/*
 * 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.sqlobject;

import java.lang.annotation.Annotation;
import java.lang.reflect.Method;
import java.util.Arrays;
import java.util.Comparator;
import java.util.List;
import java.util.Objects;
import java.util.stream.Stream;

import static java.util.stream.Collectors.toList;

Applies decorations to method handlers, according to any decorating annotations present on the method. If multiple decorating annotations are present, the order of application can be controlled using the DecoratorOrder annotation. 

This decorator is registered out of the box.

/**
 * Applies decorations to method handlers, according to any {@link SqlMethodDecoratingAnnotation decorating annotations}
 * present on the method. If multiple decorating annotations are present, the order of application can be controlled
 * using the {@link DecoratorOrder} annotation.
 * <p>
 * This decorator is registered out of the box.
 * </p>
 */
class SqlMethodAnnotatedHandlerDecorator implements HandlerDecorator {
    @Override
    public Handler decorateHandler(Handler base, Class<?> sqlObjectType, Method method) {
        Handler handler = base;

        List<Class<? extends Annotation>> annotationTypes = Stream.of(method.getAnnotations())
                .map(Annotation::annotationType)
                .filter(type -> type.isAnnotationPresent(SqlMethodDecoratingAnnotation.class))
                .collect(toList());

        Stream.of(method, sqlObjectType)
                .map(e -> e.getAnnotation(DecoratorOrder.class))
                .filter(Objects::nonNull)
                .findFirst()
                .ifPresent(order -> annotationTypes.sort(createDecoratorComparator(order).reversed()));

        List<HandlerDecorator> decorators = annotationTypes.stream()
                .map(type -> type.getAnnotation(SqlMethodDecoratingAnnotation.class))
                .map(a -> buildDecorator(a.value()))
                .collect(toList());

        for (HandlerDecorator decorator : decorators) {
            handler = decorator.decorateHandler(handler, sqlObjectType, method);
        }

        return handler;
    }

    private Comparator<Class<? extends Annotation>> createDecoratorComparator(DecoratorOrder order) {
        List<Class<? extends Annotation>> ordering = Arrays.asList(order.value());

        return Comparator.comparingInt(type -> {
            int index = ordering.indexOf(type);
            return index == -1 ? ordering.size() : index;
        });
    }

    private static HandlerDecorator buildDecorator(Class<? extends HandlerDecorator> decoratorClass) {
        try {
            return decoratorClass.getConstructor().newInstance();
        } catch (ReflectiveOperationException e) {
            throw new IllegalStateException("Decorator class " + decoratorClass + "cannot be instantiated", e);
        }
    }

}