/*
    * 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.infra.metadata.user;
  
  import com.google.common.base.Objects;
  import com.google.common.base.Strings;
  import lombok.Getter;
  import org.apache.shardingsphere.infra.annotation.HighFrequencyInvocation;
  
  /**
   * Grantee.
   */
  public final class Grantee {
      
      private static final String DELIMITER = "@";
      
      private static final String HOST_WILDCARD = "%";
      
      @Getter
      private final String username;
      
      @Getter
      private final String hostname;
      
      private final boolean isUnlimitedHost;
      
      private final int hashCode;
      
      private final String toString;
      
      public Grantee(final String value) {
          this(value.contains("@") ? value.substring(0, value.indexOf('@')) : value, value.contains("@") ? value.substring(value.indexOf('@') + 1) : "");
      }
      
      public Grantee(final String username, final String hostname) {
          this.username = username;
          this.hostname = Strings.isNullOrEmpty(hostname) ? HOST_WILDCARD : hostname;
          isUnlimitedHost = HOST_WILDCARD.equals(this.hostname);
          hashCode = Objects.hashCode(username.toUpperCase(), this.hostname.toUpperCase());
          toString = username + DELIMITER + this.hostname;
      }
      
      /**
       * Check if the grantee is acceptable.
       *
       * @param grantee grantee
       * @return if the grantee is acceptable
       */
      @HighFrequencyInvocation
      public boolean accept(final Grantee grantee) {
          return grantee.username.equalsIgnoreCase(username) && isPermittedHost(grantee);
      }
      
      private boolean isPermittedHost(final Grantee grantee) {
          return isUnlimitedHost || grantee.hostname.equalsIgnoreCase(hostname);
      }
      
      @Override
      public boolean equals(final Object obj) {
          if (obj instanceof Grantee) {
              Grantee grantee = (Grantee) obj;
              return grantee.username.equalsIgnoreCase(username) && grantee.hostname.equalsIgnoreCase(hostname);
          }
          return false;
      }
      
      @Override
      public int hashCode() {
          return hashCode;
      }
      
      @Override
      public String toString() {
          return toString;
      }
  }