Let other plugins pause station countdowns

src/main/java/net/tfminecraft/vfbuilders/api/ConstructionFreeze.java

@@ -0,0 +1,17 @@
+package net.tfminecraft.vfbuilders.api;
+
+import java.util.UUID;
+
+/**
+ * Lets another plugin pause station countdowns. Register an implementation with
+ * Bukkit's ServicesManager. Each second, registrations are asked in turn for every
+ * station still counting down, stopping at the first one that returns a reason.
+ */
+public interface ConstructionFreeze {
+
+    /**
+     * @param constructorUuid player who started the project
+     * @return why the project is paused, shown under the station timer, or null to keep counting down
+     */
+    String freezeReason(UUID constructorUuid);
+}

src/main/java/net/tfminecraft/vfbuilders/api/ConstructionFreezes.java

@@ -0,0 +1,34 @@
+package net.tfminecraft.vfbuilders.api;
+
+import java.util.UUID;
+
+import org.bukkit.Bukkit;
+import org.bukkit.plugin.RegisteredServiceProvider;
+
+/** Asks every registered {@link ConstructionFreeze} whether a project should hold. */
+public final class ConstructionFreezes {
+
+    private ConstructionFreezes() {
+    }
+
+    /** @return the first freeze reason for this constructor, or null when nothing pauses it */
+    public static String reason(UUID constructorUuid) {
+        if (constructorUuid == null) {
+            return null;
+        }
+        for (RegisteredServiceProvider<ConstructionFreeze> registration
+                : Bukkit.getServicesManager().getRegistrations(ConstructionFreeze.class)) {
+            String reason;
+            try {
+                reason = registration.getProvider().freezeReason(constructorUuid);
+            } catch (RuntimeException e) {
+                // A broken provider must not stall every station on the server.
+                continue;
+            }
+            if (reason != null) {
+                return reason;
+            }
+        }
+        return null;
+    }
+}

src/main/java/net/tfminecraft/vfbuilders/core/ActiveStation.java

@@ -8,6 +8,7 @@
 import org.bukkit.Sound;
 import org.bukkit.entity.TextDisplay;
 
+import net.tfminecraft.vfbuilders.api.ConstructionFreezes;
 import net.tfminecraft.vfbuilders.display.StationTimerDisplay;
 import net.tfminecraft.vfbuilders.events.VehicleConstructEvent;
 import net.tfminecraft.vfbuilders.loaders.BlueprintLoader;
@@ -28,6 +29,7 @@ public class ActiveStation {
     private UUID constructorUuid;
 
     private TextDisplay timerDisplay;
+    private String freezeReason;
 
 
     public ActiveStation(Location loc, Station stored) {
@@ -72,6 +74,7 @@ public void selectBlueprint(Blueprint b, UUID constructorUuid) {
         blueprint = b;
         timeLeft = b.getTime();
         this.constructorUuid = constructorUuid;
+        freezeReason = null;
         ensureDisplay();
     }
 
@@ -81,6 +84,14 @@ public boolean tick() {
             return true;
         }
 
+        String reason = ConstructionFreezes.reason(constructorUuid);
+        if (reason != null) {
+            freezeReason = reason;
+            ensureDisplay();
+            return false;
+        }
+        freezeReason = null;
+
         timeLeft--;
         ensureDisplay();
 
@@ -138,6 +149,7 @@ public void cancelConstruction() {
         spawnLoc = null;
         blueprint = null;
         constructorUuid = null;
+        freezeReason = null;
         timeLeft = 0;
     }
 
@@ -220,7 +232,7 @@ public void ensureDisplay() {
         StationTimerDisplay.purgeAtStationBlock(loc);
         StationTimerDisplay.purgeLegacyArmorStands(loc);
 
-        String text = StationTimerDisplay.formatText(blueprint.getVehicle().getName(), timeLeft);
+        String text = StationTimerDisplay.formatText(blueprint.getVehicle().getName(), timeLeft, freezeReason);
         if (timerDisplay == null || timerDisplay.isDead()) {
             timerDisplay = StationTimerDisplay.spawn(loc.getWorld(), loc, text);
         } else {

src/main/java/net/tfminecraft/vfbuilders/display/StationTimerDisplay.java

@@ -44,9 +44,17 @@ public static Location displayAnchor(Location stationBlock) {
 	}
 
 	public static String formatText(String vehicleName, int timeLeftSeconds) {
+		return formatText(vehicleName, timeLeftSeconds, null);
+	}
+
+	public static String formatText(String vehicleName, int timeLeftSeconds, String freezeReason) {
 		String name = vehicleName == null ? "Vehicle" : vehicleName;
-		return "§eConstructing §6" + name
+		String text = "§eConstructing §6" + name
 				+ "\n§7Time: §f" + TimeFormatter.formatTime(timeLeftSeconds);
+		if (freezeReason != null) {
+			text += "\n§cPaused: §7" + freezeReason;
+		}
+		return text;
 	}
 
 	public static TextDisplay spawn(World world, Location stationBlock, String text) {