/*
    * 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.datanode;
  
  import com.cedarsoftware.util.CaseInsensitiveMap.CaseInsensitiveString;
  import com.google.common.base.Objects;
  import com.google.common.base.Splitter;
  import lombok.Getter;
  import lombok.RequiredArgsConstructor;
  import lombok.ToString;
  import org.apache.shardingsphere.database.connector.core.metadata.database.metadata.DialectDatabaseMetaData;
  import org.apache.shardingsphere.database.connector.core.type.DatabaseType;
  import org.apache.shardingsphere.database.connector.core.type.DatabaseTypeRegistry;
  import org.apache.shardingsphere.infra.exception.ShardingSpherePreconditions;
  import org.apache.shardingsphere.infra.exception.kernel.metadata.datanode.InvalidDataNodeFormatException;
  
  import java.util.List;
  
  /**
   * Data node.
   */
  @RequiredArgsConstructor
  @Getter
  @ToString
  public final class DataNode {
      
      private static final String DELIMITER = ".";
      
      private static final String ASTERISK = "*";
      
      private final String dataSourceName;
      
      private final String schemaName;
      
      private final String tableName;
      
      /**
       * Constructs a data node with well-formatted string.
       *
       * @param dataNode string of data node. use {@code .} to split data source name and table name.
       */
      public DataNode(final String dataNode) {
          validateDataNodeFormat(dataNode);
          List<String> segments = Splitter.on(DELIMITER).splitToList(dataNode);
          boolean isIncludeSchema = 3 == segments.size();
          dataSourceName = segments.get(0);
          schemaName = isIncludeSchema ? segments.get(1) : null;
          tableName = segments.get(isIncludeSchema ? 2 : 1);
      }
      
      /**
       * Constructs a data node with well-formatted string.
       *
       * @param databaseName database name
       * @param databaseType database type
       * @param dataNode data node use {@code .} to split schema name and table name
       */
      public DataNode(final String databaseName, final DatabaseType databaseType, final String dataNode) {
          ShardingSpherePreconditions.checkState(dataNode.contains(DELIMITER), () -> new InvalidDataNodeFormatException(dataNode));
          DialectDatabaseMetaData dialectDatabaseMetaData = new DatabaseTypeRegistry(databaseType).getDialectDatabaseMetaData();
          boolean containsSchema = dialectDatabaseMetaData.getSchemaOption().isSchemaAvailable() && isValidDataNode(dataNode, 3);
          List<String> segments = Splitter.on(DELIMITER).limit(containsSchema ? 3 : 2).splitToList(dataNode);
          dataSourceName = segments.get(0);
          schemaName = getSchemaName(databaseName, dialectDatabaseMetaData, containsSchema, segments);
          tableName = containsSchema ? segments.get(2).toLowerCase() : segments.get(1).toLowerCase();
      }
      
      private String getSchemaName(final String databaseName, final DialectDatabaseMetaData dialectDatabaseMetaData, final boolean containsSchema, final List<String> segments) {
          return dialectDatabaseMetaData.getSchemaOption().getDefaultSchema().map(optional -> containsSchema ? segments.get(1) : ASTERISK).orElse(databaseName);
      }
      
      private boolean isValidDataNode(final String dataNodeStr, final int tier) {
          if (hasInvalidDelimiterStructure(dataNodeStr)) {
              return false;
          }
          List<String> segments = Splitter.on(DELIMITER).splitToList(dataNodeStr);
          return isAnySegmentIsEmptyOrContainsOnlyWhitespace(tier, segments);
      }
      
      private boolean hasInvalidDelimiterStructure(final String dataNodeStr) {
          return !dataNodeStr.contains(DELIMITER) || hasLeadingOrTrailingDelimiter(dataNodeStr) || hasConsecutiveDelimiters(dataNodeStr) || hasWhitespaceAroundDelimiters(dataNodeStr);
      }
      
      private boolean hasLeadingOrTrailingDelimiter(final String dataNodeStr) {
         return dataNodeStr.startsWith(DELIMITER) || dataNodeStr.endsWith(DELIMITER);
     }
     
     private boolean hasConsecutiveDelimiters(final String dataNodeStr) {
         return dataNodeStr.contains(DELIMITER + DELIMITER);
     }
     
     private boolean hasWhitespaceAroundDelimiters(final String dataNodeStr) {
         return dataNodeStr.contains(" " + DELIMITER) || dataNodeStr.contains(DELIMITER + " ");
     }
     
     private boolean isAnySegmentIsEmptyOrContainsOnlyWhitespace(final int tier, final List<String> segments) {
         return segments.stream().noneMatch(each -> each.trim().isEmpty()) && tier == segments.size();
     }
     
     /**
      * Validates the data node format based on its structure.
      *
      * @param dataNode the data node string to validate
      * @throws InvalidDataNodeFormatException if the format is invalid
      */
     private void validateDataNodeFormat(final String dataNode) {
         ShardingSpherePreconditions.checkState(isValidDataNode(dataNode, 2) || isValidDataNode(dataNode, 3), () -> new InvalidDataNodeFormatException(dataNode));
     }
     
     /**
      * Format data node as string with schema.
      *
      * @return formatted data node
      */
     public String format() {
         return null == schemaName ? formatWithoutSchema() : formatWithSchema();
     }
     
     /**
      * Format data node as string.
      *
      * @param databaseType database type
      * @return formatted data node
      */
     public String format(final DatabaseType databaseType) {
         return shouldIncludeSchema(databaseType) ? formatWithSchema() : formatWithoutSchema();
     }
     
     private boolean shouldIncludeSchema(final DatabaseType databaseType) {
         return null != schemaName && new DatabaseTypeRegistry(databaseType).getDialectDatabaseMetaData().getSchemaOption().getDefaultSchema().isPresent();
     }
     
     private String formatWithSchema() {
         return String.join(DELIMITER, dataSourceName, schemaName, tableName);
     }
     
     private String formatWithoutSchema() {
         return String.join(DELIMITER, dataSourceName, tableName);
     }
     
     @Override
     public boolean equals(final Object object) {
         if (this == object) {
             return true;
         }
         if (null == object || getClass() != object.getClass()) {
             return false;
         }
         DataNode dataNode = (DataNode) object;
         return Objects.equal(new CaseInsensitiveString(dataSourceName), new CaseInsensitiveString(dataNode.dataSourceName))
                 && Objects.equal(new CaseInsensitiveString(tableName), new CaseInsensitiveString(dataNode.tableName))
                 && Objects.equal(null == schemaName ? null : new CaseInsensitiveString(schemaName), null == dataNode.schemaName ? null : new CaseInsensitiveString(dataNode.schemaName));
     }
     
     @Override
     public int hashCode() {
         return Objects.hashCode(new CaseInsensitiveString(dataSourceName), new CaseInsensitiveString(tableName), null == schemaName ? null : new CaseInsensitiveString(schemaName));
     }
 }