remove stats system

improve operations and make them extendable more easily and let other plugins add operations, like requirements 
move requirements/operations out of ranks class as they will be used in prestiges

src/main/java/sh/okx/rankup/ranks/Rank.java

@@ -9,14 +9,16 @@ import org.bukkit.entity.Player;
 import sh.okx.rankup.Rankup;
 import sh.okx.rankup.messages.MessageBuilder;
 import sh.okx.rankup.messages.Variable;
-import sh.okx.rankup.ranks.requirements.DeductibleRequirement;
-import sh.okx.rankup.ranks.requirements.Requirement;
+import sh.okx.rankup.requirements.DeductibleRequirement;
+import sh.okx.rankup.requirements.Operation;
+import sh.okx.rankup.requirements.Requirement;
 
 import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
+import java.util.Optional;
 import java.util.Set;
-import java.util.function.BinaryOperator;
+import java.util.stream.Collectors;
 
 @RequiredArgsConstructor(access = AccessLevel.PRIVATE)
 public class Rank {
@@ -29,14 +31,14 @@ public class Rank {
   private final String rank;
   @Getter
   private final Set<Requirement> requirements;
-  private final BinaryOperator<Boolean> reducer;
+  private final Operation operation;
   private final List<String> commands;
 
   public static Rank deserialize(Rankup plugin, ConfigurationSection section) {
     String rank = section.getString("rank");
 
     Set<Requirement> requirements = new HashSet<>();
-    BinaryOperator<Boolean> reducer = null;
+    Operation operation = null;
     ConfigurationSection requirementsSection = section.getConfigurationSection("requirements");
     if (requirementsSection != null) {
       for (Map.Entry<String, Object> entry : requirementsSection.getValues(false).entrySet()) {
@@ -50,26 +52,8 @@ public class Rank {
         }
       }
 
-      String operation = section.getString("operation");
-      if (operation == null) {
-        operation = "and";
-      }
-      switch (operation) {
-        case "and":
-          reducer = (a, b) -> a && b;
-          break;
-        case "or":
-          reducer = (a, b) -> a || b;
-          break;
-        case "xor":
-          reducer = (a, b) -> (a && !b) || (b && !a);
-          break;
-        case "none":
-          reducer = (a, b) -> !a && !b;
-          break;
-        default:
-          throw new IllegalArgumentException("Invalid operation type for rank " + rank);
-      }
+      String operationName = Optional.ofNullable(section.getString("operation")).orElse("all");
+      operation = plugin.getOperationRegistry().getOperation(operationName);
     }
 
     return new Rank(plugin,
@@ -77,15 +61,14 @@ public class Rank {
         section.getString("next"),
         rank,
         requirements,
-        reducer,
+        operation,
         section.getStringList("commands"));
   }
 
   public boolean checkRequirements(Player player) {
-    return requirements.stream()
+    return operation.check(requirements.stream()
         .map(requirement -> requirement.check(player))
-        .reduce(reducer)
-        .orElse(true);
+        .collect(Collectors.toList()));
   }
 
   public boolean isInRank(Player player) {

src/main/java/sh/okx/rankup/ranks/requirements/DeductibleRequirement.java

@@ -1,24 +0,0 @@
-package sh.okx.rankup.ranks.requirements;
-
-import org.bukkit.entity.Player;
-import sh.okx.rankup.Rankup;
-
-public abstract class DeductibleRequirement extends Requirement {
-  public DeductibleRequirement(Rankup plugin, String name) {
-    super(plugin, name);
-  }
-
-  protected DeductibleRequirement(Requirement clone) {
-    super(clone);
-  }
-
-  /**
-   * Apply the effect of this requirement to the player.
-   * For money, this could be taking money away from the player.
-   * You can assume that <code>Requirement#check(Player)</code> has been called,
-   * and has returned true immediately prior to this.
-   *
-   * @param player the player to take from
-   */
-  public abstract void apply(Player player);
-}

src/main/java/sh/okx/rankup/ranks/requirements/GroupRequirement.java

@@ -1,33 +0,0 @@
-package sh.okx.rankup.ranks.requirements;
-
-import org.bukkit.entity.Player;
-import sh.okx.rankup.Rankup;
-
-public class GroupRequirement extends Requirement {
-  public GroupRequirement(Rankup plugin, String name) {
-    super(plugin, name);
-  }
-
-  protected GroupRequirement(Requirement clone) {
-    super(clone);
-  }
-
-  @Override
-  public boolean check(Player player) {
-    OUTER:
-    for (String requiredGroup : getValueString().split(" ")) {
-      for (String group : plugin.getPermissions().getPlayerGroups(player)) {
-        if (group.equalsIgnoreCase(requiredGroup)) {
-          continue OUTER;
-        }
-      }
-      return false;
-    }
-    return true;
-  }
-
-  @Override
-  public Requirement clone() {
-    return new GroupRequirement(this);
-  }
-}

src/main/java/sh/okx/rankup/ranks/requirements/MoneyRequirement.java

@@ -1,38 +0,0 @@
-package sh.okx.rankup.ranks.requirements;
-
-import net.milkbowl.vault.economy.Economy;
-import org.bukkit.entity.Player;
-import sh.okx.rankup.Rankup;
-
-public class MoneyRequirement extends DeductibleRequirement {
-  public MoneyRequirement(Rankup plugin, String name) {
-    super(plugin, name);
-  }
-
-  protected MoneyRequirement(Requirement clone) {
-    super(clone);
-  }
-
-  @Override
-  public boolean check(Player player) {
-    Economy economy = plugin.getEconomy();
-    double balance = economy.getBalance(player);
-    return balance >= getValueDouble();
-  }
-
-  @Override
-  public void apply(Player player) {
-    Economy economy = plugin.getEconomy();
-    economy.withdrawPlayer(player, getValueDouble());
-  }
-
-  @Override
-  public double getRemaining(Player player) {
-    return Math.max(0, getValueDouble() - plugin.getEconomy().getBalance(player));
-  }
-
-  @Override
-  public Requirement clone() {
-    return new MoneyRequirement(this);
-  }
-}

src/main/java/sh/okx/rankup/ranks/requirements/PlaytimeMinutesRequirement.java

@@ -1,40 +0,0 @@
-package sh.okx.rankup.ranks.requirements;
-
-import org.bukkit.Statistic;
-import org.bukkit.entity.Player;
-import sh.okx.rankup.Rankup;
-
-public class PlaytimeMinutesRequirement extends Requirement {
-  private static final int TICKS_PER_MINUTE = 20 * 60;
-  private Statistic playOneTick;
-
-  public PlaytimeMinutesRequirement(Rankup plugin, String name) {
-    super(plugin, name);
-    try {
-      playOneTick = Statistic.valueOf("PLAY_ONE_MINUTE");
-    } catch (IllegalArgumentException e) {
-      // statistic was changed in 1.13.
-      playOneTick = Statistic.valueOf("PLAY_ONE_TICK");
-    }
-  }
-
-  protected PlaytimeMinutesRequirement(PlaytimeMinutesRequirement clone) {
-    super(clone);
-    this.playOneTick = clone.playOneTick;
-  }
-
-  @Override
-  public boolean check(Player player) {
-    return player.getStatistic(playOneTick) * TICKS_PER_MINUTE >= getValueDouble();
-  }
-
-  @Override
-  public double getRemaining(Player player) {
-    return Math.max(0, getValueDouble() - (player.getStatistic(playOneTick) * TICKS_PER_MINUTE));
-  }
-
-  @Override
-  public Requirement clone() {
-    return new PlaytimeMinutesRequirement(this);
-  }
-}

src/main/java/sh/okx/rankup/ranks/requirements/Requirement.java

@@ -1,63 +0,0 @@
-package sh.okx.rankup.ranks.requirements;
-
-import lombok.Getter;
-import org.bukkit.entity.Player;
-import sh.okx.rankup.Rankup;
-
-public abstract class Requirement implements Cloneable {
-  protected Rankup plugin;
-  @Getter
-  protected String name;
-  private String value;
-
-  public Requirement(Rankup plugin, String name) {
-    this.plugin = plugin;
-    this.name = name;
-  }
-
-  protected Requirement(Requirement clone) {
-    if (clone != null) {
-      this.plugin = clone.plugin;
-      this.name = clone.name;
-      this.value = clone.value;
-    }
-  }
-
-  public void setValue(String value) {
-    this.value = value;
-  }
-
-  public String getValueString() {
-    return value;
-  }
-
-  public double getValueDouble() {
-    return Double.parseDouble(value);
-  }
-
-  public int getValueInt() {
-    return Integer.parseInt(value);
-  }
-
-
-  /**
-   * Check if a player meets this requirement
-   *
-   * @param player the player to check
-   * @return true if they meet the requirement, false otherwise
-   */
-  public abstract boolean check(Player player);
-
-  /**
-   * Get the remaining amount needed for <code>Requirement#check(Player)</code> to yield true.
-   * This is not required and is only used in placeholders.
-   *
-   * @param player the player to find the remaining amount of
-   * @return the remaining amount needed. Should be non-negative.
-   */
-  public double getRemaining(Player player) {
-    return getValueDouble();
-  }
-
-  public abstract Requirement clone();
-}

src/main/java/sh/okx/rankup/ranks/requirements/RequirementRegistry.java

@@ -1,23 +0,0 @@
-package sh.okx.rankup.ranks.requirements;
-
-import java.util.HashSet;
-import java.util.Set;
-
-public class RequirementRegistry {
-  private Set<Requirement> requirements = new HashSet<>();
-
-  public void addRequirement(Requirement requirement) {
-    requirements.add(requirement);
-  }
-
-  public Requirement newRequirement(String name, String value) {
-    for (Requirement requirement : requirements) {
-      if (requirement.getName().equalsIgnoreCase(name)) {
-        Requirement newRequirement = requirement.clone();
-        newRequirement.setValue(value);
-        return newRequirement;
-      }
-    }
-    return null;
-  }
-}

src/main/java/sh/okx/rankup/ranks/requirements/XpLevelRequirement.java

@@ -1,34 +0,0 @@
-package sh.okx.rankup.ranks.requirements;
-
-import org.bukkit.entity.Player;
-import sh.okx.rankup.Rankup;
-
-public class XpLevelRequirement extends DeductibleRequirement {
-  public XpLevelRequirement(Rankup plugin, String name) {
-    super(plugin, name);
-  }
-
-  protected XpLevelRequirement(Requirement clone) {
-    super(clone);
-  }
-
-  @Override
-  public boolean check(Player player) {
-    return player.getLevel() >= getValueInt();
-  }
-
-  @Override
-  public void apply(Player player) {
-    player.setLevel(player.getLevel() - getValueInt());
-  }
-
-  @Override
-  public double getRemaining(Player player) {
-    return Math.max(0, getValueInt() - player.getLevel());
-  }
-
-  @Override
-  public Requirement clone() {
-    return new XpLevelRequirement(this);
-  }
-}