Scenes/Game.tscn

@@ -427,6 +427,14 @@ text = "Continue"
 layout_mode = 2
 text = "Options"
 
+[node name="SaveGame" type="Button" parent="CanvasLayer/UIHandler/MainUI/Content/Menu/VBoxContainer"]
+layout_mode = 2
+text = "Save Game"
+
+[node name="LoadGame" type="Button" parent="CanvasLayer/UIHandler/MainUI/Content/Menu/VBoxContainer"]
+layout_mode = 2
+text = "Load Game"
+
 [node name="Button3" type="Button" parent="CanvasLayer/UIHandler/MainUI/Content/Menu/VBoxContainer" unique_id=2028306785]
 layout_mode = 2
 text = "Exit"
@@ -600,6 +608,8 @@ texture_normal = ExtResource("12_3so38")
 [connection signal="pressed" from="CanvasLayer/UIHandler/MainUI/Content/RobotList/VBoxContainer/Spawning/Button" to="CanvasLayer/UIHandler/MainUI/Content/RobotList" method="SpawnRobot"]
 [connection signal="pressed" from="CanvasLayer/UIHandler/MainUI/Content/Menu/VBoxContainer/Button" to="CanvasLayer/UIHandler" method="HandleMenu"]
 [connection signal="pressed" from="CanvasLayer/UIHandler/MainUI/Content/Menu/VBoxContainer/Button2" to="CanvasLayer/UIHandler" method="ShowOptions"]
+[connection signal="pressed" from="CanvasLayer/UIHandler/MainUI/Content/Menu/VBoxContainer/SaveGame" to="CanvasLayer/UIHandler" method="SaveGame"]
+[connection signal="pressed" from="CanvasLayer/UIHandler/MainUI/Content/Menu/VBoxContainer/LoadGame" to="CanvasLayer/UIHandler" method="LoadGame"]
 [connection signal="pressed" from="CanvasLayer/UIHandler/MainUI/Content/Menu/VBoxContainer/Button3" to="CanvasLayer/UIHandler" method="ExitGame"]
 [connection signal="pressed" from="CanvasLayer/UIHandler/MainUI/Content/GameOver/VBoxContainer/HBoxContainer/Negative" to="CanvasLayer/UIHandler" method="ExitGame"]
 [connection signal="pressed" from="CanvasLayer/UIHandler/MainUI/Content/GameOver/VBoxContainer/HBoxContainer/Positive" to="CanvasLayer/UIHandler" method="HideGameOver"]

Scenes/MainMenu.tscn

@@ -123,6 +123,12 @@ theme_override_styles/normal = SubResource("StyleBoxFlat_bnhvo")
 theme_override_styles/hover = SubResource("StyleBoxFlat_tt5f1")
 text = "Start Game"
 
+[node name="btnLoad" type="Button" parent="CenterContainer/VBoxContainer"]
+layout_mode = 2
+theme_override_styles/normal = SubResource("StyleBoxFlat_bnhvo")
+theme_override_styles/hover = SubResource("StyleBoxFlat_tt5f1")
+text = "Load Game"
+
 [node name="btnOptions" type="Button" parent="CenterContainer/VBoxContainer" unique_id=891656915]
 layout_mode = 2
 theme_override_styles/normal = SubResource("StyleBoxFlat_bnhvo")
@@ -136,4 +142,5 @@ theme_override_styles/hover = SubResource("StyleBoxFlat_tt5f1")
 text = "Exit Game"
 
 [connection signal="button_up" from="CenterContainer/VBoxContainer/btnPlay" to="." method="OnPlayPressed"]
+[connection signal="button_up" from="CenterContainer/VBoxContainer/btnLoad" to="." method="OnLoadPressed"]
 [connection signal="button_up" from="CenterContainer/VBoxContainer/btnExit" to="." method="OnQuitPressed"]

Scenes/TestRunner.tscn

@@ -0,0 +1,6 @@
+[gd_scene format=3]
+
+[ext_resource type="Script" path="res://Scripts/Tests/TestRunner.cs" id="1_test_runner"]
+
+[node name="TestRunner" type="Node"]
+script = ExtResource("1_test_runner")

Scripts/Core/GameData.cs

@@ -23,6 +23,7 @@ public partial class GameData
     public static SurvivalState survival = new SurvivalState();
     public static RobotStats robotStats = new RobotStats();
     public static Dictionary<int, List<Ingredient>> gateUnlocks;
+    public static bool loadSaveOnStart = false;
 
     public static Color primaryColor = new Color("#276ac2");
     public static Color lightColor = new Color("#7efff5");
@@ -32,4 +33,36 @@ public partial class GameData
     public static int seed = 12345;
 
     public static Inventory inventory = new Inventory();
+
+    public static void ResetRunState()
+    {
+        seed = 12345;
+        ruinSize = 10;
+        layerSize = 20;
+        rand = new Random(seed);
+        survival = new SurvivalState();
+        robotStats = new RobotStats();
+        inventory = new Inventory();
+        availableResearch = ResourceLoader.LoadResearch();
+        robots.Clear();
+        currentLayer = 0;
+        visibleLayer = 0;
+        lowestLayer = 0;
+        maxRobotCount = 10;
+        canMove = true;
+    }
+
+    public static void RebuildRobotStatsFromResearch()
+    {
+        robotStats = new RobotStats();
+        maxRobotCount = 10;
+
+        foreach (Research research in availableResearch.Values)
+        {
+            if (research.state == ResearchState.RESEARCHED)
+            {
+                robotStats.Apply(research.data.Effects);
+            }
+        }
+    }
 }

Scripts/Core/ResourceLoader.cs

@@ -99,14 +99,14 @@ public partial class ResourceLoader
 	{
 		Dictionary<string, float[]> weights = new Dictionary<string, float[]>()
 		{
-			{ "iron_ore", [0.05f,1] },
-			{ "tin_ore", [0.3f,0.7f] },
-			{ "copper_ore", [0.3f,0.7f] },
-			{ "mushroom", [0.3f,0.1f] },
-			{ "spider_silk", [0.8f,0.4f] },
-			{ "coal", [1,0.3f] },
-			{ "water", [0.4f,0.2f] },
-			{ "stone", [1,0.5f] },
+			{ "iron_ore", new float[] { 0.05f, 1f } },
+			{ "tin_ore", new float[] { 0.3f, 0.7f } },
+			{ "copper_ore", new float[] { 0.3f, 0.7f } },
+			{ "mushroom", new float[] { 0.3f, 0.1f } },
+			{ "spider_silk", new float[] { 0.8f, 0.4f } },
+			{ "coal", new float[] { 1f, 0.3f } },
+			{ "water", new float[] { 0.4f, 0.2f } },
+			{ "stone", new float[] { 1f, 0.5f } },
 		};
 		return weights;
 	}

Scripts/Core/SaveGameData.cs

@@ -0,0 +1,87 @@
+using System.Collections.Generic;
+
+public class SaveGameData
+{
+    public int Seed { get; set; }
+    public int CurrentLayer { get; set; }
+    public int VisibleLayer { get; set; }
+    public int LowestLayer { get; set; }
+    public int MaxRobotCount { get; set; }
+    public bool CanMove { get; set; }
+    public SurvivalSaveData Survival { get; set; }
+    public List<ItemSaveData> Inventory { get; set; }
+    public List<ResearchSaveData> Research { get; set; }
+    public List<LayerSaveData> Layers { get; set; }
+    public List<RobotSaveData> Robots { get; set; }
+}
+
+public class SurvivalSaveData
+{
+    public float Hunger { get; set; }
+    public float Thirst { get; set; }
+    public float Energy { get; set; }
+    public bool IsDead { get; set; }
+    public string DeathReason { get; set; }
+    public string CurrentStatus { get; set; }
+}
+
+public class ItemSaveData
+{
+    public string Id { get; set; }
+    public int Amount { get; set; }
+}
+
+public class ResearchSaveData
+{
+    public string Id { get; set; }
+    public ResearchState State { get; set; }
+    public double ElapsedResearchTime { get; set; }
+    public bool PaidResources { get; set; }
+}
+
+public class LayerSaveData
+{
+    public int Level { get; set; }
+    public bool IsGateOpen { get; set; }
+    public bool HasContentGenerated { get; set; }
+    public List<Ingredient> GateIngredients { get; set; }
+    public List<string> CurrentResources { get; set; }
+    public List<TileSaveData> Tiles { get; set; }
+}
+
+public class TileSaveData
+{
+    public int X { get; set; }
+    public int Y { get; set; }
+    public string CollapsedMesh { get; set; }
+    public bool ContainsLight { get; set; }
+    public bool ContainsDecoration { get; set; }
+    public bool ContainsResource { get; set; }
+    public bool WasVisited { get; set; }
+    public ResourceSaveData Resource { get; set; }
+}
+
+public class ResourceSaveData
+{
+    public string Name { get; set; }
+    public int CurrentAmount { get; set; }
+    public int MaxAmount { get; set; }
+    public bool IsEndless { get; set; }
+    public float ExtractionSpeed { get; set; }
+    public double TimeSinceLastExtraction { get; set; }
+}
+
+public class RobotSaveData
+{
+    public string Name { get; set; }
+    public string CurrentProgram { get; set; }
+    public string CurrentMessage { get; set; }
+    public string RobotType { get; set; }
+    public float X { get; set; }
+    public float Y { get; set; }
+    public float Z { get; set; }
+    public float Heat { get; set; }
+    public float Maintenance { get; set; }
+    public bool IsCoolingDown { get; set; }
+    public bool IsBroken { get; set; }
+}

Scripts/Core/SaveGameData.cs.uid

@@ -0,0 +1 @@
+uid://k530yuk4xt1x

Scripts/Core/SaveGameManager.cs

@@ -0,0 +1,357 @@
+using Godot;
+using System.Collections.Generic;
+using System.Text.Json;
+
+public static class SaveGameManager
+{
+    private const string SaveDirectory = "user://savegame";
+    private const string GameDataPath = SaveDirectory + "/gamedata.json";
+    private const string RobotsPath = SaveDirectory + "/robots.json";
+    private const string ResearchPath = SaveDirectory + "/research.json";
+    private const string LayerPrefix = SaveDirectory + "/layer_";
+    private const string JsonExtension = ".json";
+
+    private static readonly JsonSerializerOptions JsonOptions = new JsonSerializerOptions
+    {
+        WriteIndented = true
+    };
+
+    public static bool SaveExists()
+    {
+        return FileAccess.FileExists(GameDataPath);
+    }
+
+    public static void SaveGame()
+    {
+        SaveGameData saveGame = CreateSaveData();
+        CreateSaveDirectory();
+        ClearOldLayerFiles();
+
+        SaveJson(GameDataPath, CreateCoreSaveData(saveGame));
+        SaveJson(RobotsPath, saveGame.Robots);
+        SaveJson(ResearchPath, saveGame.Research);
+
+        foreach (LayerSaveData layer in saveGame.Layers)
+        {
+            SaveJson(GetLayerPath(layer.Level), layer);
+        }
+    }
+
+    public static SaveGameData LoadSaveData()
+    {
+        if (!SaveExists()) return null;
+
+        SaveGameData saveGame = LoadJson<SaveGameData>(GameDataPath);
+        if (saveGame == null) return null;
+
+        saveGame.Robots = LoadJson<List<RobotSaveData>>(RobotsPath) ?? new List<RobotSaveData>();
+        saveGame.Research = LoadJson<List<ResearchSaveData>>(ResearchPath) ?? new List<ResearchSaveData>();
+        saveGame.Layers = LoadLayerSaveData();
+
+        return saveGame;
+    }
+
+    public static SaveGameData CreateSaveData()
+    {
+        return new SaveGameData
+        {
+            Seed = GameData.seed,
+            CurrentLayer = GameData.currentLayer,
+            VisibleLayer = GameData.visibleLayer,
+            LowestLayer = GameData.lowestLayer,
+            MaxRobotCount = GameData.maxRobotCount,
+            CanMove = GameData.canMove,
+            Survival = CreateSurvivalSaveData(),
+            Inventory = CreateInventorySaveData(),
+            Research = CreateResearchSaveData(),
+            Layers = CreateLayerSaveData(),
+            Robots = CreateRobotSaveData()
+        };
+    }
+
+    public static void ApplyWorldData(SaveGameData saveGame)
+    {
+        if (saveGame == null) return;
+
+        GameData.seed = saveGame.Seed;
+        GameData.currentLayer = saveGame.CurrentLayer;
+        GameData.visibleLayer = saveGame.VisibleLayer;
+        GameData.lowestLayer = saveGame.LowestLayer;
+        GameData.maxRobotCount = saveGame.MaxRobotCount;
+        GameData.canMove = saveGame.CanMove;
+
+        ApplySurvivalData(saveGame.Survival);
+        ApplyInventoryData(saveGame.Inventory);
+        ApplyResearchData(saveGame.Research);
+        ApplyLayerData(saveGame.Layers);
+    }
+
+    private static SurvivalSaveData CreateSurvivalSaveData()
+    {
+        return new SurvivalSaveData
+        {
+            Hunger = GameData.survival.hunger,
+            Thirst = GameData.survival.thirst,
+            Energy = GameData.survival.energy,
+            IsDead = GameData.survival.isDead,
+            DeathReason = GameData.survival.deathReason,
+            CurrentStatus = GameData.survival.currentStatus
+        };
+    }
+
+    private static List<ItemSaveData> CreateInventorySaveData()
+    {
+        List<ItemSaveData> result = new List<ItemSaveData>();
+
+        foreach (Item item in GameData.inventory.items)
+        {
+            result.Add(new ItemSaveData
+            {
+                Id = item.data.Id,
+                Amount = item.currentAmount
+            });
+        }
+
+        return result;
+    }
+
+    private static List<ResearchSaveData> CreateResearchSaveData()
+    {
+        List<ResearchSaveData> result = new List<ResearchSaveData>();
+
+        foreach (Research research in GameData.availableResearch.Values)
+        {
+            result.Add(new ResearchSaveData
+            {
+                Id = research.data.Id,
+                State = research.state,
+                ElapsedResearchTime = research.elapsedResearchTime,
+                PaidResources = research.paidResources
+            });
+        }
+
+        return result;
+    }
+
+    private static List<LayerSaveData> CreateLayerSaveData()
+    {
+        List<LayerSaveData> result = new List<LayerSaveData>();
+        if (GameData.map == null) return result;
+
+        foreach (Layer layer in GameData.map)
+        {
+            if (layer == null) continue;
+
+            result.Add(new LayerSaveData
+            {
+                Level = layer.level,
+                IsGateOpen = layer.isGateOpen,
+                HasContentGenerated = layer.hasContentGenerated,
+                GateIngredients = new List<Ingredient>(layer.gateIngredients),
+                CurrentResources = new List<string>(layer.currentResources),
+                Tiles = CreateTileSaveData(layer)
+            });
+        }
+
+        return result;
+    }
+
+    private static List<TileSaveData> CreateTileSaveData(Layer layer)
+    {
+        List<TileSaveData> result = new List<TileSaveData>();
+
+        foreach (Tile tile in layer.tiles)
+        {
+            result.Add(new TileSaveData
+            {
+                X = tile.GridPosition.X,
+                Y = tile.GridPosition.Y,
+                CollapsedMesh = tile.collapsedMesh,
+                ContainsLight = tile.containsLight,
+                ContainsDecoration = tile.containsDecoration,
+                ContainsResource = tile.containsResource,
+                WasVisited = tile.wasVisited,
+                Resource = tile.resource == null ? null : tile.resource.CreateSaveData()
+            });
+        }
+
+        return result;
+    }
+
+    private static List<RobotSaveData> CreateRobotSaveData()
+    {
+        List<RobotSaveData> result = new List<RobotSaveData>();
+
+        foreach (Robot robot in GameData.robots)
+        {
+            result.Add(robot.CreateSaveData());
+        }
+
+        return result;
+    }
+
+    private static SaveGameData CreateCoreSaveData(SaveGameData saveGame)
+    {
+        return new SaveGameData
+        {
+            Seed = saveGame.Seed,
+            CurrentLayer = saveGame.CurrentLayer,
+            VisibleLayer = saveGame.VisibleLayer,
+            LowestLayer = saveGame.LowestLayer,
+            MaxRobotCount = saveGame.MaxRobotCount,
+            CanMove = saveGame.CanMove,
+            Survival = saveGame.Survival,
+            Inventory = saveGame.Inventory,
+            Research = new List<ResearchSaveData>(),
+            Layers = new List<LayerSaveData>(),
+            Robots = new List<RobotSaveData>()
+        };
+    }
+
+    private static List<LayerSaveData> LoadLayerSaveData()
+    {
+        List<LayerSaveData> result = new List<LayerSaveData>();
+
+        for (int i = 0; i < GameData.ruinSize; i++)
+        {
+            string path = GetLayerPath(i);
+            if (!FileAccess.FileExists(path)) continue;
+
+            LayerSaveData layer = LoadJson<LayerSaveData>(path);
+            if (layer != null)
+            {
+                result.Add(layer);
+            }
+        }
+
+        return result;
+    }
+
+    private static string GetLayerPath(int level)
+    {
+        return LayerPrefix + level + JsonExtension;
+    }
+
+    private static void CreateSaveDirectory()
+    {
+        DirAccess.MakeDirRecursiveAbsolute(SaveDirectory);
+    }
+
+    private static void ClearOldLayerFiles()
+    {
+        DirAccess directory = DirAccess.Open(SaveDirectory);
+        if (directory == null) return;
+
+        directory.ListDirBegin();
+        while (true)
+        {
+            string fileName = directory.GetNext();
+            if (fileName == "") break;
+            if (directory.CurrentIsDir()) continue;
+            if (!fileName.StartsWith("layer_") || !fileName.EndsWith(JsonExtension)) continue;
+
+            directory.Remove(fileName);
+        }
+        directory.ListDirEnd();
+    }
+
+    private static void SaveJson<T>(string path, T data)
+    {
+        string json = JsonSerializer.Serialize(data, JsonOptions);
+        FileAccess file = FileAccess.Open(path, FileAccess.ModeFlags.Write);
+        file.StoreString(json);
+        file.Flush();
+    }
+
+    private static T LoadJson<T>(string path)
+    {
+        if (!FileAccess.FileExists(path)) return default;
+
+        FileAccess file = FileAccess.Open(path, FileAccess.ModeFlags.Read);
+        string json = file.GetAsText();
+        return JsonSerializer.Deserialize<T>(json);
+    }
+
+    private static void ApplySurvivalData(SurvivalSaveData survival)
+    {
+        if (survival == null) return;
+
+        GameData.survival.hunger = survival.Hunger;
+        GameData.survival.thirst = survival.Thirst;
+        GameData.survival.energy = survival.Energy;
+        GameData.survival.isDead = survival.IsDead;
+        GameData.survival.deathReason = survival.DeathReason ?? "";
+        GameData.survival.currentStatus = survival.CurrentStatus ?? "";
+    }
+
+    private static void ApplyInventoryData(List<ItemSaveData> savedItems)
+    {
+        GameData.inventory = new Inventory();
+        if (savedItems == null) return;
+
+        foreach (ItemSaveData savedItem in savedItems)
+        {
+            if (!GameData.availableItems.ContainsKey(savedItem.Id)) continue;
+
+            GameData.inventory.AddItem(
+                new Item { data = GameData.availableItems[savedItem.Id] },
+                savedItem.Amount
+            );
+        }
+    }
+
+    private static void ApplyResearchData(List<ResearchSaveData> savedResearch)
+    {
+        if (savedResearch == null) return;
+
+        foreach (ResearchSaveData savedState in savedResearch)
+        {
+            if (!GameData.availableResearch.ContainsKey(savedState.Id)) continue;
+
+            Research research = GameData.availableResearch[savedState.Id];
+            research.state = savedState.State;
+            research.elapsedResearchTime = savedState.ElapsedResearchTime;
+            research.paidResources = savedState.PaidResources;
+        }
+
+        GameData.RebuildRobotStatsFromResearch();
+    }
+
+    private static void ApplyLayerData(List<LayerSaveData> savedLayers)
+    {
+        if (savedLayers == null || GameData.map == null) return;
+
+        foreach (LayerSaveData savedLayer in savedLayers)
+        {
+            if (savedLayer.Level < 0 || savedLayer.Level >= GameData.map.Length) continue;
+
+            Layer layer = GameData.map[savedLayer.Level];
+            layer.isGateOpen = savedLayer.IsGateOpen;
+            layer.hasContentGenerated = savedLayer.HasContentGenerated;
+            layer.gateIngredients = savedLayer.GateIngredients ?? new List<Ingredient>();
+            layer.currentResources = savedLayer.CurrentResources ?? new List<string>();
+
+            ApplyTileData(layer, savedLayer.Tiles);
+        }
+    }
+
+    private static void ApplyTileData(Layer layer, List<TileSaveData> savedTiles)
+    {
+        if (savedTiles == null) return;
+
+        foreach (TileSaveData savedTile in savedTiles)
+        {
+            if (savedTile.X < 0 || savedTile.X >= GameData.layerSize) continue;
+            if (savedTile.Y < 0 || savedTile.Y >= GameData.layerSize) continue;
+
+            Tile tile = layer.tiles[savedTile.X, savedTile.Y];
+            tile.collapsedMesh = savedTile.CollapsedMesh;
+            tile.containsLight = savedTile.ContainsLight;
+            tile.containsDecoration = savedTile.ContainsDecoration;
+            tile.containsResource = savedTile.ContainsResource;
+            tile.wasVisited = savedTile.WasVisited;
+            tile.resource = savedTile.Resource == null ? null : GameResource.FromSaveData(savedTile.Resource);
+            tile.ContentNode.Visible = savedTile.WasVisited || tile.collapsedMesh == "gate";
+        }
+    }
+}

Scripts/Core/SaveGameManager.cs.uid

@@ -0,0 +1 @@
+uid://quury78jfutk

Scripts/Gameplay/Crafting/GameResource.cs

@@ -19,6 +19,30 @@ public class GameResource
         item = GameData.availableItems[name];
     }
 
+    public static GameResource FromSaveData(ResourceSaveData saveData)
+    {
+        GameResource resource = new GameResource(saveData.Name);
+        resource.currentAmount = saveData.CurrentAmount;
+        resource.maxAmount = saveData.MaxAmount;
+        resource.isEndless = saveData.IsEndless;
+        resource.extractionSpeed = saveData.ExtractionSpeed;
+        resource.timeSinceLastExtraction = saveData.TimeSinceLastExtraction;
+        return resource;
+    }
+
+    public ResourceSaveData CreateSaveData()
+    {
+        return new ResourceSaveData
+        {
+            Name = name,
+            CurrentAmount = currentAmount,
+            MaxAmount = maxAmount,
+            IsEndless = isEndless,
+            ExtractionSpeed = extractionSpeed,
+            TimeSinceLastExtraction = timeSinceLastExtraction
+        };
+    }
+
     public bool Extract(double delta)
     {
         timeSinceLastExtraction += delta;

Scripts/Gameplay/Crafting/Inventory.cs

@@ -10,31 +10,49 @@ public class Inventory
 
     public bool AddItem(Item item, int amount)
     {
-        Item inventoryItem = items.Find(x => x.data.Id == item.data.Id && x.currentAmount + amount <= x.data.StackSize);
-        if (inventoryItem != null)
+        if (GetFreeCapacity(item.data.Id, item.data.StackSize) < amount)
         {
-            inventoryItem.currentAmount += amount;
-            NotifyInventoryChanged();
-            return true;
+            return false;
         }
 
-        if (items.Count < maxInventorySize * GameData.maxRobotCount)
+        int remainingAmount = amount;
+
+        foreach (Item inventoryItem in items)
         {
-            items.Add(item);
-            items[items.Count - 1].currentAmount += amount;
-            NotifyInventoryChanged();
-            return true;
+            if (inventoryItem.data.Id != item.data.Id) continue;
+            if (inventoryItem.currentAmount >= inventoryItem.data.StackSize) continue;
+
+            int amountToAdd = Math.Min(
+                remainingAmount,
+                inventoryItem.data.StackSize - inventoryItem.currentAmount
+            );
+
+            inventoryItem.currentAmount += amountToAdd;
+            remainingAmount -= amountToAdd;
+
+            if (remainingAmount <= 0)
+            {
+                NotifyInventoryChanged();
+                return true;
+            }
         }
 
-        return false;
+        while (remainingAmount > 0 && items.Count < maxInventorySize * GameData.maxRobotCount)
+        {
+            int amountToAdd = Math.Min(remainingAmount, item.data.StackSize);
+            items.Add(new Item { data = item.data, currentAmount = amountToAdd });
+            remainingAmount -= amountToAdd;
+        }
+
+        NotifyInventoryChanged();
+        return remainingAmount <= 0;
     }
 
     public bool CanCraft(List<Ingredient> neededIngredients, int amount)
     {
         foreach (Ingredient ingredient in neededIngredients)
         {
-            Item item = items.Find(x => x.data.Id == ingredient.Item && x.currentAmount >= ingredient.Amount * amount);
-            if (item == null)
+            if (GetItemAmount(ingredient.Item) < ingredient.Amount * amount)
             {
                 return false;
             }
@@ -93,4 +111,21 @@ public class Inventory
     {
         OnInventoryUpdate?.Invoke(this, EventArgs.Empty);
     }
+
+    private int GetFreeCapacity(string id, int stackSize)
+    {
+        int freeCapacity = 0;
+
+        foreach (Item item in items)
+        {
+            if (item.data.Id == id)
+            {
+                freeCapacity += stackSize - item.currentAmount;
+            }
+        }
+
+        int freeSlots = maxInventorySize * GameData.maxRobotCount - items.Count;
+        freeCapacity += freeSlots * stackSize;
+        return freeCapacity;
+    }
 }

Scripts/Gameplay/Robots/Robot.cs

@@ -155,6 +155,37 @@ public partial class Robot : Node3D
 		currentMessage = "";
 	}
 
+	public RobotSaveData CreateSaveData()
+	{
+		return new RobotSaveData
+		{
+			Name = Name,
+			CurrentProgram = currentProgram,
+			CurrentMessage = currentMessage,
+			RobotType = robotType,
+			X = Position.X,
+			Y = Position.Y,
+			Z = Position.Z,
+			Heat = heat,
+			Maintenance = maintenance,
+			IsCoolingDown = isCoolingDown,
+			IsBroken = isBroken
+		};
+	}
+
+	public void LoadSaveData(RobotSaveData saveData)
+	{
+		Name = saveData.Name;
+		currentProgram = saveData.CurrentProgram;
+		currentMessage = saveData.CurrentMessage ?? "";
+		robotType = saveData.RobotType ?? "stone_robot";
+		Position = new Vector3(saveData.X, saveData.Y, saveData.Z);
+		heat = saveData.Heat;
+		maintenance = saveData.Maintenance;
+		isCoolingDown = saveData.IsCoolingDown;
+		isBroken = saveData.IsBroken;
+	}
+
 	private bool CanExecute(double delta)
 	{
 		if (GameData.survival.isDead)

Scripts/Gameplay/Robots/RobotStats.cs

@@ -3,13 +3,13 @@ using System.Collections.Generic;
 
 public class RobotStats
 {
-    public readonly Dictionary<string, RobotTypeStats> RobotTypes = new()
+    public readonly Dictionary<string, RobotTypeStats> RobotTypes = new Dictionary<string, RobotTypeStats>
     {
-        ["stone_robot"] = new RobotTypeStats(0.75f, 0.60f, 0.80f, 0.80f, 1.40f, -0.10f),
-        ["copper_robot"] = new RobotTypeStats(1.00f, 1.00f, 1.00f, 1.00f, 1.00f, 0.00f),
-        ["tin_robot"] = new RobotTypeStats(1.00f, 1.00f, 1.00f, 1.00f, 1.00f, 0.00f),
-        ["bronze_robot"] = new RobotTypeStats(1.15f, 1.10f, 0.90f, 1.10f, 0.80f, 0.05f),
-        ["iron_robot"] = new RobotTypeStats(1.35f, 1.25f, 1.15f, 1.20f, 0.65f, 0.10f)
+        { "stone_robot", new RobotTypeStats(0.75f, 0.60f, 0.80f, 0.80f, 1.40f, -0.10f) },
+        { "copper_robot", new RobotTypeStats(1.00f, 1.00f, 1.00f, 1.00f, 1.00f, 0.00f) },
+        { "tin_robot", new RobotTypeStats(1.00f, 1.00f, 1.00f, 1.00f, 1.00f, 0.00f) },
+        { "bronze_robot", new RobotTypeStats(1.15f, 1.10f, 0.90f, 1.10f, 0.80f, 0.05f) },
+        { "iron_robot", new RobotTypeStats(1.35f, 1.25f, 1.15f, 1.20f, 0.65f, 0.10f) }
     };
     private const float BaseMinimumEfficiency = 0.35f;
 
@@ -86,7 +86,7 @@ public class RobotStats
                 break;
             case "robot_count_increase":
                 GameData.maxRobotCount += (int)effect.Value;
-            break;
+                break;
         }
     }
 }

Scripts/Tests/TestRunner.cs

@@ -0,0 +1,383 @@
+using Godot;
+using System;
+using System.Collections.Generic;
+
+public partial class TestRunner : Node
+{
+    private int passedTests = 0;
+    private int failedTests = 0;
+
+    public override void _Ready()
+    {
+        Run("Inventory adds, stacks and removes items", TestInventoryStacksAndRemovesItems);
+        Run("Inventory crafting checks stacked totals", TestInventoryCanCraftAcrossStacks);
+        Run("Survival consumes stored food and water", TestSurvivalConsumesFoodAndWater);
+        Run("Survival death disables movement", TestSurvivalDeathDisablesMovement);
+        Run("Robot research effects change robot stats", TestRobotResearchEffects);
+        Run("Research completion applies effects once", TestResearchCompletionAppliesEffectsOnce);
+        Run("Research execution pays resources and finishes", TestResearchExecutionPaysResourcesAndFinishes);
+        Run("Inventory add failure keeps inventory unchanged", TestInventoryAddFailureKeepsInventoryUnchanged);
+        Run("Resource extraction and save data roundtrip", TestResourceSaveRoundtrip);
+        Run("Robot save data roundtrip keeps robot state", TestRobotSaveRoundtrip);
+        Run("Save data captures and restores global state", TestSaveDataRestoresGlobalState);
+        Run("Split save files store and load data", TestSplitSaveFilesRoundtrip);
+        Run("Split save files include one file per saved layer", TestSplitSaveFilesIncludeLayerFiles);
+        Run("If node evaluates inventory comparisons", TestIfNodeEvaluatesInventoryComparisons);
+        Run("While node reports false conditions", TestWhileNodeReportsFalseConditions);
+        Run("For node stops after configured amount", TestForNodeStopsAfterConfiguredAmount);
+        Run("Item data readable names are stable", TestItemDataReadableNames);
+        Run("Resource files load core game data", TestResourceFilesLoadCoreData);
+
+        GD.Print($"Tests passed: {passedTests}, failed: {failedTests}");
+        GetTree().Quit(failedTests == 0 ? 0 : 1);
+    }
+
+    private void Run(string name, Action test)
+    {
+        try
+        {
+            GameData.ResetRunState();
+            test();
+            passedTests++;
+            GD.Print("[PASS] " + name);
+        }
+        catch (Exception exception)
+        {
+            failedTests++;
+            GD.PrintErr("[FAIL] " + name + ": " + exception.Message);
+        }
+    }
+
+    private void TestInventoryStacksAndRemovesItems()
+    {
+        ItemData stone = GameData.availableItems["stone"];
+        GameData.inventory.AddItem(new Item { data = stone }, stone.StackSize + 5);
+
+        AssertEqual(stone.StackSize + 5, GameData.inventory.GetItemAmount("stone"), "stone amount");
+        AssertEqual(2, GameData.inventory.items.Count, "stone stack count");
+
+        bool removed = GameData.inventory.TryRemoveItem("stone", stone.StackSize);
+
+        AssertTrue(removed, "remove should succeed");
+        AssertEqual(5, GameData.inventory.GetItemAmount("stone"), "remaining stone amount");
+    }
+
+    private void TestInventoryCanCraftAcrossStacks()
+    {
+        ItemData stone = GameData.availableItems["stone"];
+        stone.StackSize = 5;
+        GameData.inventory.AddItem(new Item { data = stone }, 8);
+
+        List<Ingredient> ingredients = new List<Ingredient>
+        {
+            new Ingredient { Item = "stone", Amount = 8 }
+        };
+
+        AssertTrue(GameData.inventory.CanCraft(ingredients, 1), "crafting should see both stacks");
+    }
+
+    private void TestSurvivalConsumesFoodAndWater()
+    {
+        GameData.inventory.AddItem(new Item { data = GameData.availableItems["mushroom"] }, 1);
+        GameData.inventory.AddItem(new Item { data = GameData.availableItems["water"] }, 1);
+        GameData.survival.hunger = 30f;
+        GameData.survival.thirst = 30f;
+
+        GameData.survival.Update(0.1);
+
+        AssertTrue(GameData.survival.hunger > 60f, "hunger should recover");
+        AssertTrue(GameData.survival.thirst > 65f, "thirst should recover");
+        AssertEqual(0, GameData.inventory.GetItemAmount("mushroom"), "mushroom consumed");
+        AssertEqual(0, GameData.inventory.GetItemAmount("water"), "water consumed");
+    }
+
+    private void TestSurvivalDeathDisablesMovement()
+    {
+        GameData.canMove = true;
+        GameData.survival.energy = 0.01f;
+
+        GameData.survival.Update(2.0);
+
+        AssertTrue(GameData.survival.isDead, "survival should be dead");
+        AssertFalse(GameData.canMove, "movement should be disabled");
+    }
+
+    private void TestRobotResearchEffects()
+    {
+        RobotStats stats = new RobotStats();
+        List<ResearchEffect> effects = new List<ResearchEffect>
+        {
+            new ResearchEffect { Stat = "robot_speed_bonus", Value = 0.25f },
+            new ResearchEffect { Stat = "robot_energy_use_reduction", Value = 0.20f },
+            new ResearchEffect { Stat = "robot_cooling_bonus", Value = 0.50f }
+        };
+
+        stats.Apply(effects);
+
+        AssertClose(12.5f, stats.GetMovementSpeed(10f), 0.001f, "movement speed");
+        AssertClose(8f, stats.GetEnergyUse(10f), 0.001f, "energy use");
+        AssertClose(15f, stats.GetCoolingRate(10f), 0.001f, "cooling");
+    }
+
+    private void TestResearchCompletionAppliesEffectsOnce()
+    {
+        ResearchData data = new ResearchData
+        {
+            Id = "test_research",
+            Inputs = new List<Ingredient>(),
+            Research = "basics",
+            CraftTime = 1.0,
+            Texture = "",
+            Effects = new List<ResearchEffect>
+            {
+                new ResearchEffect { Stat = "robot_speed_bonus", Value = 0.10f }
+            }
+        };
+
+        Research research = new Research(data);
+        research.Complete();
+        research.Complete();
+
+        AssertClose(11f, GameData.robotStats.GetMovementSpeed(10f), 0.001f, "research effect applied once");
+    }
+
+    private void TestResourceSaveRoundtrip()
+    {
+        GameResource resource = new GameResource("stone");
+        resource.Extract(2.0);
+
+        ResourceSaveData saveData = resource.CreateSaveData();
+        GameResource loadedResource = GameResource.FromSaveData(saveData);
+
+        AssertEqual(saveData.Name, loadedResource.CreateSaveData().Name, "resource name");
+        AssertEqual(saveData.CurrentAmount, loadedResource.CreateSaveData().CurrentAmount, "resource amount");
+    }
+
+    private void TestRobotSaveRoundtrip()
+    {
+        Robot robot = new Robot
+        {
+            Name = "Ada",
+            Position = new Vector3(1f, 2f, 3f),
+            heat = 44f,
+            maintenance = 55f,
+            isBroken = true,
+            isCoolingDown = true,
+            currentProgram = "Mining",
+            currentMessage = "Needs care",
+            robotType = "bronze_robot"
+        };
+
+        RobotSaveData saveData = robot.CreateSaveData();
+        Robot loadedRobot = new Robot();
+        loadedRobot.LoadSaveData(saveData);
+
+        AssertEqual("Ada", loadedRobot.Name.ToString(), "robot name");
+        AssertEqual("Mining", loadedRobot.currentProgram, "robot program");
+        AssertEqual("bronze_robot", loadedRobot.robotType, "robot type");
+        AssertClose(44f, loadedRobot.heat, 0.001f, "robot heat");
+        AssertClose(55f, loadedRobot.maintenance, 0.001f, "robot maintenance");
+        AssertTrue(loadedRobot.isBroken, "robot broken state");
+        AssertTrue(loadedRobot.isCoolingDown, "robot cooling state");
+    }
+
+    private void TestSaveDataRestoresGlobalState()
+    {
+        GameData.inventory.AddItem(new Item { data = GameData.availableItems["stone"] }, 12);
+        GameData.survival.hunger = 42f;
+        GameData.survival.thirst = 43f;
+        GameData.survival.energy = 44f;
+        GameData.lowestLayer = 3;
+        GameData.availableResearch["stoneage"].Complete();
+
+        SaveGameData saveData = SaveGameManager.CreateSaveData();
+
+        GameData.ResetRunState();
+        SaveGameManager.ApplyWorldData(saveData);
+
+        AssertEqual(12, GameData.inventory.GetItemAmount("stone"), "saved inventory");
+        AssertClose(42f, GameData.survival.hunger, 0.001f, "saved hunger");
+        AssertEqual(3, GameData.lowestLayer, "saved layer");
+        AssertEqual(ResearchState.RESEARCHED, GameData.availableResearch["stoneage"].state, "saved research");
+    }
+
+    private void TestResearchExecutionPaysResourcesAndFinishes()
+    {
+        GameData.inventory.AddItem(new Item { data = GameData.availableItems["stone"] }, 5);
+        ResearchData researchData = new ResearchData
+        {
+            Id = "stone_counterweight",
+            Inputs = new List<Ingredient>
+            {
+                new Ingredient { Item = "stone", Amount = 3 }
+            },
+            Research = "basics",
+            CraftTime = 1.0,
+            Texture = "",
+            Effects = new List<ResearchEffect>()
+        };
+
+        Research research = new Research(researchData);
+        ResearchResult result = research.Execute(1.0);
+
+        AssertEqual(ResearchResult.FINISHED, result, "research result");
+        AssertEqual(2, GameData.inventory.GetItemAmount("stone"), "research cost");
+        AssertEqual(ResearchState.RESEARCHED, research.state, "research state");
+    }
+
+    private void TestInventoryAddFailureKeepsInventoryUnchanged()
+    {
+        GameData.maxRobotCount = 1;
+        GameData.inventory.maxInventorySize = 1;
+        ItemData stone = GameData.availableItems["stone"];
+
+        bool result = GameData.inventory.AddItem(new Item { data = stone }, stone.StackSize + 1);
+
+        AssertFalse(result, "add should fail");
+        AssertEqual(0, GameData.inventory.GetItemAmount("stone"), "failed add should be atomic");
+        AssertEqual(0, GameData.inventory.items.Count, "failed add should not create stacks");
+    }
+
+    private void TestSplitSaveFilesRoundtrip()
+    {
+        GameData.inventory.AddItem(new Item { data = GameData.availableItems["water"] }, 7);
+        GameData.survival.energy = 77f;
+
+        SaveGameManager.SaveGame();
+        SaveGameData saveData = SaveGameManager.LoadSaveData();
+
+        AssertTrue(SaveGameManager.SaveExists(), "save folder should exist");
+        AssertTrue(FileAccess.FileExists("user://savegame/gamedata.json"), "gamedata file");
+        AssertTrue(FileAccess.FileExists("user://savegame/robots.json"), "robots file");
+        AssertTrue(FileAccess.FileExists("user://savegame/research.json"), "research file");
+        AssertEqual(7, saveData.Inventory[0].Amount, "saved file inventory");
+        AssertClose(77f, saveData.Survival.Energy, 0.001f, "saved file energy");
+    }
+
+    private void TestSplitSaveFilesIncludeLayerFiles()
+    {
+        GameData.ruinSize = 2;
+        GameData.map = new Layer[2];
+        GameData.map[0] = CreateTestLayer(0, "spawn");
+        GameData.map[1] = CreateTestLayer(1, "gate");
+
+        SaveGameManager.SaveGame();
+        SaveGameData saveData = SaveGameManager.LoadSaveData();
+
+        AssertTrue(FileAccess.FileExists("user://savegame/layer_0.json"), "layer 0 file");
+        AssertTrue(FileAccess.FileExists("user://savegame/layer_1.json"), "layer 1 file");
+        AssertEqual(2, saveData.Layers.Count, "loaded layer count");
+        AssertEqual("spawn", saveData.Layers[0].Tiles[0].CollapsedMesh, "layer 0 tile");
+        AssertEqual("gate", saveData.Layers[1].Tiles[0].CollapsedMesh, "layer 1 tile");
+    }
+
+    private void TestIfNodeEvaluatesInventoryComparisons()
+    {
+        GameData.inventory.AddItem(new Item { data = GameData.availableItems["stone"] }, 5);
+        IfNode node = new IfNode
+        {
+            selectedItem = new Item { data = GameData.availableItems["stone"] },
+            amount = 3,
+            comparator = "is bigger than"
+        };
+
+        AssertEqual(NodeResult.SUCCESS, node.Execute(null, 0), "if condition true");
+
+        node.amount = 8;
+        AssertEqual(NodeResult.CONDITIONFALSE, node.Execute(null, 0), "if condition false");
+    }
+
+    private void TestWhileNodeReportsFalseConditions()
+    {
+        GameData.inventory.AddItem(new Item { data = GameData.availableItems["water"] }, 2);
+        WhileNode node = new WhileNode
+        {
+            selectedItem = new Item { data = GameData.availableItems["water"] },
+            amount = 5,
+            comparator = "is bigger than or equal to"
+        };
+
+        AssertEqual(NodeResult.CONDITIONFALSE, node.Execute(null, 0), "while condition false");
+    }
+
+    private void TestForNodeStopsAfterConfiguredAmount()
+    {
+        ForNode node = new ForNode
+        {
+            amount = 2
+        };
+
+        AssertEqual(NodeResult.SUCCESS, node.Execute(null, 0), "first iteration");
+        AssertEqual(NodeResult.SUCCESS, node.Execute(null, 0), "second iteration");
+        AssertEqual(NodeResult.CONDITIONFALSE, node.Execute(null, 0), "loop finished");
+    }
+
+    private void TestItemDataReadableNames()
+    {
+        AssertEqual("Iron gear", ItemData.GetReadableName("iron_gear"), "readable name");
+        AssertEqual("iron_gear", ItemData.GetIndex("Iron Gear"), "index name");
+    }
+
+    private void TestResourceFilesLoadCoreData()
+    {
+        AssertTrue(GameData.availableItems.ContainsKey("stone"), "stone item loaded");
+        AssertTrue(GameData.availableItems.ContainsKey("water"), "water item loaded");
+        AssertTrue(GameData.availableResearch.ContainsKey("basics"), "basics research loaded");
+        AssertTrue(GameData.availableResearch.ContainsKey("iron_robotics"), "iron robotics research loaded");
+    }
+
+    private Layer CreateTestLayer(int level, string collapsedMesh)
+    {
+        Layer layer = new Layer
+        {
+            level = level,
+            currentResources = new List<string> { "stone" },
+            gateIngredients = new List<Ingredient>(),
+            tiles = new Tile[1, 1]
+        };
+
+        Tile tile = new Tile
+        {
+            GridPosition = new Vector2I(0, 0),
+            Position = Vector3.Zero,
+            collapsedMesh = collapsedMesh,
+            containsResource = true,
+            resource = new GameResource("stone")
+        };
+
+        layer.tiles[0, 0] = tile;
+        return layer;
+    }
+
+    private void AssertTrue(bool value, string message)
+    {
+        if (!value)
+        {
+            throw new Exception(message);
+        }
+    }
+
+    private void AssertFalse(bool value, string message)
+    {
+        if (value)
+        {
+            throw new Exception(message);
+        }
+    }
+
+    private void AssertEqual<T>(T expected, T actual, string message)
+    {
+        if (!EqualityComparer<T>.Default.Equals(expected, actual))
+        {
+            throw new Exception($"{message}: expected {expected}, got {actual}");
+        }
+    }
+
+    private void AssertClose(float expected, float actual, float tolerance, string message)
+    {
+        if (Math.Abs(expected - actual) > tolerance)
+        {
+            throw new Exception($"{message}: expected {expected}, got {actual}");
+        }
+    }
+}

Scripts/Tests/TestRunner.cs.uid

@@ -0,0 +1 @@
+uid://bm6a1hivjtc8e

Scripts/UI/Common/UIHandler.cs

@@ -107,6 +107,19 @@ public partial class UIHandler : Control
 		GetTree().ChangeSceneToFile("res://Scenes/MainMenu.tscn");
 	}
 
+	public void SaveGame()
+	{
+		SaveGameManager.SaveGame();
+	}
+
+	public void LoadGame()
+	{
+		if (!SaveGameManager.SaveExists()) return;
+
+		GameData.loadSaveOnStart = true;
+		GetTree().ChangeSceneToFile("res://Scenes/Game.tscn");
+	}
+
 	public void OpenUIElement(Control element)
 	{
 		if (element.Visible)

Scripts/UI/Menus/MainMenu.cs

@@ -4,6 +4,15 @@ public partial class MainMenu : Control
 {
 	public void OnPlayPressed()
 	{
+		GameData.loadSaveOnStart = false;
+		GetTree().ChangeSceneToFile("res://Scenes/Game.tscn");
+	}
+
+	public void OnLoadPressed()
+	{
+		if (!SaveGameManager.SaveExists()) return;
+
+		GameData.loadSaveOnStart = true;
 		GetTree().ChangeSceneToFile("res://Scenes/Game.tscn");
 	}
 

Scripts/World/World.cs

@@ -16,6 +16,13 @@ public partial class World : Node3D
 
 	public override void _Ready()
 	{
+		bool shouldLoadSave = loadSaveOnStart && SaveGameManager.SaveExists();
+		SaveGameData saveGame = shouldLoadSave ? SaveGameManager.LoadSaveData() : null;
+		if (saveGame != null)
+		{
+			seed = saveGame.Seed;
+		}
+
 		ResetRunState();
 		WFC.FillAdjacencies();
 
@@ -41,18 +48,27 @@ public partial class World : Node3D
 
 		map = new Layer[ruinSize];
 		GenerateWorld();
+		SetGateRequirements();
+
+		if (shouldLoadSave && saveGame != null)
+		{
+			SaveGameManager.ApplyWorldData(saveGame);
+		}
 
 		Pathfinding.BuildAStarGraph();
 
-		HandleRenderData(BuildRenderData(0));
+		HandleRenderData(BuildRenderData(visibleLayer));
 
-		Robot robot = ResourceLoader.LoadRobotPrefab().Instantiate<Robot>();
-		robot.Name = "Bob";
-		robot.Position = map[0].tiles[0, 0].Position;
-		AddChild(robot);
-		robots.Add(robot);
+		if (shouldLoadSave && saveGame != null)
+		{
+			SpawnSavedRobots(saveGame.Robots);
+		}
+		else
+		{
+			SpawnDefaultRobot();
+		}
 
-		SetGateRequirements();
+		loadSaveOnStart = false;
 	}
 
 	private Dictionary<string, MultiMeshInstance3D> CreateMultiMeshes(Dictionary<string, Mesh> meshLibrary)
@@ -94,17 +110,30 @@ public partial class World : Node3D
 		}
 	}
 
-	private void ResetRunState()
+	private void SpawnDefaultRobot()
 	{
-		survival = new SurvivalState();
-		robotStats = new RobotStats();
-		inventory = new Inventory();
-		availableResearch = ResourceLoader.LoadResearch();
-		robots.Clear();
-		currentLayer = 0;
-		visibleLayer = 0;
-		lowestLayer = 0;
-		canMove = true;
+		Robot robot = ResourceLoader.LoadRobotPrefab().Instantiate<Robot>();
+		robot.Name = "Bob";
+		robot.Position = map[0].tiles[0, 0].Position;
+		AddChild(robot);
+		robots.Add(robot);
+	}
+
+	private void SpawnSavedRobots(List<RobotSaveData> savedRobots)
+	{
+		if (savedRobots == null || savedRobots.Count <= 0)
+		{
+			SpawnDefaultRobot();
+			return;
+		}
+
+		foreach (RobotSaveData savedRobot in savedRobots)
+		{
+			Robot robot = ResourceLoader.LoadRobotPrefab().Instantiate<Robot>();
+			robot.LoadSaveData(savedRobot);
+			AddChild(robot);
+			robots.Add(robot);
+		}
 	}
 
 	private void GenerateWorld()