mTHMMY/app/src/main/java/gr/thmmy/mthmmy/utils/ParseHelpers.java

package gr.thmmy.mthmmy.utils;

import org.jsoup.nodes.Document;
import org.jsoup.nodes.Element;
import org.jsoup.select.Elements;

import java.util.ArrayList;

/**
 * This class consists exclusively of static classes (enums) and methods (excluding methods of inner
 * classes). It can be used to resolve a page's language and state or fix embedded videos html code.
 */
public class ParseHelpers {
    /**
     * Debug Tag for logging debug output to LogCat
     */
    @SuppressWarnings("unused")
    private static final String TAG = "ParseHelpers";

    /**
     * An enum describing a forum page's language by defining the types:<ul>
     * <li>{@link #PAGE_INCOMPLETE}</li>
     * <li>{@link #UNDEFINED_LANGUAGE}</li>
     * <li>{@link #ENGLISH}</li>
     * <li>{@link #ENGLISH_GUEST}</li>
     * <li>{@link #GREEK}</li>
     * </ul>
     */
    public enum Language {
        /**
         * Page language is greek.
         */
        GREEK,
        /**
         * Page language is english.
         */
        ENGLISH,
        /**
         * Page language is english and the user is guest.
         */
        ENGLISH_GUEST,
        /**
         * Page is incomplete. Data are not enough to determine the language.
         */
        PAGE_INCOMPLETE,
        /**
         * Page language is not (yet) supported.
         */
        UNDEFINED_LANGUAGE;

        /**
         * Returns one of the supported forum languages.
         *
         * @param page {@link Document} object containing this page's source code
         * @return language of this page
         * @see org.jsoup.Jsoup Jsoup
         */
        public static Language getLanguage(Document page) {
            Element welcoming = page.select("h3").first();
            if (welcoming == null) {
                Element welcomingGuest = page.select("div[id=myuser]").first();
                if (welcomingGuest != null) {
                    if (welcomingGuest.text().contains("Welcome")) return ENGLISH_GUEST;
                }
                return PAGE_INCOMPLETE;
            } else if (welcoming.text().contains("Καλώς ορίσατε")) return GREEK;
            else if (welcoming.text().contains("Hey")) return ENGLISH;
            else return UNDEFINED_LANGUAGE;
        }

        /**
         * This method defines a custom equality check for {@link Language} enums.
         * <p>Method returns true if parameter's Target is the same as the object and in the specific
         * cases described below, false otherwise.</p><ul>
         * <li>{@link #ENGLISH}.is({@link #ENGLISH_GUEST}) returns true</li>
         * <li>{@link #ENGLISH_GUEST}.is({@link #ENGLISH}) returns true</li>
         *
         * @param other another Language
         * @return true if <b>enums</b> are equal, false otherwise
         */
        public boolean is(Language other) {
            return this == ENGLISH && other == ENGLISH_GUEST
                    || this == ENGLISH_GUEST && other == ENGLISH
                    || this == other;
        }
    }

    /**
     * An enum describing the state of a forum page by defining the types:<ul>
     * <li>{@link #UNAUTHORIZED_OR_MISSING}</li>
     * <li>{@link #NEW_PM}</li>
     * <li>{@link #READY}</li>
     * </ul>
     */
    public enum State {
        /**
         * This page is either missing or is off limits.
         */
        UNAUTHORIZED_OR_MISSING,
        /**
         * The page has a popup window from a new personal message.
         */
        NEW_PM,
        /**
         * The page is ready for use.
         */
        READY;

        /**
         * This method checks the state of a page.
         *
         * @param page a {@link Document} containing this page's source code
         * @return page's State
         */
        public static State getState(Document page) {
            Elements warnings = page.select("form[id=frmLogin] tr.catbg~tr>td.windowbg");
            if (warnings != null) {
                for (Element warning : warnings) {
                    if (warning.text().contains("The topic or board you are looking for appears " +
                            "to be either missing or off limits to you."))
                        return UNAUTHORIZED_OR_MISSING;
                    else if (warning.text().contains("Το θέμα ή πίνακας που ψάχνετε ή δεν υπάρχει ή " +
                            "δεν είναι προσβάσιμο από εσάς. "))
                        return UNAUTHORIZED_OR_MISSING;
                }
            }
            return READY;
        }
    }

    /**
     * This method fixes html so that embedded videos will render properly and be lightweight.
     *
     * @param html an {@link Element} containing the (outer) html to be fixed
     * @return fixed html String
     */
    public static String youtubeEmbeddedFix(Element html) {
        //Fixes embedded videos
        Elements noembedTag = html.select("noembed");
        ArrayList<String> embededVideosUrls = new ArrayList<>();

        for (Element _noembed : noembedTag) {
            embededVideosUrls.add(_noembed.text().substring(_noembed.text()
                            .indexOf("href=\"https://www.youtube.com/watch?") + 38
                    , _noembed.text().indexOf("target") - 2));
        }

        String fixed = html.outerHtml();
        int tmp_counter = 0;
        while (fixed.contains("<embed")) {
            if (tmp_counter > embededVideosUrls.size())
                break;
            fixed = fixed.replace(
                    fixed.substring(fixed.indexOf("<embed"), fixed.indexOf("/noembed>") + 9)
                    , "<div class=\"yt\">"
                            + "<a href=\"https://www.youtube.com/"
                            + embededVideosUrls.get(tmp_counter) + "\" target=\"_blank\">"
                            + "<img class=\"embedded-video-play\" "
                            + "src=\"http://www.youtube.com/yt/brand/media/image/YouTube_light_color_icon.png\""
                            + "</a>"
                            + "<img src=\"https://img.youtube.com/vi/"
                            + embededVideosUrls.get(tmp_counter)
                            + "/default.jpg\" alt=\"\" border=\"0\" width=\"40%\">"
                            + "</div>");
        }
        return fixed;
    }
}