/*
 * Copyright (c) 2010-2016 Evolveum
 *
 * 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 com.evolveum.midpoint.web.component;

import com.evolveum.midpoint.web.resource.img.ImgResources;
import com.evolveum.midpoint.gui.api.component.BasePanel;
import com.evolveum.midpoint.web.component.util.FutureUpdateBehavior;
import com.evolveum.midpoint.web.component.util.VisibleEnableBehaviour;

import org.apache.wicket.Component;
import org.apache.wicket.ajax.AjaxRequestTarget;
import org.apache.wicket.markup.html.image.Image;
import org.apache.wicket.model.IModel;
import org.apache.wicket.model.Model;
import org.apache.wicket.request.resource.PackageResourceReference;
import org.apache.wicket.request.resource.ResourceReference;
import org.apache.wicket.util.time.Duration;
import org.springframework.security.core.Authentication;
import org.springframework.security.core.context.SecurityContextHolder;

import java.io.Serializable;
import java.util.concurrent.Future;

/**
 * @author lazyman
 */
public abstract class AsyncUpdatePanel<V, T extends Serializable> extends BasePanel<T> {

    private static final ResourceReference PRELOADER =
            new PackageResourceReference(ImgResources.class, "ajax-loader.gif");

    /**
     * Duration in seconds.
     */
    public static final int DEFAULT_TIMER_DURATION = 2;

    protected transient Future<T> future;
    private boolean loadingVisible = true;

    public AsyncUpdatePanel(String id, IModel<V> callableParameterModel) {
        this(id, callableParameterModel, Duration.seconds(DEFAULT_TIMER_DURATION));
    }

    public AsyncUpdatePanel(String id, IModel<V> callableParameterModel, Duration durationSecs) {
        super(id, new Model<T>());

        Authentication auth = SecurityContextHolder.getContext().getAuthentication();
        future = GuiComponents.submitCallable(createCallable(auth, callableParameterModel));
        FutureUpdateBehavior<T> behaviour = new FutureUpdateBehavior<T>(durationSecs, future) {

            @Override
            protected void onPostSuccess(AjaxRequestTarget target) {
                loadingVisible = false;

                AsyncUpdatePanel.this.onPostSuccess(target);
            }

            @Override
            protected void onUpdateError(AjaxRequestTarget target, Exception ex) {
                loadingVisible = false;

                AsyncUpdatePanel.this.onUpdateError(target, ex);
            }
        };
        add(behaviour);
    }

    protected abstract void onPostSuccess(AjaxRequestTarget target);

    protected abstract void onUpdateError(AjaxRequestTarget target, Exception ex);

    protected boolean isLoadingVisible() {
        return loadingVisible;
    }

    protected Component getLoadingComponent(final String markupId) {
        Image image = new Image(markupId, PRELOADER);
        image.add(new VisibleEnableBehaviour() {

            @Override
            public boolean isVisible() {
                return isLoadingVisible();
            }
        });

        return image;
    }

    protected abstract Component getMainComponent(final String markupId);

    /**
     * Create a callable that encapsulates the actual fetching of the data needed
     * by the panel for rendering.
     *
     * @param auth provides {@link org.springframework.security.core.Authentication} object (principal) for async
     *             thread which will be used with callable
     * @param callableParameterModel Model providing access to parameters needed by the callable
     * @return A callable instance that encapsulates the logic needed to obtain the panel data
     */
    protected abstract SecurityContextAwareCallable<T> createCallable(Authentication auth, IModel<V> callableParameterModel);
}