Voting.java

package com.empireminecraft.systems;

import com.empireminecraft.config.EmpireConfig;
import com.empireminecraft.config.meta.EmpireMetaKey;
import com.empireminecraft.data.EmpireUser;
import com.empireminecraft.data.items.PromoItems;
import com.empireminecraft.data.items.VotingItems;
import com.empireminecraft.features.EmpireRupees;
import com.empireminecraft.features.items.CustomItem;
import com.empireminecraft.systems.db.DbRow;
import com.empireminecraft.systems.db.DbStatement;
import com.empireminecraft.util.TaskChain;
import com.empireminecraft.util.Util;
import org.bukkit.Material;

import java.util.Calendar;
import java.util.GregorianCalendar;

import static com.empireminecraft.features.Mail.sendSystemMail;

public class Voting {
    public static void creditVote(final String player, final String service) {
        if (!EmpireUser.validateUsername(player)) {
            Util.log("Could not validate user name " + player);
            return;
        }
        if (service == null) {
            Util.logWarning("Player " + player + " voted with unknown service");
            return;
        }

        TaskChain.newChain().add(new TaskChain.GenericTask() {
                @Override
                protected void run() {
                    new VotingRewards(player, service);
                }
        }).execute();
    }

    static class VotingRewards {
        Long userId;
        Long voteBonus;
        Long lastVote;
        Long voteMax;
        Long voteMissed;
        Long yesterday;
        Long midnight;
        Long timestamp;
        int voteRupees;
        String player;
        String service;
        VotingRewards(String name, String service) {
            player = name;
            this.service = service;
            try (DbStatement stm = new DbStatement()) {
                stm.startTransaction();
                stm.query("SELECT " +
                    "lastvote, votebonus,voteitembonus, " +
                    "user_id, votemax,votelastmiss " +
                    "FROM user WHERE name = ? FOR UPDATE");

                stm.execute(player);
                DbRow rs = stm.getNextRow();
                if (rs == null) {
                    Util.log("[vote] Could not find user '" + player + "' for '" + service + "'");
                    return;
                }
                userId        = rs.get("user_id");
                voteBonus     = rs.get("votebonus");
                lastVote      = rs.get("lastvote");
                voteMax       = rs.get("votemax");
                voteMissed      = rs.get("votelastmiss");
                voteRupees = EmpireConfig.get().getInt("vote-rewards." + Util.simplifyString(service), 100);
                timestamp = System.currentTimeMillis() / 1000;


                if (timestamp - lastVote < (60*60*36)) {
                    final EmpireUser user = EmpireUser.getUser(player);
                    player = user.getName();
                    final Long lastBonus = user.getMeta(EmpireMetaKey.VOTE_LAST_BONUS).getLong();
                    if (lastBonus == null || timestamp - lastBonus > (60*60*16)) {
                        voteRupees += 100;
                        voteRupees += Math.min(voteBonus++ * 10, 500);
                        if (voteBonus > voteMax) {
                            processRupeeBonus();
                            processItemBonus();
                        }
                        user.setMeta(EmpireMetaKey.VOTE_LAST_BONUS, timestamp);
                    }
                } else if (lastVote < timestamp - (60 * 60 * 24 * 3)) { // 3 day window before losing streak
                    long daysMissed = (long) Math.floor((timestamp - lastVote) / (60 * 60 * 24));
                    voteBonus = Math.max(0, voteBonus - daysMissed);
                    voteMissed = timestamp;
                }

                lastVote = timestamp;
                stm.query("UPDATE user SET votes = votes + 1, "
                    + " lastvote = ?, votebonus = ?, votemax = ?, votelastmiss = ? WHERE user_id = ?");
                stm.executeUpdate(
                    lastVote,
                    voteBonus,
                    Math.max(voteBonus, voteMax),
                    voteMissed,
                    userId);
                stm.commit();
                EmpireRupees.credit(userId, voteRupees, 31, service + " - day bonus: " + voteBonus);
                Util.notifyPlayer(player, "&aYou successfully voted on&f " + service + " &aand earned &f" + voteRupees + "&a rupees!");
                if (voteBonus > voteMax) {
                    Util.notifyPlayer(player, "&aYour vote bonus is now &f" + voteBonus + "&a! Keep up the good work!");
                }

                Util.log("[vote] '" + player + "' voted on '" + service + "' and earned: " + voteRupees +
                    " rupees with mod:" + voteBonus);
            } catch (Exception e) {
                Util.printException("[vote] FAILED for '" + player + "' on '" + service + "'", e);
            }
        }

        private void processRupeeBonus() {
            /*
              DO NOT add any other logic after shouldGet* - do it BEFORE.
              If one of the shouldGetItem returns true, it must deliver item.
             */
            if (shouldGetEvery(5, "rupee5")) {
                voteRupees += 300;
            }
            if (shouldGetEvery(15, "rupee15")) {
                voteRupees += 1000;
            }
            if (shouldGetEvery(30, "rupee30")) {
                voteRupees += 4000;
            }
            if (shouldGetEvery(45, "rupee45")) {
                voteRupees += 7500;
            }
            if (shouldGetEvery(50, "rupee50")) {
                voteRupees += 25000;
            }
            if (shouldGetEvery(100, "rupee100")) {
                voteRupees += 40000;
            }
        }

        private void processItemBonus() {
            String str = "Vote Bonus " + voteBonus + " Reward";
            /*
              DO NOT add any other logic after shouldGet* - do it BEFORE.
              If one of the shouldGetItem returns true, it must deliver item.
             */
            if (shouldGetEvery(2, "diamond")) {
                sendSystemMail(player, str, CustomItem.newItem(Material.DIAMOND)
                    .withRange(1, Math.max(1, (int) Math.min(10, voteBonus / 5))).getDrop(0));
            }

            if (shouldGetEvery(3, "emerald")) {
                sendSystemMail(player, str, CustomItem.newItem(Material.EMERALD)
                    .withRange(1, Math.max(1, (int) Math.min(10, voteBonus / 5))).getDrop(0));
            }

            if (shouldGetEvery(20, "vaultVoucher")) {
                sendSystemMail(player, str, PromoItems.VAULT_VOUCHER);
            }

            if (shouldGetEvery(50, "stableVoucher")) {
                sendSystemMail(player, str, PromoItems.STABLE_VOUCHER);
            }

            if (shouldGetAt(20, "votersBoots")) {
                sendSystemMail(player, str, VotingItems.makeVotingItem(player, VotingItems.VOTERS_BOOTS));
            }

            if (shouldGetAt(30, "votersHead")) {
                sendSystemMail(player, str, VotingItems.makeVotingItem(player, VotingItems.VOTERS_HEAD));
            }

            if (shouldGetAt(40, "votersLegs")) {
                sendSystemMail(player, str, VotingItems.makeVotingItem(player, VotingItems.VOTERS_LEGS));
            }

            if (shouldGetAt(60, "votersChest")) {
                sendSystemMail(player, str, VotingItems.makeVotingItem(player, VotingItems.VOTERS_CHEST));
            }

            if (shouldGetAt(100, "tyCertificate")) {
                sendSystemMail(player, str, VotingItems.makeVotingThankYou(player));
            }
        }


        private boolean shouldGetEvery(int i, String key) {
            if (shouldGetAt(i, key)) {
                return true;
            } else if ((voteBonus % i == 0) && !hasMetaKey(key + voteBonus)) {
                setMetaKey(key + voteBonus);
                return true;
            }
            return false;
        }

        private boolean shouldGetAt(int i, String key) {
            if (voteBonus >= i && !hasMetaKey(key + i)) {
                setMetaKey(key + i);
                return true;
            }
            return false;
        }
        private void setMetaKey(String key) {
            EmpireMetaKey metaKey = new EmpireMetaKey("votereward." + key, 0);
            EmpireUser.getUser(player).setMeta(metaKey, "1");
        }

        private boolean hasMetaKey(String key) {
            EmpireMetaKey metaKey = new EmpireMetaKey("votereward." + key, 0);

            return EmpireUser.getUser(player).getMeta(metaKey).getString() != null;
        }
    }
}

Aikar: Here are some suggestions for improving the code if you are interested. The changes I made are tagged with comments that start with "**"

https://gist.github.com/mangstadt/88398851bcd3f0e88c4d

Thanks,
shavingfoam