Tighten editor validation coverage

TASKS.md

@@ -4,7 +4,7 @@ This backlog tracks what must change so the implementation matches `docs/design.
 
 ## Audit Snapshot
 
-- Current simulation tests pass: `54/54` in `tests/ReactorMaintenance.Simulation.Tests`.
+- Current simulation tests pass: `55/55` in `tests/ReactorMaintenance.Simulation.Tests`.
 - Godot has a usable UX scaffold and grid renderer; the full pulse playback, terminal-gated layer controls, and campaign content pass remain in later tasks.
 - Existing campaign data is the older placeholder set. These levels and manifest entries must be replaced by the tutorial plus six-group campaign from `docs/CAMPAIGN.md`.
 - Unrelated Godot metadata or generated `.uid` files are not part of this backlog unless a later implementation task intentionally touches them.

src/ReactorMaintenance.Simulation/LevelEditor.cs

@@ -144,8 +144,8 @@ public static class LevelEditor
             EEditorTool.Junction => SetFloorProp(level, position, new() { Type = EPropType.Junction }),
             EEditorTool.Door => ToggleOrSetDoor(level, position),
             EEditorTool.AllSeeingEyeTerminal => SetFloorProp(level, position, new() { Type = EPropType.AllSeeingEyeTerminal }),
-            EEditorTool.SprinklerControl => SetFloorProp(level, position, new() { Type = EPropType.SprinklerControl, SwitchState = EPropSwitchState.Enabled }),
+            EEditorTool.SprinklerControl => SetSprinklerControl(level, position),
-            EEditorTool.SprinklerValve => SetWallProp(level, position, new() { Type = EPropType.SprinklerValve, Carrier = ECarrierType.Water, OutletPosition = position.Neighbors().FirstOrDefault(level.IsFloor) }),
+            EEditorTool.SprinklerValve => SetSprinklerValve(level, position),
             EEditorTool.RemedySupply => SetFloorProp(level, position, new() { Type = EPropType.RemedySupply, RemedyType = command.RemedyType }),
             EEditorTool.ReactorControl => SetReactorControl(level, position),
             EEditorTool.Leak => SetLeak(level, position, command.Carrier),
@@ -217,6 +217,32 @@ public static class LevelEditor
         return level.InBounds(position) && level.GetTerrain(position) == ECellTerrain.Wall ? level.SetProp(position, prop) : level;
     }
 
+    private static LevelState SetSprinklerControl(LevelState level, GridPosition position)
+    {
+        var linkedValve = LevelTraversal.AllPositions(level).FirstOrDefault(candidate => level.GetProp(candidate).Type == EPropType.SprinklerValve);
+        return SetFloorProp(level, position, new() {
+            Type = EPropType.SprinklerControl,
+            SwitchState = EPropSwitchState.Enabled,
+            LinkedPosition = level.InBounds(linkedValve) && level.GetProp(linkedValve).Type == EPropType.SprinklerValve ? linkedValve : null
+        });
+    }
+
+    private static LevelState SetSprinklerValve(LevelState level, GridPosition position)
+    {
+        var next = SetWallProp(level, position, new() {
+            Type = EPropType.SprinklerValve,
+            Carrier = ECarrierType.Water,
+            OutletPosition = position.Neighbors().FirstOrDefault(level.IsFloor)
+        });
+        if (next == level)
+            return level;
+
+        var unlinkedControl = LevelTraversal.AllPositions(next).FirstOrDefault(candidate => next.GetProp(candidate) is { Type: EPropType.SprinklerControl, LinkedPosition: null });
+        return next.InBounds(unlinkedControl) && next.GetProp(unlinkedControl).Type == EPropType.SprinklerControl
+            ? next.SetProp(unlinkedControl, next.GetProp(unlinkedControl) with { LinkedPosition = position })
+            : next;
+    }
+
     private static LevelState ToggleOrSetDoor(LevelState level, GridPosition position)
     {
         if (!level.IsFloor(position))

src/ReactorMaintenance.Simulation/LevelValidator.cs

@@ -35,8 +35,9 @@ public sealed class LevelValidator
                 continue;
             }
 
-            if (!level.GetUnderground(position, prop.Carrier).IsPresent)
+            var presentCarriers = Enum.GetValues<ECarrierType>().Count(carrier => level.GetUnderground(position, carrier).IsPresent);
-                errors.Add(new("Isolation valve must sit on its matching underground carrier.", position));
+            if (presentCarriers != 1 || !level.GetUnderground(position, prop.Carrier).IsPresent)
+                errors.Add(new("Isolation valve must sit on exactly one matching underground carrier.", position));
         }
     }
 
@@ -95,6 +96,9 @@ public sealed class LevelValidator
             var westEastWalls = IsWall(level, new(position.X - 1, position.Y)) && IsWall(level, new(position.X + 1, position.Y));
             if (northSouthWalls == westEastWalls)
                 errors.Add(new("Door must be surrounded by one opposing pair of wall cells.", position));
+
+            if (!level.GetUnderground(position, ECarrierType.Electricity).IsPresent)
+                errors.Add(new("Door must have a local electricity connection.", position));
         }
     }
 

tests/ReactorMaintenance.Simulation.Tests/LevelEditorTests.cs

@@ -92,6 +92,7 @@ public sealed class LevelEditorTests
 
         Assert.Equal(EPropType.SprinklerControl, valve.GetProp(new(1, 2)).Type);
         Assert.Equal(EPropType.SprinklerValve, valve.GetProp(new(2, 2)).Type);
+        Assert.Equal(new(2, 2), valve.GetProp(new(1, 2)).LinkedPosition);
         Assert.Equal(new(2, 1), valve.GetProp(new(2, 2)).OutletPosition);
     }
 

tests/ReactorMaintenance.Simulation.Tests/SimulationEngineTests.cs

@@ -403,6 +403,20 @@ public sealed class SimulationEngineTests
         Assert.Contains(report.Errors, error => error.Message.Contains("Wall cell", StringComparison.Ordinal));
     }
 
+    [Fact]
+    public void ValidatorRejectsIsolationValveOnMultipleCarriers()
+    {
+        var level = LevelState.Create("Invalid valve", 5, 5);
+        level = level.SetUnderground(new(2, 2), ECarrierType.Fuel, new() { State = EUndergroundState.Intact });
+        level = level.SetUnderground(new(2, 2), ECarrierType.Water, new() { State = EUndergroundState.Intact });
+        level = level.SetProp(new(2, 2), new() { Type = EPropType.IsolationValve, Carrier = ECarrierType.Fuel });
+
+        var report = new LevelValidator().Validate(level);
+
+        Assert.False(report.IsValid);
+        Assert.Contains(report.Errors, error => error.Message.Contains("exactly one matching underground carrier", StringComparison.Ordinal));
+    }
+
     [Fact]
     public void LevelSerializationRoundTripsCurrentSchemaOnly()
     {