/*
 * Jitsi, the OpenSource Java VoIP and Instant Messaging client.
 *
 * Copyright @ 2015 Atlassian Pty Ltd
 *
 * 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 net.java.sip.communicator.impl.replacement.flickr;

import java.io.*;
import java.net.*;
import java.util.regex.*;

import net.java.sip.communicator.service.replacement.*;
import net.java.sip.communicator.util.*;

import org.json.simple.*;

/**
 * Implements the {@link ReplacementService} to provide previews for Flickr
 * links.
 *
 * @author Purvesh Sahoo
 */
public class ReplacementServiceFlickrImpl
    implements ReplacementService
{
    /**
     * The logger for this class.
     */
    private static final Logger logger =
        Logger.getLogger(ReplacementServiceFlickrImpl.class);

    /**
     * The regex used to match the link in the message.
     */
    public static final String FLICKR_PATTERN =
        "(https?\\:\\/\\/(www\\.)*?flickr\\.com"
        + "\\/photos\\/[0-9a-zA-Z_\\-\\@]+\\/([0-9]+)(\\/[^\"\\<]*)*)";

    /**
     * API Key required to access the Flickr api.
     */
    public static final String API_KEY = "8b5d9cee22f0f5154bf4e9846c025484";

    /**
     * Configuration label shown in the config form.
     */
    public static final String FLICKR_CONFIG_LABEL = "Flickr Images";

    /**
     * Source name; also used as property label.
     */
    public static final String SOURCE_NAME = "FLICKR";

    /**
     * Constructor for <tt>ReplacementServiceFlickrImpl</tt>.
     */
    public ReplacementServiceFlickrImpl()
    {
        logger.trace("Creating a Flickr Source.");
    }

    /**
     * Replaces the Flickr image links with their corresponding thumbnails.
     *
     * @param sourceString the original flickr image link.
     * @return replaced thumbnail image link; the original image link in case of
     *         no match.
     */
    public String getReplacement(String sourceString)
    {
        final Pattern p =
            Pattern.compile(
                "\\/photos\\/[0-9a-zA-Z_\\-\\@]+\\/([0-9]+)(\\/[^\"\\<]*)*",
                Pattern.CASE_INSENSITIVE | Pattern.DOTALL);
        Matcher m = p.matcher(sourceString);
        String thumbUrl = sourceString;

        while (m.find())
        {
            try
            {
                // API URL
                String url =
                    "http://api.flickr.com/services/rest/"
                    + "?method=flickr.photos.getInfo&api_key="
                        + API_KEY + "&photo_id=" + m.group(1)
                        + "&format=json&nojsoncallback=1";

                URL flickrURL = new URL(url);
                URLConnection conn = flickrURL.openConnection();

                BufferedReader in =
                    new BufferedReader(new InputStreamReader(conn
                        .getInputStream()));

                String inputLine, holder = "";

                while ((inputLine = in.readLine()) != null)
                    holder = inputLine;
                in.close();

                JSONObject wrapper = (JSONObject)JSONValue
                    .parseWithException(holder);

                if (wrapper.get("stat").equals("ok"))
                {
                    JSONObject result = (JSONObject)wrapper.get("photo");
                    if (!(result.isEmpty()))
                    {
                        String farmID = String.valueOf(result.get("farm"));
                        String serverID = (String)result.get("server");
                        String secret = (String)result.get("secret");

                        thumbUrl =
                            "http://farm" + farmID + ".static.flickr.com/"
                                + serverID + "/" + m.group(1) + "_" + secret
                                + "_t.jpg";
                    }
                }
            }
            catch(Throwable e)
            {
                logger.error("Error parsing", e);
            }
        }

        return thumbUrl;
    }

    /**
     * Returns the source name
     *
     * @return the source name
     */
    public String getSourceName()
    {
        return SOURCE_NAME;
    }

    /**
     * Returns the pattern of the source
     *
     * @return the source pattern
     */
    public String getPattern()
    {
        return FLICKR_PATTERN;
    }
}