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 *  Copyright (c) 2014-2019 Appsicle
 *  Copyright (c) 2019-2024 QuestDB
 *
 *  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,
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package io.questdb.griffin.engine.functions.rnd;

import io.questdb.cairo.CairoConfiguration;
import io.questdb.cairo.sql.Function;
import io.questdb.cairo.sql.Record;
import io.questdb.griffin.FunctionFactory;
import io.questdb.griffin.SqlExecutionContext;
import io.questdb.griffin.engine.functions.UuidFunction;
import io.questdb.std.IntList;
import io.questdb.std.ObjList;
import io.questdb.std.Rnd;

public class RndUuidFunctionFactory implements FunctionFactory {
    @Override
    public String getSignature() {
        return "rnd_uuid4()";
    }

    @Override
    public Function newInstance(int position, ObjList args, IntList argPositions, CairoConfiguration configuration, SqlExecutionContext sqlExecutionContext) {
        return new RndFunction(sqlExecutionContext);
    }

    private static class RndFunction extends UuidFunction implements Function {
        private final Rnd rnd;

        private RndFunction(SqlExecutionContext sqlExecutionContext) {
            // Initialize in advance, in preparation for possible calls by constant functions.
            rnd = sqlExecutionContext.getRandom();
        }

        @Override
        public long getLong128Hi(Record rec) {
            long hi = rnd.nextLong();
            // set version to 4
            hi &= 0xffffffffffff0fffL;
            hi |= 0x0000000000004000L;
            return hi;
        }

        @Override
        public long getLong128Lo(Record rec) {
            long lo = rnd.nextLong();
            // set variant to 1
            lo &= 0x3fffffffffffffffL;
            lo |= 0x8000000000000000L;
            return lo;
        }

        @Override
        public String getName() {
            return "rnd_uuid4";
        }

        @Override
        public boolean isNonDeterministic() {
            return true;
        }
    }
}