package de.mrbesen.youtubecrawler;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.LinkedList;
import java.util.List;
import java.util.Random;

import org.apache.log4j.Logger;

import com.mysql.cj.jdbc.exceptions.MysqlDataTruncation;

import de.mrbesen.youtubecrawler.Crawler.Video;

public class DB implements Runnable {

	private Connection con;
	private String server = Config.prop.getProperty("db.host", "localhost"), user = Config.prop.getProperty("db.user", "ytcrawler"), pw = Config.prop.getProperty("db.pw", ""), db = Config.prop.getProperty("db.dbname", "ytcrawler");
	private int port = Integer.parseInt(Config.prop.getProperty("db.port", "3306")); 
	private Logger log = Logger.getLogger(DB.class.getName());
	private ArrayList<String> randombuffer = new ArrayList<>(100);
	private Random rand = new Random();
	private Thread randomrefill = null;
	private int dbsize = 0;
	
	private StringBuilder tostorebuffer ;
	private int writebuffersize = 500;
	private int writebuffercurrentsize = 0;
	
	private StringBuilder totempbuffer;
	private int writetempbuffercurrentsize = 0;

	public DB() {
		try {
			connect(false);

			//set the database up!
			boolean found = false;
			ResultSet set = con.getMetaData().getCatalogs();//does the db exists?
			while(set.next()) {
				if(set.getString(1).equalsIgnoreCase(db)) {
					found = true;
					con.setCatalog(db);
					break;
				}
			}

			if(!found) {//DataBase not found, try to create
				log.warn("Database not found! tring to create!");
				//create DB, table: konten / player / Transactions
				update("CREATE DATABASE `" + db + "` /*!40100 DEFAULT CHARACTER SET latin1*/;");
				con.setCatalog(db);
				update("CREATE TABLE `videos` (`id` varchar(13) NOT NULL,`length` int(11) NOT NULL,`created` int(11) NOT NULL,`langcode` varchar(3) NOT NULL DEFAULT 'en',`category` int(11) DEFAULT NULL, PRIMARY KEY (`id`), UNIQUE KEY `id_UNIQUE` (`id`)) ENGINE=InnoDB DEFAULT CHARSET=latin1;");
				update("CREATE TABLE `temp` ( `ytid` varchar(13) NOT NULL COMMENT 'a Table to store Video ids, when they are found to process them later', PRIMARY KEY (`ytid`), UNIQUE KEY `ytid_UNIQUE` (`ytid`)) ENGINE=InnoDB DEFAULT CHARSET=utf8;");

				log.info("Database is set up!");
			}

			refillbuffer();

			//get db size
			dbsize();

			//config data
			try {
				writebuffersize = Integer.parseInt(Config.prop.getProperty("db.writebuffersize"));
			} catch(NumberFormatException e) {
				log.warn("could not read the number \"" + Config.prop.getProperty("db.writebuffersize") + "\" from the config file. db.writebuffersize");
			}
			tostorebuffer = new StringBuilder(writebuffersize);
			totempbuffer = new StringBuilder(writebuffersize);
		} catch (SQLException e) {
			log.error("Error while connecting to the database! ", e);
		}
	}

	private void dbsize() {
		try {
			ResultSet set = query("SELECT count(*) as count FROM `videos`;");
			if(set != null) {
				if(set.next()) {
					dbsize = set.getInt(1);
				}
			}
		} catch(SQLException e) {
			e.printStackTrace();
		}
	}

	public int getDBSize() {
		return dbsize;
	}

	private void connect(boolean selectdb) {
		try {
			//verbinden
			con = DriverManager.getConnection("jdbc:mysql://" + server + ":" + port + "/" + (selectdb ? db : "") + "?serverTimezone=UTC&verifyServerCertificate=false&useSSL=true&useUnicode=true&characterEncoding=utf-8", user, pw);
		}catch (SQLException e) {
			log.error("Error while connecting to the database! ", e);
		}
	}

	/**
	 * removes all videos, that are known from the db
	 * @param input
	 * @return
	 */
	public List<String> checkvideos(List<String> input) {
		if(!input.isEmpty()) {
			StringBuilder ids  = new StringBuilder();
			for(int i = 0; i < input.size(); i++) {
				ids.append(',').append(input.get(i));
			}
			String query = "SELECT `id` FROM `videos` WHERE concat('%',`id`,'%') LIKE '" + ids.toString() +  "';";
			ResultSet res = query(query);
			try {
				while(res.next()) {
					input.remove(res.getString(1));
				}
			} catch(SQLException e) {
				e.printStackTrace();
			}
		}
		return input;
	}

	/**
	 * save the list of videos to the DB
	 * @param input
	 */
	public void addVideos(ArrayList<Video> input, boolean force) {
		if(input != null) {
			if(input.size() > 0) {
				writebuffercurrentsize += input.size();
				for(int i = 0; i < input.size(); i++) {
					Video v = input.get(i);
					if(v != null)
						tostorebuffer.append(",('").append(escape(v.id)).append("',").append(v.length).append(",").append(v.created).append(",'").append(escape(v.languageCode)).append("',").append(v.categorie).append(",'").append(escape(v.title)).append("','").append(escape(v.channel)).append("','").append(escape(v.tags)).append("') ");
				}
			}
		}
		if(writebuffercurrentsize > writebuffersize || force) {
			if(tostorebuffer.length() > 10) {
				log.info("Write databuffer to DB video count: " + writebuffercurrentsize);
				dbsize += writebuffercurrentsize;
				tostorebuffer.deleteCharAt(0);//delete leading ','
				String qu = "INSERT IGNORE INTO `videos`(`id`, `length`, `created`, `langcode`, `category`, `videotitle`, `channel`, `tags`) VALUES " + tostorebuffer.toString();
				update(qu);
				
				//reset buffer
				writebuffercurrentsize = 0;
				tostorebuffer = new StringBuilder(writebuffersize);
			}
		}
	}

	private String escape(String e) {
		return e.replace("'", "\\'");
	}

	public void updateVideos(List<Video> input) {
		log.info("Updateing " + input.size() + " videos.");
		for(Video v : input) {
			if(v != null)
				updateVideo(v);
		}
	}

	private void updateVideo(Video v) {
		try {
			String qu = "UPDATE `videos` SET `length` = " + v.length + ", `created` = " + v.created + ", `langcode` = SUBSTR('" + v.languageCode + "', 1, 3) ,`category` = " + v.categorie + ",`videotitle` = SUBSTR('" + escape(v.title) + "',1,100),`channel` = SUBSTR('" + escape(v.channel) + "',1,20),`tags` = '" + escape(v.tags) + "' WHERE `id` = '" + escape(v.id) + "';";
			update(qu);
		} catch(NullPointerException e) {

		}
	}

	public LinkedList<String> getUncompleted(int limit, int offset) {
		LinkedList<String> out = new LinkedList<>();
		String sql = "SELECT `id` FROM `videos` WHERE `channel` IS NULL LIMIT " + offset + "," + limit + ";";
		ResultSet resu = query(sql);
		try {
			while(resu.next()) {
				out.add(resu.getString(1));
			}
		} catch (SQLException e) {
			log.info("error", e);
		}
		return out;
	}

	public void removeVideos(LinkedList<Video> vids) {
		log.info("Delete " + vids.size() + " videos.");
		for(Video s : vids) {
			update("DELETE FROM `videos` WHERE `id`='" + escape(s.id) + "';");
		}
	}

	/**
	 * instant query
	 * @param q
	 * @return Das resultSet der Query
	 */

	public ResultSet query(String q) {
		try {
			if(con.isClosed()) {
				connect(true);
			}
			return con.prepareStatement(q).executeQuery();
		} catch (SQLException e) {
			log.error("Fehler bim ausführen der Query: " + q, e);
		}
		return null;//ERROR!
	}

	/**
	 * instant update
	 * @param q
	 */
	public void update(String q) {
		try {
			if(con.isClosed()) {
				connect(true);
			}
			con.prepareStatement(q).executeUpdate();
		} catch (MysqlDataTruncation ignore) {
			log.info("truncated.", ignore);
		} catch (SQLException e) {
			log.error("Fehler bim ausführen der Update-Query: " + q, e);
		}
	}

	private void refillbuffer() {
		if(randomrefill == null) {
			randomrefill = new Thread(this, "Randomrefill");
			randomrefill.start();
		}
	}

	public String getRandom() {
		log.info("Get random Video");
		if(randombuffer.size() < 10 ) {
			refillbuffer();
		}
		if(randombuffer.isEmpty()) {
			log.warn("randombuffer is empty!");
			return null;
		}
		return randombuffer.remove(0);
	}

	public int getRandomCount() {
		return randombuffer.size();
	}

	public LinkedList<String> restoreTemp() {
		ResultSet res = query("SELECT * FROM `temp` LIMIT 500;");
		LinkedList<String> out = new LinkedList<>();
		log.info("RestoreTemp");
		try {
			while(res.next()) {
				out.add(res.getString(1));
			}
			update("DELETE FROM `temp` LIMIT 500;");
		} catch (Exception e) {}
		return out;
	}

	public void deleteDouble() {
		log.info("Started Delete Double");
		long start = System.currentTimeMillis();
		update("CALL deletedouble();");
		log.info("Delete Double done in " + ((System.currentTimeMillis() - start)/60000) + " min");
	}

	public void storeTemp(ArrayList<String> strings, boolean force) {
		if(strings == null)
			return;
		if(!strings.isEmpty()) {
			log.info("store Temp to buffer: " + strings.size());
			writetempbuffercurrentsize += strings.size();
			for(String s : strings) {
				totempbuffer.append(", ('").append(escape(s)).append("')");
			}
		}
		if(writetempbuffercurrentsize > writebuffersize || force) {
			log.info("Write Buffer: " + writetempbuffercurrentsize);
			totempbuffer.deleteCharAt(0);//delete leading ','
			String qu = "INSERT IGNORE INTO `temp` (`ytid`) VALUES " + totempbuffer.toString() + ";";
			update(qu);
			
			//reset
			writetempbuffercurrentsize = 0;
			totempbuffer = new StringBuilder(writebuffersize);
		}
	}


	/**
	 * Stops the randomnes-Server and disconnect
	 */
	public void stop() {
		try {
			if(con != null) {
				if(!con.isClosed()) {
					addVideos(null, true);
					con.commit();
					con.close();
				}
			}
		} catch (SQLException e) {
			e.printStackTrace();
		}
	}

	/**
	 * runable, of Thread for randomrefill
	 */
	@Override
	public void run() {
		log.info("Started Refilling.");
			try {
				ResultSet set = query("SELECT `id` FROM `videos` ORDER BY rand() LIMIT 100;");
				if(set != null) {
					while(set.next()) {
						randombuffer.add(set.getString(1));
					}
					log.info("refilled randombuffer to " + randombuffer.size() + " videos.");
				}
			} catch (SQLException e) {
				log.warn("error getting a random video", e);
			}

		if(randombuffer.isEmpty()) {
			log.error("Unable to retrieve RandomVideos");
		}
		randomrefill = null;
	}
}