// Copyright (C) 2022 The Android Open Source Project
//
// 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 com.googlesource.gerrit.modules.cache.chroniclemap;

import com.google.common.flogger.FluentLogger;
import com.google.gerrit.metrics.Counter0;
import com.google.gerrit.metrics.Description;
import com.google.gerrit.metrics.MetricMaker;
import com.google.inject.Inject;
import com.google.inject.Singleton;
import java.util.Collections;
import java.util.HashSet;
import java.util.Set;

@Singleton
class CachesWithoutChronicleMapConfigMetric {
  private static final FluentLogger logger = FluentLogger.forEnclosingClass();

  private final Set<String> uniqueCacheNames;
  private final Counter0 numberOfCachesWithoutConfig;

  @Inject
  CachesWithoutChronicleMapConfigMetric(MetricMaker metricMaker) {
    this.uniqueCacheNames = Collections.synchronizedSet(new HashSet<>());

    String metricName = "cache/chroniclemap/caches_without_configuration";
    this.numberOfCachesWithoutConfig =
        metricMaker.newCounter(
            metricName,
            new Description(
                    "The number of caches that have no chronicle map configuration provided in 'gerrit.config' and use defaults.")
                .setUnit("caches"));
  }

  void incrementForCache(String name) {
    if (uniqueCacheNames.add(name)) {
      numberOfCachesWithoutConfig.increment();
      logger.atWarning().log("Fall back to default configuration for '%s' cache", name);
    }
  }

  Set<String> cachesOnDefaults() {
    return uniqueCacheNames;
  }
}