Redo ip bans - reduce amount of db queries on login

Works by loading all ip bans on startup and querying the collection in memory
rather than making calls on every login.

src/main/java/server/ban/IpBanManager.java

@@ -0,0 +1,45 @@
+package server.ban;
+
+import database.ban.IpBan;
+import database.ban.IpBanRepository;
+import lombok.extern.slf4j.Slf4j;
+import net.jcip.annotations.ThreadSafe;
+
+import java.util.HashSet;
+import java.util.List;
+import java.util.Set;
+
+/**
+ * @author Ponk
+ */
+@ThreadSafe
+@Slf4j
+public class IpBanManager {
+    private final IpBanRepository ipBanRepository;
+    private final Set<String> bannedIps = new HashSet<>();
+
+    public IpBanManager(IpBanRepository ipBanRepository) {
+        this.ipBanRepository = ipBanRepository;
+    }
+
+    public synchronized void loadIpBans() {
+        List<IpBan> ipBans = ipBanRepository.getAllIpBans();
+        log.debug("Loaded {} ip bans", ipBans.size());
+        bannedIps.addAll(ipBans.stream().map(IpBan::ip).toList());
+    }
+
+    public synchronized boolean isBanned(String ip) {
+        return bannedIps.contains(ip);
+    }
+
+    public synchronized void banIp(String ip, int accountId) {
+        if (ip == null) {
+            throw new IllegalArgumentException("ip cannot be null");
+        }
+        // TODO: validate ip format. Or create "Ip" model class.
+
+        bannedIps.add(ip);
+        ipBanRepository.saveIpBan(accountId, ip);
+    }
+
+}