/*
    * Copyright 2016 The Netty Project
    *
    * The Netty Project 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 io.netty.handler.codec.smtp;
  
  import io.netty.buffer.ByteBuf;
  import io.netty.buffer.ByteBufUtil;
  import io.netty.util.AsciiString;
  import io.netty.util.internal.ObjectUtil;
  import io.netty.util.internal.UnstableApi;
  
  import java.util.HashMap;
  import java.util.Map;
  
  /**
   * The command part of a {@link SmtpRequest}.
   */
  @UnstableApi
  public final class SmtpCommand {
      public static final SmtpCommand EHLO = new SmtpCommand(AsciiString.cached("EHLO"));
      public static final SmtpCommand HELO = new SmtpCommand(AsciiString.cached("HELO"));
      public static final SmtpCommand AUTH = new SmtpCommand(AsciiString.cached("AUTH"));
      public static final SmtpCommand MAIL = new SmtpCommand(AsciiString.cached("MAIL"));
      public static final SmtpCommand RCPT = new SmtpCommand(AsciiString.cached("RCPT"));
      public static final SmtpCommand DATA = new SmtpCommand(AsciiString.cached("DATA"));
      public static final SmtpCommand NOOP = new SmtpCommand(AsciiString.cached("NOOP"));
      public static final SmtpCommand RSET = new SmtpCommand(AsciiString.cached("RSET"));
      public static final SmtpCommand EXPN = new SmtpCommand(AsciiString.cached("EXPN"));
      public static final SmtpCommand VRFY = new SmtpCommand(AsciiString.cached("VRFY"));
      public static final SmtpCommand HELP = new SmtpCommand(AsciiString.cached("HELP"));
      public static final SmtpCommand QUIT = new SmtpCommand(AsciiString.cached("QUIT"));
      public static final SmtpCommand EMPTY = new SmtpCommand(AsciiString.cached(""));
  
      private static final Map<String, SmtpCommand> COMMANDS = new HashMap<String, SmtpCommand>();
      static {
          COMMANDS.put(EHLO.name().toString(), EHLO);
          COMMANDS.put(HELO.name().toString(), HELO);
          COMMANDS.put(AUTH.name().toString(), AUTH);
          COMMANDS.put(MAIL.name().toString(), MAIL);
          COMMANDS.put(RCPT.name().toString(), RCPT);
          COMMANDS.put(DATA.name().toString(), DATA);
          COMMANDS.put(NOOP.name().toString(), NOOP);
          COMMANDS.put(RSET.name().toString(), RSET);
          COMMANDS.put(EXPN.name().toString(), EXPN);
          COMMANDS.put(VRFY.name().toString(), VRFY);
          COMMANDS.put(HELP.name().toString(), HELP);
          COMMANDS.put(QUIT.name().toString(), QUIT);
          COMMANDS.put(EMPTY.name().toString(), EMPTY);
      }
  
      /**
       * Returns the {@link SmtpCommand} for the given command name.
       */
      public static SmtpCommand valueOf(CharSequence commandName) {
          ObjectUtil.checkNotNull(commandName, "commandName");
          SmtpCommand command = COMMANDS.get(commandName.toString());
          return command != null ? command : new SmtpCommand(AsciiString.of(commandName));
      }
  
      private final AsciiString name;
  
      private SmtpCommand(AsciiString name) {
          SmtpUtils.validateSMTPParameter(name);
          this.name = name;
      }
  
      /**
       * Return the command name.
       */
      public AsciiString name() {
          return name;
      }
  
      void encode(ByteBuf buffer) {
          ByteBufUtil.writeAscii(buffer, name);
      }
  
      boolean isContentExpected() {
          return this.equals(DATA);
      }
  
      @Override
      public int hashCode() {
          return name.hashCode();
      }
  
      @Override
     public boolean equals(Object obj) {
         if (obj == this) {
             return true;
         }
         if (!(obj instanceof SmtpCommand)) {
             return false;
         }
         return name.contentEqualsIgnoreCase(((SmtpCommand) obj).name());
     }
 
     @Override
     public String toString() {
         return "SmtpCommand{name=" + name + '}';
     }
 }