Add QuickSave/QuickLoad with full state restore and visual rebuild

BoardState.CaptureSave/RestoreFromSave deep-copy every mutable field
(grid, pieces, demands, transformers, buffers, stock, campaign progress)
into a WorldSave slot. GameSim.QuickSave/QuickLoad expose slotted saves
and emit StateSavedEvent / StateRestoredEvent — the latter carries a
fresh BoardSnapshot so the presentation can rebuild board, pieces,
trajectories, objectives, stock, camera, and control bar in one pass.

F5/F9 trigger it in Main; harness gains quick_save/quick_load commands so
UI tests can checkpoint a scenario and resume without replaying from
scratch. Seven xUnit tests cover the roundtrip (including independence
from post-save mutations, campaign state, and multi-slot isolation).

Scripts/Automation/AutomationFacade.cs

@@ -27,6 +27,8 @@ internal class AutomationFacade
     public Action BackToMenu { get; }
     public Action<float> SetSpeed { get; }
     public Action Quit { get; }
+    public Action QuickSave { get; }
+    public Action QuickLoad { get; }
 
     public AutomationFacade(
         Func<GameSim?> sim,
@@ -41,7 +43,9 @@ internal class AutomationFacade
         Action togglePlayPause,
         Action backToMenu,
         Action<float> setSpeed,
-        Action quit)
+        Action quit,
+        Action quickSave,
+        Action quickLoad)
     {
         Sim = sim;
         Input = input;
@@ -56,5 +60,7 @@ internal class AutomationFacade
         BackToMenu = backToMenu;
         SetSpeed = setSpeed;
         Quit = quit;
+        QuickSave = quickSave;
+        QuickLoad = quickLoad;
     }
 }

Scripts/Automation/CommandDispatcher.cs

@@ -41,6 +41,8 @@ internal class CommandDispatcher
             "set_speed" => SetSpeed(args),
             "load_mission" => LoadMission(args),
             "back_to_menu" => BackToMenu(),
+            "quick_save" => QuickSave(),
+            "quick_load" => QuickLoad(),
             "quit" => Quit(),
             _ => throw new InvalidOperationException($"Unknown command: {cmd}"),
         };
@@ -221,6 +223,32 @@ internal class CommandDispatcher
         return new JsonObject();
     }
 
+    private JsonNode? QuickSave()
+    {
+        _facade.QuickSave();
+        var sim = _facade.Sim();
+        return new JsonObject
+        {
+            ["saved"] = sim != null,
+            ["turn"] = sim?.GetSnapshot().TurnNumber
+        };
+    }
+
+    private JsonNode? QuickLoad()
+    {
+        _facade.QuickLoad();
+        var sim = _facade.Sim();
+        if (sim == null) return new JsonObject { ["loaded"] = false };
+        var snap = sim.GetSnapshot();
+        return new JsonObject
+        {
+            ["loaded"] = true,
+            ["turn"] = snap.TurnNumber,
+            ["phase"] = snap.Phase.ToString(),
+            ["missionIndex"] = snap.Campaign?.CurrentMissionIndex
+        };
+    }
+
     private JsonNode? Quit()
     {
         // Defer so we can write the result first.

Scripts/Main.cs

@@ -107,7 +107,9 @@ public partial class Main : Node2D
 			togglePlayPause: TogglePlayPause,
 			backToMenu: HarnessBackToMenu,
 			setSpeed: HarnessSetSpeed,
-			quit: () => GetTree().Quit());
+			quit: () => GetTree().Quit(),
+			quickSave: OnQuickSave,
+			quickLoad: OnQuickLoad);
 
 		_automationHarness = new AutomationHarness(dir, facade);
 		AddChild(_automationHarness);
@@ -181,10 +183,23 @@ public partial class Main : Node2D
 			_rightDragged = true;
 			_camera.Position -= motion.Relative / _camera.Zoom;
 		}
-		else if (@event is InputEventKey key && key.Pressed && !key.Echo && key.Keycode == Key.Space)
+		else if (@event is InputEventKey key && key.Pressed && !key.Echo)
 		{
-			TogglePlayPause();
-			GetViewport().SetInputAsHandled();
+			if (key.Keycode == Key.Space)
+			{
+				TogglePlayPause();
+				GetViewport().SetInputAsHandled();
+			}
+			else if (key.Keycode == Key.F5)
+			{
+				OnQuickSave();
+				GetViewport().SetInputAsHandled();
+			}
+			else if (key.Keycode == Key.F9)
+			{
+				OnQuickLoad();
+				GetViewport().SetInputAsHandled();
+			}
 		}
 	}
 
@@ -767,6 +782,56 @@ public partial class Main : Node2D
 		);
 	}
 
+	private void OnQuickSave()
+	{
+		if (_sim == null) return;
+		var events = _sim.QuickSave();
+		foreach (var evt in events)
+		{
+			if (evt is StateSavedEvent saved)
+				GD.Print($"[QuickSave] Slot {saved.SlotId} — turn {saved.TurnNumber}");
+		}
+	}
+
+	private void OnQuickLoad()
+	{
+		if (_sim == null || _campaignDef == null) return;
+		if (!_sim.HasSave())
+		{
+			GD.Print("[QuickLoad] No save available");
+			return;
+		}
+
+		// Halt any running simulation loop before rebuilding visuals
+		_running = false;
+		_simTimer.Stop();
+
+		var events = _sim.QuickLoad();
+		foreach (var evt in events)
+		{
+			if (evt is StateRestoredEvent restored)
+			{
+				GD.Print($"[QuickLoad] Slot {restored.SlotId} — turn {restored.Snapshot.TurnNumber}");
+				ApplyRestoredSnapshot(restored.Snapshot);
+			}
+		}
+	}
+
+	private void ApplyRestoredSnapshot(BoardSnapshot snap)
+	{
+		if (_campaignDef == null) return;
+
+		var mission = _campaignDef.Missions[snap.Campaign!.CurrentMissionIndex];
+
+		BuildBoardFromSnapshot(snap);
+		SetupUIForMission(snap, mission);
+
+		CenterCameraOnBoard(snap.Width, snap.Height);
+		_inputMapper.SetSnapshot(snap);
+		_controlBar.UpdateTurn(snap.TurnNumber);
+		_controlBar.UpdateForPhase(snap.Phase);
+	}
+
 	private void OnMissionAdvanced()
 	{
 		// Auto-advance happened during simulation — rebuild board seamlessly

chessistics-engine/Events/WorldEvents.cs

@@ -33,3 +33,7 @@ public record TurnEndedEvent(int TurnNumber) : IWorldEvent;
 
 // Drag & drop
 public record PieceMovedByPlayerEvent(int PieceId, Coords OldStart, Coords OldEnd, Coords NewStart, Coords NewEnd) : IWorldEvent;
+
+// QuickSave/QuickLoad — presentation must rebuild all visuals from Snapshot on Restored.
+public record StateSavedEvent(int TurnNumber, int? SlotId) : IWorldEvent;
+public record StateRestoredEvent(BoardSnapshot Snapshot, int? SlotId) : IWorldEvent;

chessistics-engine/Model/BoardState.cs

@@ -222,6 +222,100 @@ public class BoardState
         }
     }
 
+    /// <summary>
+    /// Capture a deep copy of every mutable field (for QuickSave).
+    /// Immutable defs and CampaignDef are shared by reference.
+    /// </summary>
+    public WorldSave CaptureSave()
+    {
+        var grid = new CellType[Width, Height];
+        Array.Copy(Grid, grid, Grid.Length);
+
+        return new WorldSave
+        {
+            Width = Width,
+            Height = Height,
+            Grid = grid,
+            Phase = Phase,
+            TurnNumber = TurnNumber,
+            NextPieceId = NextPieceId,
+            Productions = new Dictionary<Coords, ProductionDef>(Productions),
+            ProductionBuffers = new Dictionary<Coords, int>(ProductionBuffers),
+            Demands = Demands.ToDictionary(kv => kv.Key, kv => kv.Value.Clone()),
+            Transformers = new Dictionary<Coords, TransformerDef>(Transformers),
+            TransformerInputBuffers = new Dictionary<Coords, int>(TransformerInputBuffers),
+            TransformerOutputBuffers = new Dictionary<Coords, int>(TransformerOutputBuffers),
+            Pieces = Pieces.Select(p => p.Clone()).ToList(),
+            DestroyedPieces = DestroyedPieces.Select(p => p.Clone()).ToList(),
+            RemainingStock = new Dictionary<PieceKind, int>(RemainingStock),
+            OccupiedCells = new HashSet<Coords>(OccupiedCells),
+            Campaign = Campaign == null ? null : new CampaignSaveData
+            {
+                CurrentMissionIndex = Campaign.CurrentMissionIndex,
+                CompletedMissions = new List<int>(Campaign.CompletedMissions),
+                AvailablePieceKinds = new HashSet<PieceKind>(Campaign.AvailablePieceKinds),
+                AvailableLevels = new HashSet<PieceUpgrade>(Campaign.AvailableLevels)
+            }
+        };
+    }
+
+    /// <summary>
+    /// Restore every mutable field from a save. Board dimensions can grow
+    /// or shrink; the grid is fully replaced.
+    /// </summary>
+    public void RestoreFromSave(WorldSave save)
+    {
+        Width = save.Width;
+        Height = save.Height;
+        Grid = new CellType[Width, Height];
+        Array.Copy(save.Grid, Grid, save.Grid.Length);
+
+        Phase = save.Phase;
+        TurnNumber = save.TurnNumber;
+        NextPieceId = save.NextPieceId;
+
+        Productions.Clear();
+        foreach (var kv in save.Productions) Productions[kv.Key] = kv.Value;
+
+        ProductionBuffers.Clear();
+        foreach (var kv in save.ProductionBuffers) ProductionBuffers[kv.Key] = kv.Value;
+
+        Demands.Clear();
+        foreach (var kv in save.Demands) Demands[kv.Key] = kv.Value.Clone();
+
+        Transformers.Clear();
+        foreach (var kv in save.Transformers) Transformers[kv.Key] = kv.Value;
+
+        TransformerInputBuffers.Clear();
+        foreach (var kv in save.TransformerInputBuffers) TransformerInputBuffers[kv.Key] = kv.Value;
+
+        TransformerOutputBuffers.Clear();
+        foreach (var kv in save.TransformerOutputBuffers) TransformerOutputBuffers[kv.Key] = kv.Value;
+
+        Pieces.Clear();
+        foreach (var p in save.Pieces) Pieces.Add(p.Clone());
+
+        DestroyedPieces.Clear();
+        foreach (var p in save.DestroyedPieces) DestroyedPieces.Add(p.Clone());
+
+        RemainingStock.Clear();
+        foreach (var kv in save.RemainingStock) RemainingStock[kv.Key] = kv.Value;
+
+        OccupiedCells.Clear();
+        foreach (var c in save.OccupiedCells) OccupiedCells.Add(c);
+
+        if (save.Campaign != null && Campaign != null)
+        {
+            Campaign.CurrentMissionIndex = save.Campaign.CurrentMissionIndex;
+            Campaign.CompletedMissions.Clear();
+            Campaign.CompletedMissions.AddRange(save.Campaign.CompletedMissions);
+            Campaign.AvailablePieceKinds.Clear();
+            foreach (var k in save.Campaign.AvailablePieceKinds) Campaign.AvailablePieceKinds.Add(k);
+            Campaign.AvailableLevels.Clear();
+            foreach (var u in save.Campaign.AvailableLevels) Campaign.AvailableLevels.Add(u);
+        }
+    }
+
     private void ClearBuildingAt(Coords coords)
     {
         Productions.Remove(coords);

chessistics-engine/Model/DemandState.cs

@@ -19,4 +19,9 @@ public class DemandState
     public CargoType Cargo => Definition.Cargo;
     public int Required => Definition.Amount;
     public int Deadline => Definition.Deadline;
+
+    public DemandState Clone()
+    {
+        return new DemandState(Definition, MissionIndex) { ReceivedCount = ReceivedCount };
+    }
 }

chessistics-engine/Model/PieceState.cs

@@ -40,4 +40,15 @@ public class PieceState
         EndCell = newEnd;
         CurrentCell = newStart;
     }
+
+    public PieceState Clone()
+    {
+        var clone = new PieceState(Id, Kind, StartCell, EndCell, PlacementOrder, Level)
+        {
+            CurrentCell = CurrentCell,
+            Cargo = Cargo,
+            CargoFilter = CargoFilter
+        };
+        return clone;
+    }
 }

chessistics-engine/Model/WorldSave.cs

@@ -0,0 +1,40 @@
+namespace Chessistics.Engine.Model;
+
+/// <summary>
+/// Deep copy of every mutable field needed to restore a BoardState to an
+/// earlier point. Used by QuickSave/QuickLoad for rapid iteration during
+/// UI/UX testing and by the harness to restore checkpoints.
+///
+/// Immutable refs (defs, CampaignDef) are shared; mutable state (Pieces,
+/// DemandState, buffers, stock, campaign progression) is copied by value.
+/// </summary>
+public sealed class WorldSave
+{
+    public int Width { get; init; }
+    public int Height { get; init; }
+    public CellType[,] Grid { get; init; } = new CellType[0, 0];
+    public SimPhase Phase { get; init; }
+    public int TurnNumber { get; init; }
+    public int NextPieceId { get; init; }
+
+    public Dictionary<Coords, ProductionDef> Productions { get; init; } = new();
+    public Dictionary<Coords, int> ProductionBuffers { get; init; } = new();
+    public Dictionary<Coords, DemandState> Demands { get; init; } = new();
+    public Dictionary<Coords, TransformerDef> Transformers { get; init; } = new();
+    public Dictionary<Coords, int> TransformerInputBuffers { get; init; } = new();
+    public Dictionary<Coords, int> TransformerOutputBuffers { get; init; } = new();
+    public List<PieceState> Pieces { get; init; } = new();
+    public List<PieceState> DestroyedPieces { get; init; } = new();
+    public Dictionary<PieceKind, int> RemainingStock { get; init; } = new();
+    public HashSet<Coords> OccupiedCells { get; init; } = new();
+
+    public CampaignSaveData? Campaign { get; init; }
+}
+
+public sealed class CampaignSaveData
+{
+    public int CurrentMissionIndex { get; init; }
+    public List<int> CompletedMissions { get; init; } = new();
+    public HashSet<PieceKind> AvailablePieceKinds { get; init; } = new();
+    public HashSet<PieceUpgrade> AvailableLevels { get; init; } = new();
+}

chessistics-engine/Simulation/GameSim.cs

@@ -7,6 +7,8 @@ namespace Chessistics.Engine.Simulation;
 public class GameSim
 {
     private readonly BoardState _state;
+    private readonly Dictionary<int, WorldSave> _saveSlots = new();
+    private const int DefaultSlot = 0;
 
     public GameSim(LevelDef level)
     {
@@ -33,4 +35,30 @@ public class GameSim
     }
 
     public BoardSnapshot GetSnapshot() => new(_state);
+
+    /// <summary>
+    /// Capture a full deep-copy of the world into an in-memory slot.
+    /// Returns a single StateSavedEvent — no state mutation.
+    /// </summary>
+    public IReadOnlyList<IWorldEvent> QuickSave(int slot = DefaultSlot)
+    {
+        _saveSlots[slot] = _state.CaptureSave();
+        return [new StateSavedEvent(_state.TurnNumber, slot)];
+    }
+
+    /// <summary>
+    /// Restore the world from a saved slot. Emits StateRestoredEvent with a
+    /// fresh snapshot — the presentation layer must rebuild all visuals.
+    /// Returns an empty list (no event) if the slot is empty.
+    /// </summary>
+    public IReadOnlyList<IWorldEvent> QuickLoad(int slot = DefaultSlot)
+    {
+        if (!_saveSlots.TryGetValue(slot, out var save))
+            return [];
+
+        _state.RestoreFromSave(save);
+        return [new StateRestoredEvent(new BoardSnapshot(_state), slot)];
+    }
+
+    public bool HasSave(int slot = DefaultSlot) => _saveSlots.ContainsKey(slot);
 }

chessistics-tests/Simulation/QuickSaveTests.cs

@@ -0,0 +1,181 @@
+using Chessistics.Engine.Commands;
+using Chessistics.Engine.Events;
+using Chessistics.Engine.Model;
+using Chessistics.Tests.Helpers;
+using Xunit;
+
+namespace Chessistics.Tests.Simulation;
+
+public class QuickSaveTests
+{
+    private SimHelper CreateSim()
+    {
+        var level = new BoardBuilder(4, 4)
+            .WithProduction(0, 0, "Scierie", CargoType.Wood, amount: 1)
+            .WithDemand(3, 0, "Depot", CargoType.Wood, 3, 30)
+            .WithStock(PieceKind.Rook, 3)
+            .Build();
+        return SimHelper.FromLevel(level);
+    }
+
+    [Fact]
+    public void QuickSave_ReturnsSavedEvent()
+    {
+        var sim = CreateSim();
+        var events = sim.Sim.QuickSave();
+        Assert.Single(events);
+        Assert.IsType<StateSavedEvent>(events[0]);
+    }
+
+    [Fact]
+    public void QuickLoad_WithoutSave_ReturnsEmpty()
+    {
+        var sim = CreateSim();
+        var events = sim.Sim.QuickLoad();
+        Assert.Empty(events);
+    }
+
+    [Fact]
+    public void QuickLoad_AfterSave_EmitsRestoredEvent()
+    {
+        var sim = CreateSim();
+        sim.Sim.QuickSave();
+        var events = sim.Sim.QuickLoad();
+        Assert.Single(events);
+        var restored = Assert.IsType<StateRestoredEvent>(events[0]);
+        Assert.NotNull(restored.Snapshot);
+    }
+
+    [Fact]
+    public void Save_MutateState_Load_RestoresPreviousState()
+    {
+        var sim = CreateSim();
+
+        // Place a piece, then save
+        sim.Place(PieceKind.Rook, (0, 0), (1, 0));
+        sim.Sim.QuickSave();
+
+        var beforeSnap = sim.Snapshot;
+        Assert.Single(beforeSnap.Pieces);
+        Assert.Equal(3 - 1, beforeSnap.RemainingStock[PieceKind.Rook]);
+
+        // Mutate: place another piece, step simulation
+        sim.Place(PieceKind.Rook, (0, 1), (1, 1));
+        sim.Step();
+        sim.Step();
+
+        var dirtySnap = sim.Snapshot;
+        Assert.Equal(2, dirtySnap.Pieces.Count);
+        Assert.Equal(2, dirtySnap.TurnNumber);
+
+        // Load: should match beforeSnap
+        sim.Sim.QuickLoad();
+        var afterSnap = sim.Snapshot;
+
+        Assert.Single(afterSnap.Pieces);
+        Assert.Equal(0, afterSnap.TurnNumber);
+        Assert.Equal(3 - 1, afterSnap.RemainingStock[PieceKind.Rook]);
+        Assert.Equal(beforeSnap.Pieces[0].Id, afterSnap.Pieces[0].Id);
+        Assert.Equal(beforeSnap.Pieces[0].StartCell, afterSnap.Pieces[0].StartCell);
+    }
+
+    [Fact]
+    public void Load_IsIndependent_FromFurtherChanges()
+    {
+        // Saving should not alias; mutating state after save must not affect the save.
+        var sim = CreateSim();
+        sim.Place(PieceKind.Rook, (0, 0), (1, 0));
+        sim.Sim.QuickSave();
+
+        // Mutate after save
+        sim.Place(PieceKind.Rook, (0, 1), (1, 1));
+        sim.Step();
+
+        // Load should restore to 1 piece, turn 0
+        sim.Sim.QuickLoad();
+        var snap = sim.Snapshot;
+        Assert.Single(snap.Pieces);
+        Assert.Equal(0, snap.TurnNumber);
+
+        // Mutate again, load again — save still usable
+        sim.Place(PieceKind.Rook, (0, 2), (1, 2));
+        sim.Sim.QuickLoad();
+        snap = sim.Snapshot;
+        Assert.Single(snap.Pieces);
+    }
+
+    [Fact]
+    public void QuickSave_PreservesCampaignProgression()
+    {
+        var campaign = CampaignBuilder();
+        var sim = SimHelper.FromCampaign(campaign);
+        sim.Sim.ProcessCommand(new LoadCampaignCommand());
+
+        sim.Place(PieceKind.Pawn, (0, 0), (1, 0));
+        sim.Sim.QuickSave();
+
+        var before = sim.Snapshot;
+        Assert.Equal(0, before.Campaign!.CurrentMissionIndex);
+
+        // Mutate
+        sim.Step();
+        sim.Step();
+
+        sim.Sim.QuickLoad();
+        var after = sim.Snapshot;
+        Assert.Equal(before.Campaign!.CurrentMissionIndex, after.Campaign!.CurrentMissionIndex);
+        Assert.Equal(before.Pieces.Count, after.Pieces.Count);
+        Assert.Equal(0, after.TurnNumber);
+    }
+
+    [Fact]
+    public void MultipleSlots_AreIndependent()
+    {
+        var sim = CreateSim();
+        sim.Place(PieceKind.Rook, (0, 0), (1, 0));
+        sim.Sim.QuickSave(slot: 1);
+
+        sim.Place(PieceKind.Rook, (0, 1), (1, 1));
+        sim.Sim.QuickSave(slot: 2);
+
+        // Slot 1 should have 1 piece; slot 2 should have 2
+        sim.Sim.QuickLoad(slot: 1);
+        Assert.Single(sim.Snapshot.Pieces);
+
+        sim.Sim.QuickLoad(slot: 2);
+        Assert.Equal(2, sim.Snapshot.Pieces.Count);
+    }
+
+    private static CampaignDef CampaignBuilder()
+    {
+        return new CampaignDef
+        {
+            Name = "TestCampaign",
+            InitialWidth = 4,
+            InitialHeight = 4,
+            Missions = new List<MissionDef>
+            {
+                new()
+                {
+                    Id = 1,
+                    Name = "M1",
+                    TerrainPatch = new TerrainPatch
+                    {
+                        NewWidth = 4,
+                        NewHeight = 4,
+                        Cells = new List<PatchCell>
+                        {
+                            new() { Col = 0, Row = 0, Type = CellType.Production,
+                                Production = new ProductionDef(new Coords(0, 0), "S", CargoType.Wood, 1) },
+                            new() { Col = 3, Row = 0, Type = CellType.Demand,
+                                Demand = new DemandDef(new Coords(3, 0), "D", CargoType.Wood, 3) }
+                        }
+                    },
+                    UnlockedPieces = new List<PieceKind> { PieceKind.Pawn },
+                    UnlockedLevels = new List<PieceUpgrade> { new(PieceKind.Pawn, 1) },
+                    Stock = new List<PieceStock> { new(PieceKind.Pawn, 4) }
+                }
+            }
+        };
+    }
+}

tools/automation/harness.py

@@ -268,6 +268,12 @@ class Harness:
     def back_to_menu(self) -> dict[str, Any]:
         return self.send("back_to_menu")
 
+    def quick_save(self) -> dict[str, Any]:
+        return self.send("quick_save")
+
+    def quick_load(self) -> dict[str, Any]:
+        return self.send("quick_load")
+
     def quit(self) -> dict[str, Any]:
         return self.send("quit", timeout=5.0)
 

tools/automation/test_quicksave.py

@@ -0,0 +1,48 @@
+"""End-to-end smoke test for quick save / quick load."""
+import sys
+from pathlib import Path
+
+sys.path.insert(0, str(Path(__file__).resolve().parents[2]))
+
+from tools.automation.harness import Harness
+
+
+def main():
+    with Harness.launch(run_name="quicksave") as h:
+        h.load_mission("campaign_01", 0)
+        h.screenshot("01_loaded")
+
+        initial = h.state()
+        print(f"[initial] turn={initial['turn']} pieces={len(initial['pieces'])}")
+
+        # Save a clean checkpoint
+        saved = h.quick_save()
+        print(f"[quick_save] {saved}")
+
+        # Mutate: place a piece and step
+        h.place("Pawn", (0, 0), (0, 1))
+        h.screenshot("02_after_place")
+        h.set_speed(0.1)
+        h.play()
+        import time as _t
+        _t.sleep(1.5)
+        h.pause()
+
+        dirty = h.state()
+        print(f"[dirty] turn={dirty['turn']} pieces={len(dirty['pieces'])}")
+
+        # Load — should be back to initial state
+        loaded = h.quick_load()
+        print(f"[quick_load] {loaded}")
+        h.screenshot("03_after_load")
+
+        restored = h.state()
+        print(f"[restored] turn={restored['turn']} pieces={len(restored['pieces'])}")
+
+        assert restored['turn'] == initial['turn'], "Turn mismatch after restore"
+        assert len(restored['pieces']) == len(initial['pieces']), "Piece count mismatch"
+        print("OK — quick save/load roundtrip successful")
+
+
+if __name__ == "__main__":
+    main()