/*
 * Copyright DataStax, Inc.
 *
 * 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 com.datastax.oss.driver.internal.core.type.codec.registry;

import com.datastax.oss.driver.api.core.DriverExecutionException;
import com.datastax.oss.driver.api.core.type.DataType;
import com.datastax.oss.driver.api.core.type.codec.TypeCodec;
import com.datastax.oss.driver.api.core.type.reflect.GenericType;
import com.datastax.oss.driver.shaded.guava.common.base.Throwables;
import com.datastax.oss.driver.shaded.guava.common.cache.CacheBuilder;
import com.datastax.oss.driver.shaded.guava.common.cache.CacheLoader;
import com.datastax.oss.driver.shaded.guava.common.cache.LoadingCache;
import com.datastax.oss.driver.shaded.guava.common.cache.RemovalListener;
import com.datastax.oss.driver.shaded.guava.common.util.concurrent.ExecutionError;
import com.datastax.oss.driver.shaded.guava.common.util.concurrent.UncheckedExecutionException;
import edu.umd.cs.findbugs.annotations.NonNull;
import edu.umd.cs.findbugs.annotations.Nullable;
import java.util.Objects;
import java.util.function.BiConsumer;
import java.util.function.BiFunction;
import net.jcip.annotations.ThreadSafe;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

The default codec registry implementation.
It is a caching registry based on Guava cache (note that the driver shades Guava).
/**
 * The default codec registry implementation.
 *
 * <p>It is a caching registry based on Guava cache (note that the driver shades Guava).
 */
@ThreadSafe
public class DefaultCodecRegistry extends CachingCodecRegistry {

  private static final Logger LOG = LoggerFactory.getLogger(DefaultCodecRegistry.class);

  private final LoadingCache<CacheKey, TypeCodec<?>> cache;

  
Creates a new instance that accepts user codecs, with the default built-in codecs and the
default cache behavior.
/**
   * Creates a new instance that accepts user codecs, with the default built-in codecs and the
   * default cache behavior.
   */
  public DefaultCodecRegistry(@NonNull String logPrefix) {
    this(logPrefix, CodecRegistryConstants.PRIMITIVE_CODECS);
  }

  
Creates a new instance that accepts user codecs, with the given built-in codecs and the default
cache behavior.
/**
   * Creates a new instance that accepts user codecs, with the given built-in codecs and the default
   * cache behavior.
   */
  public DefaultCodecRegistry(@NonNull String logPrefix, @NonNull TypeCodec<?>... primitiveCodecs) {
    this(logPrefix, 0, null, 0, null, primitiveCodecs);
  }

  
Same as DefaultCodecRegistry(String, TypeCodec<?>[]), but with some amount of control over cache behavior. 
Giving full access to the Guava cache API would be too much work, since it is shaded and we
have to wrap everything. If you need something that's not available here, it's easy enough to
write your own CachingCodecRegistry implementation. It's doubtful that stuff like cache
eviction is that useful anyway.
/**
   * Same as {@link #DefaultCodecRegistry(String, TypeCodec[])}, but with some amount of control
   * over cache behavior.
   *
   * <p>Giving full access to the Guava cache API would be too much work, since it is shaded and we
   * have to wrap everything. If you need something that's not available here, it's easy enough to
   * write your own CachingCodecRegistry implementation. It's doubtful that stuff like cache
   * eviction is that useful anyway.
   */
  public DefaultCodecRegistry(
      @NonNull String logPrefix,
      int initialCacheCapacity,
      @Nullable BiFunction<CacheKey, TypeCodec<?>, Integer> cacheWeigher,
      int maximumCacheWeight,
      @Nullable BiConsumer<CacheKey, TypeCodec<?>> cacheRemovalListener,
      @NonNull TypeCodec<?>... primitiveCodecs) {

    super(logPrefix, primitiveCodecs);
    CacheBuilder<Object, Object> cacheBuilder = CacheBuilder.newBuilder();
    if (initialCacheCapacity > 0) {
      cacheBuilder.initialCapacity(initialCacheCapacity);
    }
    if (cacheWeigher != null) {
      cacheBuilder.weigher(cacheWeigher::apply).maximumWeight(maximumCacheWeight);
    }
    CacheLoader<CacheKey, TypeCodec<?>> cacheLoader =
        new CacheLoader<CacheKey, TypeCodec<?>>() {
          @Override
          public TypeCodec<?> load(@NonNull CacheKey key) throws Exception {
            return createCodec(key.cqlType, key.javaType, key.isJavaCovariant);
          }
        };
    if (cacheRemovalListener != null) {
      this.cache =
          cacheBuilder
              .removalListener(
                  (RemovalListener<CacheKey, TypeCodec<?>>)
                      notification ->
                          cacheRemovalListener.accept(
                              notification.getKey(), notification.getValue()))
              .build(cacheLoader);
    } else {
      this.cache = cacheBuilder.build(cacheLoader);
    }
  }

  @Override
  protected TypeCodec<?> getCachedCodec(
      @Nullable DataType cqlType, @Nullable GenericType<?> javaType, boolean isJavaCovariant) {
    LOG.trace("[{}] Checking cache", logPrefix);
    try {
      return cache.getUnchecked(new CacheKey(cqlType, javaType, isJavaCovariant));
    } catch (UncheckedExecutionException | ExecutionError e) {
      // unwrap exception cause and throw it directly.
      Throwable cause = e.getCause();
      if (cause != null) {
        Throwables.throwIfUnchecked(cause);
        throw new DriverExecutionException(cause);
      } else {
        // Should never happen, throw just in case
        throw new RuntimeException(e.getMessage());
      }
    }
  }

  public static final class CacheKey {

    public final DataType cqlType;
    public final GenericType<?> javaType;
    public final boolean isJavaCovariant;

    public CacheKey(
        @Nullable DataType cqlType, @Nullable GenericType<?> javaType, boolean isJavaCovariant) {
      this.javaType = javaType;
      this.cqlType = cqlType;
      this.isJavaCovariant = isJavaCovariant;
    }

    @Override
    public boolean equals(Object other) {
      if (other == this) {
        return true;
      } else if (other instanceof CacheKey) {
        CacheKey that = (CacheKey) other;
        return Objects.equals(this.cqlType, that.cqlType)
            && Objects.equals(this.javaType, that.javaType)
            && this.isJavaCovariant == that.isJavaCovariant;
      } else {
        return false;
      }
    }

    @Override
    public int hashCode() {
      return Objects.hash(cqlType, javaType, isJavaCovariant);
    }
  }
}