Add attribute system with core stats and gameplay components

GameCore/ECS/World.cs

@@ -0,0 +1,113 @@
+using GameCore.Config;
+using GameCore.ECS.Interfaces;
+using GameCore.Events;
+using GameCore.Events.Interfaces;
+using GameCore.Input.Interfaces;
+
+namespace GameCore.ECS;
+
+/// <summary>
+///     The central container for the entire game state.
+///     It manages all entities, components, and systems, and orchestrates the main game loop.
+///     This class is the primary point of interaction for the Engine/Presentation layer.
+/// </summary>
+public class World(IInputService inputService, IWorldQuery worldQuery, SimulationConfig config)
+{
+    private readonly Dictionary<int, List<IComponent>> _componentsByEntityId = new();
+    private readonly EventBus _eventBus = new();
+    private readonly List<ISystem> _systems = [];
+
+    public readonly SimulationConfig Config = config;
+    public readonly IInputService InputService = inputService;
+    public readonly IWorldQuery WorldQuery = worldQuery;
+    private int _nextEntityId;
+
+    /// <summary>
+    ///     Creates a new, unique entity.
+    /// </summary>
+    /// <returns>The newly created Entity.</returns>
+    public Entity CreateEntity()
+    {
+        var id = _nextEntityId++;
+        _componentsByEntityId[id] = [];
+        return new Entity(id);
+    }
+
+    public void DestroyEntity(Entity entity)
+    {
+        _componentsByEntityId.Remove(entity.Id);
+    }
+
+    /// <summary>
+    ///     Adds a component to a given entity.
+    /// </summary>
+    public void AddComponent(Entity entity, IComponent component)
+    {
+        _componentsByEntityId[entity.Id].Add(component);
+    }
+
+    public void RemoveComponent<T>(Entity entity) where T : class, IComponent
+    {
+        if (!_componentsByEntityId.TryGetValue(entity.Id, out var components)) return;
+
+        var componentToRemove = components.OfType<T>().FirstOrDefault();
+        if (componentToRemove != null) components.Remove(componentToRemove);
+    }
+
+    /// <summary>
+    ///     Retrieves a specific type of component from an entity.
+    /// </summary>
+    /// <returns>The component instance, or null if the entity doesn't have it.</returns>
+    public T? GetComponent<T>(Entity entity) where T : class, IComponent
+    {
+        return _componentsByEntityId.TryGetValue(entity.Id, out var components)
+            ? components.OfType<T>().FirstOrDefault()
+            : null;
+    }
+
+    /// <summary>
+    ///     Finds all entities that have a specific component type.
+    /// </summary>
+    public IEnumerable<Entity> GetEntitiesWith<T>() where T : IComponent
+    {
+        return from pair in _componentsByEntityId
+            where pair.Value.Any(c => c is T)
+            select new Entity(pair.Key);
+    }
+
+    /// <summary>
+    ///     Registers a system to be run in the game loop.
+    /// </summary>
+    public void RegisterSystem(ISystem system)
+    {
+        _systems.Add(system);
+    }
+
+    /// <summary>
+    ///     Runs a single tick of the game simulation, updating all registered systems.
+    /// </summary>
+    public void Update(float deltaTime)
+    {
+        foreach (var system in _systems) system.Update(this, deltaTime);
+    }
+
+    public void PublishEvent(IEvent gameEvent)
+    {
+        _eventBus.Publish(gameEvent);
+    }
+
+    public void ProcessEvents()
+    {
+        _eventBus.ProcessEvents();
+    }
+
+    public void Subscribe<T>(Action<T> handler) where T : IEvent
+    {
+        _eventBus.Subscribe(handler);
+    }
+
+    public void Unsubscribe<T>(Action<T> handler) where T : IEvent
+    {
+        _eventBus.Unsubscribe(handler);
+    }
+}