/*******************************************************************************
 * ============LICENSE_START==================================================
 * * org.onap.dmaap
 * * ===========================================================================
 * * Copyright © 2017 AT&T Intellectual Property. All rights reserved.
 * * ===========================================================================
 * * Licensed under the Apache License, Version 2.0 (the "License");
 * * you may not use this file except in compliance with the License.
 * * You may obtain a copy of the License at
 * *
 *  *      http://www.apache.org/licenses/LICENSE-2.0
 * *
 *  * Unless required by applicable law or agreed to in writing, software
 * * distributed under the License is distributed on an "AS IS" BASIS,
 * * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * * See the License for the specific language governing permissions and
 * * limitations under the License.
 * * ============LICENSE_END====================================================
 * *
 * * ECOMP is a trademark and service mark of AT&T Intellectual Property.
 * *
 ******************************************************************************/


package org.onap.dmaap.datarouter.provisioning.utils;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.FilenameFilter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.LineNumberReader;
import java.io.Reader;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.text.ParseException;
import java.util.Date;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.TreeSet;
import java.util.zip.GZIPInputStream;

import org.apache.log4j.Logger;
import org.onap.dmaap.datarouter.provisioning.BaseServlet;
import org.onap.dmaap.datarouter.provisioning.beans.DeliveryExtraRecord;
import org.onap.dmaap.datarouter.provisioning.beans.DeliveryRecord;
import org.onap.dmaap.datarouter.provisioning.beans.ExpiryRecord;
import org.onap.dmaap.datarouter.provisioning.beans.Loadable;
import org.onap.dmaap.datarouter.provisioning.beans.LogRecord;
import org.onap.dmaap.datarouter.provisioning.beans.Parameters;
import org.onap.dmaap.datarouter.provisioning.beans.PubFailRecord;
import org.onap.dmaap.datarouter.provisioning.beans.PublishRecord;

/**
 * This class provides methods that run in a separate thread, in order to process logfiles uploaded into the spooldir.
 * These logfiles are loaded into the MariaDB LOG_RECORDS table. In a running provisioning server, there should only be
 * two places where records can be loaded into this table; here, and in the method DB.retroFit4() which may be run at
 * startup to load the old (1.0) style log tables into LOG_RECORDS;
 * <p>This method maintains an {@link RLEBitSet} which can be used to easily see what records are presently in the
 * database.
 * This bit set is used to synchronize between provisioning servers.</p>
 *
 * @author Robert Eby
 * @version $Id: LogfileLoader.java,v 1.22 2014/03/12 19:45:41 eby Exp $
 */
public class LogfileLoader extends Thread {
    /**
     * Default number of log records to keep when pruning.  Keep 10M by default.
     */
    public static final long DEFAULT_LOG_RETENTION = 10000000L;
    /**
     * NOT USED: Percentage of free space required before old records are removed.
     */
    public static final int REQUIRED_FREE_PCT = 20;

    /**
     * This is a singleton -- there is only one LogfileLoader object in the server
     */
    private static LogfileLoader p;

    /**
     * Get the singleton LogfileLoader object, and start it if it is not running.
     *
     * @return the LogfileLoader
     */
    public static synchronized LogfileLoader getLoader() {
        if (p == null)
            p = new LogfileLoader();
        if (!p.isAlive())
            p.start();
        return p;
    }

    /**
     * The PreparedStatement which is loaded by a <i>Loadable</i>.
     */
    public static final String INSERT_SQL = "insert into LOG_RECORDS values (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)";
    /**
     * Each server can assign this many IDs
     */
    private static final long SET_SIZE = (1L << 56);

    private final Logger logger;
    private final DB db;
    private final String spooldir;
    private final long set_start;
    private final long set_end;
    private RLEBitSet seq_set;
    private long nextid;
    private boolean idle;

    private LogfileLoader() {
        this.logger = Logger.getLogger("org.onap.dmaap.datarouter.provisioning.internal");
        this.db = new DB();
        this.spooldir = db.getProperties().getProperty("org.onap.dmaap.datarouter.provserver.spooldir");
        this.set_start = getIdRange();
        this.set_end = set_start + SET_SIZE - 1;
        this.seq_set = new RLEBitSet();
        this.nextid = 0;
        this.idle = false;

        // This is a potentially lengthy operation, so has been moved to run()
        //initializeNextid();
        this.setDaemon(true);
        this.setName("LogfileLoader");
    }

    private long getIdRange() {
        long n;
        if (BaseServlet.isInitialActivePOD())
            n = 0;
        else if (BaseServlet.isInitialStandbyPOD())
            n = SET_SIZE;
        else
            n = SET_SIZE * 2;
        String r = String.format("[%X .. %X]", n, n + SET_SIZE - 1);
        logger.debug("This server shall assign RECORD_IDs in the range " + r);
        return n;
    }

    /**
     * Return the bit set representing the record ID's that are loaded in this database.
     *
     * @return the bit set
     */
    public RLEBitSet getBitSet() {
        return seq_set;
    }

    /**
     * True if the LogfileLoader is currently waiting for work.
     *
     * @return true if idle
     */
    public boolean isIdle() {
        return idle;
    }

    /**
     * Run continuously to look for new logfiles in the spool directory and import them into the DB.
     * The spool is checked once per second.  If free space on the MariaDB filesystem falls below
     * REQUIRED_FREE_PCT (normally 20%) then the oldest logfile entries are removed and the LOG_RECORDS
     * table is compacted until free space rises above the threshold.
     */
    @Override
    public void run() {
        initializeNextid();    // moved from the constructor
        while (true) {
            try {
                File dirfile = new File(spooldir);
                while (true) {
                    // process IN files
                    File[] infiles = dirfile.listFiles(new FilenameFilter() {
                        @Override
                        public boolean accept(File dir, String name) {
                            return name.startsWith("IN.");
                        }
                    });

                    if (infiles.length == 0) {
                        idle = true;
                        try {
                            Thread.sleep(1000L);
                        } catch (InterruptedException e) {
                            Thread.currentThread().interrupt();
                        }
                        idle = false;
                    } else {
                        // Remove old rows
                        if (pruneRecords()) {
                            // Removed at least some entries, recompute the bit map
                            initializeNextid();
                        }

                        // Process incoming logfiles
                        for (File f : infiles) {
                            if (logger.isDebugEnabled())
                                logger.debug("PROV8001 Starting " + f + " ...");
                            long time = System.currentTimeMillis();
                            int[] n = process(f);
                            time = System.currentTimeMillis() - time;
                            logger.info(String
                                    .format("PROV8000 Processed %s in %d ms; %d of %d records.",
                                            f.toString(), time, n[0], n[1]));
                            f.delete();
                        }
                    }
                }
            } catch (Exception e) {
                logger.warn("PROV0020: Caught exception in LogfileLoader: " + e);
            }
        }
    }

    boolean pruneRecords() {
        boolean did1 = false;
        long count = countRecords();
        long threshold = DEFAULT_LOG_RETENTION;
        Parameters param = Parameters.getParameter(Parameters.PROV_LOG_RETENTION);
        if (param != null) {
            try {
                long n = Long.parseLong(param.getValue());
                // This check is to prevent inadvertent errors from wiping the table out
                if (n > 1000000L)
                    threshold = n;
            } catch (NumberFormatException e) {
                // ignore
            }
        }
        logger.debug("Pruning LOG_RECORD table: records in DB=" + count + ", threshold=" + threshold);
        if (count > threshold) {
            count -= threshold;                        // we need to remove this many records;
            Map<Long, Long> hist = getHistogram();    // histogram of records per day
            // Determine the cutoff point to remove the needed number of records
            long sum = 0;
            long cutoff = 0;
            for (Long day : new TreeSet<Long>(hist.keySet())) {
                sum += hist.get(day);
                cutoff = day;
                if (sum >= count)
                    break;
            }
            cutoff++;
            cutoff *= 86400000L;        // convert day to ms
            logger.debug("  Pruning records older than=" + (cutoff / 86400000L) + " (" + new Date(cutoff) + ")");

            Connection conn = null;
            try {
                // Limit to a million at a time to avoid typing up the DB for too long.
                conn = db.getConnection();
                try(PreparedStatement ps = conn.prepareStatement("DELETE from LOG_RECORDS where EVENT_TIME < ? limit 1000000")) {
                    ps.setLong(1, cutoff);
                    while (count > 0) {
                        if (!ps.execute()) {
                            int dcount = ps.getUpdateCount();
                            count -= dcount;
                            logger.debug("  " + dcount + " rows deleted.");
                            did1 |= (dcount != 0);
                            if (dcount == 0)
                                count = 0;    // prevent inf. loops
                        } else {
                            count = 0;    // shouldn't happen!
                        }
                    }
                }
             try(Statement stmt = conn.createStatement()) {
                 stmt.execute("OPTIMIZE TABLE LOG_RECORDS");
             }
            } catch (SQLException e) {
                System.err.println(e);
                logger.error(e);
            } finally {
                db.release(conn);
            }
        }
        return did1;
    }

    long countRecords() {
        long count = 0;
        Connection conn = null;
        try {
            conn = db.getConnection();
           try(Statement stmt = conn.createStatement()) {
               try(ResultSet rs = stmt.executeQuery("SELECT COUNT(*) as COUNT from LOG_RECORDS")) {
                   if (rs.next()) {
                       count = rs.getLong("COUNT");
                   }
               }
           }
         } catch (SQLException e) {
            System.err.println(e);
            logger.error(e);
        } finally {
            db.release(conn);
        }
        return count;
    }

    Map<Long, Long> getHistogram() {
        Map<Long, Long> map = new HashMap<Long, Long>();
        Connection conn = null;
        try {
            logger.debug("  LOG_RECORD table histogram...");
            conn = db.getConnection();
            try(Statement stmt = conn.createStatement()) {
                try(ResultSet rs = stmt.executeQuery("SELECT FLOOR(EVENT_TIME/86400000) AS DAY, COUNT(*) AS COUNT FROM LOG_RECORDS GROUP BY DAY")) {
                    while (rs.next()) {
                        long day = rs.getLong("DAY");
                        long cnt = rs.getLong("COUNT");
                        map.put(day, cnt);
                        logger.debug("  " + day + "  " + cnt);
                    }
                }
            }
           } catch (SQLException e) {
            System.err.println(e);
            logger.error(e);
        } finally {
            db.release(conn);
        }
        return map;
    }

    private void initializeNextid() {
        Connection conn = null;
        try {
            conn = db.getConnection();
            RLEBitSet nbs = new RLEBitSet();
            try(Statement stmt = conn.createStatement()) {
                // Build a bitset of all records in the LOG_RECORDS table
                // We need to run this SELECT in stages, because otherwise we run out of memory!
                final long stepsize = 6000000L;
                boolean go_again = true;
                for (long i = 0; go_again; i += stepsize) {
                    String sql = String.format("select RECORD_ID from LOG_RECORDS LIMIT %d,%d", i, stepsize);
                    try (ResultSet rs = stmt.executeQuery(sql)) {
                        go_again = false;
                        while (rs.next()) {
                            long n = rs.getLong("RECORD_ID");
                            nbs.set(n);
                            go_again = true;
                        }
                    }
                }
            }
            seq_set = nbs;
            // Compare with the range for this server
            // Determine the next ID for this set of record IDs
            RLEBitSet tbs = (RLEBitSet) nbs.clone();
            RLEBitSet idset = new RLEBitSet();
            idset.set(set_start, set_start + SET_SIZE);
            tbs.and(idset);
            long t = tbs.length();
            nextid = (t == 0) ? set_start : (t - 1);
            if (nextid >= set_start + SET_SIZE) {
                // Handle wraparound, when the IDs reach the end of our "range"
                Long[] last = null;
                Iterator<Long[]> li = tbs.getRangeIterator();
                while (li.hasNext()) {
                    last = li.next();
                }
                if (last != null) {
                    tbs.clear(last[0], last[1] + 1);
                    t = tbs.length();
                    nextid = (t == 0) ? set_start : (t - 1);
                }
            }
            logger.debug(String.format("initializeNextid, next ID is %d (%x)", nextid, nextid));
        } catch (SQLException e) {
            System.err.println(e);
            logger.error(e);
        } finally {
            db.release(conn);
        }
    }

    @SuppressWarnings("resource")
    int[] process(File f) {
        int ok = 0, total = 0;
        try {
            Connection conn = db.getConnection();
            PreparedStatement ps = conn.prepareStatement(INSERT_SQL);
            Reader r = f.getPath().endsWith(".gz")
                    ? new InputStreamReader(new GZIPInputStream(new FileInputStream(f)))
                    : new FileReader(f);
            try(LineNumberReader in = new LineNumberReader(r)) {
                String line;
                while ((line = in.readLine()) != null) {
                    try {
                        for (Loadable rec : buildRecords(line)) {
                            rec.load(ps);
                            if (rec instanceof LogRecord) {
                                LogRecord lr = ((LogRecord) rec);
                                if (!seq_set.get(lr.getRecordId())) {
                                    ps.executeUpdate();
                                    seq_set.set(lr.getRecordId());
                                } else
                                    logger.debug("Duplicate record ignored: " + lr.getRecordId());
                            } else {
                                if (++nextid > set_end)
                                    nextid = set_start;
                                ps.setLong(18, nextid);
                                ps.executeUpdate();
                                seq_set.set(nextid);
                            }
                            ps.clearParameters();
                            ok++;
                        }
                    } catch (SQLException e) {
                        logger.warn("PROV8003 Invalid value in record: " + line);
                        logger.debug(e);
                    } catch (NumberFormatException e) {
                        logger.warn("PROV8004 Invalid number in record: " + line);
                        logger.debug(e);
                    } catch (ParseException e) {
                        logger.warn("PROV8005 Invalid date in record: " + line);
                        logger.debug(e);
                    } catch (Exception e) {
                        logger.warn("PROV8006 Invalid pattern in record: " + line);
                        logger.debug(e);
                    }
                    total++;
                }
            }
            ps.close();
            db.release(conn);
            conn = null;
        } catch (FileNotFoundException e) {
            logger.warn("PROV8007 Exception reading " + f + ": " + e);
        } catch (IOException e) {
            logger.warn("PROV8007 Exception reading " + f + ": " + e);
        } catch (SQLException e) {
            logger.warn("PROV8007 Exception reading " + f + ": " + e);
        }
        return new int[]{ok, total};
    }

    Loadable[] buildRecords(String line) throws ParseException {
        String[] pp = line.split("\\|");
        if (pp != null && pp.length >= 7) {
            String rtype = pp[1].toUpperCase();
            if (rtype.equals("PUB") && pp.length == 11) {
                // Fields are: date|PUB|pubid|feedid|requrl|method|ctype|clen|srcip|user|status
                return new Loadable[]{new PublishRecord(pp)};
            }
            if (rtype.equals("DEL") && pp.length == 12) {
                // Fields are: date|DEL|pubid|feedid|subid|requrl|method|ctype|clen|user|status|xpubid
                String[] subs = pp[4].split("\\s+");
                if (subs != null) {
                    Loadable[] rv = new Loadable[subs.length];
                    for (int i = 0; i < subs.length; i++) {
                        // create a new record for each individual sub
                        pp[4] = subs[i];
                        rv[i] = new DeliveryRecord(pp);
                    }
                    return rv;
                }
            }
            if (rtype.equals("EXP") && pp.length == 11) {
                // Fields are: date|EXP|pubid|feedid|subid|requrl|method|ctype|clen|reason|attempts
                ExpiryRecord e = new ExpiryRecord(pp);
                if (e.getReason().equals("other"))
                    logger.info("Invalid reason '" + pp[9] + "' changed to 'other' for record: " + e.getPublishId());
                return new Loadable[]{e};
            }
            if (rtype.equals("PBF") && pp.length == 12) {
                // Fields are: date|PBF|pubid|feedid|requrl|method|ctype|clen-expected|clen-received|srcip|user|error
                return new Loadable[]{new PubFailRecord(pp)};
            }
            if (rtype.equals("DLX") && pp.length == 7) {
                // Fields are: date|DLX|pubid|feedid|subid|clen-tosend|clen-sent
                return new Loadable[]{new DeliveryExtraRecord(pp)};
            }
            if (rtype.equals("LOG") && (pp.length == 19 || pp.length == 20)) {
                // Fields are: date|LOG|pubid|feedid|requrl|method|ctype|clen|type|feedFileid|remoteAddr|user|status|subid|fileid|result|attempts|reason|record_id
                return new Loadable[]{new LogRecord(pp)};
            }
        }
        logger.warn("PROV8002 bad record: " + line);
        return new Loadable[0];
    }

    /**
     * The LogfileLoader can be run stand-alone by invoking the main() method of this class.
     *
     * @param a ignored
     * @throws InterruptedException
     */
    public static void main(String[] a) throws InterruptedException {
        LogfileLoader.getLoader();
        Thread.sleep(200000L);
    }
}