More AI fixes/improvements:

- AI characters can refuel the reactor when needed.
- AIObjectiveContainItem.CanBeCompleted returns true if the target item cannot be obtained or if the container cannot be reached.
- AI characters only weld leaks that are part of some submarine (i.e. not ruins).

Barotrauma/BarotraumaClient/Source/Characters/AI/CrewCommander.cs

@@ -250,7 +250,7 @@ namespace Barotrauma
             var existingOrder = characterFrame.children.Find(c => c.UserData is Order);
             if (existingOrder != null) characterFrame.RemoveChild(existingOrder);
             
-            var orderFrame = new GUIFrame(new Rectangle(-5, characterFrame.Rect.Height, characterFrame.Rect.Width, 30 + order.Options.Length * 15), "InnerFrame", characterFrame);
+            var orderFrame = new GUIFrame(new Rectangle(-5, 40, characterFrame.Rect.Width, 30 + order.Options.Length * 15), "InnerFrame", characterFrame);
             /*orderFrame.OutlineColor = Color.LightGray * 0.5f;*/
             orderFrame.Padding = new Vector4(5.0f, 5.0f, 5.0f, 5.0f);
             orderFrame.UserData = order;

Barotrauma/BarotraumaShared/Content/Items/Reactor/reactor.xml

@@ -23,6 +23,7 @@
 
     <Reactor canbeselected = "true">
       <GuiFrame rect="0,0,760,460" alignment="Center" style="ItemUI"/>
+      <RequiredSkill name="Construction" level="30"/>
       <StatusEffect type="InWater" target="This" Temperature="-500.0"/>
       <StatusEffect type="OnActive" target="Contained" targetnames="Fuel Rod, Heat Absorber, Temperature Control Circuit" Condition="-0.1" />
       <sound file="reactor.ogg" type="OnActive" range="2000.0" volume="FissionRate" volumemultiplier="0.02" loop="true"/>
@@ -55,8 +56,7 @@
 
   <Item
     name="Fuel Rod"
-    Tags="smallitem"
+    Tags="smallitem,reactorfuel"    
-    
     price="200">
 
     <Deconstruct time="10">
@@ -73,8 +73,7 @@
 
   <Item
     name="Incendium Fuel Rod"
-    Tags="smallitem"
+    Tags="smallitem,reactorfuel"    
-    
     spritecolor="0.5,0.0,0.0,1.0">
 
     <Deconstruct time="10">

Barotrauma/BarotraumaShared/Source/Characters/AI/Objectives/AIObjectiveContainItem.cs

@@ -1,19 +1,27 @@
 using Barotrauma.Items.Components;
 using Microsoft.Xna.Framework;
+using System;
 using System.Linq;
 
 namespace Barotrauma
 {
     class AIObjectiveContainItem: AIObjective
     {
+        public int MinContainedAmount = 1;
+
         private string[] itemNames;
 
         private ItemContainer container;
-        
+
-        bool isCompleted;
+        private bool isCompleted;
 
         public bool IgnoreAlreadyContainedItems;
 
+        public Func<Item, float> GetItemPriority;
+
+        private AIObjectiveGetItem getItemObjective;
+        private AIObjectiveGoTo goToObjective;
+
         public AIObjectiveContainItem(Character character, string itemName, ItemContainer container)
             : this(character, new string[] { itemName }, container)
         {
@@ -28,7 +36,28 @@ namespace Barotrauma
 
         public override bool IsCompleted()
         {
-            return isCompleted || itemNames.Any(name => container.Inventory.FindItem(name) != null);
+            if (isCompleted) return true;
+
+            int containedItemCount = 0;
+            foreach (Item item in container.Inventory.Items)
+            {
+                if (item != null && itemNames.Any(name => item.Prefab.NameMatches(name) || item.HasTag(name))) containedItemCount++;
+            }
+
+            return containedItemCount >= MinContainedAmount;
+        }
+
+        public override bool CanBeCompleted
+        {
+            get
+            {
+                if (goToObjective != null)
+                {
+                    return goToObjective.CanBeCompleted;
+                }
+
+                return getItemObjective == null || !getItemObjective.CanBeCompleted;
+            }
         }
 
         public override float GetPriority(AIObjectiveManager objectiveManager)
@@ -49,9 +78,10 @@ namespace Barotrauma
             var itemToContain = character.Inventory.FindItem(itemNames);
             if (itemToContain == null)
             {
-                var getItem = new AIObjectiveGetItem(character, itemNames);
+                getItemObjective = new AIObjectiveGetItem(character, itemNames);
-                getItem.IgnoreContainedItems = IgnoreAlreadyContainedItems;
+                getItemObjective.GetItemPriority = GetItemPriority;
-                AddSubObjective(getItem);
+                getItemObjective.IgnoreContainedItems = IgnoreAlreadyContainedItems;
+                AddSubObjective(getItemObjective);
                 return;
             }
 
@@ -68,9 +98,10 @@ namespace Barotrauma
             else
             {
                 if (Vector2.Distance(character.Position, container.Item.Position) > container.Item.InteractDistance
-                    && !container.Item.IsInsideTrigger(character.Position))
+                    && !container.Item.IsInsideTrigger(character.WorldPosition))
                 {
-                    AddSubObjective(new AIObjectiveGoTo(container.Item, character));
+                    goToObjective = new AIObjectiveGoTo(container.Item, character);
+                    AddSubObjective(goToObjective);
                     return;
                 }
 

Barotrauma/BarotraumaShared/Source/Characters/AI/Objectives/AIObjectiveFixLeaks.cs

@@ -106,6 +106,9 @@ namespace Barotrauma
                 if (gap.ConnectedWall == null) continue;
                 if (gap.ConnectedDoor != null || gap.Open <= 0.0f) continue;
 
+                //TODO: prevent the AI characters from fixing leaks in the enemy sub in sub-vs-sub missions if/when multiplayer bots are implemented
+                if (gap.Submarine == null) continue;
+
                 float gapPriority = GetGapFixPriority(gap);
 
                 int index = 0;

Barotrauma/BarotraumaShared/Source/Characters/AI/Objectives/AIObjectiveGetItem.cs

@@ -1,5 +1,6 @@
 using Barotrauma.Items.Components;
 using Microsoft.Xna.Framework;
+using System;
 using System.Collections.Generic;
 using System.Linq;
 
@@ -7,6 +8,8 @@ namespace Barotrauma
 {
     class AIObjectiveGetItem : AIObjective
     {
+        public Func<Item, float> GetItemPriority;
+
         private string[] itemNames;
 
         private Item targetItem, moveToTarget;
@@ -19,6 +22,8 @@ namespace Barotrauma
 
         private AIObjectiveGoTo goToObjective;
 
+        private float currItemPriority;
+
         private bool equip;
 
         public override bool CanBeCompleted
@@ -172,8 +177,20 @@ namespace Barotrauma
                     if (owner != null && !owner.IsDead) continue;
                 }
 
-                //ignore if item is further away than the currently targeted item
+                float itemPriority = 0.0f;
-                if (moveToTarget != null && Vector2.DistanceSquared((rootContainer ?? item).Position, character.Position) > currDist) continue;
+                if (GetItemPriority != null)
+                {
+                    //ignore if the item has zero priority
+                    itemPriority = GetItemPriority(item);
+                    if (itemPriority <= 0.0f) continue;
+                }
+
+                itemPriority = itemPriority - Vector2.Distance((rootContainer ?? item).Position, character.Position) * 0.01f;
+
+                //ignore if the item has a lower priority than the currently selected one
+                if (moveToTarget != null && itemPriority < currItemPriority) continue;
+
+                currItemPriority = itemPriority;
 
                 targetItem = item;
                 moveToTarget = rootContainer ?? item;

Barotrauma/BarotraumaShared/Source/Items/Components/ItemComponent.cs

@@ -399,7 +399,7 @@ namespace Barotrauma.Items.Components
 
             float[] skillSuccess = new float[requiredSkills.Count];
 
-            for (int i = 0; i < requiredSkills.Count; i++ )
+            for (int i = 0; i < requiredSkills.Count; i++)
             {
                 int characterLevel = character.GetSkillLevel(requiredSkills[i].Name);
 
@@ -408,7 +408,7 @@ namespace Barotrauma.Items.Components
 
             float average = skillSuccess.Average();
 
-            return (average+100.0f)/2.0f;        
+            return (average + 100.0f) / 2.0f;
         }
 
         public virtual void FlipX() { }

Barotrauma/BarotraumaShared/Source/Items/Components/Machines/Reactor.cs

@@ -3,6 +3,7 @@ using Lidgren.Network;
 using Microsoft.Xna.Framework;
 using System;
 using System.Collections.Generic;
+using System.Linq;
 using System.Xml.Linq;
 
 namespace Barotrauma.Items.Components
@@ -141,6 +142,9 @@ namespace Barotrauma.Items.Components
 
         public float AvailableFuel { get; set; }
 
+        private float availableHeat, availableCooling;
+        private float prevTemperature, temperatureChange;
+
         [Serialize(500.0f, true)]
         public float ShutDownTemp
         {
@@ -191,12 +195,20 @@ namespace Barotrauma.Items.Components
 
             fissionRate = Math.Min(fissionRate, AvailableFuel);
 
-            float heat = 80 * fissionRate * (AvailableFuel / 2000.0f);
+            //the amount of cooling is always non-zero, so that the reactor always needs 
-            float heatDissipation = 50 * coolingRate + Math.Max(ExtraCooling, 5.0f);
+            //to generate some amount of heat to prevent the temperature from dropping
+            availableCooling = Math.Max(ExtraCooling, 5.0f);
+            availableHeat = 80 * (AvailableFuel / 2000.0f);
 
-            float deltaTemp = (((heat - heatDissipation) * 5) - temperature) / 10000.0f;
+            float heat = availableHeat * fissionRate;
+            float heatDissipation = 50 * coolingRate + availableCooling;
+
+            float deltaTemp = (((heat - heatDissipation) * 5) - temperature) / 10000.0f;            
             Temperature = temperature + deltaTemp;
 
+            temperatureChange = Temperature - prevTemperature;
+            prevTemperature = temperature;
+
             if (temperature > fireTemp && temperature - deltaTemp < fireTemp)
             {
 #if CLIENT
@@ -345,37 +357,71 @@ namespace Barotrauma.Items.Components
 
         public override bool AIOperate(float deltaTime, Character character, AIObjectiveOperateItem objective)
         {
+            float degreeOfSuccess = DegreeOfSuccess(character);
+
+            //characters with insufficient skill levels don't refuel the reactor
+            if (degreeOfSuccess > 0.2f)
+            {
+                //remove used-up fuel from the reactor
+                var containedItems = item.ContainedItems;
+                foreach (Item item in containedItems)
+                {
+                    if (item != null && item.Condition <= 0.0f)
+                    {
+                        item.Drop();
+                    }
+                }
+
+                //the temperature is too low and not increasing even though the fission rate is high and cooling low
+                // -> we need more fuel
+                if (temperature < load * 0.5f && temperatureChange <= 0.0f && fissionRate > 0.9f && coolingRate < 0.1f)
+                {
+                    var containFuelObjective = new AIObjectiveContainItem(character, new string[] { "Fuel Rod", "reactorfuel" }, item.GetComponent<ItemContainer>());
+                    containFuelObjective.MinContainedAmount = containedItems.Count(i => i != null && i.Prefab.NameMatches("Fuel Rod") || i.HasTag("reactorfuel")) + 1;
+                    containFuelObjective.GetItemPriority = (Item fuelItem) =>
+                    {
+                        if (fuelItem.ParentInventory?.Owner is Item)
+                        {
+                            //don't take fuel from other reactors
+                            if (((Item)fuelItem.ParentInventory.Owner).GetComponent<Reactor>() != null) return 0.0f;
+                        }
+                        return 1.0f;
+                    };
+                    objective.AddSubObjective(containFuelObjective);
+
+                    return false;
+                }
+            }
+
+
             switch (objective.Option.ToLowerInvariant())
-             {
+            {
-                 case "power up":
+                case "power up":
-                     float tempDiff = load - temperature;
+                    float tempDiff = load - temperature;
 
-                     shutDownTemp = Math.Min(load + 1000.0f, 7500.0f);
+                    shutDownTemp = Math.Min(load + 1000.0f, 7500.0f);
 
-                     //temperature too high/low
+                    //characters with insufficient skill levels simply set the autotemp on instead of trying to adjust the temperature manually
-                     if (Math.Abs(tempDiff)>500.0f)
+                    if (Math.Abs(tempDiff) < 500.0f || degreeOfSuccess < 0.5f)
-                     {
+                    {
-                         AutoTemp = false;
+                        AutoTemp = true;
-                         FissionRate += deltaTime * 100.0f * Math.Sign(tempDiff);
+                    }
-                         CoolingRate -= deltaTime * 100.0f * Math.Sign(tempDiff);
+                    else
-                     }
+                    {
-                     //temperature OK
+                        AutoTemp = false;
-                     else
+                        //higher skill levels make the character adjust the temperature faster
-                     {
+                        FissionRate += deltaTime * 100.0f * Math.Sign(tempDiff) * degreeOfSuccess;
-                         AutoTemp = true;
+                        CoolingRate -= deltaTime * 100.0f * Math.Sign(tempDiff) * degreeOfSuccess;
-                     }
+                    }                    
+                    break;
+                case "shutdown":
+                    shutDownTemp = 0.0f;
+                    break;
+            }
 
-                     break;
+            return false;
-                 case "shutdown":
-
-                     shutDownTemp = 0.0f;
-
-                     break;
-             }
-
-             return false;
         }
-        
+
         public override void ReceiveSignal(int stepsTaken, string signal, Connection connection, Item source, Character sender, float power)
         {
             switch (connection.Name)