package org.kuali.common.devops.presigned;
   
   import static com.amazonaws.auth.SigningAlgorithm.HmacSHA1;
   import static com.google.common.collect.Lists.newArrayList;
   import static java.lang.Integer.toHexString;
   import static org.apache.commons.lang.StringUtils.leftPad;
   import static org.kuali.common.util.Encodings.UTF8;
   import static org.kuali.common.util.encrypt.Encryption.getDefaultEncryptor;
   import static org.kuali.common.util.log.Loggers.newLogger;
  
  import java.net.URL;
  import java.util.List;
  
  import javax.crypto.Mac;
  import javax.crypto.spec.SecretKeySpec;
  
  import org.junit.Test;
  import org.kuali.common.aws.model.ImmutableAWSCredentials;
  import org.kuali.common.util.encrypt.Encryptor;
  import org.slf4j.Logger;
  
  import com.amazonaws.AmazonClientException;
  import com.amazonaws.auth.AWSCredentials;
  import com.amazonaws.auth.SigningAlgorithm;
  import com.amazonaws.services.s3.AmazonS3Client;
  import com.amazonaws.services.s3.model.GeneratePresignedUrlRequest;
  import com.google.common.base.Joiner;
  
  public class GeneratePreSignedURL {
  
  	private static final Logger logger = newLogger();
  
  	@Test
  	public void test() {
  		try {
  			String secretKey = getSecretKey();
  			// long expiration = System.currentTimeMillis() + 1000 * 60 * 60 * 72;
  			long expiration = 1396678108436L;
  			String stringToSign = "GET\n\n\n1396678108\n/maven.kuali.org/private/com/oracle/jdk6/1.6.0-u43/jdk6-1.6.0-u43.pom";
  			// String stringToSign = "GET\n";
  			// 3a5fcf0bed9ba1360a0d9da111ff393feed3a098 - right
  			// 0854b02544b44e62ef9b9d5bf74d4aadea115e13 - wrong
  			byte[] bytes = hmacsha1bytes(stringToSign, secretKey);
  			List<String> byteList = newArrayList();
  			for (byte b : bytes) {
  				int i = b & 0xff;
  				byteList.add(leftPad(Integer.toString(i), 4, " "));
  			}
  			List<String> rawBytes = newArrayList();
  			for (byte b : bytes) {
  				rawBytes.add(leftPad(b + "", 4, " "));
  			}
  			logger.info(Joiner.on(' ').join(rawBytes));
  			logger.info(Joiner.on(' ').join(byteList));
  			List<String> hexList = hex(bytes);
  			for (int i = 0; i < hexList.size(); i++) {
  				String padded = leftPad(hexList.get(i), 4, " ");
  				hexList.set(i, padded);
  			}
  			logger.info(Joiner.on(' ').join(hexList));
  			System.out.println("expiration=" + expiration);
  			String bucket = "maven.kuali.org";
  			String key = "private/com/oracle/jdk6/1.6.0-u43/jdk6-1.6.0-u43.pom";
  			GeneratePresignedUrlRequest request = new GeneratePresignedUrlRequest(bucket, key);
  			request.setExpiration(new java.util.Date(expiration));
  			AWSCredentials foundation = getFoundationCreds(secretKey);
  			AmazonS3Client client = new AmazonS3Client(foundation);
  			URL url = client.generatePresignedUrl(request);
  			logger.info(url.toString());
  		} catch (Throwable e) {
  			e.printStackTrace();
  		}
  	}
  
  	protected String hmacsha1hex(String data, String key) throws Exception {
  		return null; // hex(hmacsha1bytes(data, key));
  	}
  
  	protected byte[] hmacsha1bytes(String data, String key) throws Exception {
  		return sign(data.getBytes(UTF8), key.getBytes(UTF8), HmacSHA1);
  	}
  
  	protected byte[] sign(byte[] data, byte[] key, SigningAlgorithm algorithm) throws AmazonClientException {
  		try {
  			Mac mac = Mac.getInstance(algorithm.toString());
  			mac.init(new SecretKeySpec(key, algorithm.toString()));
  			return mac.doFinal(data);
  		} catch (Exception e) {
  			throw new AmazonClientException("Unable to calculate a request signature: " + e.getMessage(), e);
  		}
  	}
  
  	private String getSecretKey() {
  		Encryptor enc = getDefaultEncryptor();
  		return enc.decrypt("5wLZjsZuyGvsbIPPXUz0XVBUhJUbOkaeqx3rZ7l+9Nc5/4WaTyn4dvlWlyVfRlzO/GSfvkRaQ+A=");
  	}
  
  	private AWSCredentials getFoundationCreds(String secretKey) {
  		Encryptor enc = getDefaultEncryptor();
 		String accessKey = enc.decrypt("PmSynm07/94iRu9BQCXrfp+ieOEfC9CIyL+u/R84LU8=");
 		return ImmutableAWSCredentials.build(accessKey, secretKey);
 	}
 
 	protected List<String> hex(byte[] bytes) {
 		List<String> list = newArrayList();
 		for (byte b : bytes) {
 			int i = b & 0xff;
 			String hex = leftPad(toHexString(i), 2, "0");
 			list.add(hex);
 		}
 		return list;
 	}
 }