/*
 * 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.hadoop.hbase.io.crypto.tls;

import org.apache.yetus.audience.InterfaceAudience;

/**
 * This enum represents the file type of a KeyStore or TrustStore. Currently, JKS (Java keystore),
 * PEM, PKCS12, and BCFKS types are supported.
 * <p/>
 * This file has been copied from the Apache ZooKeeper project.
 * @see <a href=
 *      "https://github.com/apache/zookeeper/blob/c74658d398cdc1d207aa296cb6e20de00faec03e/zookeeper-server/src/main/java/org/apache/zookeeper/common/KeyStoreFileType.java">Base
 *      revision</a>
 */
@InterfaceAudience.Private
public enum KeyStoreFileType {
  JKS(".jks"),
  PEM(".pem"),
  PKCS12(".p12"),
  BCFKS(".bcfks");

  private final String defaultFileExtension;

  KeyStoreFileType(String defaultFileExtension) {
    this.defaultFileExtension = defaultFileExtension;
  }

  /**
   * The property string that specifies that a key store or trust store should use this store file
   * type.
   */
  public String getPropertyValue() {
    return this.name();
  }

  /**
   * The file extension that is associated with this file type.
   */
  public String getDefaultFileExtension() {
    return defaultFileExtension;
  }

  /**
   * Converts a property value to a StoreFileType enum. If the property value is <code>null</code>
   * or an empty string, returns <code>null</code>.
   * @param propertyValue the property value.
   * @return the KeyStoreFileType, or <code>null</code> if <code>propertyValue</code> is
   *         <code>null</code> or empty.
   * @throws IllegalArgumentException if <code>propertyValue</code> is not one of "JKS", "PEM",
   *                                  "BCFKS", "PKCS12", or empty/null.
   */
  public static KeyStoreFileType fromPropertyValue(String propertyValue) {
    if (propertyValue == null || propertyValue.length() == 0) {
      return null;
    }
    return KeyStoreFileType.valueOf(propertyValue.toUpperCase());
  }

  /**
   * Detects the type of KeyStore / TrustStore file from the file extension. If the file name ends
   * with ".jks", returns <code>StoreFileType.JKS</code>. If the file name ends with ".pem", returns
   * <code>StoreFileType.PEM</code>. If the file name ends with ".p12", returns
   * <code>StoreFileType.PKCS12</code>. If the file name ends with ".bckfs", returns
   * <code>StoreFileType.BCKFS</code>. Otherwise, throws an IllegalArgumentException.
   * @param filename the filename of the key store or trust store file.
   * @return a KeyStoreFileType.
   * @throws IllegalArgumentException if the filename does not end with ".jks", ".pem", "p12" or
   *                                  "bcfks".
   */
  public static KeyStoreFileType fromFilename(String filename) {
    int i = filename.lastIndexOf('.');
    if (i >= 0) {
      String extension = filename.substring(i);
      for (KeyStoreFileType storeFileType : KeyStoreFileType.values()) {
        if (storeFileType.getDefaultFileExtension().equals(extension)) {
          return storeFileType;
        }
      }
    }
    throw new IllegalArgumentException(
      "Unable to auto-detect store file type from file name: " + filename);
  }

  /**
   * If <code>propertyValue</code> is not null or empty, returns the result of
   * <code>KeyStoreFileType.fromPropertyValue(propertyValue)</code>. Else, returns the result of
   * <code>KeyStoreFileType.fromFileName(filename)</code>.
   * @param propertyValue property value describing the KeyStoreFileType, or null/empty to
   *                      auto-detect the type from the file name.
   * @param filename      file name of the key store file. The file extension is used to auto-detect
   *                      the KeyStoreFileType when <code>propertyValue</code> is null or empty.
   * @return a KeyStoreFileType.
   * @throws IllegalArgumentException if <code>propertyValue</code> is not one of "JKS", "PEM",
   *                                  "PKCS12", "BCFKS", or empty/null.
   * @throws IllegalArgumentException if <code>propertyValue</code>is empty or null and the type
   *                                  could not be determined from the file name.
   */
  public static KeyStoreFileType fromPropertyValueOrFileName(String propertyValue,
    String filename) {
    KeyStoreFileType result = KeyStoreFileType.fromPropertyValue(propertyValue);
    if (result == null) {
      result = KeyStoreFileType.fromFilename(filename);
    }
    return result;
  }
}
