public RexNode convertCall()

in calcite-adapter/src/main/java/software/amazon/documentdb/jdbc/query/DocumentDbQueryMappingService.java [257:304]
43 lines of code
10 McCabe index (conditional complexity)

            public RexNode convertCall(final SqlRexContext cx, final SqlCall call) {
                // TIMESTAMPDIFF(unit, t1, t2) => (t2 - t1) UNIT
                final RexBuilder rexBuilder = cx.getRexBuilder();
                final SqlLiteral unitLiteral = call.operand(0);
                TimeUnit unit = getSymbolValue(unitLiteral, TimeUnit.class);
                final SqlTypeName sqlTypeName = unit == TimeUnit.NANOSECOND
                        ? SqlTypeName.BIGINT
                        : SqlTypeName.INTEGER;
                final BigDecimal multiplier;
                final BigDecimal divider;
                switch (unit) {
                    case MICROSECOND:
                    case MILLISECOND:
                    case NANOSECOND:
                    case WEEK:
                        multiplier = BigDecimal.valueOf(DateTimeUtils.MILLIS_PER_SECOND);
                        divider = unit.multiplier;
                        unit = TimeUnit.SECOND;
                        break;
                    default:
                        multiplier = BigDecimal.ONE;
                        divider = BigDecimal.ONE;
                }
                final SqlIntervalQualifier qualifier =
                        new SqlIntervalQualifier(unit, null, SqlParserPos.ZERO);
                final RexNode op2 = cx.convertExpression(call.operand(2));
                final RexNode op1 = cx.convertExpression(call.operand(1));
                final RelDataType intervalType =
                        cx.getTypeFactory().createTypeWithNullability(
                                cx.getTypeFactory().createSqlIntervalType(qualifier),
                                op1.getType().isNullable() || op2.getType().isNullable());
                final RexCall rexCall = (RexCall) rexBuilder.makeCall(
                        intervalType, SqlStdOperatorTable.MINUS_DATE,
                        ImmutableList.of(op2, op1));
                final RelDataType intType =
                        cx.getTypeFactory().createTypeWithNullability(
                                cx.getTypeFactory().createSqlType(sqlTypeName),
                                SqlTypeUtil.containsNullable(rexCall.getType()));

                // If dealing with year, quarter, or month we will calculate the difference using date parts
                // and do not need any integer division.
                if (unit == TimeUnit.YEAR || unit == TimeUnit.QUARTER || unit == TimeUnit.MONTH) {
                    return rexBuilder.makeReinterpretCast(intType, rexCall, rexBuilder.makeLiteral(false));
                }

                final RexNode e = rexBuilder.makeCast(intType, rexCall);
                return rexBuilder.multiplyDivide(e, multiplier, divider);
            }