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 * to you under the Apache License, Version 2.0 (the            *
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 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY       *
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package org.apache.james.blob.cassandra.cache;

import java.time.Duration;
import java.time.temporal.ChronoUnit;
import java.util.Objects;
import java.util.Optional;

import org.apache.commons.configuration2.Configuration;
import org.apache.james.util.DurationParser;
import org.apache.james.util.SizeFormat;

import com.google.common.base.Preconditions;

public class CassandraCacheConfiguration {

    public static class Builder {
        private static final Duration DEFAULT_READ_TIMEOUT = Duration.ofMillis(100);
        private static final Duration MAX_READ_TIMEOUT = Duration.ofHours(1);
        private static final Duration DEFAULT_TTL = Duration.ofDays(7);
        private static final int DEFAULT_BYTE_THRESHOLD_SIZE = 8 * 1024;

        private Optional<Duration> readTimeout = Optional.empty();
        private Optional<Integer> sizeThresholdInBytes = Optional.empty();
        private Optional<Duration> ttl = Optional.empty();

        public Builder timeOut(Duration timeout) {
            Preconditions.checkNotNull(timeout, "'Read timeout' must not to be null");
            Preconditions.checkArgument(timeout.toMillis() > 0, "'Read timeout' needs to be positive");
            Preconditions.checkArgument(timeout.getSeconds() <= MAX_READ_TIMEOUT.getSeconds(),
                "'Read timeout' needs to be less than %s sec", MAX_READ_TIMEOUT.getSeconds());

            this.readTimeout = Optional.of(timeout);
            return this;
        }

        public Builder sizeThresholdInBytes(int sizeThresholdInBytes) {
            Preconditions.checkArgument(sizeThresholdInBytes >= 0, "'Threshold size' needs to be positive");

            this.sizeThresholdInBytes = Optional.of(sizeThresholdInBytes);
            return this;
        }

        public Builder ttl(Duration ttl) {
            Preconditions.checkNotNull(ttl, "'TTL' must not to be null");
            Preconditions.checkArgument(ttl.getSeconds() > 0, "'TTL' needs to be positive");
            Preconditions.checkArgument(ttl.getSeconds() < Integer.MAX_VALUE,
                "'TTL' must not greater than %s sec", Integer.MAX_VALUE);

            this.ttl = Optional.of(ttl);
            return this;
        }

        public Builder ttl(Optional<Duration> ttl) {
            ttl.ifPresent(this::ttl);
            return this;
        }

        public Builder timeOut(Optional<Duration> timeOut) {
            timeOut.ifPresent(this::timeOut);
            return this;
        }

        public Builder sizeThresholdInBytes(Optional<Integer> sizeThresholdInBytes) {
            sizeThresholdInBytes.ifPresent(this::sizeThresholdInBytes);
            return this;
        }

        public CassandraCacheConfiguration build() {
            return new CassandraCacheConfiguration(
                readTimeout.orElse(DEFAULT_READ_TIMEOUT),
                sizeThresholdInBytes.orElse(DEFAULT_BYTE_THRESHOLD_SIZE),
                ttl.orElse(DEFAULT_TTL));
        }
    }

    public static final CassandraCacheConfiguration DEFAULT = builder().build();

    public static Builder builder() {
        return new Builder();
    }

    public static CassandraCacheConfiguration from(Configuration configuration) {
        Optional<Duration> ttl = Optional.ofNullable(configuration.getString("cache.cassandra.ttl", null))
            .map(value -> DurationParser.parse(value, ChronoUnit.SECONDS));
        Optional<Duration> timeOut = Optional.ofNullable(configuration.getString("cache.cassandra.timeout", null))
            .map(value -> DurationParser.parse(value, ChronoUnit.SECONDS));
        Optional<Integer> sizeThreshold = Optional.ofNullable(configuration.getString("cache.sizeThresholdInBytes", null))
            .map(SizeFormat::parseAsByteCount)
            .map(Math::toIntExact);

        return builder()
            .ttl(ttl)
            .timeOut(timeOut)
            .sizeThresholdInBytes(sizeThreshold)
            .build();
    }

    private final Duration readTimeOut;
    private final int sizeThresholdInBytes;
    private final Duration ttl;

    private CassandraCacheConfiguration(Duration timeout, int sizeThresholdInBytes, Duration ttl) {
        this.readTimeOut = timeout;
        this.sizeThresholdInBytes = sizeThresholdInBytes;
        this.ttl = ttl;
    }

    public Duration getReadTimeOut() {
        return readTimeOut;
    }

    public Duration getTtl() {
        return ttl;
    }

    public int getSizeThresholdInBytes() {
        return sizeThresholdInBytes;
    }

    @Override
    public final boolean equals(Object o) {
        if (o instanceof CassandraCacheConfiguration) {
            CassandraCacheConfiguration that = (CassandraCacheConfiguration) o;

            return Objects.equals(this.sizeThresholdInBytes, that.sizeThresholdInBytes)
                && Objects.equals(this.readTimeOut, that.readTimeOut)
                && Objects.equals(this.ttl, that.ttl);
        }
        return false;
    }

    @Override
    public final int hashCode() {
        return Objects.hash(readTimeOut, sizeThresholdInBytes, ttl);
    }
}
