Add Godot level editing save path

TASKS.md

@@ -146,6 +146,10 @@ This backlog tracks what must change so the implementation matches `docs/design.
 - [x] Add test/build helpers for level construction.
   - Prefer shared builders for linear networks, forks, leaks, wall electricity faces, doors, controls, consumers, and reactors.
   - Avoid duplicating low-level array setup across tests.
+- [x] Add Godot level editing support.
+  - Expose editor tool, carrier, and remedy selection from the level screen.
+  - Apply `LevelEditor` commands to grid clicks in edit mode.
+  - Validate and save edited levels back through `LevelSerializer`.
 
 ## P1 Godot UX Integration
 

src/ReactorMaintenance.Godot/Data/GameSession.cs

@@ -10,9 +10,10 @@ public sealed class GameSession
     public event StateChangedHandler? LevelWon;
     public event StateChangedHandler? LevelLost;
 
-    public void Initialize(LevelState levelState)
+    public void Initialize(LevelState levelState, string levelPath)
     {
         LevelState = levelState;
+        LevelPath = levelPath;
         m_StartSnapshot = LevelSerializer.Deserialize(LevelSerializer.Serialize(levelState));
     }
 
@@ -82,6 +83,27 @@ public sealed class GameSession
         LevelStateChanged?.Invoke(this);
     }
 
+    public void ApplyEditorTool(GridPosition position, EditorToolCommand command)
+    {
+        LevelState = LevelEditor.Apply(LevelState, position, command);
+        LevelStateChanged?.Invoke(this);
+    }
+
+    public string ValidateForSave()
+    {
+        var report = m_Validator.Validate(LevelState);
+        if (!report.IsValid)
+            return report.Errors[0].Message;
+
+        return report.Warnings.Count > 0 ? report.Warnings[0].Message : "Level is valid.";
+    }
+
+    public void SaveLevel()
+    {
+        LevelStateLoader.Save(LevelPath, LevelState);
+        m_StartSnapshot = LevelSerializer.Deserialize(LevelSerializer.Serialize(LevelState));
+    }
+
     private void OnPulseAdvanced()
     {
         CheckOutcome();
@@ -101,6 +123,7 @@ public sealed class GameSession
     public GlobalState GlobalState => LevelState.Global;
     public IReadOnlyList<Forecast> Forecasts => LevelState.Forecasts;
     public IReadOnlyList<LeakState> Leaks => LevelState.Leaks;
+    public string LevelPath { get; private set; } = string.Empty;
     public IReadOnlyList<ReactorState> Reactors => LevelState.Reactors;
     public IReadOnlyList<PropState> Props => LevelState.Props;
     public ECellTerrain[] Terrain => LevelState.Terrain;
@@ -111,5 +134,6 @@ public sealed class GameSession
     public delegate void StateChangedHandler(GameSession sender);
 
     private readonly SimulationEngine m_Engine = new();
+    private readonly LevelValidator m_Validator = new();
     private LevelState m_StartSnapshot = null!;
 }

src/ReactorMaintenance.Godot/Data/LevelStateLoader.cs

@@ -31,4 +31,20 @@ public static class LevelStateLoader
                 $"Failed to deserialize level from {path}: {ex.Message}", ex);
         }
     }
+
+    public static void Save(string path, LevelState level)
+    {
+        if (string.IsNullOrWhiteSpace(path))
+            throw new ArgumentException("Level path must not be null or empty.", nameof(path));
+
+        var report = new LevelValidator().Validate(level);
+        if (!report.IsValid)
+            throw new InvalidOperationException(report.Errors[0].Message);
+
+        using var file = FileAccess.Open(path, FileAccess.ModeFlags.Write);
+        if (file is null)
+            throw new IOException($"Could not open level file for writing: {path}");
+
+        file.StoreString(LevelSerializer.Serialize(level));
+    }
 }

src/ReactorMaintenance.Godot/Screens/LevelScreen.cs

@@ -37,6 +37,7 @@ public partial class LevelScreen : ScreenBase
         m_GridViewport = CreateGridViewport();
         gridColumn.AddChild(m_GridViewport);
         gridColumn.AddChild(CreateLayerControls());
+        gridColumn.AddChild(CreateEditorControls());
         split.AddChild(gridColumn);
 
         m_Inspector = new();
@@ -137,7 +138,7 @@ public partial class LevelScreen : ScreenBase
 
     private void OnMoveAction()
     {
-        if (m_Session is null) return;
+        if (m_Session is null || m_EditMode) return;
 
         var current = m_Session.RobotPosition;
         var next = current with { X = current.X + 1 };
@@ -150,12 +151,13 @@ public partial class LevelScreen : ScreenBase
 
     private void OnInteractAction()
     {
+        if (!m_EditMode)
             m_Session?.InteractProp();
     }
 
     private void OnRepairAction()
     {
-        if (m_Session is null) return;
+        if (m_Session is null || m_EditMode) return;
 
         foreach (var leak in m_Session.Leaks)
         {
@@ -167,6 +169,65 @@ public partial class LevelScreen : ScreenBase
         }
     }
 
+    private Control CreateEditorControls()
+    {
+        var controls = new HBoxContainer();
+
+        var editToggle = new CheckBox {
+            Text = "Edit",
+            ButtonPressed = m_EditMode,
+            TooltipText = "Apply level editor tools on grid clicks"
+        };
+        editToggle.Toggled += pressed => {
+            m_EditMode = pressed;
+            SetEditorStatus(pressed ? CurrentValidationText() : "Play mode");
+        };
+        controls.AddChild(editToggle);
+
+        m_ToolSelect = new();
+        foreach (var tool in Enum.GetValues<EEditorTool>())
+            m_ToolSelect.AddItem(EditorToolLabel(tool), (int)tool);
+        m_ToolSelect.Select((int)EEditorTool.Cursor);
+        controls.AddChild(m_ToolSelect);
+
+        m_CarrierSelect = new();
+        foreach (var carrier in Enum.GetValues<ECarrierType>())
+            m_CarrierSelect.AddItem(carrier.ToString(), (int)carrier);
+        controls.AddChild(m_CarrierSelect);
+
+        m_RemedySelect = new();
+        foreach (var remedy in Enum.GetValues<ERemedyType>())
+            m_RemedySelect.AddItem(remedy.ToString(), (int)remedy);
+        controls.AddChild(m_RemedySelect);
+
+        controls.AddChild(CreateButton("Save JSON", SaveEditedLevel, "Validate and save this level JSON"));
+
+        m_EditorStatus = new() {
+            Text = "Play mode",
+            AutowrapMode = TextServer.AutowrapMode.WordSmart,
+            SizeFlagsHorizontal = SizeFlags.ExpandFill
+        };
+        controls.AddChild(m_EditorStatus);
+
+        return controls;
+    }
+
+    private void SaveEditedLevel()
+    {
+        if (m_Session is null)
+            return;
+
+        try
+        {
+            m_Session.SaveLevel();
+            SetEditorStatus($"Saved {m_Session.LevelPath}");
+        }
+        catch (Exception ex)
+        {
+            SetEditorStatus(ex.Message);
+        }
+    }
+
     private void UpdateUI()
     {
         if (m_Session is null || m_Inspector is null || m_ForecastList is null || m_InventoryStrip is null)
@@ -275,11 +336,64 @@ public partial class LevelScreen : ScreenBase
             return;
 
         var destination = new GridPosition(cell.X, cell.Y);
+        if (m_EditMode)
+        {
+            m_Session.ApplyEditorTool(destination, CurrentEditorCommand());
+            SetEditorStatus(CurrentValidationText());
+            return;
+        }
+
         if (m_Session.RobotPosition.ManhattanDistance(destination) == 1)
             m_Session.MoveRobot(destination);
     }
 
+    private EditorToolCommand CurrentEditorCommand()
+    {
+        return new() {
+            Tool = SelectedEnum(m_ToolSelect, EEditorTool.Cursor),
+            Carrier = SelectedEnum(m_CarrierSelect, ECarrierType.Fuel),
+            RemedyType = SelectedEnum(m_RemedySelect, ERemedyType.FuelNeutralizer)
+        };
+    }
+
+    private string CurrentValidationText()
+    {
+        return m_Session?.ValidateForSave() ?? "No level loaded.";
+    }
+
+    private void SetEditorStatus(string text)
+    {
+        if (m_EditorStatus is not null)
+            m_EditorStatus.Text = text;
+    }
+
+    private static TEnum SelectedEnum<TEnum>(OptionButton? select, TEnum fallback) where TEnum : struct, Enum
+    {
+        if (select is null)
+            return fallback;
+
+        var id = select.GetSelectedId();
+        return Enum.IsDefined(typeof(TEnum), id) ? (TEnum)Enum.ToObject(typeof(TEnum), id) : fallback;
+    }
+
+    private static string EditorToolLabel(EEditorTool tool)
+    {
+        return tool switch {
+            EEditorTool.AllSeeingEyeTerminal => "Eye Terminal",
+            EEditorTool.IsolationValve => "Isolation Valve",
+            EEditorTool.RemedySupply => "Remedy Supply",
+            EEditorTool.ReactorControl => "Reactor Control",
+            EEditorTool.SprinklerControl => "Sprinkler Control",
+            EEditorTool.SprinklerValve => "Sprinkler Valve",
+            EEditorTool.SurfaceHazard => "Surface Hazard",
+            _ => tool.ToString()
+        };
+    }
+
     private AppController? m_App;
+    private OptionButton? m_CarrierSelect;
+    private bool m_EditMode;
+    private Label? m_EditorStatus;
     private ForecastList? m_ForecastList;
     private GridViewport? m_GridViewport;
     private LevelHeader? m_Header;
@@ -290,5 +404,7 @@ public partial class LevelScreen : ScreenBase
     private int m_LevelNumber;
     private bool m_OutcomeVisible;
     private CanvasLayer? m_OverlayLayer;
+    private OptionButton? m_RemedySelect;
     private GameSession? m_Session;
+    private OptionButton? m_ToolSelect;
 }

src/ReactorMaintenance.Godot/Scripts/AppController.cs

@@ -50,7 +50,7 @@ public partial class AppController : Control
         var level = m_Session.CurrentLevel;
         var gameSession = new GameSession();
         var levelState = LevelStateLoader.Load(level.LevelPath);
-        gameSession.Initialize(levelState);
+        gameSession.Initialize(levelState, level.LevelPath);
         ShowScreen<LevelScreen>("res://Scenes/LevelScreen.tscn", screen => screen.Configure(this, gameSession, level, m_Session.LevelNumber, m_Session.LevelCount));
     }