package cz.xelfi.feedbook;

import com.google.code.facebookapi.FacebookException;

import com.google.code.facebookapi.FacebookJaxbRestClient;

import com.google.code.facebookapi.Permission;

import com.sun.syndication.feed.rss.Channel;

import com.sun.syndication.feed.rss.Item;

import com.sun.syndication.io.WireFeedInput;

import java.awt.Desktop;

import java.io.IOException;

import java.net.URI;

import java.net.URISyntaxException;

import java.net.URL;

import java.util.prefs.Preferences;

import org.xml.sax.InputSource;

public class Main {

    private static String APP_KEY;

    private static String APP_SEC;

    private static String APP_FEED;

    // BEGIN: feedbook-login

    private static String login() 

    throws IOException, FacebookException, URISyntaxException {

        FacebookJaxbRestClient login = new FacebookJaxbRestClient(

            APP_KEY, APP_SEC

        );

        final String token = login.auth_createToken();

        final URI u = new URI("http://www.facebook.com/login.php?"

                + "api_key=" + APP_KEY + "&auth_token=" + token);

        String msg = "authentication";

        browser(msg, u);

        return login.auth_getSession(token, false); 

    }

    // END: feedbook-login

    private static void browser(String msg, URI u) throws IOException {

        System.out.println(msg + ": " + u);

        try {

            Desktop.getDesktop().browse(u);

        } catch (Exception ex) {

            Runtime.getRuntime().exec("xdg-open " + u);

        }

        System.out.println("Visit the browser and press enter...");

        System.in.read();

    }

    public static void main( String[] args) throws Exception {

        Preferences prefs = Preferences.userNodeForPackage(Main.class);

        if (args.length == 3) {

            prefs.put("id", args[0]);

            prefs.put("secret", args[1]);

            prefs.put("feed", args[2]);

        } else {

            if (args.length != 0) {

                usage();

                return;

            }

        }

        APP_KEY = prefs.get("id", null);

        APP_SEC = prefs.get("secret", null);

        APP_FEED = prefs.get("feed", null);

        if (APP_FEED == null || APP_SEC == null || APP_KEY == null) {

            usage();

            return;

        }

        WireFeedInput rssInput = new WireFeedInput();

        URL rssUrl = new URL(APP_FEED);

        Channel rss = (Channel)rssInput.build(new InputSource(rssUrl.openStream()));;

        FacebookJaxbRestClient fb;

        Long user;

        for (;;) {

            final String stored = prefs.get("session", null);

            if (stored != null) {

                try {

                    fb = new FacebookJaxbRestClient(APP_KEY, APP_SEC, stored);

                    user = fb.users_getLoggedInUser();

                    break;

                } catch (FacebookException ex) {

                    System.err.println(ex.getMessage());

                }

            }

            final String session = login();

            fb = new FacebookJaxbRestClient(APP_KEY, APP_SEC, session);

            user = fb.users_getLoggedInUser();

            prefs.put("session", session);

            break;

        }

        // BEGIN: feedbook-permission

        while (!fb.users_hasAppPermission(Permission.SHARE_ITEM)) {

            URI u = new URI("https://graph.facebook.com/oauth/authorize?"

                    + "client_id=" + APP_KEY

                    + "&redirect_uri=http://www.facebook.com/connect/login_success.html"

                    + "&scope=publish_stream");

            browser("Need permission to publish links", u);

        }

        // END: feedbook-permission

        Preferences n = prefs.node("feeds");

        int cnt = 0;

        for (Object o : rss.getItems()) {

            Item item = (Item) o;

            String hex = Integer.toHexString(item.getLink().hashCode());

            if (n.getLong(hex, -1L) != -1L) {

                continue;

            }

            cnt++;

            // BEGIN: feedbook-publish-link

            System.out.printf(

                "link: %s date: %s title: %s\n", 

                item.getLink(), item.getPubDate(), item.getTitle()

            );

            Long ok = fb.links_post(user, item.getLink(), item.getTitle());

            System.out.println("posted as " + ok);

            // END: feedbook-publish-link

            n.putLong(hex, ok);

            n.put(hex + ".url", item.getLink());

        }

        System.out.println("Published " + cnt + " feed item(s)");

    }

    private static void usage() {

        System.out.println("Invoke with three parameters: "

                + "<facebook_app_key> "

                + "<facebook_app_secret "

                + "<rss_feed_url>");

    }

}