storagehub/src/main/java/org/gcube/data/access/storagehub/storage/backend/impl/S3Backend.java

package org.gcube.data.access.storagehub.storage.backend.impl;

import java.io.InputStream;
import java.util.HashMap;
import java.util.Map;
import java.util.function.Function;

import org.gcube.common.authorization.library.provider.AuthorizationProvider;
import org.gcube.common.storagehub.model.items.nodes.Content;
import org.gcube.common.storagehub.model.items.nodes.PayloadBackend;
import org.gcube.common.storagehub.model.storages.MetaInfo;
import org.gcube.common.storagehub.model.storages.StorageBackend;

import io.minio.CopyObjectArgs;
import io.minio.CopySource;
import io.minio.GetObjectArgs;
import io.minio.MinioClient;
import io.minio.PutObjectArgs;
import io.minio.RemoveObjectArgs;
import io.minio.StatObjectArgs;
import io.minio.StatObjectResponse;

public class S3Backend extends StorageBackend{

	Function<Void, String> keyGenerator; 
	String bucketName;
	MinioClient client;
	
	private static final long PART_SIZE = 100000000; 

	public S3Backend(PayloadBackend payloadConfiguration, Function<Void, String> keyGenerator) {
		super(payloadConfiguration);
		this.keyGenerator = keyGenerator;
		Map<String, Object> parameters = payloadConfiguration.getParameters();
		this.bucketName = (String)parameters.get("bucketName");
		String accessKey = (String)parameters.get("key");
		String secret = (String)parameters.get("secret");
		String url = (String)parameters.get("url");
		client =
			    MinioClient.builder()
			        .endpoint(url)
			        .credentials(accessKey, secret)
			        .build();
	}

	@Override
	public MetaInfo onCopy(Content content, String newParentPath, String newName) {

		String sourceKey = content.getStorageId();
		String destinationKey = keyGenerator.apply(null);

		try {
			CopySource source = CopySource.builder().bucket(bucketName).object(sourceKey).build();
			// Copy the object into a new object in the same bucket.
			CopyObjectArgs copyObjRequest = CopyObjectArgs.builder().source(source).bucket(bucketName).object(destinationKey).build();
			client.copyObject(copyObjRequest);
		} catch (Exception e) {
			throw new RuntimeException("error copying file on s3", e);
		} 
		return new MetaInfo(content.getSize(), destinationKey, null, getPayloadConfiguration());
	}

	@Override
	public MetaInfo onMove(Content content, String newParentPath) {
		//new contentPath can be set as remotePath to the storage backend ?
		return new MetaInfo(content.getSize(),content.getStorageId(), content.getRemotePath(), getPayloadConfiguration());
	}

	@Override
	public void onDelete(Content content) {
		try {
						
			String storageId = content.getStorageId();
			
			client.removeObject(RemoveObjectArgs.builder().bucket(bucketName).object(storageId).build());
		
		} catch (Exception e) {
			throw new RuntimeException("error deleting file on s3", e);
		} 

	}
	
	@Override
	public MetaInfo upload(InputStream stream, String relativePath, String name) {
		return this.upload(stream, relativePath, name, null);
	}
	
	@Override
	public MetaInfo upload(InputStream stream, String relativePath, String name, Long size) {
		try {
			String storageId = keyGenerator.apply(null);
			
			Map<String, String> headers = new HashMap<>();
			headers.put("X-Amz-Storage-Class", "REDUCED_REDUNDANCY");
			Map<String, String> userMetadata = new HashMap<>();
			userMetadata.put("user", AuthorizationProvider.instance.get().getClient().getId());
			client.putObject(
			    PutObjectArgs.builder().bucket(bucketName).object(storageId).stream(
			    		stream, size == null || size<=0?-1:size, size == null || size<=0?PART_SIZE:-1)
			        .headers(headers).tags(userMetadata)
			        .build());
	
			
			long fileSize;
			if (size != null && size>0)
				fileSize = size;
			else {
				StatObjectResponse resp = client.statObject(StatObjectArgs.builder().bucket(bucketName).object(storageId).build());
				fileSize = resp.size();
			}
			
			return new MetaInfo(fileSize,storageId, null, getPayloadConfiguration());
		} catch (Exception e) {
			throw new RuntimeException("error uploading file on s3", e);
		} 
		
	}

	@Override
	public InputStream download(Content content) {
		try {
			String storageId = content.getStorageId();
			InputStream inputStream = client.getObject(GetObjectArgs.builder().bucket(bucketName).object(storageId).build());
			return inputStream;
		} catch (Exception e) {
			throw new RuntimeException("error downloading file from s3",e);
		} 
	}

	@Override
	public String getTotalSizeStored() {
		// TODO Auto-generated method stub
		return null;
	}

	@Override
	public String getTotalItemsCount() {
		// TODO Auto-generated method stub
		return null;
	}

}