package de.mrbesen.youtubecrawler;

import java.io.IOException;
import java.util.LinkedList;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import org.apache.log4j.Logger;

public class CrawlerThread implements Runnable {

	private static Pattern linkpattern = Pattern.compile("href=\"\\/watch\\?v=");

	private Logger log  = Logger.getLogger(this.getClass().getName());
	private Crawler parent;
	Thread thread;
	
	LinkedList<String> todo = new LinkedList<>();//videos, this thread should crawl
	LinkedList<String> crawled = new LinkedList<>();//videos this thread had crawled
	LinkedList<String> found = new LinkedList<>();//videos this thread had found

	boolean requested = true;//is a request pending?
	boolean lockforreport = false;
	
	public CrawlerThread( Crawler root) {
		parent = root;
		root.request(this);
	}
	
	void setThread(Thread t) {
		thread = t;
	}

	LinkedList<String> undone() {
		return todo;
	}
	
	int undoneSize() {
		return todo.size();
	}
	
	@Override
	public void run() {
		while(parent.isCrawling()) {
			while(!todo.isEmpty() && parent.isCrawling()) {
				if(lockforreport) {
					try {
						Thread.sleep(10);
					} catch(InterruptedException e) {
						lockforreport = false;
					}
				}
				crawl(todo.removeFirst());
				if(todo.size() < parent.requestlimit && !requested) {
					requested = true;
					parent.request(this);
				}
			}
			
			if(todo.isEmpty() && !requested) {
				requested = true;
				parent.request(this);
			}
			
			log.warn("No Object left!");
			Thread.yield();
			try {
				Thread.sleep(10000);//sleep for 10 seconds
			} catch (InterruptedException ignored) {}
		}
		log.info("Stopped.");
	}

	/**
	 * returns a linkedlist of all crawled videos
	 * @return
	 */
	LinkedList<String>[] report() {
		lockforreport = true;
		LinkedList<String>[] out = new LinkedList[] {(LinkedList) crawled, (LinkedList) found};
		crawled = new LinkedList<>();
		found = new LinkedList<>();
		lockforreport = false;
		thread.interrupt();
		return out;
	}

	private void crawl(String videoid) {
		try {
			crawled.add(videoid);

//			log.info("crawling: " + videoid);
			HTTPS con =  new HTTPS("https://youtube.com/watch?v=" + videoid);
			String s = con.getContent();
			Matcher matcher = linkpattern.matcher(s);
			while(matcher.find()) {
				int beginytid = matcher.end();
				int endxtid = s.indexOf('"', beginytid);
				int endid = s.indexOf('&', beginytid);
				if(endid < endxtid) {
					endxtid = endid;
				}
				String ytid = s.substring(beginytid, endxtid);
				if(ytid.length() > 9 && ytid.length() <= 12) {
					found.add(ytid);
				} else {
//					log.warn("youtube id has wrong length: \"" + ytid + "\"");
				}
			}
		} catch(IOException e) {
			e.printStackTrace();
		}
	}
}