/*
    * Copyright 2023 LINE Corporation
    *
    * LINE Corporation 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:
    *
    *   https://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.linecorp.centraldogma.server;
  
  import java.io.IOException;
  import java.nio.charset.StandardCharsets;
  import java.nio.file.Files;
  import java.nio.file.Paths;
  import java.util.Base64;
  import java.util.List;
  
  import com.google.common.collect.ImmutableList;
  
  enum DefaultConfigValueConverter implements ConfigValueConverter {
      INSTANCE;
  
      private static final String PLAINTEXT = "plaintext";
      private static final String FILE = "file";
      private static final String BASE64 = "base64";
      private static final String ENV = "env";
  
      // TODO(minwoox): Add more prefixes such as classpath, url, etc.
      private static final List<String> SUPPORTED_PREFIXES = ImmutableList.of(PLAINTEXT, FILE, BASE64, ENV);
  
      @Override
      public List<String> supportedPrefixes() {
          return SUPPORTED_PREFIXES;
      }
  
      @Override
      public String convert(String prefix, String value) {
          switch (prefix) {
              case PLAINTEXT:
                  return value;
              case FILE:
                  try {
                      return new String(Files.readAllBytes(Paths.get(value)), StandardCharsets.UTF_8);
                  } catch (IOException e) {
                      throw new RuntimeException("failed to read a file: " + value, e);
                  }
              case BASE64:
                  return new String(Base64.getDecoder().decode(value), StandardCharsets.UTF_8).trim();
              case ENV:
                  return System.getenv(value);
              default:
                  // Should never reach here.
                  throw new Error();
          }
      }
  }