content: /*
   * Copyright 1999-2017 Alibaba Group Holding Ltd.
   *
   * 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 com.alibaba.druid.sql.visitor.functions;
  
  import com.alibaba.druid.sql.ast.SQLExpr;
  import com.alibaba.druid.sql.ast.expr.SQLIntegerExpr;
  import com.alibaba.druid.sql.ast.expr.SQLMethodInvokeExpr;
  import com.alibaba.druid.sql.visitor.SQLEvalVisitor;
  import com.alibaba.druid.sql.visitor.SQLEvalVisitorUtils;
  
  import java.util.List;
  
  import static com.alibaba.druid.sql.visitor.SQLEvalVisitor.EVAL_VALUE;
  
  public class Least implements Function {
      public static final Least instance = new Least();
  
      public Object eval(SQLEvalVisitor visitor, SQLMethodInvokeExpr x) {
          Object result = null;
          for (SQLExpr item : x.getArguments()) {
              item.accept(visitor);
  
              Object itemValue = item.getAttributes().get(EVAL_VALUE);
              if (result == null) {
                  result = itemValue;
              } else {
                  if (SQLEvalVisitorUtils.lt(itemValue, result)) {
                      result = itemValue;
                  }
              }
          }
  
          return result;
      }
  
      public Object eval(SQLMethodInvokeExpr x) {
          List<SQLExpr> arguments = x.getArguments();
  
          if (arguments.size() > 0) {
              SQLExpr p0 = arguments.get(0);
              if (p0 instanceof SQLIntegerExpr && ((SQLIntegerExpr) p0).getNumber() instanceof Integer) {
                  int val = ((SQLIntegerExpr) p0).getNumber().intValue();
                  for (int i = 1; i < arguments.size(); i++) {
                      SQLExpr param = arguments.get(i);
                      if (param instanceof SQLIntegerExpr && ((SQLIntegerExpr) param).getNumber() instanceof Integer) {
                          int paramVal = ((SQLIntegerExpr) param).getNumber().intValue();
                          if (paramVal < val) {
                              val = paramVal;
                          }
                      } else {
                          return SQLEvalVisitor.EVAL_ERROR;
                      }
                  }
                  return val;
              }
          }
  
          return SQLEvalVisitor.EVAL_ERROR;
      }
  }
  