/*

  *   SONEWS News Server

  *   see AUTHORS for the list of contributors

  *

  *   This program is free software: you can redistribute it and/or modify

  *   it under the terms of the GNU General Public License as published by

  *   the Free Software Foundation, either version 3 of the License, or

  *   (at your option) any later version.

  *

  *   This program is distributed in the hope that it will be useful,

  *   but WITHOUT ANY WARRANTY; without even the implied warranty of

  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

  *   GNU General Public License for more details.

  *

  *   You should have received a copy of the GNU General Public License

  *   along with this program.  If not, see <http://www.gnu.org/licenses/>.

  */

 package org.sonews.storage.impl;

 import java.sql.Connection;

 import java.sql.DriverManager;

 import java.sql.PreparedStatement;

 import java.sql.ResultSet;

 import java.sql.Statement;

 import java.util.ArrayList;

 import java.util.Collections;

 import java.util.List;

 import java.util.logging.Level;

 import java.util.logging.Logger;

 import org.sonews.config.Config;

 import org.sonews.feed.Subscription;

 import org.sonews.storage.Article;

 import org.sonews.storage.ArticleHead;

 import org.sonews.storage.DrupalArticle;

 import org.sonews.storage.DrupalMessage;

 import static org.sonews.storage.DrupalMessage.parseArticleID;

 import static org.sonews.storage.DrupalMessage.parseGroupID;

 import org.sonews.storage.Group;

 import org.sonews.storage.Storage;

 import org.sonews.storage.StorageBackendException;

 import org.sonews.util.Pair;

 /**

  *

  * @author František Kučera (frantovo.cz)

  */

 public class DrupalDatabase implements Storage {

 	private static final Logger log = Logger.getLogger(DrupalDatabase.class.getName());

 	public static final String CHARSET = "UTF-8";

 	public static final String CRLF = "\r\n";

 	protected Connection conn = null;

 	// TODO: správná doména

 	private String myDomain = "nntp.i1984.cz";

 	public DrupalDatabase() throws StorageBackendException {

 		connectDatabase();

 	}

 	private void connectDatabase() throws StorageBackendException {

 		try {

 			// Load database driver

 			String driverClass = Config.inst().get(Config.LEVEL_FILE, Config.STORAGE_DBMSDRIVER, "java.lang.Object");

 			Class.forName(driverClass);

 			// Establish database connection

 			String url = Config.inst().get(Config.LEVEL_FILE, Config.STORAGE_DATABASE, "<not specified>");

 			String username = Config.inst().get(Config.LEVEL_FILE, Config.STORAGE_USER, "root");

 			String password = Config.inst().get(Config.LEVEL_FILE, Config.STORAGE_PASSWORD, "");

 			conn = DriverManager.getConnection(url, username, password);

 			/**

 			 * Kódování češtiny:

 			 * SET NAMES utf8 → dobrá čeština

 			 *		Client characterset:    utf8

 			 *		Conn.  characterset:    utf8

 			 * SET CHARACTER SET utf8; → dobrá čeština jen pro SLECT, ale při volání funkce se zmrší

 			 *		Client characterset:    utf8

 			 *		Conn.  characterset:    latin1

 			 * 

 			 * Správné řešení:

 			 *		V JDBC URL musí být: ?useUnicode=true&characterEncoding=UTF-8

 			 */

 			conn.setTransactionIsolation(Connection.TRANSACTION_SERIALIZABLE);

 			if (conn.getTransactionIsolation() != Connection.TRANSACTION_SERIALIZABLE) {

 				log.warning("Database is NOT fully serializable!");

 			}

 		} catch (Exception e) {

 			throw new StorageBackendException(e);

 		}

 	}

 	protected static void close(Connection connection, Statement statement, ResultSet resultSet) {

 		if (resultSet != null) {

 			try {

 				resultSet.close();

 			} catch (Exception e) {

 			}

 		}

 		if (statement != null) {

 			try {

 				statement.close();

 			} catch (Exception e) {

 			}

 		}

 		if (connection != null) {

 			try {

 				connection.close();

 			} catch (Exception e) {

 			}

 		}

 	}

 	@Override

 	public List<Group> getGroups() throws StorageBackendException {

 		PreparedStatement ps = null;

 		ResultSet rs = null;

 		try {

 			ps = conn.prepareStatement("SELECT * FROM nntp_group");

 			rs = ps.executeQuery();

 			List<Group> skupiny = new ArrayList<Group>();

 			while (rs.next()) {

 				skupiny.add(new Group(rs.getString("name"), rs.getInt("id"), Group.READONLY));

 			}

 			return skupiny;

 		} catch (Exception e) {

 			throw new StorageBackendException(e);

 		} finally {

 			close(null, ps, rs);

 		}

 	}

 	@Override

 	public Group getGroup(String name) throws StorageBackendException {

 		PreparedStatement ps = null;

 		ResultSet rs = null;

 		try {

 			ps = conn.prepareStatement("SELECT * FROM nntp_group WHERE name = ?");

 			ps.setString(1, name);

 			rs = ps.executeQuery();

 			while (rs.next()) {

 				return new Group(rs.getString("name"), rs.getInt("id"), Group.READONLY);

 			}

 			return null;

 		} catch (Exception e) {

 			throw new StorageBackendException(e);

 		} finally {

 			close(null, ps, rs);

 		}

 	}

 	@Override

 	public boolean isGroupExisting(String groupname) throws StorageBackendException {

 		return getGroup(groupname) != null;

 	}

 	@Override

 	public Article getArticle(String messageID) throws StorageBackendException {

 		Long articleID = parseArticleID(messageID);

 		Long groupID = parseGroupID(messageID);

 		if (articleID == null || groupID == null) {

 			log.log(Level.SEVERE, "Invalid messageID: {0}", new Object[]{messageID});

 			return null;

 		} else {

 			return getArticle(articleID, groupID);

 		}

 	}

 	@Override

 	public Article getArticle(long articleID, long groupID) throws StorageBackendException {

 		PreparedStatement ps = null;

 		ResultSet rs = null;

 		try {

 			ps = conn.prepareStatement("SELECT * FROM nntp_article WHERE id = ? AND group_id = ?");

 			ps.setLong(1, articleID);

 			ps.setLong(2, groupID);

 			rs = ps.executeQuery();

 			if (rs.next()) {

 				DrupalMessage m = new DrupalMessage(rs, myDomain, true);

 				return new DrupalArticle(m);

 			} else {

 				return null;

 			}

 		} catch (Exception e) {

 			throw new StorageBackendException(e);

 		} finally {

 			close(null, ps, rs);

 		}

 	}

 	@Override

 	public List<Pair<Long, ArticleHead>> getArticleHeads(Group group, long first, long last) throws StorageBackendException {

 		PreparedStatement ps = null;

 		ResultSet rs = null;

 		try {

 			ps = conn.prepareStatement("SELECT * FROM nntp_article WHERE group_id = ? AND id >= ? AND id <= ? ORDER BY id");

 			ps.setLong(1, group.getInternalID());

 			ps.setLong(2, first);

 			ps.setLong(3, last);

 			rs = ps.executeQuery();

 			List<Pair<Long, ArticleHead>> heads = new ArrayList<Pair<Long, ArticleHead>>();

 			while (rs.next()) {

 				DrupalMessage m = new DrupalMessage(rs, myDomain, false);

 				String headers = m.getHeaders();

 				heads.add(new Pair<Long, ArticleHead>(rs.getLong("id"), new ArticleHead(headers)));

 			}

 			return heads;

 		} catch (Exception e) {

 			throw new StorageBackendException(e);

 		} finally {

 			close(null, ps, rs);

 		}

 	}

 	@Override

 	public long getArticleIndex(Article article, Group group) throws StorageBackendException {

 		Long id = parseArticleID(article.getMessageID());

 		if (id == null) {

 			throw new StorageBackendException("Invalid messageID: " + article.getMessageID());

 		} else {

 			return id;

 		}

 	}

 	@Override

 	public List<Long> getArticleNumbers(long groupID) throws StorageBackendException {

 		PreparedStatement ps = null;

 		ResultSet rs = null;

 		try {

 			ps = conn.prepareStatement("SELECT id FROM nntp_article WHERE group_id = ?");

 			ps.setLong(1, groupID);

 			rs = ps.executeQuery();

 			List<Long> articleNumbers = new ArrayList<Long>();

 			while (rs.next()) {

 				articleNumbers.add(rs.getLong(1));

 			}

 			return articleNumbers;

 		} catch (Exception e) {

 			throw new StorageBackendException(e);

 		} finally {

 			close(null, ps, rs);

 		}

 	}

 	@Override

 	public int getFirstArticleNumber(Group group) throws StorageBackendException {

 		PreparedStatement ps = null;

 		ResultSet rs = null;

 		try {

 			ps = conn.prepareStatement("SELECT min(id) FROM nntp_article WHERE group_id = ?");

 			ps.setLong(1, group.getInternalID());

 			rs = ps.executeQuery();

 			rs.next();

 			return rs.getInt(1);

 		} catch (Exception e) {

 			throw new StorageBackendException(e);

 		} finally {

 			close(null, ps, rs);

 		}

 	}

 	@Override

 	public int getLastArticleNumber(Group group) throws StorageBackendException {

 		PreparedStatement ps = null;

 		ResultSet rs = null;

 		try {

 			ps = conn.prepareStatement("SELECT max(id) FROM nntp_article WHERE group_id = ?");

 			ps.setLong(1, group.getInternalID());

 			rs = ps.executeQuery();

 			rs.next();

 			return rs.getInt(1);

 		} catch (Exception e) {

 			throw new StorageBackendException(e);

 		} finally {

 			close(null, ps, rs);

 		}

 	}

 	@Override

 	public boolean isArticleExisting(String messageID) throws StorageBackendException {

 		Long articleID = parseArticleID(messageID);

 		Long groupID = parseGroupID(messageID);

 		if (articleID == null || groupID == null) {

 			return false;

 		} else {

 			PreparedStatement ps = null;

 			ResultSet rs = null;

 			try {

 				ps = conn.prepareStatement("SELECT count(*) FROM nntp_article WHERE id = ? AND group_id = ?");

 				ps.setLong(1, articleID);

 				ps.setLong(2, groupID);

 				rs = ps.executeQuery();

 				rs.next();

 				return rs.getInt(1) == 1;

 			} catch (Exception e) {

 				throw new StorageBackendException(e);

 			} finally {

 				close(null, ps, rs);

 			}

 		}

 	}

 	@Override

 	public int countArticles() throws StorageBackendException {

 		PreparedStatement ps = null;

 		ResultSet rs = null;

 		try {

 			ps = conn.prepareStatement("SELECT count(*) FROM nntp_article");

 			rs = ps.executeQuery();

 			rs.next();

 			return rs.getInt(1);

 		} catch (Exception e) {

 			throw new StorageBackendException(e);

 		} finally {

 			close(null, ps, rs);

 		}

 	}

 	@Override

 	public int countGroups() throws StorageBackendException {

 		PreparedStatement ps = null;

 		ResultSet rs = null;

 		try {

 			ps = conn.prepareStatement("SELECT count(*) FROM nntp_group");

 			rs = ps.executeQuery();

 			rs.next();

 			return rs.getInt(1);

 		} catch (Exception e) {

 			throw new StorageBackendException(e);

 		} finally {

 			close(null, ps, rs);

 		}

 	}

 	@Override

 	public int getPostingsCount(String groupname) throws StorageBackendException {

 		PreparedStatement ps = null;

 		ResultSet rs = null;

 		try {

 			ps = conn.prepareStatement("SELECT count(*) FROM nntp_article WHERE group_name = ?");

 			ps.setString(1, groupname);

 			rs = ps.executeQuery();

 			rs.next();

 			return rs.getInt(1);

 		} catch (Exception e) {

 			throw new StorageBackendException(e);

 		} finally {

 			close(null, ps, rs);

 		}

 	}

 	@Override

 	public List<Pair<Long, String>> getArticleHeaders(Group group, long start, long end, String header, String pattern) throws StorageBackendException {

 		log.log(Level.SEVERE, "TODO: getArticleHeaders {0} / {1} / {2} / {3} / {4}", new Object[]{group, start, end, header, pattern});

 		/** TODO: */

 		return Collections.emptyList();

 	}

 	/**

 	 * Checks username and password.

 	 * @param username

 	 * @param password

 	 * @return true if credentials are valid | false otherwise

 	 * @throws StorageBackendException it there is any error during authentication process 

 	 * (but should not be thrown if only bad thing is wrong username or password)

 	 */

 	@Override

 	public boolean authenticateUser(String username,

 			char[] password) throws StorageBackendException {

 		PreparedStatement ps = null;

 		ResultSet rs = null;

 		try {

 			ps = conn.prepareStatement("SELECT nntp_login(?, ?)");

 			ps.setString(1, username);

 			ps.setString(2, String.copyValueOf(password));

 			rs = ps.executeQuery();

 			rs.next();

 			return rs.getInt(1) == 1;

 		} catch (Exception e) {

 			throw new StorageBackendException(e);

 		} finally {

 			close(null, ps, rs);

 		}

 	}

 	/**

 	 * Validates article and if OK, calls {@link #insertArticle(java.lang.String, java.lang.String, java.lang.String, java.lang.Long, java.lang.Long) }

 	 * @param article

 	 * @throws StorageBackendException 

 	 */

 	@Override

 	public void addArticle(Article article) throws StorageBackendException {

 		if (article.getAuthenticatedUser() == null) {

 			log.log(Level.SEVERE, "User was not authenticated, so his article was rejected.");

 			throw new StorageBackendException("User must be authenticated to post articles");

 		} else {

 			try {

 				DrupalMessage m = new DrupalMessage(article);

 				Long parentID = m.getParentID();

 				Long groupID = m.getGroupID();

 				if (parentID == null || groupID == null) {

 					throw new StorageBackendException("No valid In-Reply-To header was found → rejecting posted message.");

 				} else {

 					String subject = m.getSubject();

 					String text = m.getBodyXhtmlFragment();

 					if (subject == null || subject.length() < 1) {

 						String plainText = m.getBodyPlainText();

 						subject = plainText.substring(0, Math.min(32, plainText.length()));

 						if (subject.length() < plainText.length()) {

 							subject = subject + "…";

 						}

 					}

 					insertArticle(article.getAuthenticatedUser(), subject, text, parentID, groupID);

 					log.log(Level.INFO, "User ''{0}'' has posted an article", article.getAuthenticatedUser());

 				}

 			} catch (Exception e) {

 				throw new StorageBackendException(e);

 			}

 		}

 	}

 	/**

 	 * Physically stores article in database.

 	 * @param subject

 	 * @param text

 	 * @param parentID

 	 * @param groupID 

 	 */

 	private void insertArticle(String sender, String subject, String text, Long parentID, Long groupID) throws StorageBackendException {

 		PreparedStatement ps = null;

 		ResultSet rs = null;

 		try {

 			ps = conn.prepareStatement("SELECT nntp_post_article(?, ?, ?, ?, ?)");

 			ps.setString(1, sender);

 			ps.setString(2, subject);

 			ps.setString(3, text);

 			ps.setLong(4, parentID);

 			ps.setLong(5, groupID);

 			rs = ps.executeQuery();

 			rs.next();

 			Long articleID = rs.getLong(1);

 			log.log(Level.INFO, "Article was succesfully stored as {0}", articleID);

 		} catch (Exception e) {

 			throw new StorageBackendException(e);

 		} finally {

 			close(null, ps, rs);

 		}

 	}

 	@Override

 	public void addEvent(long timestamp, int type, long groupID) throws StorageBackendException {

 		log.log(Level.SEVERE, "TODO: addEvent {0} / {1} / {2}", new Object[]{timestamp, type, groupID});

 	}

 	@Override

 	public void addGroup(String groupname, int flags) throws StorageBackendException {

 		log.log(Level.SEVERE, "TODO: addGroup {0} / {1}", new Object[]{groupname, flags});

 	}

 	@Override

 	public void delete(String messageID) throws StorageBackendException {

 		log.log(Level.SEVERE, "TODO: delete {0}", new Object[]{messageID});

 	}

 	@Override

 	public String getConfigValue(String key) throws StorageBackendException {

 		//log.log(Level.SEVERE, "TODO: getConfigValue {0}", new Object[]{key});

 		return null;

 	}

 	@Override

 	public void setConfigValue(String key, String value) throws StorageBackendException {

 		log.log(Level.SEVERE, "TODO: setConfigValue {0} = {1}", new Object[]{key, value});

 	}

 	@Override

 	public int getEventsCount(int eventType, long startTimestamp, long endTimestamp, Group group) throws StorageBackendException {

 		log.log(Level.SEVERE, "TODO: getEventsCount {0} / {1} / {2} / {3}", new Object[]{eventType, startTimestamp, endTimestamp, group});

 		return 0;

 	}

 	@Override

 	public double getEventsPerHour(int key, long gid) throws StorageBackendException {

 		log.log(Level.SEVERE, "TODO: getEventsPerHour {0} / {1}", new Object[]{key, gid});

 		return 0;

 	}

 	@Override

 	public List<String> getGroupsForList(String listAddress) throws StorageBackendException {

 		log.log(Level.SEVERE, "TODO: getGroupsForList {0}", new Object[]{listAddress});

 		return Collections.emptyList();

 	}

 	@Override

 	public List<String> getListsForGroup(String groupname) throws StorageBackendException {

 		log.log(Level.SEVERE, "TODO: getListsForGroup {0}", new Object[]{groupname});

 		return Collections.emptyList();

 	}

 	@Override

 	public String getOldestArticle() throws StorageBackendException {

 		log.log(Level.SEVERE, "TODO: getOldestArticle");

 		return null;

 	}

 	@Override

 	public List<Subscription> getSubscriptions(int type) throws StorageBackendException {

 		log.log(Level.SEVERE, "TODO: getSubscriptions {0}", new Object[]{type});

 		return Collections.emptyList();

 	}

 	@Override

 	public void purgeGroup(Group group) throws StorageBackendException {

 		log.log(Level.SEVERE, "TODO: purgeGroup {0}", new Object[]{group});

 	}

 	@Override

 	public boolean update(Article article) throws StorageBackendException {

 		log.log(Level.SEVERE, "TODO: update {0}", new Object[]{article});

 		throw new StorageBackendException("Not implemented yet.");

 	}

 	@Override

 	public boolean update(Group group) throws StorageBackendException {

 		log.log(Level.SEVERE, "TODO: update {0}", new Object[]{group});

 		throw new StorageBackendException("Not implemented yet.");

 	}

 }