/**
 * Copyright 2009-2020 the original author or authors.
 *
 * 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 net.javacrumbs.shedlock.spring.aop;

import net.javacrumbs.shedlock.core.LockConfiguration;
import net.javacrumbs.shedlock.core.LockingTaskExecutor;
import net.javacrumbs.shedlock.core.LockingTaskExecutor.TaskResult;
import net.javacrumbs.shedlock.spring.annotation.SchedulerLock;
import org.aopalliance.aop.Advice;
import org.aopalliance.intercept.MethodInterceptor;
import org.aopalliance.intercept.MethodInvocation;
import net.javacrumbs.shedlock.support.annotation.NonNull;
import org.springframework.aop.Pointcut;
import org.springframework.aop.support.AbstractPointcutAdvisor;
import org.springframework.aop.support.ComposablePointcut;
import org.springframework.aop.support.annotation.AnnotationMatchingPointcut;

import java.lang.annotation.Annotation;
import java.util.Optional;

class MethodProxyScheduledLockAdvisor extends AbstractPointcutAdvisor {
    private final Pointcut pointcut = new ComposablePointcut(methodPointcutFor(net.javacrumbs.shedlock.core.SchedulerLock.class))
        .union(methodPointcutFor(SchedulerLock.class));

    private final Advice advice;

    MethodProxyScheduledLockAdvisor(SpringLockConfigurationExtractor lockConfigurationExtractor, LockingTaskExecutor lockingTaskExecutor) {
        this.advice = new LockingInterceptor(lockConfigurationExtractor, lockingTaskExecutor);
    }

    @NonNull
    private static AnnotationMatchingPointcut methodPointcutFor(Class<? extends Annotation> methodAnnotationType) {
        return new AnnotationMatchingPointcut(
            null,
            methodAnnotationType,
            true
        );
    }

    /**
     * Get the Pointcut that drives this advisor.
     */
    @NonNull
    @Override
    public Pointcut getPointcut() {
        return pointcut;
    }

    @NonNull
    @Override
    public Advice getAdvice() {
        return advice;
    }

    private static class LockingInterceptor implements MethodInterceptor {
        private final SpringLockConfigurationExtractor lockConfigurationExtractor;
        private final LockingTaskExecutor lockingTaskExecutor;

        LockingInterceptor(SpringLockConfigurationExtractor lockConfigurationExtractor, LockingTaskExecutor lockingTaskExecutor) {
            this.lockConfigurationExtractor = lockConfigurationExtractor;
            this.lockingTaskExecutor = lockingTaskExecutor;
        }

        @Override
        public Object invoke(MethodInvocation invocation) throws Throwable {
            Class<?> returnType = invocation.getMethod().getReturnType();
            if (returnType.isPrimitive() && !void.class.equals(returnType)) {
                throw new LockingNotSupportedException("Can not lock method returning primitive value");
            }

            LockConfiguration lockConfiguration = lockConfigurationExtractor.getLockConfiguration(invocation.getThis(), invocation.getMethod()).get();
            TaskResult<Object> result = lockingTaskExecutor.executeWithLock(invocation::proceed, lockConfiguration);

            if (Optional.class.equals(returnType)) {
                return toOptional(result);
            } else {
                return result.getResult();
            }
        }

        private static Object toOptional(TaskResult<Object> result) {
            if (result.wasExecuted()) {
                return result.getResult();
            } else {
                return Optional.empty();
            }
        }
    }
}