/*
 * 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 org.jdbi.v3.core.mapper;

import static org.jdbi.v3.core.internal.JdbiStreams.toStream;

import java.lang.reflect.Type;
import java.util.List;
import java.util.Optional;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.CopyOnWriteArrayList;

import org.jdbi.v3.core.array.SqlArrayMapperFactory;
import org.jdbi.v3.core.config.ConfigRegistry;
import org.jdbi.v3.core.config.JdbiConfig;
import org.jdbi.v3.core.generic.GenericType;

Configuration registry for ColumnMapperFactory instances. /**
 * Configuration registry for {@link ColumnMapperFactory} instances.
 */
public class ColumnMappers implements JdbiConfig<ColumnMappers> {
    private final List<ColumnMapperFactory> factories = new CopyOnWriteArrayList<>();
    private final ConcurrentHashMap<Type, ColumnMapper<?>> cache = new ConcurrentHashMap<>();
    private ConfigRegistry registry;

    public ColumnMappers() {
        factories.add(new BuiltInMapperFactory());
        factories.add(new SqlArrayMapperFactory());
    }

    @Override
    public void setRegistry(ConfigRegistry registry) {
        this.registry = registry;
    }

    private ColumnMappers(ColumnMappers that) {
        factories.addAll(that.factories);
        cache.putAll(that.cache);
    }

    
Register a column mapper which will have its parameterized type inspected to determine what it maps to. Column mappers may be reused by RowMapper to map individual columns. 

The parameter must be concretely parameterized, we use the type argument T to
determine if it applies to a given type.
Params:
mapper – the column mapper
Throws:
UnsupportedOperationException – if the ColumnMapper is not a concretely parameterized type
Returns:
this/**
     * Register a column mapper which will have its parameterized type inspected to determine what it maps to.
     * Column mappers may be reused by {@link RowMapper} to map individual columns.
     * <p>
     * The parameter must be concretely parameterized, we use the type argument T to
     * determine if it applies to a given type.
     *
     * @param mapper the column mapper
     * @return this
     * @throws UnsupportedOperationException if the ColumnMapper is not a concretely parameterized type
     */
    public ColumnMappers register(ColumnMapper<?> mapper) {
        return this.register(new InferredColumnMapperFactory(mapper));
    }

    
Register a column mapper for a given explicit Type Column mappers may be reused by RowMapper to map individual columns. 
Params:
type – the type to match with equals.
mapper – the column mapper
Returns:
this/**
     * Register a column mapper for a given explicit {@link Type}
     * Column mappers may be reused by {@link RowMapper} to map individual columns.
     *
     * @param type the type to match with equals.
     * @param mapper the column mapper
     * @return this
     */
    public ColumnMappers register(Type type, ColumnMapper<?> mapper) {
        return this.register(ColumnMapperFactory.of(type, mapper));
    }

    
Register a column mapper factory.
 Column mappers may be reused by RowMapper to map individual columns. 
Params:
factory – the column mapper factory
Returns:
this/**
     * Register a column mapper factory.
     * <p>
     * Column mappers may be reused by {@link RowMapper} to map individual columns.
     *
     * @param factory the column mapper factory
     * @return this
     */
    public ColumnMappers register(ColumnMapperFactory factory) {
        factories.add(0, factory);
        cache.clear();
        return this;
    }

    
Obtain a column mapper for the given type.
Params:
type – the target type to map to
Type parameters:
<T> – the type to map
Returns:
a ColumnMapper for the given type, or empty if no column mapper is registered for the given type./**
     * Obtain a column mapper for the given type.
     *
     * @param <T> the type to map
     * @param type the target type to map to
     * @return a ColumnMapper for the given type, or empty if no column mapper is registered for the given type.
     */
    @SuppressWarnings("unchecked")
    public <T> Optional<ColumnMapper<T>> findFor(Class<T> type) {
        ColumnMapper<T> mapper = (ColumnMapper<T>) findFor((Type) type).orElse(null);
        return Optional.ofNullable(mapper);
    }

    
Obtain a column mapper for the given type.
Params:
type – the target type to map to
Type parameters:
<T> – the type to map
Returns:
a ColumnMapper for the given type, or empty if no column mapper is registered for the given type./**
     * Obtain a column mapper for the given type.
     *
     * @param <T> the type to map
     * @param type the target type to map to
     * @return a ColumnMapper for the given type, or empty if no column mapper is registered for the given type.
     */
    @SuppressWarnings("unchecked")
    public <T> Optional<ColumnMapper<T>> findFor(GenericType<T> type) {
        ColumnMapper<T> mapper = (ColumnMapper<T>) findFor(type.getType()).orElse(null);
        return Optional.ofNullable(mapper);
    }

    
Obtain a column mapper for the given type.
Params:
type – the target type to map to
Returns:
a ColumnMapper for the given type, or empty if no column mapper is registered for the given type./**
     * Obtain a column mapper for the given type.
     *
     * @param type the target type to map to
     * @return a ColumnMapper for the given type, or empty if no column mapper is registered for the given type.
     */
    public Optional<ColumnMapper<?>> findFor(Type type) {
        // ConcurrentHashMap can enter an infinite loop on nested computeIfAbsent calls.
        // Since column mappers can decorate other column mappers, we have to populate the cache the old fashioned way.
        // See https://bugs.openjdk.java.net/browse/JDK-8062841, https://bugs.openjdk.java.net/browse/JDK-8142175
        ColumnMapper<?> cached = cache.get(type);

        if (cached != null) {
            return Optional.of(cached);
        }

        Optional<ColumnMapper<?>> mapper = factories.stream()
                .flatMap(factory -> toStream(factory.build(type, registry)))
                .findFirst();

        mapper.ifPresent(m -> cache.put(type, m));

        return mapper;
    }

    @Override
    public ColumnMappers createCopy() {
        return new ColumnMappers(this);
    }
}