/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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 org.apache.geronimo.microprofile.metrics.common;

import org.eclipse.microprofile.metrics.Histogram;
import org.eclipse.microprofile.metrics.Meter;
import org.eclipse.microprofile.metrics.Snapshot;
import org.eclipse.microprofile.metrics.Timer;

import javax.json.bind.annotation.JsonbProperty;
import javax.json.bind.annotation.JsonbTransient;
import java.time.Duration;
import java.util.concurrent.Callable;
import java.util.concurrent.TimeUnit;

public class TimerImpl implements Timer {
    private final Histogram histogram;
    private final Meter meter;

    public TimerImpl(final String unit) {
        this.histogram = new HistogramImpl(unit);
        this.meter = new MeterImpl(unit);
    }

    @Override
    public void update(final Duration duration) {
        if (duration.isNegative() || duration.isZero()) {
            return;
        }
        histogram.update(duration.toNanos());
        meter.mark();
    }

    @Override
    public <T> T time(final Callable<T> event) throws Exception {
        try (final Context context = time()) {
            return event.call();
        }
    }

    @Override
    public void time(final Runnable event) {
        try {
            time(() -> {
                event.run();
                return null;
            });
        } catch (final RuntimeException e) {
            throw e;
        } catch (final Exception e) {
            throw new IllegalStateException(e);
        }
    }

    @Override
    public Context time() {
        return new ContextImpl();
    }

    @Override
    public Duration getElapsedTime() {
        return null;
    }

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

    @Override
    @JsonbProperty("fifteenMinRate")
    public double getFifteenMinuteRate() {
        return meter.getFifteenMinuteRate();
    }

    @Override
    @JsonbProperty("fiveMinRate")
    public double getFiveMinuteRate() {
        return meter.getFiveMinuteRate();
    }

    @Override
    public double getMeanRate() {
        return meter.getMeanRate();
    }

    @Override
    @JsonbProperty("oneMinRate")
    public double getOneMinuteRate() {
        return meter.getOneMinuteRate();
    }

    @Override
    @JsonbTransient
    public Snapshot getSnapshot() {
        return histogram.getSnapshot();
    }

    public double getP50() {
        return getSnapshot().getMedian();
    }

    public double getP75() {
        return getSnapshot().get75thPercentile();
    }

    public double getP95() {
        return getSnapshot().get95thPercentile();
    }

    public double getP98() {
        return getSnapshot().get98thPercentile();
    }

    public double getP99() {
        return getSnapshot().get99thPercentile();
    }

    public double getP999() {
        return getSnapshot().get999thPercentile();
    }

    public long getMax() {
        return getSnapshot().getMax();
    }

    public double getMean() {
        return getSnapshot().getMean();
    }

    public long getMin() {
        return getSnapshot().getMin();
    }

    public double getStddev() {
        return getSnapshot().getStdDev();
    }

    private class ContextImpl implements Context {
        private final long start = System.nanoTime();

        @Override
        public long stop() {
            final long duration = System.nanoTime() - start;
            update(Duration.ofNanos(duration));
            return duration;
        }

        @Override
        public void close() {
            stop();
        }
    }
}