/*
 * 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.type;

import org.apache.calcite.rel.type.RelDataType;
import org.apache.calcite.sql.SqlCallBinding;
import org.apache.calcite.sql.SqlOperator;
import org.apache.calcite.sql.SqlOperatorBinding;
import org.apache.calcite.sql.SqlUtil;

import com.google.common.collect.ImmutableList;

import java.util.Collections;
import java.util.List;

import static org.apache.calcite.util.Static.RESOURCE;

/**
 * Parameter type-checking strategy where all operand types except last one must be the same.
 */
public class SameOperandTypeExceptLastOperandChecker extends SameOperandTypeChecker {
  //~ Instance fields --------------------------------------------------------

  protected final String lastOperandTypeName;

  //~ Constructors -----------------------------------------------------------

  public SameOperandTypeExceptLastOperandChecker(
      int nOperands, String lastOperandTypeName) {
    super(nOperands);
    this.lastOperandTypeName = lastOperandTypeName;
  }

  //~ Methods ----------------------------------------------------------------

  protected boolean checkOperandTypesImpl(
      SqlOperatorBinding operatorBinding,
      boolean throwOnFailure,
      SqlCallBinding callBinding) {
    int nOperandsActual = nOperands;
    if (nOperandsActual == -1) {
      nOperandsActual = operatorBinding.getOperandCount();
    }
    assert !(throwOnFailure && (callBinding == null));
    RelDataType[] types = new RelDataType[nOperandsActual];
    final List<Integer> operandList =
        getOperandList(operatorBinding.getOperandCount());
    for (int i : operandList) {
      if (operatorBinding.isOperandNull(i, false)) {
        if (throwOnFailure) {
          throw callBinding.getValidator().newValidationError(
              callBinding.operand(i), RESOURCE.nullIllegal());
        } else {
          return false;
        }
      }
      types[i] = operatorBinding.getOperandType(i);
    }
    int prev = -1;
    for (int i : operandList) {
      if (prev >= 0 && i != operandList.get(operandList.size() - 1)) {
        if (!SqlTypeUtil.isComparable(types[i], types[prev])) {
          if (!throwOnFailure) {
            return false;
          }

          // REVIEW jvs 5-June-2005: Why don't we use
          // newValidationSignatureError() here?  It gives more
          // specific diagnostics.
          throw callBinding.newValidationError(
              RESOURCE.needSameTypeParameter());
        }
      }
      prev = i;
    }
    return true;
  }

  public String getAllowedSignatures(SqlOperator op, String opName) {
    final String typeName = getTypeName();
    if (nOperands == -1) {
      return SqlUtil.getAliasedSignature(op, opName,
          ImmutableList.of(typeName, typeName, "..."));
    } else {
      List<String> types = Collections.nCopies(nOperands - 1, typeName);
      types.add(lastOperandTypeName);
      return SqlUtil.getAliasedSignature(op, opName, types);
    }
  }
}

// End SameOperandTypeExceptLastOperandChecker.java
