/*
 * Copyright © 2020 Cask Data, Inc.
 *
 * 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.
 */

package io.cdap.delta.app;

import io.cdap.cdap.api.metrics.Metrics;
import io.cdap.delta.api.DMLOperation;

import java.util.Arrays;
import java.util.Map;
import java.util.stream.Collectors;

/**
 * Emits metrics about DDL and DML events.
 */
public class EventMetrics {
  private final Metrics metrics;
  private final String prefix;
  private final Map<DMLOperation, Integer> dmlEventCounts;
  private int ddlEventCount;

  public EventMetrics(Metrics metrics, String prefix) {
    this.metrics = metrics;
    this.prefix = prefix;
    this.dmlEventCounts = Arrays.stream(DMLOperation.values()).collect(Collectors.toMap(o -> o, o -> 0));
    this.ddlEventCount = 0;
  }

  public void incrementDMLCount(DMLOperation op) {
    dmlEventCounts.put(op, dmlEventCounts.get(op) + 1);
  }

  public void incrementDDLCount() {
    ddlEventCount++;
  }

  public void emitMetrics() {
    for (DMLOperation op : dmlEventCounts.keySet()) {
      metrics.count(String.format("%s.dml.%s", prefix, op.name().toLowerCase()), dmlEventCounts.get(op));
      dmlEventCounts.put(op, 0);
    }
    metrics.count(String.format("%s.ddl", prefix), ddlEventCount);
    ddlEventCount = 0;
  }
}

@@ -1266,32 +1266,45 @@
 ;%0A  %7D%0A%0A  public 
+synchronized 
 void incrementDM
@@ -1395,24 +1395,37 @@
 %7D%0A%0A  public 
+synchronized 
 void increme
@@ -1474,16 +1474,29 @@
  public 
+synchronized 
 void emi

synchronize EventMetrics to prevent race conditions