/*******************************************************************************
 * ============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;

import java.io.IOException;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
import java.util.HashMap;
import java.util.Map;
import java.util.TimeZone;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.json.JSONException;
import org.onap.dmaap.datarouter.provisioning.beans.EventLogRecord;
import org.onap.dmaap.datarouter.provisioning.utils.DB;
import org.onap.dmaap.datarouter.provisioning.utils.LOGJSONObject;

import static org.onap.dmaap.datarouter.provisioning.utils.HttpServletUtils.sendResponseError;

/**
 * This Servlet handles requests to the <Statistics API> and  <Statistics consilidated
 * resultset>,
 *
 * @author Manish Singh
 * @version $Id: StatisticsServlet.java,v 1.11 2016/08/10 17:27:02 Manish Exp $
 */
@SuppressWarnings("serial")

public class StatisticsServlet extends BaseServlet {

    private static final long TWENTYFOUR_HOURS = (24 * 60 * 60 * 1000L);
    private static final String FMT1 = "yyyy-MM-dd'T'HH:mm:ss'Z'";
    private static final String FMT2 = "yyyy-MM-dd'T'HH:mm:ss.SSS'Z'";
    public static final String FEEDID = "FEEDID";


    /**
     * DELETE a logging URL -- not supported.
     */
    @Override
    public void doDelete(HttpServletRequest req, HttpServletResponse resp) {
        String message = "DELETE not allowed for the logURL.";
        EventLogRecord elr = new EventLogRecord(req);
        elr.setMessage(message);
        elr.setResult(HttpServletResponse.SC_METHOD_NOT_ALLOWED);
        eventlogger.error(elr.toString());
        sendResponseError(resp, HttpServletResponse.SC_METHOD_NOT_ALLOWED, message, eventlogger);
    }

    /**
     * GET a Statistics URL -- retrieve Statistics data for a feed or subscription. See the
     * <b>Statistics API</b> document for details on how this     method should be invoked.
     */
    @Override
    public void doGet(HttpServletRequest req, HttpServletResponse resp) {
        Map<String, String> map = buildMapFromRequest(req);
        if (map.get("err") != null) {
            sendResponseError(resp, HttpServletResponse.SC_BAD_REQUEST, "Invalid arguments: " + map.get("err"), eventlogger);
            return;
        }
        // check Accept: header??
        resp.setStatus(HttpServletResponse.SC_OK);
        resp.setContentType(LOGLIST_CONTENT_TYPE);
        String outputType = "json";
        if (req.getParameter(FEEDID) == null && req.getParameter(GROUPID) == null) {
            try {
                resp.getOutputStream().print("Invalid request, Feedid or Group ID is required.");
            } catch (IOException ioe) {
                eventlogger.error("PROV0171 StatisticsServlet.doGet: " + ioe.getMessage(), ioe);
            }
        }
        if (req.getParameter(FEEDID) != null && req.getParameter(GROUPID) == null) {
            map.put(FEEDIDS, req.getParameter(FEEDID).replace("|", ","));
        }
        if (req.getParameter(GROUPID) != null && req.getParameter(FEEDID) == null) {
            StringBuilder groupid1;
            try {
                groupid1 = this.getFeedIdsByGroupId(Integer.parseInt(req.getParameter(GROUPID)));
                map.put(FEEDIDS, groupid1.toString());
            } catch (NumberFormatException | SQLException e) {
                eventlogger.error("PROV0172 StatisticsServlet.doGet: " + e.getMessage(), e);
            }
        }
        if (req.getParameter(GROUPID) != null && req.getParameter(FEEDID) != null) {
            StringBuilder groupid1;
            try {
                groupid1 = this.getFeedIdsByGroupId(Integer.parseInt(req.getParameter(GROUPID)));
                groupid1.append(",");
                groupid1.append(req.getParameter(FEEDID).replace("|", ","));
                map.put(FEEDIDS, groupid1.toString());
            } catch (NumberFormatException | SQLException e) {
                eventlogger.error("PROV0173 StatisticsServlet.doGet: " + e.getMessage(), e);
            }
        }
        if (req.getParameter(SUBID) != null && req.getParameter(FEEDID) != null) {
            String subidstr = "and e.DELIVERY_SUBID in("
                + req.getParameter(SUBID).replace("|", ",") + ")";
            map.put(SUBID, subidstr);
        }
        if (req.getParameter(SUBID) != null && req.getParameter(GROUPID) != null) {
            String subidstr = "and e.DELIVERY_SUBID in("
                + req.getParameter(SUBID).replace("|", ",") + ")";
            map.put(SUBID, subidstr);
        }
        if (req.getParameter("type") != null) {
            map.put(EVENT_TYPE, req.getParameter("type").replace("|", ","));
        }
        if (req.getParameter(OUTPUT_TYPE) != null) {
            map.put(OUTPUT_TYPE, req.getParameter(OUTPUT_TYPE));
        }
        if (req.getParameter(START_TIME) != null) {
            map.put(START_TIME, req.getParameter(START_TIME));
        }
        if (req.getParameter(END_TIME) != null) {
            map.put(END_TIME, req.getParameter(END_TIME));
        }
        if (req.getParameter("time") != null) {
            map.put(START_TIME, req.getParameter("time"));
            map.put(END_TIME, null);
        }
        if (req.getParameter(OUTPUT_TYPE) != null) {
            outputType = req.getParameter(OUTPUT_TYPE);
        }
        try {
            this.getRecordsForSQL(map, outputType, resp.getOutputStream(), resp);
        } catch (IOException ioe) {
            eventlogger.error("PROV0174 StatisticsServlet.doGet: " +  ioe.getMessage(), ioe);
        }

    }


    /**
     * rsToJson - Converting RS to JSON object
     *
     * @param out ServletOutputStream, rs as ResultSet
     * @throws IOException, SQLException
     */
    public void rsToCSV(ResultSet rs, ServletOutputStream out) throws IOException, SQLException {
        String header = "FEEDNAME,FEEDID,FILES_PUBLISHED,PUBLISH_LENGTH, FILES_DELIVERED, "
            + "DELIVERED_LENGTH, SUBSCRIBER_URL, SUBID, PUBLISH_TIME,DELIVERY_TIME, AverageDelay\n";
        out.write(header.getBytes());

        while (rs.next()) {
            String line = rs.getString("FEEDNAME")
                + ","
                + rs.getString(FEEDID)
                + ","
                + rs.getString("FILES_PUBLISHED")
                + ","
                + rs.getString("PUBLISH_LENGTH")
                + ","
                + rs.getString("FILES_DELIVERED")
                + ","
                + rs.getString("DELIVERED_LENGTH")
                + ","
                + rs.getString("SUBSCRIBER_URL")
                + ","
                + rs.getString("SUBID")
                + ","
                + rs.getString("PUBLISH_TIME")
                + ","
                + rs.getString("DELIVERY_TIME")
                + ","
                + rs.getString("AverageDelay")
                + ","
                + "\n";
            out.write(line.getBytes());
            out.flush();
        }
    }

    /**
     * rsToJson - Converting RS to JSON object
     *
     * @param out ServletOutputStream, rs as ResultSet
     * @throws IOException, SQLException
     */
    private void rsToJson(ResultSet rs, ServletOutputStream out) throws IOException, SQLException {
        String[] fields = {"FEEDNAME", FEEDID, "FILES_PUBLISHED", "PUBLISH_LENGTH", "FILES_DELIVERED",
            "DELIVERED_LENGTH", "SUBSCRIBER_URL", "SUBID", "PUBLISH_TIME", "DELIVERY_TIME",
            "AverageDelay"};
        StringBuilder line = new StringBuilder();
        line.append("[\n");
        while (rs.next()) {
            LOGJSONObject j2 = new LOGJSONObject();
            for (String key : fields) {
                Object v = rs.getString(key);
                if (v != null) {
                    j2.put(key.toLowerCase(), v);
                } else {
                    j2.put(key.toLowerCase(), "");
                }
            }
            line.append(j2.toString());
            line.append(",\n");
        }
        line.append("]");
        out.print(line.toString());
    }

    /**
     * getFeedIdsByGroupId - Getting FEEDID's by GROUP ID.
     *
     * @throws SQLException Query SQLException.
     */
    private StringBuilder getFeedIdsByGroupId(int groupIds) throws SQLException {
        DB db = null;
        Connection conn = null;
        ResultSet resultSet = null;
        String sqlGoupid = null;
        StringBuilder feedIds = new StringBuilder();
        try {
            db = new DB();
            conn = db.getConnection();
            sqlGoupid = " SELECT FEEDID from FEEDS  WHERE GROUPID = ?";
            try (PreparedStatement prepareStatement = conn.prepareStatement(sqlGoupid)) {
                prepareStatement.setInt(1, groupIds);
                resultSet = prepareStatement.executeQuery();
                while (resultSet.next()) {
                    feedIds.append(resultSet.getInt(FEEDID));
                    feedIds.append(",");
                }
                feedIds.deleteCharAt(feedIds.length() - 1);
                eventlogger.info("PROV0177 StatisticsServlet.getFeedIdsByGroupId: feedIds = " + feedIds.toString());
            }
        } catch (SQLException e) {
            eventlogger.error("PROV0175 StatisticsServlet.getFeedIdsByGroupId: " + e.getMessage(), e);
        } finally {
            try {
                if (resultSet != null) {
                    resultSet.close();
                }
                if (conn != null) {
                    db.release(conn);
                }
            } catch (Exception e) {
                eventlogger.error("PROV0176 StatisticsServlet.getFeedIdsByGroupId: " + e.getMessage(), e);
            }
        }
        return feedIds;
    }


    /**
     * queryGeneretor - Generating sql query
     *
     * @param map as key value pare of all user input fields
     */
    private String queryGeneretor(Map<String, String> map) throws ParseException {

        String sql;
        String eventType = null;
        String feedids = null;
        String startTime = null;
        String endTime = null;
        String subid = " ";
        if (map.get(EVENT_TYPE) != null) {
            eventType =  map.get(EVENT_TYPE);
        }
        if (map.get(FEEDIDS) != null) {
            feedids = map.get(FEEDIDS);
        }
        if (map.get(START_TIME) != null) {
            startTime = map.get(START_TIME);
        }
        if (map.get(END_TIME) != null) {
            endTime =  map.get(END_TIME);
        }
        if ("all".equalsIgnoreCase(eventType)) {
            eventType = "PUB','DEL, EXP, PBF";
        }
        if (map.get(SUBID) != null) {
            subid = map.get(SUBID);
        }

        eventlogger.info("Generating sql query to get Statistics resultset. ");

        if (endTime == null && startTime == null) {

            sql = "SELECT (SELECT NAME FROM FEEDS AS f WHERE f.FEEDID in(" + feedids
                + ") and f.FEEDID=e.FEEDID) AS FEEDNAME, e.FEEDID as FEEDID, (SELECT COUNT(*) FROM LOG_RECORDS AS c WHERE c.FEEDID in("
                + feedids
                + ") and c.FEEDID=e.FEEDID AND c.TYPE='PUB') AS FILES_PUBLISHED,(SELECT SUM(content_length) FROM LOG_RECORDS AS c WHERE c.FEEDID in("
                + feedids
                + ")  and c.FEEDID=e.FEEDID AND c.TYPE='PUB') AS PUBLISH_LENGTH, COUNT(e.EVENT_TIME) as FILES_DELIVERED,  sum(m.content_length) as DELIVERED_LENGTH,SUBSTRING_INDEX(e.REQURI,'/',+3) as SUBSCRIBER_URL, e.DELIVERY_SUBID as SUBID, e.EVENT_TIME AS PUBLISH_TIME, m.EVENT_TIME AS DELIVERY_TIME,  AVG(e.EVENT_TIME - m.EVENT_TIME)/1000 as AverageDelay FROM LOG_RECORDS e JOIN LOG_RECORDS m ON m.PUBLISH_ID = e.PUBLISH_ID AND e.FEEDID IN ("
                + feedids + ") " + subid + " AND m.STATUS=204 AND e.RESULT=204  group by SUBID";

            return sql;
        } else if (startTime != null && endTime == null) {

            long inputTimeInMilli = 60000 * Long.parseLong(startTime);
            Calendar cal = Calendar.getInstance(TimeZone.getTimeZone("GMT"));
            long currentTimeInMilli = cal.getTimeInMillis();
            long compareTime = currentTimeInMilli - inputTimeInMilli;

            sql = "SELECT (SELECT NAME FROM FEEDS AS f WHERE f.FEEDID in(" + feedids
                + ") and f.FEEDID=e.FEEDID) AS FEEDNAME, e.FEEDID as FEEDID, (SELECT COUNT(*) FROM LOG_RECORDS AS c WHERE c.FEEDID in("
                + feedids
                + ") and c.FEEDID=e.FEEDID AND c.TYPE='PUB') AS FILES_PUBLISHED,(SELECT SUM(content_length) FROM LOG_RECORDS AS c WHERE c.FEEDID in("
                + feedids
                + ")  and c.FEEDID=e.FEEDID AND c.TYPE='PUB') AS PUBLISH_LENGTH, COUNT(e.EVENT_TIME) as FILES_DELIVERED,  sum(m.content_length) as DELIVERED_LENGTH,SUBSTRING_INDEX(e.REQURI,'/',+3) as SUBSCRIBER_URL, e.DELIVERY_SUBID as SUBID, e.EVENT_TIME AS PUBLISH_TIME, m.EVENT_TIME AS DELIVERY_TIME,  AVG(e.EVENT_TIME - m.EVENT_TIME)/1000 as AverageDelay FROM LOG_RECORDS e JOIN LOG_RECORDS m ON m.PUBLISH_ID = e.PUBLISH_ID AND e.FEEDID IN ("
                + feedids + ") " + subid + " AND m.STATUS=204 AND e.RESULT=204 and e.event_time>="
                + compareTime + " group by SUBID";

            return sql;

        } else {
            SimpleDateFormat inFormat = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss");
            Date startDate = inFormat.parse(startTime);
            Date endDate = inFormat.parse(endTime);

            long startInMillis = startDate.getTime();
            long endInMillis = endDate.getTime();

            sql = "SELECT (SELECT NAME FROM FEEDS AS f WHERE f.FEEDID in(" + feedids
                + ") and f.FEEDID=e.FEEDID) AS FEEDNAME, e.FEEDID as FEEDID, (SELECT COUNT(*) FROM LOG_RECORDS AS c WHERE c.FEEDID in("
                + feedids
                + ") and c.FEEDID=e.FEEDID AND c.TYPE='PUB') AS FILES_PUBLISHED,(SELECT SUM(content_length) FROM LOG_RECORDS AS c WHERE c.FEEDID in("
                + feedids
                + ")  and c.FEEDID=e.FEEDID AND c.TYPE='PUB') AS PUBLISH_LENGTH, COUNT(e.EVENT_TIME) as FILES_DELIVERED,  sum(m.content_length) as DELIVERED_LENGTH,SUBSTRING_INDEX(e.REQURI,'/',+3) as SUBSCRIBER_URL, e.DELIVERY_SUBID as SUBID, e.EVENT_TIME AS PUBLISH_TIME, m.EVENT_TIME AS DELIVERY_TIME,  AVG(e.EVENT_TIME - m.EVENT_TIME)/1000 as AverageDelay FROM LOG_RECORDS e JOIN LOG_RECORDS m ON m.PUBLISH_ID = e.PUBLISH_ID AND e.FEEDID IN ("
                + feedids + ") " + subid + " AND m.STATUS=204 AND e.RESULT=204 and e.event_time between " + startInMillis
                + " and " + endInMillis + " group by SUBID";


            return sql;
        }
    }


    /**
     * PUT a Statistics URL -- not supported.
     */
    @Override
    public void doPut(HttpServletRequest req, HttpServletResponse resp) {
        String message = "PUT not allowed for the StatisticsURL.";
        EventLogRecord elr = new EventLogRecord(req);
        elr.setMessage(message);
        elr.setResult(HttpServletResponse.SC_METHOD_NOT_ALLOWED);
        eventlogger.error(elr.toString());
        sendResponseError(resp, HttpServletResponse.SC_METHOD_NOT_ALLOWED, message, eventlogger);
    }

    /**
     * POST a Statistics URL -- not supported.
     */
    @Override
    public void doPost(HttpServletRequest req, HttpServletResponse resp) {
        String message = "POST not allowed for the StatisticsURL.";
        EventLogRecord elr = new EventLogRecord(req);
        elr.setMessage(message);
        elr.setResult(HttpServletResponse.SC_METHOD_NOT_ALLOWED);
        eventlogger.error(elr.toString());
        sendResponseError(resp, HttpServletResponse.SC_METHOD_NOT_ALLOWED, message, eventlogger);
    }

    private Map<String, String> buildMapFromRequest(HttpServletRequest req) {
        Map<String, String> map = new HashMap<>();
        String s = req.getParameter("type");
        if (s != null) {
            if ("pub".equals(s) || "del".equals(s) || "exp".equals(s)) {
                map.put("type", s);
            } else {
                map.put("err", "bad type");
                return map;
            }
        } else {
            map.put("type", "all");
        }
        map.put("publishSQL", "");
        map.put("statusSQL", "");
        map.put("resultSQL", "");
        map.put(REASON_SQL, "");

        s = req.getParameter("publishId");
        if (s != null) {
            if (s.indexOf("'") >= 0) {
                map.put("err", "bad publishId");
                return map;
            }
            map.put("publishSQL", " AND PUBLISH_ID = '" + s + "'");
        }

        s = req.getParameter("statusCode");
        if (s != null) {
            String sql = null;
            switch (s) {
                case "success":
                    sql = " AND STATUS >= 200 AND STATUS < 300";
                    break;
                case "redirect":
                    sql = " AND STATUS >= 300 AND STATUS < 400";
                    break;
                case "failure":
                    sql = " AND STATUS >= 400";
                    break;
                default:
                    try {
                        int n = Integer.parseInt(s);
                        if ((n >= 100 && n < 600) || (n == -1)) {
                            sql = " AND STATUS = " + n;
                        }
                    } catch (NumberFormatException e) {
                        eventlogger.error("Failed to parse input", e);
                    }
                    break;
            }
            if (sql == null) {
                map.put("err", "bad statusCode");
                return map;
            }
            map.put("statusSQL", sql);
            map.put("resultSQL", sql.replaceAll("STATUS", "RESULT"));
        }

        s = req.getParameter("expiryReason");
        if (s != null) {
            map.put("type", "exp");
            switch (s) {
                case "notRetryable":
                    map.put(REASON_SQL, " AND REASON = 'notRetryable'");
                    break;
                case "retriesExhausted":
                    map.put(REASON_SQL, " AND REASON = 'retriesExhausted'");
                    break;
                case "diskFull":
                    map.put(REASON_SQL, " AND REASON = 'diskFull'");
                    break;
                case "other":
                    map.put(REASON_SQL, " AND REASON = 'other'");
                    break;
                default:
                    map.put("err", "bad expiryReason");
                    return map;
            }
        }

        long stime = getTimeFromParam(req.getParameter("start"));
        if (stime < 0) {
            map.put("err", "bad start");
            return map;
        }
        long etime = getTimeFromParam(req.getParameter("end"));
        if (etime < 0) {
            map.put("err", "bad end");
            return map;
        }
        if (stime == 0 && etime == 0) {
            etime = System.currentTimeMillis();
            stime = etime - TWENTYFOUR_HOURS;
        } else if (stime == 0) {
            stime = etime - TWENTYFOUR_HOURS;
        } else if (etime == 0) {
            etime = stime + TWENTYFOUR_HOURS;
        }
        map.put("timeSQL", String.format(" AND EVENT_TIME >= %d AND EVENT_TIME <= %d", stime, etime));
        return map;
    }

    private long getTimeFromParam(final String s) {
        if (s == null) {
            return 0;
        }
        try {
            // First, look for an RFC 3339 date
            String fmt = (s.indexOf('.') > 0) ? FMT2 : FMT1;
            SimpleDateFormat sdf = new SimpleDateFormat(fmt);
            Date d = sdf.parse(s);
            return d.getTime();
        } catch (ParseException e) {
            intlogger.error("Exception in getting Time :- " + e.getMessage(), e);
        }
        try {
            // Also allow a long (in ms); useful for testing
            return Long.parseLong(s);
        } catch (NumberFormatException e) {
            intlogger.error("Exception in getting Time :- " + e.getMessage(), e);
        }
        intlogger.info("Error parsing time=" + s);
        return -1;
    }

    private void getRecordsForSQL(Map<String, String> map, String outputType, ServletOutputStream out, HttpServletResponse resp) {
        try {
            String filterQuery = this.queryGeneretor(map);
            eventlogger.debug("SQL Query for Statistics resultset. " + filterQuery);
            intlogger.debug(filterQuery);
            long start = System.currentTimeMillis();
            DB db = new DB();
            try (Connection conn = db.getConnection()) {
                try (ResultSet rs = conn.prepareStatement(filterQuery).executeQuery()) {
                    if ("csv".equals(outputType)) {
                        resp.setContentType("application/octet-stream");
                        Date date = new Date();
                        SimpleDateFormat dateFormat = new SimpleDateFormat("dd-MM-YYYY HH:mm:ss");
                        resp.setHeader("Content-Disposition",
                            "attachment; filename=\"result:" + dateFormat.format(date) + ".csv\"");
                        eventlogger.info("Generating CSV file from Statistics resultset");
                        rsToCSV(rs, out);
                    } else {
                        eventlogger.info("Generating JSON for Statistics resultset");
                        this.rsToJson(rs, out);
                    }
                }
                db.release(conn);
            } catch (SQLException e) {
                eventlogger.error("SQLException:" + e);
            }
            intlogger.debug("Time: " + (System.currentTimeMillis() - start) + " ms");
        } catch (IOException e) {
            eventlogger.error("IOException - Generating JSON/CSV:" + e);
        } catch (JSONException e) {
            eventlogger.error("JSONException - executing SQL query:" + e);
        } catch (ParseException e) {
            eventlogger.error("ParseException - executing SQL query:" + e);
        }
    }
}