/*
 * Copyright 2005-2010 the original author or authors.
 * 
 * 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.wamblee.wicket.jquery;

import java.util.Arrays;

import org.apache.wicket.Component;
import org.apache.wicket.Page;
import org.apache.wicket.behavior.IBehavior;
import org.apache.wicket.markup.html.IHeaderResponse;
import org.wamblee.wicket.behavior.CompositeBehavior;

/**
 * Abstract JQuery hehavior class that performs some useful basic behaviors for
 * the behavior such as:
 * <ul>
 * <li>Creating a ready function which will be invoked for the component</li>
 * <li>Checking that the component is not a page</li>
 * <li>Creating a call to an intialization function from the ready handler using the component id </li>
 * </ul>
 * 
 * @author Erik Brakkee
 * 
 */
public class AbstractJQueryBehavior extends CompositeBehavior {

    private Component component;
    private String function;

    /**
     * Constructs the behavior.
     * 
     * @param aFunction
     *            Ready function to be invoked.
     * @param aBehaviors
     *            Behaviors to add in addition to the basic JQuery stuff.
     */
    public AbstractJQueryBehavior(String aFunction, IBehavior... aBehaviors) {
        super(getBehaviors(aBehaviors));
        function = aFunction;
    }

    private static IBehavior[] getBehaviors(IBehavior[] aBehaviors) {
        IBehavior[] behaviors = new IBehavior[aBehaviors.length + 1];
        behaviors[0] = new JQueryHeaderContributor();
        for (int i = 0; i < aBehaviors.length; i++) {
            behaviors[i + 1] = aBehaviors[i];
        }
        return behaviors;
    }

    @Override
    public void bind(Component aComponent) {
        if (component != null) {
            throw new IllegalStateException(
                "this kind of handler cannot be attached to " +
                    "multiple components; it is already attached to component " +
                    component + ", but component " + aComponent +
                    " wants to be attached too");
        }
        if (aComponent instanceof Page) {
            throw new IllegalStateException(
                "This behavior cannot be applied to a page: " + aComponent);
        }
        component = aComponent;
        super.bind(aComponent);
        aComponent.setOutputMarkupId(true);
    }

    @Override
    public void renderHead(IHeaderResponse aResponse) {
        super.renderHead(aResponse);
        String jsString = createReadyFunction(function, component);
        aResponse.renderJavascript(jsString, null);
    }

    /**
     * Creates a jQuery ready handler that invokes a given javascript function
     * with the id of a component.
     * 
     * @param aFunction
     *            Javascript function to invoke.
     * @param aComponent
     *            Component to invoke the id for.
     * @return
     */
    public static String createReadyFunction(String aFunction,
        Component aComponent) {
        if (!aComponent.getOutputMarkupId()) {
            throw new IllegalStateException(
                "The component " +
                    aComponent +
                    " does not have its markup id set so this ready handler will not have any effect");
        }
        StringBuffer js = new StringBuffer();
        js.append("jQuery(function(){");
        js.append("org.wamblee." + aFunction + "(\"#" +
            aComponent.getMarkupId() + "\");");
        js.append("});");
        String jsString = js.toString();
        return jsString;
    }
}