add permission check event

src/main/java/com/flemmli97/flan/api/ClaimPermissionEvent.java

@@ -0,0 +1,34 @@
+package com.flemmli97.flan.api;
+
+import com.sun.istack.internal.Nullable;
+import net.fabricmc.fabric.api.event.Event;
+import net.fabricmc.fabric.api.event.EventFactory;
+import net.minecraft.server.network.ServerPlayerEntity;
+import net.minecraft.util.ActionResult;
+import net.minecraft.util.math.BlockPos;
+
+public interface ClaimPermissionEvent {
+
+    Event<ClaimPermissionEvent> CHECK = EventFactory.createArrayBacked(ClaimPermissionEvent.class,
+            (listeners) -> (player, permission, pos) -> {
+                for (ClaimPermissionEvent event : listeners) {
+                    ActionResult result = event.check(player, permission, pos);
+
+                    if (result != ActionResult.PASS) {
+                        return result;
+                    }
+                }
+
+                return ActionResult.PASS;
+            }
+    );
+
+    /**
+     * Callback for when permissions are checked
+     * @param player The corresponding player. Can be null if the check is e.g. caused by tnt explosions
+     * @param permission The permission to check
+     * @param pos The block pos where the action is occuring
+     * @return ActionResult#PASS to do nothing. ActionResult#FAIL to prevent the action. Else to allow the action
+     */
+    ActionResult check(@Nullable ServerPlayerEntity player, ClaimPermission permission, BlockPos pos);
+}

src/main/java/com/flemmli97/flan/claim/Claim.java

@@ -1,6 +1,7 @@
 package com.flemmli97.flan.claim;
 
 import com.flemmli97.flan.api.ClaimPermission;
+import com.flemmli97.flan.api.ClaimPermissionEvent;
 import com.flemmli97.flan.api.PermissionRegistry;
 import com.flemmli97.flan.config.ConfigHandler;
 import com.flemmli97.flan.player.PlayerClaimData;
@@ -17,6 +18,7 @@ import net.minecraft.server.network.ServerPlayerEntity;
 import net.minecraft.server.world.ServerWorld;
 import net.minecraft.text.LiteralText;
 import net.minecraft.text.Text;
+import net.minecraft.util.ActionResult;
 import net.minecraft.util.Formatting;
 import net.minecraft.util.math.BlockPos;
 
@@ -181,6 +183,9 @@ public class Claim implements IPermissionContainer {
     }
 
     public boolean canInteract(ServerPlayerEntity player, ClaimPermission perm, BlockPos pos, boolean message) {
+        ActionResult res = ClaimPermissionEvent.CHECK.invoker().check(player, perm, pos);
+        if (res != ActionResult.PASS)
+            return res != ActionResult.FAIL;
         if (perm != null) {
             ClaimPermission.PermissionFlag flag = perm.test.test(this, player, pos);
             if (flag != ClaimPermission.PermissionFlag.PASS) {