/*
 * Copyright (c) "Neo4j"
 * Neo4j Sweden AB [http://neo4j.com]
 *
 * This file is part of Neo4j.
 *
 * 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.neo4j.driver.internal.util;

import io.netty.util.internal.PlatformDependent;
import java.io.IOException;
import java.util.concurrent.atomic.AtomicReference;
import org.neo4j.driver.internal.messaging.Message;
import org.neo4j.driver.internal.messaging.MessageFormat;
import org.neo4j.driver.internal.messaging.ResponseMessageHandler;
import org.neo4j.driver.internal.messaging.response.FailureMessage;
import org.neo4j.driver.internal.packstream.PackInput;
import org.neo4j.driver.internal.packstream.PackOutput;

public class FailingMessageFormat implements MessageFormat {
    private final MessageFormat delegate;
    private final AtomicReference<Throwable> writerThrowableRef = new AtomicReference<>();
    private final AtomicReference<Throwable> readerThrowableRef = new AtomicReference<>();
    private final AtomicReference<FailureMessage> readerFailureRef = new AtomicReference<>();

    public FailingMessageFormat(MessageFormat delegate) {
        this.delegate = delegate;
    }

    public void makeWriterThrow(Throwable error) {
        writerThrowableRef.set(error);
    }

    public void makeReaderThrow(Throwable error) {
        readerThrowableRef.set(error);
    }

    public void makeReaderFail(FailureMessage failureMsg) {
        readerFailureRef.set(failureMsg);
    }

    @Override
    public Writer newWriter(PackOutput output) {
        return new ThrowingWriter(delegate.newWriter(output), writerThrowableRef);
    }

    @Override
    public Reader newReader(PackInput input) {
        return new ThrowingReader(delegate.newReader(input), readerThrowableRef, readerFailureRef);
    }

    private record ThrowingWriter(Writer delegate, AtomicReference<Throwable> throwableRef) implements Writer {

        @Override
        public void write(Message msg) throws IOException {
            var error = throwableRef.getAndSet(null);
            if (error != null) {
                PlatformDependent.throwException(error);
            } else {
                delegate.write(msg);
            }
        }
    }

    private record ThrowingReader(
            Reader delegate, AtomicReference<Throwable> throwableRef, AtomicReference<FailureMessage> failureRef)
            implements Reader {

        @Override
        public void read(ResponseMessageHandler handler) throws IOException {
            var error = throwableRef.getAndSet(null);
            if (error != null) {
                PlatformDependent.throwException(error);
                return;
            }

            var failureMsg = failureRef.getAndSet(null);
            if (failureMsg != null) {
                handler.handleFailureMessage(failureMsg.code(), failureMsg.message());
                return;
            }

            delegate.read(handler);
        }
    }
}
