/*

  * This software is licensed under the Apache License, Version 2.0

  * (the "License") agreement; 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.

  */

 package net.admin4j.jdbc.driver;

 import java.util.ArrayList;

 import java.util.Comparator;

 import java.util.HashMap;

 import java.util.HashSet;

 import java.util.Map;

 import java.util.Set;

 import java.util.TreeSet;

 import java.util.concurrent.ConcurrentHashMap;

 import net.admin4j.config.Admin4JConfiguration;

 import net.admin4j.deps.commons.lang3.Validate;

 import net.admin4j.timer.DataMeasure;

 import net.admin4j.timer.TaskTimer;

 import net.admin4j.vo.DataMeasurementSummaryVO;

 import org.slf4j.Logger;

 import org.slf4j.LoggerFactory;

 /**

  * Tracks performance metrics for SQL Statements

  * @author D. Ashmore

  *

  */

 class SqlStatementTimerRegistry {

     private static final SqlStatementTimerRegistry singleton = new SqlStatementTimerRegistry();

     private Map<String, SqlTaskTimer> registeredDataMeasures

         = new ConcurrentHashMap<String, SqlTaskTimer>();

     public static final Integer DEFAULT_NBR_SQL_STATEMENTS = 50; 

     private static Integer nbrRetainedSqlStatements = DEFAULT_NBR_SQL_STATEMENTS;

     public static final Long DEFAULT_SQL_RETENTION_TIME_IN_MILLIS = 60L * 60L * 6L * 1000L; // 6 hrs

     private static Long sqlRetentionTimeInMillis = DEFAULT_SQL_RETENTION_TIME_IN_MILLIS;

     static {

         if (Admin4JConfiguration.getSqlNbrRetainedSqlStatements() != null) {

             nbrRetainedSqlStatements = Admin4JConfiguration.getSqlNbrRetainedSqlStatements();

         }

         if (Admin4JConfiguration.getSqlRetentionTimeInMillis() != null) {

             sqlRetentionTimeInMillis = Admin4JConfiguration.getSqlRetentionTimeInMillis();

         }

     }

     public static void register(SqlTaskTimer timer) {

         singleton.registeredDataMeasures.put(timer.getLabel(), timer);

     }

     public static SqlTaskTimer findTaskTimer(String label) {

         Validate.notEmpty(label, "Null or blank label not allowed.");

         return singleton.registeredDataMeasures.get(label);

     }

     public static void delete(String label) {

         singleton.registeredDataMeasures.remove(label);

     }

     public static Map<String,Set<DataMeasurementSummaryVO>> getDataSummaryMap() {

         TreeSet<SqlTaskTimer> set = new TreeSet<SqlTaskTimer>(new TaskTimerComparable());

         set.addAll(singleton.registeredDataMeasures.values());

         HashSet<SqlTaskTimer> topSet = new HashSet<SqlTaskTimer>();

         for (SqlTaskTimer timer: set) {

             if (topSet.size() < nbrRetainedSqlStatements && extractDataMeasure(timer).getLastObservationTime() > createEarliestTime()) {

                 topSet.add(timer);

             }

         }

         Map<String,Set<DataMeasurementSummaryVO>> summaryMap = new HashMap<String,Set<DataMeasurementSummaryVO>>();

         Set<DataMeasurementSummaryVO> summarySet;

         DataMeasurementSummaryVO summary;

         for (SqlTaskTimer timer :topSet) {

             summarySet = new HashSet<DataMeasurementSummaryVO>();

             summaryMap.put(timer.getDriverContext() + "-" + timer.getLabel(), summarySet);

             for (DataMeasure measure: timer.getDataMeasures()) {

                 summary = measure.getDataMeasurementSummary();

                 summary.setLabel(timer.getLabel());

                 summarySet.add(summary);

             }

         }

         return summaryMap;

     }

     private static Long createEarliestTime() {

         return System.currentTimeMillis() - sqlRetentionTimeInMillis;

     }

     protected static void clearAll() {

         singleton.registeredDataMeasures.clear();

     }

     private static class TaskTimerComparable implements Comparator<TaskTimer> {

         /* (non-Javadoc)

          * @see java.util.Comparator#compare(java.lang.Object, java.lang.Object)

          */

         public int compare(TaskTimer timer1, TaskTimer timer2) {

             SqlStatementSummaryDataMeasure measure1 = extractDataMeasure(timer1);

             SqlStatementSummaryDataMeasure measure2 = extractDataMeasure(timer2);

             // Intentionally reverse order.

             if (measure1.getTotal() < measure2.getTotal()) {

                 return 1;

             }

             else if (measure1.getTotal() > measure2.getTotal()) {

                 return -1;

             }

             else {

                 return -1 * timer1.getLabel().compareTo(timer2.getLabel());

             }

         }

     }

     @SuppressWarnings({ "unchecked", "rawtypes" })

     private static SqlStatementSummaryDataMeasure extractDataMeasure(

             TaskTimer timer1) {

         return (SqlStatementSummaryDataMeasure)new ArrayList(timer1.getDataMeasures()).get(0);

     }

     protected static void setNbrRetainedSqlStatements(Integer nbrSqlStatements) {

         SqlStatementTimerRegistry.nbrRetainedSqlStatements = nbrSqlStatements;

     }

     protected static void setSqlRetentionTimeInMillis(Long sqlRetentionTimeInMillis) {

         SqlStatementTimerRegistry.sqlRetentionTimeInMillis = sqlRetentionTimeInMillis;

     }

 }