content: /*
   * Copyright (C) 2016-2023 ActionTech.
   * License: http://www.gnu.org/licenses/gpl.html GPL version 2 or higher.
   */
  
  package com.actiontech.dble.plan.common.item.function.castfunc;
  
  import com.actiontech.dble.backend.mysql.CharsetUtil;
  import com.actiontech.dble.plan.common.field.Field;
  import com.actiontech.dble.plan.common.item.Item;
  import com.actiontech.dble.plan.common.item.function.strfunc.ItemStrFunc;
  import com.alibaba.druid.sql.ast.SQLExpr;
  import com.alibaba.druid.sql.ast.expr.SQLIdentifierExpr;
  import com.alibaba.druid.sql.ast.expr.SQLMethodInvokeExpr;
  
  import java.io.UnsupportedEncodingException;
  import java.util.List;
  
  public class ItemFuncConvCharset extends ItemStrFunc {
      private String mysqlCharset;
      private String javaCharset;
  
      public ItemFuncConvCharset(Item a, String charset, int charsetIndex) {
          super(a, charsetIndex);
          mysqlCharset = charset;
          javaCharset = CharsetUtil.getJavaCharset(charset);
      }
  
      @Override
      public final String funcName() {
          return "CONVERT";
      }
  
      @Override
      public void fixLengthAndDec() {
  
      }
  
      @Override
      public String valStr() {
          String argVal = args.get(0).valStr();
          if (argVal == null) {
              nullValue = true;
              return null;
          }
          try {
              return new String(argVal.getBytes(), javaCharset);
          } catch (UnsupportedEncodingException e) {
              LOGGER.info("convert using charset exception", e);
              nullValue = true;
              return null;
          }
      }
  
      @Override
      public SQLExpr toExpression() {
          SQLMethodInvokeExpr method = new SQLMethodInvokeExpr(funcName());
          method.addArgument(args.get(0).toExpression());
          method.setUsing(new SQLIdentifierExpr(mysqlCharset));
          return method;
      }
  
      @Override
      protected Item cloneStruct(boolean forCalculate, List<Item> calArgs, boolean isPushDown, List<Field> fields) {
          List<Item> newArgs;
          if (!forCalculate)
              newArgs = cloneStructList(args);
          else
              newArgs = calArgs;
          return new ItemFuncConvCharset(newArgs.get(0), mysqlCharset, charsetIndex);
      }
  
  }
  