/* *************************************************************************
 
                               IT Mill Toolkit 

               Development of Browser User Interfaces Made Easy

                    Copyright (C) 2000-2006 IT Mill Ltd
                     
   *************************************************************************

   This product is distributed under commercial license that can be found
   from the product package on license.pdf. Use of this product might 
   require purchasing a commercial license from IT Mill Ltd. For guidelines 
   on usage, see licensing-guidelines.html

   *************************************************************************
   
   For more information, contact:
   
   IT Mill Ltd                           phone: +358 2 4802 7180
   Ruukinkatu 2-4                        fax:   +358 2 4802 7181
   20540, Turku                          email:  info@itmill.com
   Finland                               company www: www.itmill.com
   
   Primary source for information and releases: www.itmill.com

   ********************************************************************** */

package com.itmill.toolkit.ui;

import com.itmill.toolkit.Application;
import com.itmill.toolkit.event.EventRouter;
import com.itmill.toolkit.event.MethodEventSource;
import com.itmill.toolkit.terminal.*;

import java.util.Collection;
import java.util.LinkedList;
import java.util.Locale;
import java.util.Map;
import java.util.Set;
import java.util.HashSet;
import java.lang.reflect.Method;

/** An abstract class that defines default implementation for the
 * {@link Component} interface. Basic UI components that are not derived
 * from an external component can inherit this class to easily qualify as a
 * IT Mill Toolkit component. Most components in the toolkit do
 * just that.
 *
 * @author IT Mill Ltd.
 * @version @VERSION@
 * @since 3.0
 */
public abstract class AbstractComponent
	implements Component, MethodEventSource {

	/* Private members ************************************************* */

	/** Look-and-feel style of the component. */
	private String style;

	/** Caption text. */
	private String caption;
    
    /** Application specific data object. */
    private Object applicationData;

	/** Icon to be shown together with caption. */
	private Resource icon;

	/** Is the component enable (its normal usage is allowed). */
	private boolean enabled = true;

	/** Is the component visible (it is rendered). */
	private boolean visible = true;

	/** Is the component read-only ? */
	private boolean readOnly = false;

	/** Description of the usage (XML). */
	private String description = null;

	/** The container this component resides in. */
	private Component parent = null;

	/** The EventRouter used for the event model. */
	private EventRouter eventRouter = null;

	/** The internal error message of the component. */
	private ErrorMessage componentError = null;

	/** List of event variable change event handling dependencies */
	private Set dependencies = null;

	/** Immediate mode: if true, all variable changes are required to be sent
	 * from the terminal immediately
	 */
	private boolean immediate = false;

	/** Locale of this component. */
	private Locale locale;

	/** List of repaint request listeners or null if not listened at all */
	private LinkedList repaintRequestListeners = null;

	/** Are all the repaint listeners notified about recent changes ? */
	private boolean repaintRequestListenersNotified = false;

	/* Constructor ***************************************************** */

	/** Constructs a new Component */
	public AbstractComponent() {
	}

	/* Get/Set component properties ************************************ */

	/** Gets the UIDL tag corresponding to the component.
	 * 
	 * @return component's UIDL tag as <code>String</code>
	 */
	public abstract String getTag();

	/* Gets the component's style.
	 * Don't add a JavaDoc comment here, we use the default documentation
	 * from implemented interface.
	 */
	public String getStyle() {
		return this.style;
	}

	/* Sets the component's style.
	 * Don't add a JavaDoc comment here, we use the default documentation
	 * from implemented interface.
	 */
	public void setStyle(String style) {
		this.style = style;
		requestRepaint();
	}

	/* Get's the component's caption.
	 * Don't add a JavaDoc comment here, we use the default documentation
	 * from implemented interface.
	 */
	public String getCaption() {
		return this.caption;
	}

	/** Sets the component's caption <code>String</code>. Caption is the
	 * visible name of the component. This method will trigger a
	 * {@link com.itmill.toolkit.terminal.Paintable.RepaintRequestEvent RepaintRequestEvent}.
	 * 
	 * @param caption new caption <code>String</code> for the component
	 */
	public void setCaption(String caption) {
		this.caption = caption;
		requestRepaint();
	}

	/* Don't add a JavaDoc comment here, we use the default documentation
	 * from implemented interface.
	 */
	public Locale getLocale() {
		if (this.locale != null)
			return this.locale;
		if (this.parent != null)
			return parent.getLocale();
		Application app = this.getApplication();
		if (app != null)
			return app.getLocale();
		return null;
	}

	/** Sets the locale of this component.
	 * @param locale The locale to become this component's locale.
	 */
	public void setLocale(Locale locale) {
		this.locale = locale;
	}

	/* Gets the component's icon resource.
	 * Don't add a JavaDoc comment here, we use the default documentation
	 * from implemented interface.
	 */
	public Resource getIcon() {
		return this.icon;
	}

	/** Sets the component's icon.  This method will trigger a
	  * {@link com.itmill.toolkit.terminal.Paintable.RepaintRequestEvent RepaintRequestEvent}.
	  * 
	  * @param icon the icon to be shown with the component's caption
	  */
	public void setIcon(Resource icon) {
		this.icon = icon;
		requestRepaint();
	}

	/* Tests if the component is enabled or not.
	 * Don't add a JavaDoc comment here, we use the default documentation
	 * from implemented interface.
	 */
	public boolean isEnabled() {
		return this.enabled && isVisible();
	}

	/* Enables or disables the component.
	 * Don't add a JavaDoc comment here, we use the default documentation
	 * from implemented interface.
	 */
	public void setEnabled(boolean enabled) {
		if (this.enabled != enabled) {
			this.enabled = enabled;
			requestRepaint();
		}
	}

	/* Tests if the component is in the immediate mode.
	 * Don't add a JavaDoc comment here, we use the default documentation
	 * from implemented interface.
	 */
	public boolean isImmediate() {
		return immediate;
	}

	/** Sets the component's immediate mode to the specified status. This
	 * method will trigger a 
	 * {@link com.itmill.toolkit.terminal.Paintable.RepaintRequestEvent RepaintRequestEvent}.
	 * 
	 * @param immediate boolean value specifying if the component should
	 * be in the immediate mode after the call.
	 * @see Component#isImmediate()
	 */
	public void setImmediate(boolean immediate) {
		this.immediate = immediate;
		requestRepaint();
	}

	/* Tests if the component is visible.
	 * Don't add a JavaDoc comment here, we use the default documentation
	 * from implemented interface.
	 */
	public boolean isVisible() {
		return this.visible;
	}

	/* Sets the components visibility.
	 * Don't add a JavaDoc comment here, we use the default documentation
	 * from implemented interface.
	 */
	public void setVisible(boolean visible) {

		if (this.visible != visible) {
			this.visible = visible;
			// Instead of requesting repaint normally we 
			// fire the event directly to assure that the 
			// event goes through event in the component might
			// now be invisible
			fireRequestRepaintEvent(null);
		}
	}

	/** <p>Gets the component's description. The description can be used to
	 * briefly describe the state of the component to the user. The
	 * description string may contain certain XML tags:</p>
	 * 
	 * <p><table border=1>
	 * <tr><td width=120><b>Tag</b></td>
	 *     <td width=120><b>Description</b></td>
	 *     <td width=120><b>Example</b></td>
	 * </tr>
	 * <tr><td>&lt;b></td>
	 *     <td>bold</td>
	 *     <td><b>bold text</b></td>
	 * </tr>
	 * <tr><td>&lt;i></td>
	 *     <td>italic</td>
	 *     <td><i>italic text</i></td>
	 * </tr>
	 * <tr><td>&lt;u></td>
	 *     <td>underlined</td>
	 *     <td><u>underlined text</u></td>
	 * </tr>
	 * <tr><td>&lt;br></td>
	 *     <td>linebreak</td>
	 *     <td>N/A</td>
	 * </tr>
	 * <tr><td>&lt;ul><br>&lt;li>item1<br>&lt;li>item1<br>&lt;/ul></td>
	 *      <td>item list</td>
	 *      <td><ul><li>item1 <li>item2</ul></td>
	 * </tr>
	 * </table></p>
	 * 
	 * <p>These tags may be nested.</p>
	 * 
	 * @return component's description <code>String</code>
	 */
	public String getDescription() {
		return this.description;
	}

	/** Sets the component's description. See {@link #getDescription()} for
	 * more information on what the description is. This method will trigger
	 * a {@link com.itmill.toolkit.terminal.Paintable.RepaintRequestEvent RepaintRequestEvent}.
	 *
	 * @param description new description string for the component
	 */
	public void setDescription(String description) {
		this.description = description;
		requestRepaint();
	}

	/* Gets the component's parent component.
	 * Don't add a JavaDoc comment here, we use the default documentation
	 * from implemented interface.
	 */
	public Component getParent() {
		return this.parent;
	}

	/* Set the parent component.
	 * Don't add a JavaDoc comment here, we use the default documentation
	 * from implemented interface.
	 */
	public void setParent(Component parent) {

		// If the parent is not changed, dont do nothing
		if (parent == this.parent)
			return;

		// Send detach event if the component have been connected to a window
		if (getApplication() != null) {
			detach();
			this.parent = null;
		}

		// Connect to new parent
		this.parent = parent;

		// Send attach event if connected to a window
		if (getApplication() != null)
			attach();
	}

	/** Get the error message for this component.
	 * 
	 * @return ErrorMessage containing the description of the error state
	 * of the component or null, if the component contains no errors. Extending
	 * classes should override this method if they support other error message
	 * types such as validation errors or buffering errors. The returned error
	 * message contains information about all the errors.
	 */
	public ErrorMessage getErrorMessage() {
		return this.componentError;
	}

	/** Gets the component's error message. 
	 * @link Terminal.ErrorMessage#ErrorMessage(String, int)
	 *
	 * @return component's error message
	 */
	public ErrorMessage getComponentError() {
		return this.componentError;
	}

	/** Sets the component's error message. The message may contain certain
	 * XML tags, for more information see
	 * @link Component.ErrorMessage#ErrorMessage(String, int)
	 * 
	 * @param errorMessage new <code>ErrorMessage</code> of the component
	 */
	public void setComponentError(ErrorMessage componentError) {
		this.componentError = componentError;
		fireComponentErrorEvent();
		requestRepaint();
	}

	/* Tests if the component is in read-only mode.
	 * Don't add a JavaDoc comment here, we use the default documentation
	 * from implemented interface.
	 */
	public boolean isReadOnly() {
		return readOnly;
	}

	/* Set the component's read-only mode.
	 * Don't add a JavaDoc comment here, we use the default documentation
	 * from implemented interface.
	 */
	public void setReadOnly(boolean readOnly) {
		this.readOnly = readOnly;
		requestRepaint();
	}

	/* Get the parent window of the component.
	 * Don't add a JavaDoc comment here, we use the default documentation
	 * from implemented interface.
	 */
	public Window getWindow() {
		if (parent == null)
			return null;
		else
			return parent.getWindow();
	}

	/* Notify the component that it's attached to a window.
	 * Don't add a JavaDoc comment here, we use the default documentation
	 * from implemented interface.
	 */
	public void attach() {
	}

	/* Detach the component from application. 
	 * Don't add a JavaDoc comment here, we use the default documentation
	 * from implemented interface.
	 */
	public void detach() {
	}

	/* Get the parent application of the component.
	 * Don't add a JavaDoc comment here, we use the default documentation
	 * from implemented interface.
	 */
	public Application getApplication() {
		if (parent == null)
			return null;
		else
			return parent.getApplication();
	}

	/* Component painting ********************************************** */

	/* Documented in super interface */
	public void requestRepaintRequests() {
		repaintRequestListenersNotified = false;
	}

	/* Paints the component into a UIDL stream. 
	 * Don't add a JavaDoc comment here, we use the default documentation
	 * from implemented interface.
	 */
	public final void paint(PaintTarget target) throws PaintException {

		if (!target.startTag(this, this.getTag())) {
			if (getStyle() != null && getStyle().length() > 0)
				target.addAttribute("style", getStyle());
			if (isReadOnly())
				target.addAttribute("readonly", true);
			if (!isVisible())
				target.addAttribute("invisible", true);
			if (isImmediate())
				target.addAttribute("immediate", true);
			if (!isEnabled())
				target.addAttribute("disabled", true);
			if (getCaption() != null)
				target.addAttribute("caption", getCaption());
			if (getIcon() != null)
				target.addAttribute("icon", getIcon());

			// Only paint content of visible components.
			if (isVisible()) {
				paintContent(target);

				String desc = getDescription();
				if (desc != null && description.length() > 0) {
					target.startTag("description");
					target.addUIDL(getDescription());
					target.endTag("description");
				}

				ErrorMessage error = getErrorMessage();
				if (error != null)
					error.paint(target);
			}
		}
		target.endTag(this.getTag());

		repaintRequestListenersNotified = false;
	}

	/** Paints any needed component-specific things to the given UIDL
	 * stream. The more general {@link #paint(PaintTarget)} method handles
	 * all general attributes common to all components, and it calls this
	 * method to paint any component-specific attributes to the UIDL stream.
	 * 
	 * @param target target UIDL stream where the component should paint
	 * itself to
	 * @throws PaintException if the operation failed
	 */
	public void paintContent(PaintTarget target) throws PaintException {

	}

	/* Documentation copied from interface */
	public void requestRepaint() {

		// The effect of the repaint request is identical to case where a
		// child requests repaint
		childRequestedRepaint(null);
	}

	/* Documentation copied from interface */
	public void childRequestedRepaint(Collection alreadyNotified) {

		// Invisible components do not need repaints
		if (!isVisible())
			return;

		fireRequestRepaintEvent(alreadyNotified);
	}

	/** Fire repaint request event */
	private void fireRequestRepaintEvent(Collection alreadyNotified) {

		// Notify listeners only once
		if (!repaintRequestListenersNotified) {

			// Notify the listeners
			if (repaintRequestListeners != null
				&& !repaintRequestListeners.isEmpty()) {
				Object[] listeners = repaintRequestListeners.toArray();
				RepaintRequestEvent event = new RepaintRequestEvent(this);
				for (int i = 0; i < listeners.length; i++) {
					if (alreadyNotified == null)
						alreadyNotified = new LinkedList();
					if (!alreadyNotified.contains(listeners[i])) {
						(
							(
								RepaintRequestListener) listeners[i])
									.repaintRequested(
							event);
						alreadyNotified.add(listeners[i]);
						repaintRequestListenersNotified = true;
					}
				}
			}

			// Notify the parent
			Component parent = getParent();
			if (parent != null)
				parent.childRequestedRepaint(alreadyNotified);
		}
	}

	/* Documentation copied from interface */
	public void addListener(RepaintRequestListener listener) {
		if (repaintRequestListeners == null)
			repaintRequestListeners = new LinkedList();
		if (!repaintRequestListeners.contains(listener)) {
			repaintRequestListeners.add(listener);
		}
	}

	/* Documentation copied from interface */
	public void removeListener(RepaintRequestListener listener) {
		if (repaintRequestListeners != null) {
			repaintRequestListeners.remove(listener);
			if (repaintRequestListeners.isEmpty())
				repaintRequestListeners = null;
		}
	}

	/* Component variable changes ************************************** */

	/* Invoked when the value of a variable has changed.
	 * Don't add a JavaDoc comment here, we use the default documentation
	 * from implemented interface.
	 */
	public void changeVariables(Object source, Map variables) {

	}

	/* Adds a variable-change dependency to this component.
	 * Don't add a JavaDoc comment here, we use the default documentation
	 * from implemented interface.
	 */
	public void dependsOn(VariableOwner depended) {

		// Assure that the list exists
		if (dependencies == null)
			dependencies = new HashSet();

		// Add to the list of dependencies
		if (depended != null)
			dependencies.add(depended);
	}

	/* Removes a dependency from the component.
	 * Don't add a JavaDoc comment here, we use the default documentation
	 * from implemented interface.
	 */
	public void removeDirectDependency(VariableOwner depended) {

		// Remove the listener if necessary
		if (dependencies != null && depended != null)
			dependencies.remove(depended);
	}

	/* Gets the set of depended components.
	 * Don't add a JavaDoc comment here, we use the default documentation
	 * from implemented interface.
	 */
	public Set getDirectDependencies() {
		return dependencies;
	}

	/* General event framework *************************************** */

	private static final Method COMPONENT_EVENT_METHOD;

	static {
		try {
			COMPONENT_EVENT_METHOD =
				Component.Listener.class.getDeclaredMethod(
					"componentEvent",
					new Class[] { Component.Event.class });
		} catch (java.lang.NoSuchMethodException e) {
			// This should never happen
			e.printStackTrace();
			throw new java.lang.RuntimeException();
		}
	}

	/** <p>Registers a new listener with the specified activation method to
	 * listen events generated by this component. If the activation method
	 * does not have any arguments the event object will not be passed to it
	 * when it's called.</p>
	 * 
	 * <p>For more information on the inheritable event mechanism
	 * see the 
	 * {@link com.itmill.toolkit.event com.itmill.toolkit.event package documentation}.</p>
	 * 
	 * @param eventType type of the listened event. Events of this type or
	 * its subclasses activate the listener.
	 * @param object the object instance who owns the activation method
	 * @param method the activation method
	 * @throws java.lang.IllegalArgumentException unless <code>method</code>
	 * has exactly one match in <code>object</code>
	 */
	public void addListener(Class eventType, Object object, Method method) {
		if (eventRouter == null)
			eventRouter = new EventRouter();
		eventRouter.addListener(eventType, object, method);
	}

	/** <p>Registers a new listener with the specified activation method to
	 * listen events generated by this component. If the activation method
	 * does not have any arguments the event object will not be passed to it
	 * when it's called.</p>
	 * 
	 * <p>This version of <code>addListener</code> gets the name of the
	 * activation method as a parameter. The actual method is reflected from
	 * <code>object</code>, and unless exactly one match is found,
	 * <code>java.lang.IllegalArgumentException</code> is thrown.</p>
	 * 
	 * <p>For more information on the inheritable event mechanism
	 * see the 
	 * {@link com.itmill.toolkit.event com.itmill.toolkit.event package documentation}.</p>
	 * 
	 * @param eventType type of the listened event. Events of this type or
	 * its subclasses activate the listener.
	 * @param object the object instance who owns the activation method
	 * @param methodName the name of the activation method
	 * @throws java.lang.IllegalArgumentException unless <code>method</code>
	 * has exactly one match in <code>object</code>
	 */
	public void addListener(
		Class eventType,
		Object object,
		String methodName) {
		if (eventRouter == null)
			eventRouter = new EventRouter();
		eventRouter.addListener(eventType, object, methodName);
	}

	/** Removes all registered listeners matching the given parameters.
	 * Since this method receives the event type and the listener object as
	 * parameters, it will unregister all <code>object</code>'s methods that
	 * are registered to listen to events of type <code>eventType</code>
	 * generated by this component.
	 * 
	 * <p>For more information on the inheritable event mechanism
	 * see the 
	 * {@link com.itmill.toolkit.event com.itmill.toolkit.event package documentation}.</p>
	 * 
	 * @param eventType exact event type the <code>object</code> listens to
	 * @param target target object that has registered to listen to events
	 * of type <code>eventType</code> with one or more methods
	 */
	public void removeListener(Class eventType, Object target) {
		if (eventRouter != null)
			eventRouter.removeListener(eventType, target);
	}

	/** Removes one registered listener method. The given method owned by
	 * the given object will no longer be called when the specified events
	 * are generated by this component.
	 * 
	 * <p>For more information on the inheritable event mechanism
	 * see the 
	 * {@link com.itmill.toolkit.event com.itmill.toolkit.event package documentation}.</p>
	 * 
	 * @param eventType exact event type the <code>object</code> listens to
	 * @param target target object that has registered to listen to events
	 * of type <code>eventType</code> with one or more methods
	 * @param method the method owned by <code>target</code> that's
	 * registered to listen to events of type <code>eventType</code>
	 */
	public void removeListener(Class eventType, Object target, Method method) {
		if (eventRouter != null)
			eventRouter.removeListener(eventType, target, method);
	}

	/** <p>Removes one registered listener method. The given method owned by
	 * the given object will no longer be called when the specified events
	 * are generated by this component.</p>
	 * 
	 * <p>This version of <code>removeListener</code> gets the name of the
	 * activation method as a parameter. The actual method is reflected from
	 * <code>target</code>, and unless exactly one match is found,
	 * <code>java.lang.IllegalArgumentException</code> is thrown.</p>
	 * 
	 * <p>For more information on the inheritable event mechanism
	 * see the 
	 * {@link com.itmill.toolkit.event com.itmill.toolkit.event package documentation}.</p>
	 * 
	 * @param eventType exact event type the <code>object</code> listens to
	 * @param target target object that has registered to listen to events
	 * of type <code>eventType</code> with one or more methods
	 * @param methodName name of the method owned by <code>target</code>
	 * that's registered to listen to events of type <code>eventType</code>
	 */
	public void removeListener(
		Class eventType,
		Object target,
		String methodName) {
		if (eventRouter != null)
			eventRouter.removeListener(eventType, target, methodName);
	}

	/** Send event to all listeners
	 * @param event Event to be sent to all listeners
	 */
	protected void fireEvent(Component.Event event) {

		if (eventRouter != null)
			eventRouter.fireEvent(event);

	}

	/* Component event framework *************************************** */

	/* Registers a new listener to listen events generated by this
	 * component.
	 * Don't add a JavaDoc comment here, we use the default documentation
	 * from implemented interface.
	 */
	public void addListener(Component.Listener listener) {

		if (eventRouter == null)
			eventRouter = new EventRouter();

		eventRouter.addListener(
			Component.Event.class,
			listener,
			COMPONENT_EVENT_METHOD);
	}

	/* Removes a previously registered listener from this component.
	 * Don't add a JavaDoc comment here, we use the default documentation
	 * from implemented interface.
	 */
	public void removeListener(Component.Listener listener) {

		if (eventRouter != null) {
			eventRouter.removeListener(
				Component.Event.class,
				listener,
				COMPONENT_EVENT_METHOD);
		}
	}

	/** Emits a component event. It is transmitted to all registered
	 * listeners interested in such events.
	 */
	protected void fireComponentEvent() {
		fireEvent(new Component.Event(this));
	}

	/** Emits a component error event. It is transmitted to all registered
	 * listeners interested in such events.
	 */
	protected void fireComponentErrorEvent() {
		fireEvent(new Component.ErrorEvent(this.getComponentError(),this));
	}

	/** Sets application specific data object.
     * 
     * @param data Application specific data.
     * @since 3.1
	 */
    public void setData(Object data) {
        this.applicationData = data;
    }
    
    /** Gets application specific data.
     * 
     * @return Application specific data set with setData function.
     * @since 3.1
     */
    public Object getData() {
        return this.applicationData;
    }
}