/*
 * Copyright 2011 Instituto Superior Tecnico
 * 
 *      https://fenix-ashes.ist.utl.pt/
 * 
 *   This file is part of the vaadin-framework.
 *
 *   The vaadin-framework Infrastructure 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
 *   3 of the License, or (at your option) any later version.*
 *
 *   vaadin-framework 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 vaadin-framework. If not, see <http://www.gnu.org/licenses/>.
 * 
 */
package pt.ist.vaadinframework;

import java.util.EmptyStackException;
import java.util.HashMap;
import java.util.Map;
import java.util.Stack;

import org.apache.commons.lang.StringUtils;

import pt.ist.vaadinframework.annotation.EmbeddedComponentUtils;
import pt.ist.vaadinframework.fragment.FragmentQuery;
import pt.ist.vaadinframework.ui.EmbeddedComponentContainer;

import com.vaadin.ui.UriFragmentUtility;
import com.vaadin.ui.UriFragmentUtility.FragmentChangedEvent;
import com.vaadin.ui.VerticalLayout;
import com.vaadin.ui.Window;

/**
 * @author Pedro Santos (pedro.miguel.santos@ist.utl.pt), Sérgio Silva
 *         (sergio.silva@ist.utl.pt)
 */
public class EmbeddedWindow extends Window {
    final UriFragmentUtility fragmentUtility = new UriFragmentUtility();

    private final Stack<String> history = new Stack<>();

    private final Map<String, EmbeddedComponentContainer> pageCache = new HashMap<>();

    public void open(String fragment) {
        fragmentUtility.setFragment(fragment);
    }

    public void back() {
        try {
            history.pop(); // consume current
            fragmentUtility.setFragment(history.pop());
        } catch (EmptyStackException e) {
            // back fails quietly if no history is available
        }
    }

    public void refresh() {
        loadFragment(history.peek(), false);
    }

    public FragmentQuery getFragment() {
        return new FragmentQuery("#" + fragmentUtility.getFragment());
    }

    public EmbeddedWindow() {
        setImmediate(true);
        final VerticalLayout layout = new VerticalLayout();
        layout.addComponent(fragmentUtility);
        fragmentUtility.addListener(new UriFragmentUtility.FragmentChangedListener() {
            @Override
            public void fragmentChanged(FragmentChangedEvent source) {
                String fragment = source.getUriFragmentUtility().getFragment();
                loadFragment(fragment, true);
            }
        });
        setContent(layout);
    }

    private void loadFragment(String fragment, boolean logHistory) {
        FragmentQuery query = new FragmentQuery("#" + fragment);

        EmbeddedComponentContainer page = null;
        if (pageCache.containsKey(fragment)) {
            page = pageCache.get(fragment);
        } else {
            try {
                Class<? extends EmbeddedComponentContainer> requestedType = EmbeddedApplication.getPage(query.getPath());
                if (requestedType == null) {
                    showNotification("Página não encontrada", "A página pedida não foi encontrada no servidor",
                            Notification.TYPE_ERROR_MESSAGE);
                    VaadinFrameworkLogger.getLogger().info("O fragmento: " + fragment + " não foi encontrado");
                } else {
                    EmbeddedComponentContainer container = requestedType.newInstance();
                    if (container.isAllowedToOpen(query.getParams())) {
                        container.setArguments(query.getParams());
                        if (EmbeddedComponentUtils.getAnnotation(requestedType).persistent()) {
                            pageCache.put(fragment, container);
                        }
                        page = container;
                    } else {
                        showNotification("Acesso negado", "Não tem permissões para aceder a esta página",
                                Notification.TYPE_ERROR_MESSAGE);
                        VaadinFrameworkLogger.getLogger().info("O fragmento: " + fragment + " não pode ser acedido");
                    }
                }
            } catch (InstantiationException e) {
                throw new PageLoadingError(e);
            } catch (IllegalAccessException e) {
                throw new PageLoadingError(e);
            }
        }
        if (page != null) {
            getContent().removeAllComponents();
            getContent().addComponent(fragmentUtility);
            getContent().addComponent(page);
            if (logHistory) {
                history.push(fragment);
                VaadinFrameworkLogger.getLogger().info("history: " + StringUtils.join(history, " > "));
            }
        }
    }
}