/*
 * Copyright (c) 2018 Oracle and/or its affiliates. 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.
 */

package io.helidon.metrics;

import java.util.Optional;
import java.util.concurrent.atomic.LongAdder;

import javax.json.JsonObjectBuilder;

import org.eclipse.microprofile.metrics.Counter;
import org.eclipse.microprofile.metrics.Metadata;

/**
 * Implementation of {@link Counter}.
 */
final class HelidonCounter extends MetricImpl implements Counter {
    private final Counter delegate;

    private HelidonCounter(String registryType, Metadata metadata, Counter delegate) {
        super(registryType, metadata);

        this.delegate = delegate;
    }

    static HelidonCounter create(String registryType, Metadata metadata) {
        return create(registryType, metadata, new CounterImpl());
    }

    static HelidonCounter create(String registryType, Metadata metadata, Counter metric) {
        return new HelidonCounter(registryType, metadata, metric);
    }

    @Override
    public void inc() {
        delegate.inc();
    }

    @Override
    public void inc(long n) {
        delegate.inc(n);
    }

    @Override
    public void dec() {
        delegate.dec();
    }

    @Override
    public void dec(long n) {
        delegate.dec(n);
    }

    @Override
    public long getCount() {
        return delegate.getCount();
    }

    @Override
    protected void prometheusData(StringBuilder sb, String name, String tags) {
        String nameWithUnits = prometheusNameWithUnits(name, Optional.empty());
        prometheusType(sb, nameWithUnits, getType());
        prometheusHelp(sb, nameWithUnits);
        sb.append(nameWithUnits).append(tags).append(" ").append(getCount()).append('\n');
    }

    @Override
    public void jsonData(JsonObjectBuilder builder) {
        builder.add(getName(), getCount());
    }

    private static class CounterImpl implements Counter {
        private final LongAdder adder = new LongAdder();

        @Override
        public void inc() {
            adder.increment();
        }

        @Override
        public void inc(long n) {
            adder.add(n);
        }

        @Override
        public void dec() {
            adder.decrement();
        }

        @Override
        public void dec(long n) {
            adder.add(-n);
        }

        @Override
        public long getCount() {
            return adder.sum();
        }
    }
}
