From 6c10fcdca96205573c4f24347a6a5919ca66280a Mon Sep 17 00:00:00 2001
From: BONNe1704 <bonne@bonne.id.lv>
Date: Thu, 9 May 2019 11:22:01 +0300
Subject: [PATCH] Fix NPE when opening ChallengesGUI (#116).

Add code that removes challenges level from all its challenges, if level is deleted.
Add protection code that shows admins that something is not correct if challenge level is not in database.
---
 .../bentobox/challenges/ChallengesManager.java    | 14 ++++++++++++++
 .../bentobox/challenges/panel/CommonGUI.java      | 15 +++++++++++++--
 .../bentobox/challenges/tasks/TryToComplete.java  |  7 ++++---
 src/main/resources/locales/en-US.yml              |  1 +
 4 files changed, 32 insertions(+), 5 deletions(-)

diff --git a/src/main/java/world/bentobox/challenges/ChallengesManager.java b/src/main/java/world/bentobox/challenges/ChallengesManager.java
index f27b6db..c15427f 100644
--- a/src/main/java/world/bentobox/challenges/ChallengesManager.java
+++ b/src/main/java/world/bentobox/challenges/ChallengesManager.java
@@ -1462,6 +1462,20 @@ public class ChallengesManager
         if (this.levelCacheData.containsKey(challengeLevel.getUniqueId()))
         {
             this.levelCacheData.remove(challengeLevel.getUniqueId());
+
+            // Remove challenge level from challenges object.
+            if (!challengeLevel.getChallenges().isEmpty())
+            {
+                challengeLevel.getChallenges().forEach(challengeID -> {
+                    Challenge challenge = this.getChallenge(challengeID);
+
+                    if (challenge != null)
+                    {
+                        challenge.setLevel(ChallengesManager.FREE);
+                    }
+                });
+            }
+
             this.levelDatabase.deleteObject(challengeLevel);
         }
     }
diff --git a/src/main/java/world/bentobox/challenges/panel/CommonGUI.java b/src/main/java/world/bentobox/challenges/panel/CommonGUI.java
index a061962..219a2be 100644
--- a/src/main/java/world/bentobox/challenges/panel/CommonGUI.java
+++ b/src/main/java/world/bentobox/challenges/panel/CommonGUI.java
@@ -298,8 +298,19 @@ public abstract class CommonGUI
 			{
 				case 'l':
 				{
-					result.add(this.user.getTranslation("challenges.gui.challenge-description.level",
-						"[level]", manager.getLevel(challenge).getFriendlyName()));
+					ChallengeLevel level = manager.getLevel(challenge);
+
+					if (level == null)
+					{
+						result.add(this.user.getTranslation("challenges.errors.missing-level",
+							"[level]", challenge.getLevel()));
+					}
+					else
+					{
+						result.add(this.user.getTranslation("challenges.gui.challenge-description.level",
+							"[level]", level.getFriendlyName()));
+					}
+
 					break;
 				}
 				case 's':
diff --git a/src/main/java/world/bentobox/challenges/tasks/TryToComplete.java b/src/main/java/world/bentobox/challenges/tasks/TryToComplete.java
index cf7e060..ca915a8 100644
--- a/src/main/java/world/bentobox/challenges/tasks/TryToComplete.java
+++ b/src/main/java/world/bentobox/challenges/tasks/TryToComplete.java
@@ -359,12 +359,13 @@ public class TryToComplete
         // Mark as complete
         this.manager.setChallengeComplete(this.user, this.world, this.challenge, result.getFactor());
 
-        // Check level completion.
-        if (!result.wasCompleted())
+        // Check level completion for non-free challenges
+        if (!result.wasCompleted() &&
+            !this.challenge.getLevel().equals(ChallengesManager.FREE))
         {
             ChallengeLevel level = this.manager.getLevel(this.challenge);
 
-            if (!this.manager.isLevelCompleted(this.user, this.world, level))
+            if (level != null && !this.manager.isLevelCompleted(this.user, this.world, level))
             {
                 if (this.manager.validateLevelCompletion(this.user, this.world, level))
                 {
diff --git a/src/main/resources/locales/en-US.yml b/src/main/resources/locales/en-US.yml
index 22706b0..7b3dc26 100755
--- a/src/main/resources/locales/en-US.yml
+++ b/src/main/resources/locales/en-US.yml
@@ -364,6 +364,7 @@ challenges:
         defaults-file-exist: '&cdefault.json already exists. Use overwrite mode to replace it!'
         defaults-file-error: '&cThere was an error while creating default.json file! Check console!'
         no-challenges: '&cChallenges are not implemented in current world!'
+        missing-level: '&cChallenge Level [level] is not defined in database. It may case some errors!'
 protection:
     flags:
         CHALLENGES_ISLAND_PROTECTION: