package me.despawningbone.discordbot.utils;

import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.net.URLConnection;
import java.util.AbstractMap;
import java.util.ArrayList;
import java.util.List;
import java.util.Map.Entry;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import org.apache.commons.io.IOUtils;
import org.apache.commons.lang3.StringEscapeUtils;

@SuppressWarnings("deprecation")
public class GoogleSearch {
	
    public static List<Entry<String, String>> search(String search, int num) throws IOException {
        String query = "https://www.google.com/search?q=" + search + "&num=" + num;
    	//String query = "https://www.google.com/search?q=site:https://osu.ppy.sh/+searchbigblack&amp;num=100&amp;gbv=1&amp;sei=u4V8Wo2GIczfvASZtoaQCQ";
        String page = getSearchContent(query);
        return parseLinks(page);
    }
 
    /**
     * The method will return the search page result in a {@link String} object
     * 
     * @param path
     *            the google search query
     * @return the content as {@link String} object
     * @throws Exception
     */
    public static String getSearchContent(String path) throws IOException {
    	final String agent = "Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:57.0)";
        //final String agent = "Mozilla/5.0 (compatible; Googlebot/2.1; +http://www.google.com/bot.html)";
        URL url = new URL(path);
        final URLConnection connection = url.openConnection();
        /**
         * User-Agent is mandatory otherwise Google will return HTTP response
         * code: 403
         */
        connection.setRequestProperty("User-Agent", agent);
        final InputStream stream = connection.getInputStream();
        return IOUtils.toString(stream, "UTF-8");
    }
 
    /**
     * Parse all links
     * 
     * @param html
     *            the page
     * @return the list with all URLSs
     * @throws Exception
     */
    public static List<Entry<String, String>> parseLinks(String html) {
    	List<Entry<String, String>> result = new ArrayList<Entry<String, String>>();
        //System.out.println(html);
        String pattern1 = "<h3 class=\"r\"><a href=\"/url?q=";
        String pattern2 = "\">";
        String pattern3 = "</a></h3>";
        Pattern p = Pattern.compile(Pattern.quote(pattern1) + "(.*?)" + Pattern.quote(pattern2) + "(.*?)" + Pattern.quote(pattern3));
        //result = new ArrayList<String>(Arrays.asList(html.split(" "))).stream().filter(p.asPredicate()).collect(Collectors.toList());
        
        Matcher m = p.matcher(html);
 
        while (m.find()) {
            String section = m.group(0).trim();
            String url = "", title = "";
            url = section.substring(section.indexOf("/url?q=") + 7);
			url = StringEscapeUtils.unescapeXml(url.substring(0, url.indexOf("&amp;")));
			title = section.substring(section.lastIndexOf("\">") + 2);
			title = StringEscapeUtils.unescapeXml(title.substring(0, title.lastIndexOf("</a></h3>")));
            result.add(new AbstractMap.SimpleEntry<String, String>(title, url));
        }
        return result;
    }
}