly
     * match one with which the observer was previously registered.
     * @param prefixes the prefix to identify which instances of the
     * observer to be removed
     * @param o the observer to be removed
     * @see #addObserver
     */
    public void removeObserver(String[] prefixes, Observer o) {
	for (int i = 0; i < prefixes.length; i++) {
	    removeObserver(prefixes[i], o);
	}
    }

    /**
     * Show a dialog to allow the user to edit the set of preferences.
     * A collection of editing panes must be provided that each provide
     * the GUI to edit a subset of the preferences.
     * @param f the parent frame for the dialog
     * @param panes the editing panes to be displayed in the dialog
     * @param helpBroker a help broker to be used to provide context sensitive
     * 		help for the dialog
     */
    public void showDialog(JFrame f, Pane[] panes, HelpBroker helpBroker) {
	//System.err.println("Preferences.showDialog");
	PrefsDialog d = new PrefsDialog(f, panes, helpBroker);
	d.setVisible(true);
	//System.err.println("Preferences.showDialog done");
    }

    private void setPreferences(Pane[] panes) {
	Map m = new Map() {
	    public void clear() {
		throw new UnsupportedOperationException();
	    }
	    public boolean containsKey(Object key) {
		return props.containsKey(key);
	    }
	    public boolean containsValue(Object value) {
		return props.containsValue(value);
	    }
	    public Set entrySet() {
		return props.entrySet();
	    }
	    public boolean equals(Object o) {
		return props.equals(o);
	    }
	    public Object get(Object key) {
		return props.get(key);
	    }
	    public int hashCode() {
		return props.hashCode();
	    }
	    public boolean isEmpty() {
		return props.isEmpty();
	    }
	    public Set keySet() {
		return props.keySet();
	    }
	    public Object put(Object key, Object value) {
		Object oldValue = props.get(key);
		if (oldValue == null || !oldValue.equals(value))
		    setPreference((String)key, (String)value);
		return oldValue;
	    }
	    public void putAll(Map m) {
		throw new UnsupportedOperationException();
	    }
	    public Object remove(Object key) {
		throw new UnsupportedOperationException();
	    }
	    public int size() {
		return props.size();
	    }
	    public Collection values() {
		return props.values();
	    }
	};

	for (int i = 0; i < panes.length; i++)
	    panes[i].save(m);
    }

    private File prefsFile;
    private Properties props;
    private Hashtable observers = new Hashtable();
    private boolean isUpToDate;
    private long fileModifiedTime;

    /**
     * An abstract class for a GUI panel that can be displayed to
     * allow the user to edit some of the user preferences.
     * A pane may have child panes, containing additional groups
     * of preferences relevant to but not contained on this pane.
     */
    public static abstract class Pane extends JPanel {
	/**
	 * Set the help ID that gives the context sensitive help for
	 * this panel. The help will be displayed in the help broker
	 * specified when the dialog is displayed.
	 * @param helpID the ID for the context sensitive help for this panel
	 * @see Preferences#showDialog
	 */
	protected void setHelp(String helpID) {
	    CSH.setHelpIDString(this, helpID);
	}

	/**
	 * Get a text string which identifies the group of user preferences
	 * that can be edited on the panel.
	 * @return a text string to identify the preferences on this panel
	 */
	public abstract String getText();

	/**
	 * Load the values of the user preferences relevant to this panel
	 * from a given map object.
	 * @param m the map from which to load the user preferences into the
	 * GUI components
	 */
	public void load(Map m) {
	    Pane[] p = getChildPanes();
	    if (p != null) {
		for (int i = 0; i < p.length; i++)
		    p[i].load(m);
	    }
	}

	/**
	 * Save the values of the user preferences relevant to this panel
	 * into a given map object.
	 * @param m the map to which to save the user preferences from the
	 * GUI components
	 */
	public void save(Map m) {
	    Pane[] p = getChildPanes();
	    if (p != null) {
		for (int i = 0; i < p.length; i++)
		    p[i].save(m);
	    }
	}

        /**
         * Analyze the current values entered by the user and determine if
         * they are valid.  If they are, the return value should be null.
         * By default the return value is null.
         * @return null if all the values are valid.  Otherwise, an
         *    <b>internationalized</b> string.
         * @see com.sun.javatest.util.I18NResourceBundle
         */
        public String validateValues() {
            return null;
        }

	/**
	 * Get the set of child panes, if any, containing additional groups
	 * of preferences relevant to but not contained on this pane.
	 * @return an array of child panes, or null if none
	 */
	public Pane[] getChildPanes() {
	    return null;
	}
    }

    private class PrefsDialog 
	extends JDialog // can't be ToolDialog because might change desktop style
	implements ActionListener, TreeModel, TreeSelectionListener, WindowListener
    {
	PrefsDialog(JFrame f, Pane[] panes, HelpBroker helpBroker) {
	    // Don't use the argument frame 'f' as the parent of the dialog
	    // in case that frame is disposed while "apply"ing preferences.
	    // Instead, we use null (private hidden frame) as the parent, 
	    // and merely center the dialog over the argument frame.
	    super((JFrame)null, /*modal:*/true);
	    owner = f;
	    this.panes = panes;
	    this.helpBroker = helpBroker;

	    uif = new UIFactory(getClass(), helpBroker);
	    initGUI();

	    //System.err.println("Prefs.dialog addWindowListener " + owner.getName());
	    owner.addWindowListener(this);
	}

	public void setVisible(boolean b) {
	    if (b) {
		for (int i = 0; i < panes.length; i++)
		    panes[i].load(props);
	    }
	    super.setVisible(b);

	    if (!b) {
		//System.err.println("Prefs.dialog removeWindowListener " + owner.getName());
		owner.removeWindowListener(this);
	    }
	}

	private void initGUI() {
	    //prefsTreeLeafIcon = uif.createIcon("prefs.leaf");
	    setName("prefs");
	    setTitle(uif.getI18NString("prefs.title"));
            if (helpBroker != null) {
                helpBroker.enableHelpKey(getRootPane(), "ui.prefs.dialog.csh", null);
            }
	    Desktop.addHelpDebugListener(this);
	    uif.setAccessibleDescription(this, "prefs");

	    main = uif.createPanel("prefs.main", new BorderLayout(), false);
	    
	    initTree();    // add into main, WEST
	    initPanes();   // add into main, CENTER
	    initButtons(); // add into main, SOUTH

	    setContentPane(main);
	    Object[] path = new Object[2];
	    path[0] = tree.getModel().getRoot();
	    path[1] = getChildren(this)[0];	// assumes we always have at least one
	    tree.setSelectionPath(new TreePath(path));

	    pack();
	    setLocationRelativeTo(owner);
	    
	    getRootPane().setDefaultButton(okBtn);
	}

	private void initTree() {
	    tree = new JTree(this);
	    tree.setName("prefs.tree");
	    tree.addTreeSelectionListener(this);
	    tree.setEditable(false);
	    tree.setShowsRootHandles(true);
	    tree.setRootVisible(false);
	    uif.setAccessibleInfo(tree, "prefs.tree");

	    int dpi = uif.getDotsPerInch();
	    tree.setPreferredSize(new Dimension(2 * dpi, dpi));
	    tree.setVisibleRowCount(10);

	    tree.setCellRenderer(new DefaultTreeCellRenderer() {
		public Component getTreeCellRendererComponent(JTree tree, Object value,
						      boolean selected,
						      boolean expanded,
						      boolean leaf, int row,
						      boolean hasFocus) {
		    if (value instanceof Pane) {
			return super.getTreeCellRendererComponent(tree, ((Pane)value).getText(),
			    selected, expanded, leaf, row, hasFocus);
		    } else {
			return super.getTreeCellRendererComponent(tree, value,
			    selected, expanded, leaf, row, hasFocus);
		    }
		}
		/*
		public Icon getLeafIcon() {
		    // consider use of blank icon?
		    return prefsTreeLeafIcon;
		}
		*/
	    });
	    tree.getSelectionModel().setSelectionMode(TreeSelectionModel.SINGLE_TREE_SELECTION);
            tree.expandRow(2);  // expand two levels

	    // construct the tree side
	    JComponent treeStuff = uif.createScrollPane(tree);
	    treeStuff.setBorder(BorderFactory.createEtchedBorder());
	    
	    main.add(treeStuff, BorderLayout.WEST);
	}

	private void initButtons() {
	    okBtn = uif.createButton("prefs.ok", this);
	    cancelBtn = uif.createCancelButton("prefs.cancel", this);
	    helpBtn = uif.createHelpButton("prefs.help", "ui.prefs.dialog.csh");

	    JButton[] btns = { okBtn, cancelBtn, helpBtn };
	    
	    // set all the buttons to the same preferred size, per JL&F
	    Dimension maxBtnDims = new Dimension();
	    for (int i = 0; i < btns.length; i++) {
		Dimension d = btns[i].getPreferredSize();
		maxBtnDims.width = Math.max(maxBtnDims.width, d.width);
		maxBtnDims.height = Math.max(maxBtnDims.height, d.height);
	    }

	    for (int i = 0; i < btns.length; i++) 
		btns[i].setPreferredSize(maxBtnDims);
	   
	    JPanel p = uif.createPanel("prefs.btns", false);
	    p.setLayout(new GridBagLayout());
	    GridBagConstraints c = new GridBagConstraints();
	    c.anchor = GridBagConstraints.EAST;
	    c.insets.top = 5;
	    c.insets.bottom = 11;  // value from JL&F Guidelines
	    c.insets.right = 11;   // value from JL&F Guidelines
	    c.weightx = 1;         // first button absorbs space to the left
	    
	    for (int i = 0; i < btns.length; i++) {
		p.add(btns[i], c);
		c.weightx = 0;
	    }
	    
	    main.add(p, BorderLayout.SOUTH);

	    InputMap inputMap = p.getInputMap(JComponent.WHEN_IN_FOCUSED_WINDOW);
	    ActionMap actionMap = p.getActionMap();
	    inputMap.put(KeyStroke.getKeyStroke(KeyEvent.VK_ESCAPE, 0), UIFactory.CANCEL);
	    actionMap.put(UIFactory.CANCEL, new AbstractAction() {
		    public void actionPerformed(ActionEvent e) {
			cancelBtn.doClick(250);
		    }
		});
	}
	
	private void initPanes() {
	    deck = uif.createPanel("prefs.deck", new CardLayout(), false);
	    addAllPanes(deck, panes);

	    int dpi = uif.getDotsPerInch();
	    Dimension maxPrefSize = new Dimension(3 * dpi, 2 * dpi);
	    for (int i  = 0; i < deck.getComponentCount(); i++) {
		Dimension d = deck.getComponent(i).getPreferredSize();
		maxPrefSize.width = Math.max(maxPrefSize.width, d.width);
		maxPrefSize.height = Math.max(maxPrefSize.height, d.height);
	    }
	    deck.setPreferredSize(maxPrefSize);

	    main.add(deck, BorderLayout.CENTER);
	}

	private void addAllPanes(JPanel deck, Pane[] panes) {
	    for (int i = 0; i < panes.length; i++) {
		Pane pane = panes[i];

		JPanel p = uif.createPanel("prefs.card" + cardNum++, false);
		p.setLayout(new BorderLayout());
		JLabel head = new JLabel(pane.getText());
		head.setBorder(BorderFactory.createEmptyBorder(10, 10, 10, 10));
		p.add(head, BorderLayout.NORTH);

		pane.setBorder(BorderFactory.createEmptyBorder(10, 10, 10, 10));
		p.add(uif.createScrollPane(pane), BorderLayout.CENTER);
		deck.add(p, pane.getText());

		if (pane.getChildPanes() != null)
		    addAllPanes(deck, pane.getChildPanes());
	    }
	}

	private int cardNum;

	// ---------- ActionListener -------------------------------

	public void actionPerformed(ActionEvent e) {
	    Object src = e.getSource();
	    if (src == okBtn) {
                boolean b = okToSave();

                if (!b)
                    return;

		setPreferences(panes); 
		save();
		setVisible(false);
	    }
		else if (src == cancelBtn) {
			for (int i = 0; i < panes.length; i++)
				panes[i].load(props);
			setVisible(false);
		}
	}

        private boolean okToSave() {
            String reason = null;
            for (int i = 0; i < panes.length; i++) {
                reason = panes[i].validateValues();
                if (reason != null) {
                    tree.setSelectionPath(new TreePath(new Object[] {this, panes[i]}));
                    break;
                }

                Pane[] p = panes[i].getChildPanes();
                if (p != null) {
                    for (int j = 0; j < p.length; j++) {
                        reason = p[j].validateValues();
                        if (reason != null) {
                            tree.setSelectionPath(new TreePath(
                                new Object[] {this, panes[i], p[j]}));
                            break;
                        }
                    }   // for j

                    if (reason != null)
                        break;
                }
            }   // for i

            if (reason != null) {
                // show error dialog
                uif.showLiteralError(uif.getI18NString("prefs.badPref.title"),
                                     reason);
                return false;
            } else {
                return true;
            }
        }

	// ---------- TreeSelectionListener ---------------------------------

	public void valueChanged(TreeSelectionEvent e) {
	    TreePath path = e.getNewLeadSelectionPath();
	    if (path != null) {
		Pane pane = (Pane) (path.getLastPathComponent());
		((CardLayout)(deck.getLayout())).show(deck, pane.getText());
	    }
	}

	// --------- TreeModel --------------------------------------

	public Object getChild(Object parent, int index) {
	    return getChildren(parent)[index];
	}
	
	public int getChildCount(Object parent) {
	    return getChildren(parent).length;
	}
	
	public int getIndexOfChild(Object parent, Object child) {
	    Pane[] children = getChildren(parent);
	    for (int i = 0; i < children.length; i++) {
		if (children[i] == child) 
		    return i;
	    }
	    return -1;
	}
	
	public Object getRoot() {
	    return this;
	}
	
	public boolean isLeaf(Object node) {
	    Pane[] children = getChildren(node);
	    return (children == null || children.length == 0);
	}

	// --------- TreeModelListener ---------------------------------------
	
	public void addTreeModelListener(TreeModelListener l) {
	}
	
	public void removeTreeModelListener(TreeModelListener l) {
	} 

	public void valueForPathChanged(TreePath path, Object newValue) {
	}

	// --------- WindowListener -----------------------------------------
	
	public void windowOpened(WindowEvent e) {
	    //System.err.println("Prefs.dialog " + e);
	}
	
	public void windowClosing(WindowEvent e) {
	    //System.err.println("Prefs.dialog " + e);
	}
	
	public void windowClosed(WindowEvent e) {
	    //System.err.println("Prefs.dialog " + e);
	}
	
	public void windowIconified(WindowEvent e) {
	    //System.err.println("Prefs.dialog " + e);
	}
	
	public void windowDeiconified(WindowEvent e) {
	    //System.err.println("Prefs.dialog " + e + " (" + e.getSource() + ")");
	    if (e.getSource() == owner)
		toFront();
	}
	
	public void windowActivated(WindowEvent e) {
	    //System.err.println("Prefs.dialog " + e + " (" + e.getSource() + ")");
	    if (e.getSource() == owner)
		toFront();
	}
	
	public void windowDeactivated(WindowEvent e) {
	    //System.err.println("Prefs.dialog " + e);
	}

	// ------------------------------------------------------------------
	
	private Pane[] getChildren(Object parent) {
	    return (parent == this ? panes : ((Pane)parent).getChildPanes());
	}
 
	private JFrame owner;
	private HelpBroker helpBroker;
	private Pane[] panes;
	private UIFactory uif;
	private JPanel main;
	private JPanel deck;
	private JButton okBtn;
	private JButton cancelBtn;
	private JButton helpBtn;
	private JTree tree;
	// private Icon prefsTreeLeafIcon;
    }

    private static I18NResourceBundle i18n = I18NResourceBundle.getBundleForClass(Preferences.class);
}
