Add plan_server_players_online and plan_network_players_online placeholders

Affects issues:
- Close #3693

Plan/common/src/main/java/com/djrapitops/plan/delivery/domain/DateObj.java

@@ -26,7 +26,7 @@ import java.util.Objects;
 public class DateObj<T> implements DateHolder {
 
     private final long date;
-    private final T value;
+    private T value;
 
     public DateObj(long date, T value) {
         this.date = date;
@@ -42,6 +42,10 @@ public class DateObj<T> implements DateHolder {
         return value;
     }
 
+    public void setValue(T value) {
+        this.value = value;
+    }
+
     @Override
     public boolean equals(Object o) {
         if (this == o) return true;

Plan/common/src/main/java/com/djrapitops/plan/delivery/domain/mutators/DateObjMutator.java

@@ -0,0 +1,39 @@
+/*
+ *  This file is part of Player Analytics (Plan).
+ *
+ *  Plan is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU Lesser General Public License v3 as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  Plan is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU Lesser General Public License for more details.
+ *
+ *  You should have received a copy of the GNU Lesser General Public License
+ *  along with Plan. If not, see <https://www.gnu.org/licenses/>.
+ */
+package com.djrapitops.plan.delivery.domain.mutators;
+
+import com.djrapitops.plan.delivery.domain.DateObj;
+import com.djrapitops.plan.utilities.comparators.DateHolderRecentComparator;
+
+import java.util.List;
+import java.util.Optional;
+
+/**
+ * @author AuroraLS3
+ */
+public class DateObjMutator<T> {
+
+    private final List<DateObj<T>> dateObjects;
+
+    public DateObjMutator(List<DateObj<T>> dateObjects) {this.dateObjects = dateObjects;}
+
+    public Optional<DateObj<T>> mostRecent() {
+        if (dateObjects.isEmpty()) return Optional.empty();
+        dateObjects.sort(new DateHolderRecentComparator());
+        return Optional.of(dateObjects.get(0));
+    }
+}

Plan/common/src/main/java/com/djrapitops/plan/placeholder/ServerPlaceHolders.java

@@ -17,6 +17,8 @@
 package com.djrapitops.plan.placeholder;
 
 import com.djrapitops.plan.commands.use.Arguments;
+import com.djrapitops.plan.delivery.domain.DateObj;
+import com.djrapitops.plan.delivery.domain.mutators.DateObjMutator;
 import com.djrapitops.plan.delivery.formatting.Formatter;
 import com.djrapitops.plan.delivery.formatting.Formatters;
 import com.djrapitops.plan.gathering.ServerUptimeCalculator;
@@ -84,6 +86,22 @@ public class ServerPlaceHolders implements Placeholders {
 
         Database database = dbSystem.getDatabase();
 
+        placeholders.registerStatic("network_players_online",
+                parameters -> {
+                    DateObj<Long> count = new DateObj<>(System.currentTimeMillis(), 0L);
+                    for (Server proxy : database.query(ServerQueries.fetchProxyServers())) {
+                        ServerUUID proxyUUID = proxy.getUuid();
+                        new DateObjMutator<>(database.query(TPSQueries.fetchPlayersOnlineOfServer(fiveMinAgo(), now(), proxyUUID)))
+                                .mostRecent()
+                                .ifPresent(playersOnline -> {
+                                    if (Math.abs(count.getDate() - playersOnline.getDate()) > TimeUnit.MINUTES.toMillis(2L)) {
+                                        count.setValue(count.getValue() + playersOnline.getValue());
+                                    }
+                                });
+                    }
+                    return count.getValue();
+                });
+
         placeholders.registerStatic("server_players_registered_total",
                 parameters -> database.query(PlayerCountQueries.newPlayerCount(0, now(), getServerUUID(parameters))));
 
@@ -132,6 +150,14 @@ public class ServerPlaceHolders implements Placeholders {
         placeholders.registerStatic("network_players_unique_month",
                 parameters -> database.query(PlayerCountQueries.uniquePlayerCount(monthAgo(), now())));
 
+        placeholders.registerStatic("server_players_online",
+                parameters -> new DateObjMutator<>(
+                        database.query(TPSQueries.fetchPlayersOnlineOfServer(fiveMinAgo(), now(), getServerUUID(parameters))))
+                        .mostRecent()
+                        .map(DateObj::getValue)
+                        .map(String::valueOf)
+                        .orElse("-"));
+
         placeholders.registerStatic("server_tps_day",
                 parameters -> decimals.apply(database.query(TPSQueries.averageTPS(dayAgo(), now(), getServerUUID(parameters)))));
 
@@ -270,7 +296,7 @@ public class ServerPlaceHolders implements Placeholders {
         );
     }
 
-    interface QueryCreator<T> {
+    public interface QueryCreator<T> {
         Query<Optional<TopListQueries.TopListEntry<T>>> apply(Integer number, Long timespan, @Untrusted Arguments parameters);
     }
 

Plan/common/src/main/java/com/djrapitops/plan/utilities/MiscUtils.java

@@ -48,6 +48,10 @@ public class MiscUtils {
         return System.currentTimeMillis();
     }
 
+    public static long fiveMinAgo() {
+        return now() - TimeUnit.MINUTES.toMillis(5L);
+    }
+
     public static long dayAgo() {
         return now() - TimeUnit.DAYS.toMillis(1L);
     }