/*
 * Copyright © 2021 DataSQRL (contact@datasqrl.com)
 *
 * 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.datasqrl.function.translation.postgres.builtinflink;

import com.datasqrl.function.CalciteFunctionUtil;
import com.datasqrl.function.translation.PostgresSqlTranslation;
import com.datasqrl.function.translation.SqlTranslation;
import com.google.auto.service.AutoService;
import java.util.ArrayList;
import org.apache.calcite.sql.SqlCall;
import org.apache.calcite.sql.SqlLiteral;
import org.apache.calcite.sql.SqlWriter;
import org.apache.calcite.sql.parser.SqlParserPos;

@AutoService(SqlTranslation.class)
public class EltSqlTranslation extends PostgresSqlTranslation {

  public EltSqlTranslation() {
    super(CalciteFunctionUtil.lightweightOp("ELT"));
  }

  @Override
  public void unparse(SqlCall call, SqlWriter writer, int leftPrec, int rightPrec) {
    var operands = new ArrayList<>(call.getOperandList());
    var idx = (SqlLiteral) operands.remove(0);
    var idxVal = idx.intValue(false);

    // Postgres idx starts at 1
    var idxLit = SqlLiteral.createExactNumeric(String.valueOf(idxVal + 1), SqlParserPos.ZERO);

    // (ARRAY[...])[idx]
    var paren = writer.startList("(", ")");
    writer.keyword("ARRAY");
    var argBrack = writer.startList("[", "]");
    CalciteFunctionUtil.writeOperands(writer, operands);
    writer.endList(argBrack);
    writer.endList(paren);
    var idxBrack = writer.startList("[", "]");
    idxLit.unparse(writer, 0, 0);
    writer.endList(idxBrack);
  }
}
