content: /*
   * 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.calcite.sql.fun;
  
  import org.apache.calcite.rel.type.RelDataType;
  import org.apache.calcite.sql.SqlCall;
  import org.apache.calcite.sql.SqlFunction;
  import org.apache.calcite.sql.SqlFunctionCategory;
  import org.apache.calcite.sql.SqlIntervalQualifier;
  import org.apache.calcite.sql.SqlKind;
  import org.apache.calcite.sql.SqlLiteral;
  import org.apache.calcite.sql.SqlNode;
  import org.apache.calcite.sql.SqlOperatorBinding;
  import org.apache.calcite.sql.SqlUtil;
  import org.apache.calcite.sql.SqlWriter;
  import org.apache.calcite.sql.parser.SqlParserPos;
  import org.apache.calcite.sql.type.OperandTypes;
  import org.apache.calcite.sql.type.ReturnTypes;
  import org.apache.calcite.sql.type.SqlOperandTypeChecker;
  import org.apache.calcite.sql.type.SqlOperandTypeInference;
  import org.apache.calcite.sql.type.SqlReturnTypeInference;
  import org.apache.calcite.sql.validate.SqlMonotonicity;
  import org.apache.calcite.sql.validate.SqlValidator;
  import org.apache.calcite.sql.validate.SqlValidatorScope;
  
  import org.checkerframework.checker.nullness.qual.Nullable;
  
  import static com.google.common.base.Preconditions.checkArgument;
  
  /**
   * Definition of the "FLOOR" and "CEIL" built-in SQL functions.
   */
  public class SqlFloorFunction extends SqlMonotonicUnaryFunction {
    //~ Constructors -----------------------------------------------------------
    private SqlFloorFunction(String name, SqlKind kind,
        @Nullable SqlReturnTypeInference returnTypeInference,
        @Nullable SqlOperandTypeInference operandTypeInference,
        @Nullable SqlOperandTypeChecker operandTypeChecker,
        SqlFunctionCategory funcType) {
      super(name, kind, returnTypeInference, operandTypeInference, operandTypeChecker, funcType);
    }
    public SqlFloorFunction(SqlKind kind) {
      super(kind.name(), kind, ReturnTypes.ARG0_OR_EXACT_NO_SCALE, null,
          OperandTypes.NUMERIC_OR_INTERVAL.or(
              OperandTypes.sequence("'" + kind + "(<DATE> TO <TIME_UNIT>)'\n"
                      + "'" + kind + "(<TIME> TO <TIME_UNIT>)'\n"
                      + "'" + kind + "(<TIMESTAMP> TO <TIME_UNIT>)'",
                  OperandTypes.DATETIME,
                  OperandTypes.ANY)),
          SqlFunctionCategory.NUMERIC);
      checkArgument(kind == SqlKind.FLOOR || kind == SqlKind.CEIL);
    }
  
    public SqlFloorFunction withName(String name) {
      return new SqlFloorFunction(name, getKind(), getReturnTypeInference(),
          getOperandTypeInference(), getOperandTypeChecker(), getFunctionType());
    }
  
    public SqlFloorFunction withReturnTypeInference(SqlReturnTypeInference returnTypeInference) {
      return new SqlFloorFunction(getName(), getKind(), returnTypeInference,
          getOperandTypeInference(), getOperandTypeChecker(), getFunctionType());
    }
  
    //~ Methods ----------------------------------------------------------------
  
    @Override public SqlMonotonicity getMonotonicity(SqlOperatorBinding call) {
      // Monotonic iff its first argument is, but not strict.
      return call.getOperandMonotonicity(0).unstrict();
    }
  
    @Override public void unparse(SqlWriter writer, SqlCall call, int leftPrec,
        int rightPrec) {
      final SqlWriter.Frame frame = writer.startFunCall(getName());
      if (call.operandCount() == 2) {
        call.operand(0).unparse(writer, 0, 100);
        writer.sep("TO");
        SqlIntervalQualifier.asIdentifier(call.operand(1))
            .unparse(writer, 100, 0);
      } else {
        call.operand(0).unparse(writer, 0, 0);
      }
      writer.endFunCall(frame);
    }
  
    @Override public RelDataType deriveType(SqlValidator validator,
        SqlValidatorScope scope, SqlCall call) {
      // To prevent operator rewriting by SqlFunction#deriveType.
      for (SqlNode operand : call.getOperandList()) {
        RelDataType nodeType = validator.deriveType(scope, operand);
        validator.setValidatedNodeType(operand, nodeType);
      }
      return validateOperands(validator, scope, call);
    }
  
    @Override public void validateCall(SqlCall call, SqlValidator validator,
        SqlValidatorScope scope, SqlValidatorScope operandScope) {
      super.validateCall(call, validator, scope, operandScope);
  
      if (call.operandCount() > 1) {
        // This is either a time unit or a time frame:
        //
        //  * In "FLOOR(x TO YEAR)" operand 1 is a SqlIntervalQualifier with
        //    startUnit = YEAR and timeFrameName = null.
        //
        //  * In "FLOOR(x TO MINUTE15)" operand 1 is a SqlIntervalQualifier with
        //    startUnit = EPOCH and timeFrameName = 'MINUTE15'.
        //
        // If the latter, check that timeFrameName is valid.
        validator.validateTimeFrame(
            (SqlIntervalQualifier) call.getOperandList().get(1));
      }
    }
  
    @Override public String getName() {
      return kind.name();
    }
  
    /**
     * Copies a {@link SqlCall}, replacing the time unit operand with the given
     * literal.
     *
     * @param call Call
     * @param literal Literal to replace time unit with
     * @param pos Parser position
     * @return Modified call
     */
    public static SqlCall replaceTimeUnitOperand(SqlCall call, String literal, SqlParserPos pos) {
      SqlLiteral literalNode = SqlLiteral.createCharString(literal, null, pos);
      return call.getOperator().createCall(call.getFunctionQuantifier(), pos,
          call.getOperandList().get(0), literalNode);
    }
  
    /**
     * Most dialects that natively support datetime floor will use this.
     * In those cases the call will look like TRUNC(datetime, 'year').
     *
     * @param writer SqlWriter
     * @param call SqlCall
     * @param funName Name of the sql function to call
     * @param datetimeFirst Specify the order of the datetime &amp; timeUnit
     * arguments
     */
    public static void unparseDatetimeFunction(SqlWriter writer, SqlCall call,
        String funName, Boolean datetimeFirst) {
      SqlFunction func =
          new SqlFunction(funName, SqlKind.OTHER_FUNCTION,
              ReturnTypes.ARG0_NULLABLE_VARYING, null, null,
              SqlFunctionCategory.STRING);
  
      SqlCall call1;
      if (datetimeFirst) {
        call1 = call;
      } else {
        // switch order of operands
        SqlNode op1 = call.operand(0);
        SqlNode op2 = call.operand(1);
  
        call1 = call.getOperator().createCall(call.getParserPosition(), op2, op1);
      }
  
      SqlUtil.unparseFunctionSyntax(func, writer, call1, false);
    }
  }
  