/**
 * 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 com.twitter.distributedlog.service.stream.limiter;

import com.twitter.distributedlog.config.DynamicDistributedLogConfiguration;
import com.twitter.distributedlog.exceptions.OverCapacityException;
import com.twitter.distributedlog.limiter.ChainedRequestLimiter;
import com.twitter.distributedlog.limiter.ComposableRequestLimiter.OverlimitFunction;
import com.twitter.distributedlog.limiter.RequestLimiter;
import com.twitter.distributedlog.service.stream.StreamManager;
import com.twitter.distributedlog.service.stream.StreamOp;
import com.twitter.distributedlog.rate.MovingAverageRate;
import org.apache.bookkeeper.feature.Feature;
import org.apache.bookkeeper.stats.StatsLogger;

/**
 * Request limiter for the service instance (global request limiter).
 */
public class ServiceRequestLimiter extends DynamicRequestLimiter<StreamOp> {
    private final StatsLogger limiterStatLogger;
    private final MovingAverageRate serviceRps;
    private final MovingAverageRate serviceBps;
    private final StreamManager streamManager;

    public ServiceRequestLimiter(DynamicDistributedLogConfiguration dynConf,
                                 StatsLogger statsLogger,
                                 MovingAverageRate serviceRps,
                                 MovingAverageRate serviceBps,
                                 StreamManager streamManager,
                                 Feature disabledFeature) {
        super(dynConf, statsLogger, disabledFeature);
        this.limiterStatLogger = statsLogger;
        this.streamManager = streamManager;
        this.serviceRps = serviceRps;
        this.serviceBps = serviceBps;
        this.limiter = build();
    }

    @Override
    public RequestLimiter<StreamOp> build() {
        int rpsStreamAcquireLimit = dynConf.getRpsStreamAcquireServiceLimit();
        int rpsSoftServiceLimit = dynConf.getRpsSoftServiceLimit();
        int rpsHardServiceLimit = dynConf.getRpsHardServiceLimit();
        int bpsStreamAcquireLimit = dynConf.getBpsStreamAcquireServiceLimit();
        int bpsSoftServiceLimit = dynConf.getBpsSoftServiceLimit();
        int bpsHardServiceLimit = dynConf.getBpsHardServiceLimit();

        RequestLimiterBuilder rpsHardLimiterBuilder = RequestLimiterBuilder.newRpsLimiterBuilder()
            .statsLogger(limiterStatLogger.scope("rps_hard_limit"))
            .limit(rpsHardServiceLimit)
            .overlimit(new OverlimitFunction<StreamOp>() {
                @Override
                public void apply(StreamOp request) throws OverCapacityException {
                    throw new OverCapacityException("RPS limit exceeded for the service instance");
                }
            });

        RequestLimiterBuilder rpsSoftLimiterBuilder = RequestLimiterBuilder.newRpsLimiterBuilder()
            .statsLogger(limiterStatLogger.scope("rps_soft_limit"))
            .limit(rpsSoftServiceLimit);

        RequestLimiterBuilder bpsHardLimiterBuilder = RequestLimiterBuilder.newBpsLimiterBuilder()
            .statsLogger(limiterStatLogger.scope("bps_hard_limit"))
            .limit(bpsHardServiceLimit)
            .overlimit(new OverlimitFunction<StreamOp>() {
                @Override
                public void apply(StreamOp request) throws OverCapacityException {
                    throw new OverCapacityException("BPS limit exceeded for the service instance");
                }
            });

        RequestLimiterBuilder bpsSoftLimiterBuilder = RequestLimiterBuilder.newBpsLimiterBuilder()
            .statsLogger(limiterStatLogger.scope("bps_soft_limit"))
            .limit(bpsSoftServiceLimit);

        ChainedRequestLimiter.Builder<StreamOp> builder = new ChainedRequestLimiter.Builder<StreamOp>();
        builder.addLimiter(new StreamAcquireLimiter(streamManager, serviceRps, rpsStreamAcquireLimit, limiterStatLogger.scope("rps_acquire")));
        builder.addLimiter(new StreamAcquireLimiter(streamManager, serviceBps, bpsStreamAcquireLimit, limiterStatLogger.scope("bps_acquire")));
        builder.addLimiter(bpsHardLimiterBuilder.build());
        builder.addLimiter(bpsSoftLimiterBuilder.build());
        builder.addLimiter(rpsHardLimiterBuilder.build());
        builder.addLimiter(rpsSoftLimiterBuilder.build());
        builder.statsLogger(limiterStatLogger);
        return builder.build();
    }
}