/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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.apache.airavata.mft.transport.local;

import org.apache.airavata.mft.core.ConnectorContext;
import org.apache.airavata.mft.core.ResourceTypes;
import org.apache.airavata.mft.core.api.Connector;
import org.apache.airavata.mft.resource.client.ResourceServiceClient;
import org.apache.airavata.mft.resource.client.ResourceServiceClientBuilder;
import org.apache.airavata.mft.resource.stubs.local.resource.LocalResource;
import org.apache.airavata.mft.resource.stubs.local.resource.LocalResourceGetRequest;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.*;

public class LocalReceiver implements Connector {

    private static final Logger logger = LoggerFactory.getLogger(LocalReceiver.class);

    private LocalResource resource;
    private boolean initialized;

    @Override
    public void init(String resourceId, String credentialToken, String resourceServiceHost, int resourceServicePort,
                     String secretServiceHost, int secretServicePort) throws Exception {
        this.initialized = true;

        ResourceServiceClient resourceClient = ResourceServiceClientBuilder.buildClient(resourceServiceHost, resourceServicePort);
        this.resource = resourceClient.local().getLocalResource(LocalResourceGetRequest.newBuilder().setResourceId(resourceId).build());
    }

    @Override
    public void destroy() {

    }

    private void checkInitialized() {
        if (!initialized) {
            throw new IllegalStateException("Local Receiver is not initialized");
        }
    }

    @Override
    public void startStream(ConnectorContext context) throws Exception {
        logger.info("Starting local receiver stream for transfer {}", context.getTransferId());

        checkInitialized();


        if (ResourceTypes.FILE.equals(this.resource.getResourceCase().name())) {
            OutputStream streamOs = context.getStreamBuffer().getOutputStream();
            FileInputStream fis = new FileInputStream(new File(resource.getFile().getResourcePath()));

            long fileSize = context.getMetadata().getResourceSize();

            byte[] buf = new byte[1024];
            while (true) {
                int bufSize = 0;

                if (buf.length < fileSize) {
                    bufSize = buf.length;
                } else {
                    bufSize = (int) fileSize;
                }
                bufSize = fis.read(buf, 0, bufSize);

                if (bufSize < 0) {
                    break;
                }

                streamOs.write(buf, 0, bufSize);
                streamOs.flush();

                fileSize -= bufSize;
                if (fileSize == 0L)
                    break;
            }

            fis.close();
            streamOs.close();
            logger.info("Completed local receiver stream for transfer {}", context.getTransferId());

        } else {
            logger.error("Resource {} should be a FILE type. Found a {}",
                    this.resource.getResourceId(), this.resource.getResourceCase().name());
            throw new Exception("Resource " + this.resource.getResourceId() + " should be a FILE type. Found a " +
                    this.resource.getResourceCase().name());
        }
    }
}