/*
    * Copyright 2021 TiKV Project Authors.
    *
    * Licensed 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.tikv.common.expression;
  
  import com.google.common.collect.ImmutableList;
  import java.util.List;
  import java.util.Objects;
  import org.tikv.common.exception.TiExpressionException;
  import org.tikv.common.meta.TiColumnInfo;
  import org.tikv.common.meta.TiTableInfo;
  import org.tikv.common.types.DataType;
  
  public class ColumnRef extends Expression {
    private final String name;
  
    @Deprecated
    public ColumnRef(String name) {
      this.name = name;
    }
  
    public ColumnRef(String name, DataType dataType) {
      super(dataType);
      resolved = true;
      this.name = name;
    }
  
    public static ColumnRef create(String name, TiTableInfo table) {
      name = name.replaceAll("`", "");
      TiColumnInfo col = table.getColumn(name);
      if (col != null) {
        return new ColumnRef(name, col.getType());
      }
  
      throw new TiExpressionException(
          String.format("Column name %s not found in table %s", name, table));
    }
  
    @Deprecated
    public static ColumnRef create(String name) {
      return new ColumnRef(name);
    }
  
    public static ColumnRef create(String name, DataType dataType) {
      return new ColumnRef(name, dataType);
    }
  
    public static ColumnRef create(String name, TiColumnInfo columnInfo) {
      return new ColumnRef(name, columnInfo.getType());
    }
  
    public String getName() {
      return name.toLowerCase();
    }
  
    public void resolve(TiTableInfo table) {
      TiColumnInfo columnInfo = null;
      for (TiColumnInfo col : table.getColumns()) {
        if (col.matchName(name)) {
          this.dataType = col.getType();
          columnInfo = col;
          break;
        }
      }
      if (columnInfo == null) {
        throw new TiExpressionException(
            String.format("No Matching column %s from table %s", name, table.getName()));
      }
  
      if (columnInfo.getId() == 0) {
        throw new TiExpressionException("Zero Id is not a referable column id");
      }
    }
  
    public boolean matchName(String name) {
      return this.name.equalsIgnoreCase(name);
    }
  
    @Override
    public DataType getDataType() {
      return dataType;
    }
  
    @Override
    public boolean isResolved() {
     return resolved;
   }
 
   @Override
   public boolean equals(Object another) {
     if (this == another) {
       return true;
     }
 
     if (another instanceof ColumnRef) {
       ColumnRef that = (ColumnRef) another;
       if (isResolved() && that.isResolved()) {
         return name.equalsIgnoreCase(that.name)
             && this.dataType.equals(((ColumnRef) another).dataType);
       } else {
         return name.equalsIgnoreCase(that.name);
       }
 
     } else {
       return false;
     }
   }
 
   @Override
   public int hashCode() {
     if (isResolved()) {
       return Objects.hash(this.name.toLowerCase(), this.dataType);
     } else {
       return Objects.hashCode(name.toLowerCase());
     }
   }
 
   @Override
   public String toString() {
     if (dataType != null) {
       return String.format("%s@%s", getName(), dataType.getName());
     } else {
       return String.format("[%s]", getName());
     }
   }
 
   @Override
   public List<Expression> getChildren() {
     return ImmutableList.of();
   }
 
   @Override
   public <R, C> R accept(Visitor<R, C> visitor, C context) {
     return visitor.visit(this, context);
   }
 }