/*
 * 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.photos.wicket;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.logging.Logger;
import javax.inject.Inject;

import org.apache.wicket.PageParameters;
import org.apache.wicket.markup.html.basic.Label;
import org.apache.wicket.markup.html.image.Image;
import org.apache.wicket.markup.html.link.Link;
import org.apache.wicket.markup.html.panel.Panel;
import org.apache.wicket.resource.ByteArrayResource;
import org.wamblee.photos.model.Album;
import org.wamblee.photos.model.Photo;
import org.wamblee.photos.model.PhotoEntry;
import org.wamblee.photos.model.plumbing.AuthorizedPhotos;

/**
 * Homepage
 */
public class PhotoPanel extends Panel {

    private static final Logger LOGGER = Logger.getLogger(PhotoPanel.class.getName());

    private static final long serialVersionUID = 1L;
    public static final int MAX_ROWS = 5;
    public static final int MAX_COLUMNS = 5;

    @Inject
    @AuthorizedPhotos
    private transient Album authorized;

    private String path;

    /**
     * Constructor that is invoked when page is invoked without a session.
     *
     * @param parameters Page parameters
     */
    public PhotoPanel(String aId, final PageParameters parameters) throws Exception {
        super(aId);

        path = parameters.getString("path", "/");
        if (!path.startsWith("/")) {
            info("Invalid album '" + path + "', showing root album instead");
            path = "/";
        }
        add(new Label("path", path));

        String parentPath = getParentPath();

        Link prevLink = new Link("prevLink") {
            @Override
            public void onClick() {
                Photo before = getPrevPhoto();
                if (before == null) {
                    return;
                }
                PageParameters pars = new PageParameters();
                pars.put("path", before.getPath());
                setResponsePage(HomePage.class, pars);
            }

            @Override
            public boolean isEnabled() {
                return getPrevPhoto() != null;
            }
        };

        add(prevLink);

        Link nextLink = new Link("nextLink") {
            @Override
            public void onClick() {
                Photo after = getNextPhoto();
                if (after == null) {
                    return;
                }
                PageParameters pars = new PageParameters();
                pars.put("path", after.getPath());
                setResponsePage(HomePage.class, pars);
            }

            @Override
            public boolean isEnabled() {
                return getNextPhoto() != null;
            }
        };

        add(nextLink);

        Link parentLink = new Link("parentLink") {
            {
                if ("/".equals(path)) {
                    setEnabled(false);
                }
            }

            @Override
            public void onClick() {
                PageParameters pars = new PageParameters();

                pars.put("path", getParentPath());
                pars.put("index", 0);
                setResponsePage(HomePage.class, pars);
            }
        };

        add(parentLink);

        Image image = new Image("photo", new ByteArrayResource("image/jpeg", getData(getPhoto())));
        add(image);
    }

    private Photo getPhoto() {
        PhotoEntry current = authorized.getEntry(path);
        if (current instanceof Album) {
            throw new RuntimeException("PhotoPanel can only show a photo: " + current.getClass().getName());
        }
        return (Photo) current;
    }

    private Photo getPrevPhoto() {
        return getAlbum().findPhotoBefore(getPhoto().getId());
    }

    private Photo getNextPhoto() {
        return getAlbum().findPhotoAfter(getPhoto().getId());
    }

    private Album getAlbum() {
        return (Album) getAuthorizedPhotos().getEntry(getParentPath());
    }

    private String getParentPath() {
        String parentPath = path.substring(0, path.lastIndexOf("/"));
        if (parentPath.length() == 0) {
            parentPath = "/";
        }
        return parentPath;
    }

    private byte[] getData(Photo aPhoto) {
        try (InputStream is = aPhoto.getPhoto()) {
            return getBytes(is);
        }
        catch (IOException e) {
            // to improve.
            throw new RuntimeException("Cannot read photo", e);
        }
    }

    private byte[] getBytes(InputStream is) throws IOException {
        ByteArrayOutputStream bos = new ByteArrayOutputStream();
        byte[] block = new byte[1024];
        int n = is.read(block);
        while (n > 0) {
            bos.write(block, 0, n);
            n = is.read(block);
        }
        return bos.toByteArray();
    }

    private Album getAuthorizedPhotos() {
        return authorized;
    }
}