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/*
 * 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 com.hazelcast.org.apache.calcite.sql.fun;

import com.hazelcast.org.apache.calcite.rel.type.RelDataType;
import com.hazelcast.org.apache.calcite.sql.SqlAggFunction;
import com.hazelcast.org.apache.calcite.sql.SqlCall;
import com.hazelcast.org.apache.calcite.sql.SqlFunctionCategory;
import com.hazelcast.org.apache.calcite.sql.SqlJsonConstructorNullClause;
import com.hazelcast.org.apache.calcite.sql.SqlKind;
import com.hazelcast.org.apache.calcite.sql.SqlLiteral;
import com.hazelcast.org.apache.calcite.sql.SqlNode;
import com.hazelcast.org.apache.calcite.sql.SqlWriter;
import com.hazelcast.org.apache.calcite.sql.parser.SqlParserPos;
import com.hazelcast.org.apache.calcite.sql.type.InferTypes;
import com.hazelcast.org.apache.calcite.sql.type.OperandTypes;
import com.hazelcast.org.apache.calcite.sql.type.ReturnTypes;
import com.hazelcast.org.apache.calcite.sql.type.SqlTypeFamily;
import com.hazelcast.org.apache.calcite.sql.validate.SqlValidator;
import com.hazelcast.org.apache.calcite.sql.validate.SqlValidatorScope;
import com.hazelcast.org.apache.calcite.util.Optionality;

import com.hazelcast.org.checkerframework.checker.nullness.qual.Nullable;

import java.util.Objects;

/**
 * The JSON_OBJECTAGG aggregate function.
 */
public class SqlJsonArrayAggAggFunction extends SqlAggFunction {
  private final SqlJsonConstructorNullClause nullClause;

  public SqlJsonArrayAggAggFunction(SqlKind kind,
      SqlJsonConstructorNullClause nullClause) {
    super(kind + "_" + nullClause.name(), null, kind, ReturnTypes.VARCHAR_2000,
        InferTypes.ANY_NULLABLE, OperandTypes.family(SqlTypeFamily.ANY),
        SqlFunctionCategory.SYSTEM, false, false, Optionality.OPTIONAL);
    this.nullClause = Objects.requireNonNull(nullClause, "nullClause");
  }

  @Override public void unparse(SqlWriter writer, SqlCall call, int leftPrec,
      int rightPrec) {
    assert call.operandCount() == 1;
    final SqlWriter.Frame frame = writer.startFunCall("JSON_ARRAYAGG");
    call.operand(0).unparse(writer, leftPrec, rightPrec);
    writer.keyword(nullClause.sql);
    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 SqlCall createCall(@Nullable SqlLiteral functionQualifier,
      SqlParserPos pos, @Nullable SqlNode... operands) {
    assert operands.length == 1 || operands.length == 2;
    final SqlNode valueExpr = operands[0];
    if (operands.length == 2) {
      final SqlNode orderList = operands[1];
      if (orderList != null) {
        // call has an order by clause, e.g. json_arrayagg(col_1 order by col_1)
        return SqlStdOperatorTable.WITHIN_GROUP.createCall(SqlParserPos.ZERO,
            createCall_(functionQualifier, pos, valueExpr), orderList);
      }
    }
    return createCall_(functionQualifier, pos, valueExpr);
  }

  private SqlCall createCall_(@Nullable SqlLiteral functionQualifier, SqlParserPos pos,
      @Nullable SqlNode valueExpr) {
    return super.createCall(functionQualifier, pos, valueExpr);
  }

  public SqlJsonArrayAggAggFunction with(SqlJsonConstructorNullClause nullClause) {
    return this.nullClause == nullClause ? this
        : new SqlJsonArrayAggAggFunction(getKind(), nullClause);
  }

  public SqlJsonConstructorNullClause getNullClause() {
    return nullClause;
  }
}