Convert a discord snowflake to unix timestamp using PostgreSQL

snowflake_to_unix.sql

CREATE FUNCTION snowflake_to_unix_timestamp(snowflake BIGINT) RETURNS TIMESTAMP
    LANGUAGE plpgsql
    PARALLEL SAFE
    IMMUTABLE
AS
$BODY$
BEGIN
    -- message_id::BIT(64) AS bits
    -- bits::BIT(42) AS timestamp_bits
    -- timestamp_bits::BIGINT AS discord_epoch
    -- discord_epoch + 1420070400000 AS unix
    -- to_timestamp(unix / 1000.0) as timestamp
    RETURN to_timestamp(( snowflake::BIT(64)::BIT(42)::BIGINT + 1420070400000 ) / 1000.0);
END;
$BODY$;