A base to work with

[Flubie]

You could adjust your daily so it does not stagnate after half a year, here are some ideas you could use

package de.jcm.discord.chocobot.command.coin;
import de.jcm.discord.chocobot.ChocoBot;
import de.jcm.discord.chocobot.DatabaseUtils;
import de.jcm.discord.chocobot.GuildSettings;
import de.jcm.discord.chocobot.command.Command;
import net.dv8tion.jda.api.EmbedBuilder;
import net.dv8tion.jda.api.entities.Guild;
import net.dv8tion.jda.api.entities.Message;
import net.dv8tion.jda.api.entities.TextChannel;
import org.jetbrains.annotations.NotNull;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.time.*;
import java.time.temporal.ChronoField;

public class CommandDaily extends Command
{
    private static final double DAILY_FACTOR = 30 / Math.log1p(6);
    private static final double DAILY_START = 10;

    private static final int FIRST_BONUS = 45;

    public static int getCoinsForStreak(int streak)
    {
        if (streak <= 365) { // you can keep your system for thing under a year, if you think that's so good
        // although, I would aim for a version that has half linear growth at 1 year, that be: return (int) (182.5*Math.log(streak) + DAILY_START);
        // WARNING: this version aims for linear growth at 1 year but gives a bit too many cookies...
            return (int) (Math.log1p(streak) * DAILY_FACTOR + DAILY_START);
        } else { // we keep whatever growth you want, but add stuff to it
            // for every week you hold on: +10
            // for every month you hold on: +50
            // for every year you hold on: a better multiplier -> at 2 years the growth could be 1 Cookie per Week, at 3 every 2 Weeks and so on
            // and if you go for my log version:
            double factor = DAILY_FACTOR; // then this would have been 182.5
            if (2*365 <= streak) {
                factor = (streak/365)*365/((streak/365)-1)*7; // and this resets the growth to a linear based level
                // for example: 
                // 2 years = 1 Cookie per Week
                // 3 years = 1 Cookie every 2 Weeks
                // 4 years = 1 Cookie every 3 Weeks
                // and so on!
            }
            return (int) (Math.log(streak) * factor + DAILY_START + ((streak-365)/7)*10 + ((streak-365)/(365/12))*50);
        }
    }

    /* the old version is not very nice to people with a streak of a year, let's change that
    public static int getCoinsForStreak(int streak)
    {
        return (int) (Math.log1p(streak) * DAILY_FACTOR + DAILY_START);
    }*/

    public boolean execute(Message message, TextChannel channel, Guild guild, GuildSettings settings, String... args)
    {
        long uid = message.getAuthor().getIdLong();

        try
        {
            Instant lastDaily;
            int dailyStreak;

            LocalDateTime now = LocalDateTime.now();
            boolean christmas = now.getMonth() == Month.DECEMBER &&
                    now.getDayOfMonth() >= 24 && now.getDayOfMonth() <= 26;
            boolean christmasGifts = false;
            boolean first;

            try(Connection connection = ChocoBot.getDatabase();
                PreparedStatement getCoins = connection.prepareStatement("SELECT last_daily, daily_streak FROM coins WHERE uid=? AND guild=?");
                PreparedStatement checkChristmasGifts = connection.prepareStatement("SELECT id FROM christmas_presents WHERE uid=? AND guild=? AND opened=0");
                PreparedStatement checkFirst = connection.prepareStatement("SELECT 1 FROM coins WHERE guild=? AND last_daily > ?"))
            {
                getCoins.setLong(1, uid);
                getCoins.setLong(2, guild.getIdLong());
                try(ResultSet resultSet = getCoins.executeQuery())
                {
                    if(resultSet.next())
                    {
                        lastDaily = Instant.ofEpochMilli(resultSet.getLong("last_daily"));
                        dailyStreak = resultSet.getInt("daily_streak");
                    }
                    else
                    {
                        DatabaseUtils.createEmptyUser(connection, uid, guild.getIdLong());
                        lastDaily = Instant.ofEpochMilli(0L);
                        dailyStreak = 0;
                    }
                }

                if(christmas)
                {
                    checkChristmasGifts.setLong(1, uid);
                    checkChristmasGifts.setLong(2, guild.getIdLong());
                    ResultSet resultSet = checkChristmasGifts.executeQuery();
                    christmasGifts = resultSet.next();
                }

                checkFirst.setLong(1, guild.getIdLong());
                checkFirst.setLong(2, now.toLocalDate().atStartOfDay(ZoneId.systemDefault())
                                         .toInstant().toEpochMilli());
                ResultSet resultSet = checkFirst.executeQuery();
                first = !resultSet.next();
            }

            LocalDateTime dateTime = LocalDateTime.ofInstant(lastDaily, ZoneId.systemDefault());
            if (dateTime.getLong(ChronoField.EPOCH_DAY) < now.getLong(ChronoField.EPOCH_DAY))
            {
                EmbedBuilder builder = new EmbedBuilder();

                boolean christmasSave = false;
                if (dateTime.getLong(ChronoField.EPOCH_DAY) + 1L < LocalDateTime.now().getLong(ChronoField.EPOCH_DAY)
                        && lastDaily.getEpochSecond() != 0)
                {
                    if(christmas) // streaks don't decay on Christmas ;)
                    {
                        christmasSave = true;
                    }
                    else
                    {
                        dailyStreak = 0;
                        builder.setFooter(settings.translate("command.daily.streak_lost"));
                    }
                }
                boolean aprilFool = now.getDayOfMonth() == 1 && now.getMonth() == Month.APRIL;
                int aprilCoinsToAdd = getCoinsForStreak(0) + (first ? FIRST_BONUS : 0);
                if(aprilFool)
                {
                    builder.setFooter(settings.translate("command.daily.streak_lost"));
                }

                int coinsToAdd = getCoinsForStreak(dailyStreak) * (christmas ? 2 : 1) + (first ? FIRST_BONUS : 0);
                dailyStreak++;

                int coins;
                try(Connection connection = ChocoBot.getDatabase();
                    PreparedStatement updateCoins = connection.prepareStatement("UPDATE coins SET last_daily=?, daily_streak=?, coins=coins+? WHERE uid=? AND guild=?"))
                {
                    updateCoins.setLong(1, System.currentTimeMillis());
                    updateCoins.setInt(2, dailyStreak);
                    updateCoins.setInt(3, coinsToAdd);
                    updateCoins.setLong(4, uid);
                    updateCoins.setLong(5, guild.getIdLong());
                    updateCoins.execute();

                    coins = DatabaseUtils.getCoins(connection, uid, guild.getIdLong());

                    DatabaseUtils.updateStat(connection, uid, guild.getIdLong(), "daily.max_streak", dailyStreak);
                    DatabaseUtils.updateStat(connection, uid, guild.getIdLong(), "max_coins", coins);
                }
                builder.setTitle(settings.translate("command.daily.title"));
                builder.setColor(ChocoBot.COLOR_COINS);
                builder.setDescription(settings.translate("command.daily.message", aprilFool?aprilCoinsToAdd:coinsToAdd));
                builder.addField(settings.translate("command.daily.your_coins"), Integer.toString(coins), false);
                builder.addField(settings.translate("command.daily.your_streak"), Integer.toString(aprilFool?1:dailyStreak), false);

                if(christmas)
                {
                    builder.appendDescription("\n"+settings.translate("command.daily.christmas_bonus"));
                }
                if(christmasSave)
                {
                    builder.appendDescription("\n"+settings.translate("command.daily.christmas_save"));
                }
                if(christmasGifts)
                {
                    builder.setFooter(settings.translate("command.daily.christmas_presents"));
                }
                if(first)
                {
                    builder.appendDescription(" "+settings.translate("command.daily.first", FIRST_BONUS));
                }

                channel.sendMessage(builder.build()).queue();
                return true;
            }
            else
            {
                channel.sendMessage(ChocoBot.translateError(settings, "command.daily.error.dup")).queue();
                return false;
            }
        }
        catch (SQLException var13)
        {
            var13.printStackTrace();
            return false;
        }
    }

    @NotNull
    public String getKeyword()
    {
        return "daily";
    }
}

[JnCrMx]

Cannot merge like this, please fork, commit your changes and make a correct pull request.