/**
 * 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.config;

import com.twitter.distributedlog.DistributedLogConfiguration;
import com.twitter.distributedlog.bk.QuorumConfig;

import static com.twitter.distributedlog.DistributedLogConfiguration.*;

/**
 * Whitelist dynamic configuration by adding an accessor to this class.
 */
public class DynamicDistributedLogConfiguration extends ConcurrentBaseConfiguration {

    private final ConcurrentBaseConfiguration defaultConfig;

    public DynamicDistributedLogConfiguration(ConcurrentBaseConfiguration defaultConfig) {
        this.defaultConfig = defaultConfig;
    }

    private static int getInt(ConcurrentBaseConfiguration configuration,
                              String newKey,
                              String oldKey,
                              int defaultValue) {
        return configuration.getInt(newKey, configuration.getInt(oldKey, defaultValue));
    }

    /**
     * Get retention period in hours
     *
     * @return retention period in hours
     */
    public int getRetentionPeriodHours() {
        return getInt(
                this,
                BKDL_RETENTION_PERIOD_IN_HOURS,
                BKDL_RETENTION_PERIOD_IN_HOURS_OLD,
                getInt(defaultConfig,
                        BKDL_RETENTION_PERIOD_IN_HOURS,
                        BKDL_RETENTION_PERIOD_IN_HOURS_OLD,
                        BKDL_RETENTION_PERIOD_IN_HOURS_DEFAULT)
        );
    }

    /**
     * A lower threshold bytes per second limit on writes to the distributedlog proxy.
     *
     * @return Bytes per second write limit
     */
    public int getBpsSoftWriteLimit() {
        return getInt(DistributedLogConfiguration.BKDL_BPS_SOFT_WRITE_LIMIT,
            defaultConfig.getInt(DistributedLogConfiguration.BKDL_BPS_SOFT_WRITE_LIMIT,
                DistributedLogConfiguration.BKDL_BPS_SOFT_WRITE_LIMIT_DEFAULT));
    }

    /**
     * An upper threshold bytes per second limit on writes to the distributedlog proxy.
     *
     * @return Bytes per second write limit
     */
    public int getBpsHardWriteLimit() {
        return getInt(DistributedLogConfiguration.BKDL_BPS_HARD_WRITE_LIMIT,
            defaultConfig.getInt(DistributedLogConfiguration.BKDL_BPS_HARD_WRITE_LIMIT,
                DistributedLogConfiguration.BKDL_BPS_HARD_WRITE_LIMIT_DEFAULT));
    }

    /**
     * A lower threshold requests per second limit on writes to the distributedlog proxy.
     *
     * @return Requests per second write limit
     */
    public int getRpsSoftWriteLimit() {
        return getInt(DistributedLogConfiguration.BKDL_RPS_SOFT_WRITE_LIMIT,
            defaultConfig.getInt(DistributedLogConfiguration.BKDL_RPS_SOFT_WRITE_LIMIT,
                DistributedLogConfiguration.BKDL_RPS_SOFT_WRITE_LIMIT_DEFAULT));
    }

    /**
     * An upper threshold requests per second limit on writes to the distributedlog proxy.
     *
     * @return Requests per second write limit
     */
    public int getRpsHardWriteLimit() {
        return getInt(DistributedLogConfiguration.BKDL_RPS_HARD_WRITE_LIMIT,
            defaultConfig.getInt(DistributedLogConfiguration.BKDL_RPS_HARD_WRITE_LIMIT,
                DistributedLogConfiguration.BKDL_RPS_HARD_WRITE_LIMIT_DEFAULT));
    }

    /**
     * A lower threshold requests per second limit on writes to the distributedlog proxy globally.
     *
     * @return Requests per second write limit
     */
    public int getRpsSoftServiceLimit() {
        return getInt(DistributedLogConfiguration.BKDL_RPS_SOFT_SERVICE_LIMIT,
            defaultConfig.getInt(DistributedLogConfiguration.BKDL_RPS_SOFT_SERVICE_LIMIT,
                DistributedLogConfiguration.BKDL_RPS_SOFT_SERVICE_LIMIT_DEFAULT));
    }

    /**
     * An upper threshold requests per second limit on writes to the distributedlog proxy globally.
     *
     * @return Requests per second write limit
     */
    public int getRpsHardServiceLimit() {
        return getInt(DistributedLogConfiguration.BKDL_RPS_HARD_SERVICE_LIMIT,
            defaultConfig.getInt(DistributedLogConfiguration.BKDL_RPS_HARD_SERVICE_LIMIT,
                DistributedLogConfiguration.BKDL_RPS_HARD_SERVICE_LIMIT_DEFAULT));
    }

    /**
     * When 60min average rps for the entire service instance hits this value, new streams will be
     * rejected.
     *
     * @return Requests per second limit
     */
    public int getRpsStreamAcquireServiceLimit() {
        return getInt(DistributedLogConfiguration.BKDL_RPS_STREAM_ACQUIRE_SERVICE_LIMIT,
            defaultConfig.getInt(DistributedLogConfiguration.BKDL_RPS_STREAM_ACQUIRE_SERVICE_LIMIT,
                DistributedLogConfiguration.BKDL_RPS_STREAM_ACQUIRE_SERVICE_LIMIT_DEFAULT));
    }

    /**
     * A lower threshold bytes per second limit on writes to the distributedlog proxy globally.
     *
     * @return Bytes per second write limit
     */
    public int getBpsSoftServiceLimit() {
        return getInt(DistributedLogConfiguration.BKDL_BPS_SOFT_SERVICE_LIMIT,
            defaultConfig.getInt(DistributedLogConfiguration.BKDL_BPS_SOFT_SERVICE_LIMIT,
                DistributedLogConfiguration.BKDL_BPS_SOFT_SERVICE_LIMIT_DEFAULT));
    }

    /**
     * An upper threshold bytes per second limit on writes to the distributedlog proxy globally.
     *
     * @return Bytes per second write limit
     */
    public int getBpsHardServiceLimit() {
        return getInt(DistributedLogConfiguration.BKDL_BPS_HARD_SERVICE_LIMIT,
            defaultConfig.getInt(DistributedLogConfiguration.BKDL_BPS_HARD_SERVICE_LIMIT,
                DistributedLogConfiguration.BKDL_BPS_HARD_SERVICE_LIMIT_DEFAULT));
    }

    /**
     * When 60min average bps for the entire service instance hits this value, new streams will be
     * rejected.
     *
     * @return Bytes per second limit
     */
    public int getBpsStreamAcquireServiceLimit() {
        return getInt(DistributedLogConfiguration.BKDL_BPS_STREAM_ACQUIRE_SERVICE_LIMIT,
            defaultConfig.getInt(DistributedLogConfiguration.BKDL_BPS_STREAM_ACQUIRE_SERVICE_LIMIT,
                DistributedLogConfiguration.BKDL_BPS_STREAM_ACQUIRE_SERVICE_LIMIT_DEFAULT));
    }

    /**
     * Get percent of write bytes which should be delayed by BKDL_EI_INJECTED_WRITE_DELAY_MS.
     *
     * @return percent of writes to delay.
     */
    public double getEIInjectedWriteDelayPercent() {
        return getDouble(DistributedLogConfiguration.BKDL_EI_INJECTED_WRITE_DELAY_PERCENT,
            defaultConfig.getDouble(DistributedLogConfiguration.BKDL_EI_INJECTED_WRITE_DELAY_PERCENT,
                DistributedLogConfiguration.BKDL_EI_INJECTED_WRITE_DELAY_PERCENT_DEFAULT));
    }

    /**
     * Get amount of time to delay writes for in writer failure injection.
     *
     * @return millis to delay writes for.
     */
    public int getEIInjectedWriteDelayMs() {
        return getInt(DistributedLogConfiguration.BKDL_EI_INJECTED_WRITE_DELAY_MS,
            defaultConfig.getInt(DistributedLogConfiguration.BKDL_EI_INJECTED_WRITE_DELAY_MS,
                DistributedLogConfiguration.BKDL_EI_INJECTED_WRITE_DELAY_MS_DEFAULT));
    }

    /**
     * Get output buffer size
     *
     * @return buffer size
     */
    public int getOutputBufferSize() {
        return getInt(
                this,
                BKDL_OUTPUT_BUFFER_SIZE,
                BKDL_OUTPUT_BUFFER_SIZE_OLD,
                getInt(defaultConfig,
                        BKDL_OUTPUT_BUFFER_SIZE,
                        BKDL_OUTPUT_BUFFER_SIZE_OLD,
                        BKDL_OUTPUT_BUFFER_SIZE_DEFAULT)
        );
    }

    /**
     * Get Periodic Log Flush Frequency in seconds
     *
     * @return periodic flush frequency
     */
    public int getPeriodicFlushFrequencyMilliSeconds() {
        return getInt(DistributedLogConfiguration.BKDL_PERIODIC_FLUSH_FREQUENCY_MILLISECONDS,
            defaultConfig.getInt(DistributedLogConfiguration.BKDL_PERIODIC_FLUSH_FREQUENCY_MILLISECONDS,
                DistributedLogConfiguration.BKDL_PERIODIC_FLUSH_FREQUENCY_MILLISECONDS_DEFAULT));
    }

    /**
     * Get the number of entries that readahead worker reads as a batch from bookkeeper
     *
     * @return the batch size
     */
    public int getReadAheadBatchSize() {
        return getInt(
                this,
                BKDL_READAHEAD_BATCHSIZE,
                BKDL_READAHEAD_BATCHSIZE_OLD,
                getInt(defaultConfig,
                        BKDL_READAHEAD_BATCHSIZE,
                        BKDL_READAHEAD_BATCHSIZE_OLD,
                        BKDL_READAHEAD_BATCHSIZE_DEFAULT)
        );
    }

    /**
     * Get the maximum number of {@link com.twitter.distributedlog.LogRecord } that readahead worker will cache.
     *
     * @return the maximum number
     */
    public int getReadAheadMaxRecords() {
        return getInt(
                this,
                BKDL_READAHEAD_MAX_RECORDS,
                BKDL_READAHEAD_MAX_RECORDS_OLD,
                getInt(defaultConfig,
                        BKDL_READAHEAD_MAX_RECORDS,
                        BKDL_READAHEAD_MAX_RECORDS_OLD,
                        BKDL_READAHEAD_MAX_RECORDS_DEFAULT)
        );
    }

    /**
     * Whether to enable ledger allocator pool or not.
     * It is disabled by default.
     *
     * @return whether using ledger allocator pool or not.
     */
    public boolean getEnableLedgerAllocatorPool() {
        return getBoolean(BKDL_ENABLE_LEDGER_ALLOCATOR_POOL,
                defaultConfig.getBoolean(
                        BKDL_ENABLE_LEDGER_ALLOCATOR_POOL,
                        BKDL_ENABLE_LEDGER_ALLOCATOR_POOL_DEFAULT));
    }

    /**
     * Get the quorum config.
     *
     * @return quorum config
     */
    public QuorumConfig getQuorumConfig() {
        int ensembleSize = getInt(
                this,
                BKDL_BOOKKEEPER_ENSEMBLE_SIZE,
                BKDL_BOOKKEEPER_ENSEMBLE_SIZE_OLD,
                getInt(defaultConfig,
                        BKDL_BOOKKEEPER_ENSEMBLE_SIZE,
                        BKDL_BOOKKEEPER_ENSEMBLE_SIZE_OLD,
                        BKDL_BOOKKEEPER_ENSEMBLE_SIZE_DEFAULT));
        int writeQuorumSize = getInt(
                this,
                BKDL_BOOKKEEPER_WRITE_QUORUM_SIZE,
                BKDL_BOOKKEEPER_WRITE_QUORUM_SIZE_OLD,
                getInt(defaultConfig,
                        BKDL_BOOKKEEPER_WRITE_QUORUM_SIZE,
                        BKDL_BOOKKEEPER_WRITE_QUORUM_SIZE_OLD,
                        BKDL_BOOKKEEPER_WRITE_QUORUM_SIZE_DEFAULT));
        int ackQuorumSize = getInt(
                this,
                BKDL_BOOKKEEPER_ACK_QUORUM_SIZE,
                BKDL_BOOKKEEPER_ACK_QUORUM_SIZE_OLD,
                getInt(defaultConfig,
                        BKDL_BOOKKEEPER_ACK_QUORUM_SIZE,
                        BKDL_BOOKKEEPER_ACK_QUORUM_SIZE_OLD,
                        BKDL_BOOKKEEPER_ACK_QUORUM_SIZE_DEFAULT));
        return new QuorumConfig(ensembleSize, writeQuorumSize, ackQuorumSize);
    }

    /**
     * Get the maximum number of partitions of each stream allowed to be acquired per proxy.
     *
     * @return maximum number of partitions of each stream allowed to be acquired
     * @see DistributedLogConfiguration#getMaxAcquiredPartitionsPerProxy()
     */
    public int getMaxAcquiredPartitionsPerProxy() {
        return getInt(
                BKDL_MAX_ACQUIRED_PARTITIONS_PER_PROXY,
                defaultConfig.getInt(
                        BKDL_MAX_ACQUIRED_PARTITIONS_PER_PROXY,
                        BKDL_MAX_ACQUIRED_PARTITIONS_PER_PROXY_DEFAULT)
        );
    }

    /**
     * Get the maximum number of partitions of each stream allowed to cache per proxy.
     *
     * @return maximum number of partitions of each stream allowed to cache
     * @see DistributedLogConfiguration#getMaxAcquiredPartitionsPerProxy()
     */
    public int getMaxCachedPartitionsPerProxy() {
        return getInt(
                BKDL_MAX_CACHED_PARTITIONS_PER_PROXY,
                defaultConfig.getInt(
                        BKDL_MAX_CACHED_PARTITIONS_PER_PROXY,
                        BKDL_MAX_CACHED_PARTITIONS_PER_PROXY_DEFAULT)
        );
    }

    /**
     * Check whether the durable write is enabled.
     *
     * @return true if durable write is enabled. otherwise, false.
     */
    public boolean isDurableWriteEnabled() {
        return getBoolean(BKDL_IS_DURABLE_WRITE_ENABLED,
                defaultConfig.getBoolean(
                        BKDL_IS_DURABLE_WRITE_ENABLED,
                        BKDL_IS_DURABLE_WRITE_ENABLED_DEFAULT));
    }

    /**
     * Get the flag whether to deserialize recordset on reads.
     *
     * @return flag whether to deserialize recordset on reads.
     */
    public boolean getDeserializeRecordSetOnReads() {
        return getBoolean(BKDL_DESERIALIZE_RECORDSET_ON_READS,
                defaultConfig.getBoolean(
                        BKDL_DESERIALIZE_RECORDSET_ON_READS,
                        BKDL_DESERIALIZE_RECORDSET_ON_READS_DEFAULT));
    }

}