/*
Wotonomy: OpenStep design patterns for pure Java applications.
Copyright (C) 2000 Blacksmith, Inc.

This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.

This library 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
Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public
License along with this library; if not, see http://www.gnu.org
*/

package net.wotonomy.web;

import java.util.Enumeration;
import java.util.HashMap;
import java.util.Map;

import net.wotonomy.foundation.NSArray;
import net.wotonomy.foundation.NSDictionary;
import net.wotonomy.foundation.NSMutableDictionary;

/**
 * The base class for dynamic WOElements. Dynamic elements are expected to do
 * something useful with user-entered data in the request and with any binding
 * associations with the context's current WOComponent.
 *
 * @author michael@mpowers.net
 * @author $Author: cgruber $
 * @version $Revision: 905 $
 */
public abstract class WODynamicElement extends WOElement {
	private static final long serialVersionUID = -5383805382837136590L;
	protected String name;
	protected WOElement rootElement;
	protected NSDictionary associations;

	/**
	 * The default constructor.
	 */
	protected WODynamicElement() {
		name = null;
		associations = new NSMutableDictionary();
		rootElement = null;
	}

	/**
	 * Required constructor specifying the class name of the component, a map of
	 * associations, and the root element of the tree that contains this element
	 * (which may be null). The map keys correspond to properties of this element,
	 * and the values are associations to be applied to the context's current
	 * component.
	 */
	public WODynamicElement(String aName, NSDictionary anAssociationMap, WOElement aRootElement) {
		this();
		name = aName;
		associations = anAssociationMap;
		rootElement = aRootElement;
	}

	/**
	 * Package access only. Called to initialize the component with the proper
	 * context before the start of the request-response cycle. If the context has a
	 * current component, that component becomes this component's parent.
	 */
	@Override
	void ensureAwakeInContext(WOContext aContext) {
		if (rootElement != null) {
			rootElement.ensureAwakeInContext(aContext);
		}
	}

	/**
	 * Use this method to get a map with the properties that start with a question
	 * mark. These are supposed to go at the end of a URL, and it is very useful for
	 * components that generate URLs, specially with direct actions.
	 * 
	 * @param c The component where the values of the properties have to be
	 *          retrieved from.
	 */
	Map urlFields(WOComponent c) {
		HashMap map = new HashMap(associations.count());
		Enumeration enumeration = associations.keyEnumerator();
		while (enumeration.hasMoreElements()) {
			String key = (String) enumeration.nextElement();
			if (key.charAt(0) == '?') {
				map.put(key.substring(1), valueForProperty(key, c));
			}
		}
		return map;
	}

	/** Convenience method for getting the value of an association. */
	Object valueForProperty(String key, WOComponent c) {
		WOAssociation a = (WOAssociation) associations.objectForKey(key);
		if (a != null)
			return a.valueInComponent(c);
		return null;
	}

	/** Convenience method for getting the string value of an association. */
	String stringForProperty(String key, WOComponent c) {
		WOAssociation a = (WOAssociation) associations.objectForKey(key);
		Object result = null;
		if (a != null)
			result = a.valueInComponent(c);
		if (result == null)
			return null;
		return result.toString();
	}

	/** Convenience method for getting the string value of an association. */
	boolean booleanForProperty(String key, WOComponent c) {
		WOAssociation a = (WOAssociation) associations.objectForKey(key);
		Object result = null;
		if (a != null)
			result = a.valueInComponent(c);
		if (result == null)
			return false;
		if (result.toString().toLowerCase().equals("true"))
			return true;
		return Boolean.TRUE.equals(result);
	}

	/** Convenience method for setting the value of an association. */
	void setValueForProperty(String key, Object value, WOComponent c) {
		WOAssociation a = (WOAssociation) associations.objectForKey(key);
		if (a != null && a.isValueSettable())
			a.setValue(value, c);
	}

	/**
	 * this method composes a String suitable for inclusion inside a HTML tag. It
	 * includes the key-value pairs of all the associations not mentioned in the
	 * standardProperties parameter. This is very useful for including extra
	 * properties in tags without having to worry if the HTML specification has
	 * changed or if non-standard tags are being used.
	 * 
	 * @param c                  The component where the associations' values should
	 *                           be retrieved from.
	 * @param standardProperties An array of Strings with all the associations that
	 *                           should be excluded from the resulting string.
	 */
	String additionalHTMLProperties(WOComponent c, NSArray standardProperties) {
		Enumeration enumeration = associations.keyEnumerator();
		StringBuffer buf = new StringBuffer();
		while (enumeration.hasMoreElements()) {
			String key = (String) enumeration.nextElement();
			if (!(standardProperties.containsObject(key) || key.charAt(0) == '?')) {
				buf.append(' ');
				buf.append(key);
				buf.append("=\"");
				buf.append(valueForProperty(key, c));
				buf.append('\"');
			}
		}
		return buf.toString();
	}

	/**
	 * This method is called to retrieve user-entered data from the request.
	 * WOElements should retrieve data from the request based on their elementID and
	 * set values in the context's current WOComponent, typically those values that
	 * are associated with the element in the binding. This implementation does
	 * nothing.
	 */
	@Override
	public void takeValuesFromRequest(WORequest aRequest, WOContext aContext) {

	}

	/**
	 * This method is called on all objects and elements of the application until a
	 * non-null value is returned. WOElements should first check to see if they are
	 * the target of an action by checking the WOContext's senderID to see if it
	 * matches this element's elementID. If this element is the target, it should
	 * perform an appropriate action on the context's current WOComponent, usually
	 * the action specified in the binding, and return the result of that action.
	 * This implementation returns null.
	 */
	@Override
	public WOActionResults invokeAction(WORequest aRequest, WOContext aContext) {
		return null;
	}

	/**
	 * This method is called on all elements of the content tree to build a response
	 * to a user request. The message should be forwarded to any child elements so
	 * that the entire tree is traversed. This implementation does nothing.
	 */
	@Override
	public void appendToResponse(WOResponse aResponse, WOContext aContext) {
		// does nothing
	}

	@Override
	public WOResponse generateResponse() {
		return null;
	}

}