Copyright Microsoft Corporation
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.
/**
 * Copyright Microsoft Corporation
 * 
 * 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 com.microsoft.azure.storage;

import java.net.URI;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;

import javax.crypto.Mac;
import javax.crypto.spec.SecretKeySpec;

import com.microsoft.azure.storage.core.Base64;
import com.microsoft.azure.storage.core.SR;
import com.microsoft.azure.storage.core.Utility;

Represents storage account credentials, based on storage account and access key, for accessing the Microsoft Azure
storage services.
/**
 * Represents storage account credentials, based on storage account and access key, for accessing the Microsoft Azure
 * storage services.
 */
public final class StorageCredentialsAccountAndKey extends StorageCredentials {

    
Stores the Account name for the credentials.
/**
     * Stores the Account name for the credentials.
     */
    private String accountName;

    
Stores a reference to the hmacsha256 Mac.
/**
     * Stores a reference to the hmacsha256 Mac.
     */
    private Mac hmacSha256;

    
Stores the key.
/**
     * Stores the key.
     */
    private byte[] key;

    
Creates an instance of the StorageCredentialsAccountAndKey class, using the specified storage
account name and access key; the specified access key is in the form of a byte array.
Params:
accountName – 
           A String that represents the name of the storage account.
key – 
           An array of bytes that represent the account access key./**
     * Creates an instance of the <code>StorageCredentialsAccountAndKey</code> class, using the specified storage
     * account name and access key; the specified access key is in the form of a byte array.
     * 
     * @param accountName
     *            A <code>String</code> that represents the name of the storage account.
     * @param key
     *            An array of bytes that represent the account access key.
     */
    public StorageCredentialsAccountAndKey(final String accountName, final byte[] key) {
        if (Utility.isNullOrEmptyOrWhitespace(accountName)) {
            throw new IllegalArgumentException(SR.INVALID_ACCOUNT_NAME);
        }

        if (key == null || key.length == 0) {
            throw new IllegalArgumentException(SR.INVALID_KEY);
        }

        this.accountName = accountName;
        this.key = key;
    }

    
Creates an instance of the StorageCredentialsAccountAndKey class, using the specified storage
account name and access key; the specified access key is stored as a String.
Params:
accountName – 
           A String that represents the name of the storage account.
key – 
           A String that represents the Base-64-encoded account access key./**
     * Creates an instance of the <code>StorageCredentialsAccountAndKey</code> class, using the specified storage
     * account name and access key; the specified access key is stored as a <code>String</code>.
     * 
     * @param accountName
     *            A <code>String</code> that represents the name of the storage account.
     * @param key
     *            A <code>String</code> that represents the Base-64-encoded account access key.
     */
    public StorageCredentialsAccountAndKey(final String accountName, final String key) {
        this(accountName, Base64.decode(key));
    }

    
Gets the account name.
Returns:
A String that contains the account name./**
     * Gets the account name.
     * 
     * @return A <code>String</code> that contains the account name.
     */
    @Override
    public String getAccountName() {
        return this.accountName;
    }
    
    
Exports the value of the access key to a Base64-encoded string.
Returns:
A String that represents the Base64-encoded access key./**
     * Exports the value of the access key to a Base64-encoded string.
     * 
     * @return A <code>String</code> that represents the Base64-encoded access key.
     */
    public String exportBase64EncodedKey() {
        return Base64.encode(this.key);
    }

    
Exports the value of the access key to an array of bytes.
Returns:
A byte array that represents the access key./**
     * Exports the value of the access key to an array of bytes.
     * 
     * @return A byte array that represents the access key.
     */
    public byte[] exportKey() {
        final byte[] copy = this.key.clone();
        return copy;
    }
    
    
Sets the account name.
Params:
accountName – 
         A String that contains the account name./**
     * Sets the account name.
     * 
     * @param accountName
     *          A <code>String</code> that contains the account name.
     */
    public void setAccountName(String accountName) {
        this.accountName = accountName;
    }
    
    
Sets the name of the access key to be used when signing the request.
Params:
key – 
       A String that represents the name of the access key to be used when signing the request./**
     * Sets the name of the access key to be used when signing the request.
     * 
     * @param key
     *        A <code>String</code> that represents the name of the access key to be used when signing the request.
     */
    public synchronized void updateKey(final String key) {
        this.updateKey(Base64.decode(key));
    }
    
    
Sets the name of the access key to be used when signing the request.
Params:
key – 
       A String that represents the name of the access key to be used when signing the request./**
     * Sets the name of the access key to be used when signing the request.
     * 
     * @param key
     *        A <code>String</code> that represents the name of the access key to be used when signing the request.
     */
    public synchronized void updateKey(final byte[] key) {
        if (key == null || key.length == 0) {
            throw new IllegalArgumentException(SR.INVALID_KEY);
        }

        this.key = key;
        this.hmacSha256 = null;
    }

    
Returns a String that represents this instance, optionally including sensitive data.
Params:
exportSecrets – 
           true to include sensitive data in the return string; otherwise, false.
Returns:
A String that represents this object, optionally including sensitive data./**
     * Returns a <code>String</code> that represents this instance, optionally including sensitive data.
     * 
     * @param exportSecrets
     *            <code>true</code> to include sensitive data in the return string; otherwise, <code>false</code>.
     * 
     * @return A <code>String</code> that represents this object, optionally including sensitive data.
     */
    @Override
    public String toString(final boolean exportSecrets) {
        return String.format("%s=%s;%s=%s", CloudStorageAccount.ACCOUNT_NAME_NAME, this.getAccountName(),
                CloudStorageAccount.ACCOUNT_KEY_NAME, exportSecrets ? this.exportBase64EncodedKey()
                        : "[key hidden]");
    }

    @Override
    public URI transformUri(URI resourceUri, OperationContext opContext) {
        return resourceUri;
    }

    @Override
    public StorageUri transformUri(StorageUri resourceUri, OperationContext opContext) {
        return resourceUri;
    }
    
    
Gets the HmacSha256 associated with the account key.
Throws:
InvalidKeyException – 
            If the key is not a valid storage key.
Returns:
A MAC created with the account key./**
     * Gets the HmacSha256 associated with the account key.
     * 
     * @return A <code>MAC</code> created with the account key.
     * 
     * @throws InvalidKeyException
     *             If the key is not a valid storage key.
     */
    public synchronized Mac getHmac256() throws InvalidKeyException {
        if (this.hmacSha256 == null) {
            // Initializes the HMAC-SHA256 Mac and SecretKey.
            try {
                this.hmacSha256 = Mac.getInstance("HmacSHA256");
            }
            catch (final NoSuchAlgorithmException e) {
                throw new IllegalArgumentException();
            }
            this.hmacSha256.init(new SecretKeySpec(this.key, "HmacSHA256"));
        }
        return this.hmacSha256;
    }
}