/*
 * 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.transaction.internal;

import java.lang.reflect.Method;

import org.jdbi.v3.core.Handle;
import org.jdbi.v3.core.HandleCallback;
import org.jdbi.v3.core.transaction.TransactionException;
import org.jdbi.v3.core.transaction.TransactionIsolationLevel;
import org.jdbi.v3.sqlobject.Handler;
import org.jdbi.v3.sqlobject.HandlerDecorator;
import org.jdbi.v3.sqlobject.transaction.Transaction;

public class TransactionDecorator implements HandlerDecorator {
    @Override
    public Handler decorateHandler(Handler base, Class<?> sqlObjectType, Method method) {
        final Transaction txnAnnotation = method.getAnnotation(Transaction.class);
        final TransactionIsolationLevel isolation = txnAnnotation.value();
        final boolean readOnly = txnAnnotation.readOnly();

        return (target, args, handle) -> {
            Handle h = handle.getHandle();

            if (h.isInTransaction() && h.isReadOnly() && !readOnly) {
                throw new TransactionException("Tried to execute a nested @Transaction(readOnly=false) "
                        + "inside a readOnly transaction");
            }

            HandleCallback<Object, Exception> callback = th -> base.invoke(target, args, handle);

            final boolean flipReadOnly = readOnly != h.isReadOnly();
            if (flipReadOnly) {
                h.setReadOnly(readOnly);
            }

            try {
                return h.inTransaction(isolation, callback);
            } finally {
                if (flipReadOnly) {
                    h.setReadOnly(!readOnly);
                }
            }
        };
    }
}