/*
    * 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.shardingsphere.db.protocol.postgresql.packet.handshake;
  
  import lombok.Getter;
  import org.apache.shardingsphere.db.protocol.postgresql.packet.PostgreSQLPacket;
  import org.apache.shardingsphere.db.protocol.postgresql.payload.PostgreSQLPacketPayload;
  
  import java.util.HashMap;
  import java.util.Map;
  
  /**
   * Startup packet for PostgreSQL.
   */
  public final class PostgreSQLComStartupPacket extends PostgreSQLPacket {
      
      private static final String DATABASE_NAME_KEY = "database";
      
      private static final String USER_NAME_KEY = "user";
      
      private static final String CLIENT_ENCODING_KEY = "client_encoding";
      
      @Getter
      private final int version;
      
      private final Map<String, String> parametersMap = new HashMap<>();
      
      public PostgreSQLComStartupPacket(final PostgreSQLPacketPayload payload) {
          payload.skipReserved(4);
          version = payload.readInt4();
          while (payload.bytesBeforeZero() > 0) {
              parametersMap.put(payload.readStringNul(), payload.readStringNul());
          }
      }
      
      /**
       * Get database.
       * 
       * @return database
       */
      public String getDatabase() {
          return parametersMap.get(DATABASE_NAME_KEY);
      }
      
      /**
       * Get username.
       * 
       * @return username
       */
      public String getUsername() {
          return parametersMap.get(USER_NAME_KEY);
      }
      
      /**
       * Get client encoding.
       * 
       * @return client encoding
       */
      public String getClientEncoding() {
          return parametersMap.getOrDefault(CLIENT_ENCODING_KEY, "UTF8");
      }
      
      @Override
      protected void write(final PostgreSQLPacketPayload payload) {
      }
  }