// Copyright 2008, 2009 The Apache Software Foundation
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package org.apache.tapestry5.corelib.components;

import org.apache.tapestry5.*;
import org.apache.tapestry5.annotations.Environmental;
import org.apache.tapestry5.annotations.Parameter;
import org.apache.tapestry5.annotations.SupportsInformalParameters;
import org.apache.tapestry5.corelib.internal.ComponentActionSink;
import org.apache.tapestry5.corelib.internal.FormSupportAdapter;
import org.apache.tapestry5.corelib.internal.HiddenFieldPositioner;
import org.apache.tapestry5.dom.Element;
import org.apache.tapestry5.ioc.annotations.Inject;
import org.apache.tapestry5.services.*;
import org.slf4j.Logger;

/**
 * A FormFragment is a portion of a Form that may be selectively displayed.  Form elements inside a FormFragment will
 * automatically bypass validation when the fragment is invisible.  The trick is to also bypass server-side form
 * processing for such fields when the form is submitted; client-side logic "removes" the {@link
 * org.apache.tapestry5.corelib.components.Form#FORM_DATA form data} for the fragment if it is invisible when the form
 * is submitted; alternately, client-side logic can simply remove the form fragment element (including its visible and
 * hidden fields) to prevent server-side processing.
 * <p/>
 * The client-side element has a new property, formFragment, added to it.  The formFragment object has new methods to
 * control the client-side behavior of the fragment: <dl> <dt>hide()</dt> <dd>Hides the element, using the configured
 * client-side animation effect.</dd> <dt>hideAndRemove()</dt> <dd>As with hide(), but the element is removed from the
 * DOM after being hidden.</dd> <dt>show()</dt> <dd>Makes the element visible, using the configured client-side
 * animation effect.</dd> <dt>toggle()</dt> <dd>Invokes hide() or show() as necessary.</dd> <dt>setVisible()</dt>
 * <dd>Passed a boolean parameter, invokes hide() or show() as necessary.</dd> </dl>
 *
 * @see org.apache.tapestry5.corelib.mixins.TriggerFragment
 */
@SupportsInformalParameters
public class FormFragment implements ClientElement
{
    /**
     * Determines if the fragment is intially visible or initially invisible (the default). This is only used when
     * rendering; when the form is submitted, the hidden field value is used to determine whether the elements within
     * the fragment should be processed (or ignored if still invisible).
     */
    @Parameter
    private boolean visible;

    /**
     * Name of a function on the client-side Tapestry.ElementEffect object that is invoked to make the fragment visible.
     * If not specified, then the default "slidedown" function is used.
     */
    @Parameter(defaultPrefix = BindingConstants.LITERAL)
    private String show;

    /**
     * Name of a function on the client-side Tapestry.ElementEffect object that is invoked when the fragment is to be
     * hidden. If not specified, the default "slideup" function is used.
     */
    @Parameter(defaultPrefix = BindingConstants.LITERAL)
    private String hide;

    /**
     * The element to render for each iteration of the loop. The default comes from the template, or "div" if the
     * template did not specific an element.
     */
    @Parameter(defaultPrefix = BindingConstants.LITERAL)
    private String element;

    /**
     * If bound, then the id attribute of the rendered element will be this exact value. If not bound, then a unique id
     * is generated for the element.
     */
    @Parameter(name = "id", defaultPrefix = BindingConstants.LITERAL)
    private String idParameter;


    @Inject
    private Environment environment;

    @Environmental
    private RenderSupport renderSupport;

    @Inject
    private ComponentSource componentSource;

    @Inject
    private ComponentResources resources;

    @Environmental
    private ClientBehaviorSupport clientBehaviorSupport;

    private String clientId;

    private ComponentActionSink componentActions;

    @Inject
    private Request request;

    @Inject
    private Logger logger;

    @Inject
    private HiddenFieldLocationRules rules;

    private HiddenFieldPositioner hiddenFieldPositioner;

    @Inject
    private ClientDataEncoder clientDataEncoder;

    String defaultElement()
    {
        return resources.getElementName("div");
    }

    /**
     * Renders a &lt;div&gt; tag and provides an override of the {@link org.apache.tapestry5.services.FormSupport}
     * environmental.
     */
    void beginRender(MarkupWriter writer)
    {
        FormSupport formSupport = environment.peekRequired(FormSupport.class);

        String id = resources.getId();

        clientId = resources.isBound("id") ? idParameter : renderSupport.allocateClientId(id);

        hiddenFieldPositioner = new HiddenFieldPositioner(writer, rules);

        Element element = writer.element(this.element, "id", clientId);

        resources.renderInformalParameters(writer);

        if (!visible)
            element.addClassName(CSSClassConstants.INVISIBLE);

        clientBehaviorSupport.addFormFragment(clientId, show, hide);

        componentActions = new ComponentActionSink(logger, clientDataEncoder);

        // Here's the magic of environmentals ... we can create a wrapper around
        // the normal FormSupport environmental that intercepts some of the behavior.
        // Here we're setting aside all the actions inside the FormFragment so that we
        // can control whether those actions occur when the form is submitted.

        FormSupport override = new FormSupportAdapter(formSupport)
        {
            @Override
            public <T> void store(T component, ComponentAction<T> action)
            {
                componentActions.store(component, action);
            }

            @Override
            public <T> void storeAndExecute(T component, ComponentAction<T> action)
            {
                componentActions.store(component, action);

                action.execute(component);
            }
        };

        // Tada!  Now all the enclosed components will use our override of FormSupport,
        // until we pop it off.

        environment.push(FormSupport.class, override);

    }

    /**
     * Closes the &lt;div&gt; tag and pops off the {@link org.apache.tapestry5.services.FormSupport} environmental
     * override.
     *
     * @param writer
     */
    void afterRender(MarkupWriter writer)
    {
        hiddenFieldPositioner.getElement().attributes(
                "type", "hidden",

                "name", Form.FORM_DATA,

                "id", clientId + ":hidden",

                "value", componentActions.getClientData()
        );

        writer.end(); // div

        environment.pop(FormSupport.class);
    }

    public String getClientId()
    {
        return clientId;
    }
}

@@ -5167,48 +5167,8 @@
 );%0A%0A
-        String id = resources.getId();%0A%0A
     
@@ -5253,18 +5253,25 @@
 lientId(
-id
+resources
 );%0A%0A    

Allow setting the id of a FormFragment component