/*
    * 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.binder.segment.from;
  
  import com.cedarsoftware.util.CaseInsensitiveMap;
  import lombok.RequiredArgsConstructor;
  import org.apache.shardingsphere.sql.parser.sql.common.segment.dml.item.ProjectionSegment;
  import org.apache.shardingsphere.sql.parser.sql.common.segment.dml.item.ShorthandProjectionSegment;
  
  import java.util.Collection;
  import java.util.Map;
  import java.util.Optional;
  
  /**
   * Simple table segment binder context.
   */
  @RequiredArgsConstructor
  public final class SimpleTableSegmentBinderContext implements TableSegmentBinderContext {
      
      private final Map<String, ProjectionSegment> columnLabelProjectionSegments;
      
      public SimpleTableSegmentBinderContext(final Collection<ProjectionSegment> projectionSegments) {
          columnLabelProjectionSegments = new CaseInsensitiveMap<>(projectionSegments.size(), 1F);
          projectionSegments.forEach(each -> putColumnLabelProjectionSegments(each, columnLabelProjectionSegments));
      }
      
      private void putColumnLabelProjectionSegments(final ProjectionSegment projectionSegment, final Map<String, ProjectionSegment> columnLabelProjectionSegments) {
          if (projectionSegment instanceof ShorthandProjectionSegment) {
              ((ShorthandProjectionSegment) projectionSegment).getActualProjectionSegments().forEach(each -> columnLabelProjectionSegments.put(each.getColumnLabel(), each));
          } else {
              columnLabelProjectionSegments.put(projectionSegment.getColumnLabel(), projectionSegment);
          }
      }
      
      @Override
      public Optional<ProjectionSegment> findProjectionSegmentByColumnLabel(final String columnLabel) {
          return Optional.ofNullable(columnLabelProjectionSegments.get(columnLabel));
      }
      
      @Override
      public Collection<ProjectionSegment> getProjectionSegments() {
          return columnLabelProjectionSegments.values();
      }
  }