Add AI components and systems for enhanced enemy behavior and pathfinding

GameCore/AI/AIAimSystem.cs

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+using GameCore.Combat;
+using GameCore.ECS;
+using GameCore.ECS.Interfaces;
+using GameCore.Input;
+using GameCore.Physics;
+using GameCore.Player;
+
+namespace GameCore.AI;
+
+public class AIAimSystem : ISystem
+{
+    private const float MinAimDistance = 0.5f;
+
+    public void Update(World world, float deltaTime)
+    {
+        var entities = world.GetEntitiesWith<AIComponent>();
+        foreach (var entity in entities)
+        {
+            if (world.GetComponent<PlayerComponent>(entity) != null)
+            {
+                world.Logger.Warn("AI entity has PlayerComponent; skipping AI aim processing.");
+                continue;
+            }
+
+            var ai = world.GetComponent<AIComponent>(entity);
+            var input = world.GetComponent<InputStateComponent>(entity);
+            var pos = world.GetComponent<PositionComponent>(entity);
+            var weapon = world.GetComponent<WeaponComponent>(entity);
+
+            if (ai == null || input == null || pos == null || weapon == null)
+            {
+                if (input != null) input.IsFiring = false;
+                continue;
+            }
+
+            input.IsFiring = false;
+
+            if (ai.CurrentState == AIState.Chase || ai.CurrentState == AIState.Attack)
+            {
+                var vectorToTarget = ai.LastKnownTargetPosition - input.MuzzlePosition;
+                var distanceToTarget = vectorToTarget.Length();
+
+                if (distanceToTarget > MinAimDistance)
+                {
+                    var directionToTarget = vectorToTarget.Normalize();
+                    input.MuzzleDirection = directionToTarget;
+                    input.LookDirection = directionToTarget;
+                }
+            }
+
+            if (ai.CurrentState == AIState.Attack) input.IsFiring = true;
+        }
+    }
+}

GameCore/AI/AIComponent.cs

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+using GameCore.ECS;
+using GameCore.ECS.Interfaces;
+using GameCore.Math;
+
+namespace GameCore.AI;
+
+public class AIComponent : IComponent
+{
+    public AIState CurrentState { get; set; } = AIState.Idle;
+    public Entity? Target { get; set; }
+    public float StateTimer { get; set; } = 0.0f;
+    public Vector3 LastKnownTargetPosition { get; set; } = Vector3.Zero;
+
+    public float SightRange { get; set; } = 20.0f;
+    public float FieldOfView { get; set; } = 90.0f; // in degrees
+    public float AttackRange { get; set; } = 10.0f;
+    public float ChaseGiveUpTime { get; set; } = 5.0f;
+    public float ReactionTime { get; set; } = 0.5f;
+    public float AttackRangeBufferPercent { get; set; } = 0.2f;
+}

GameCore/AI/AIPathfindingSystem.cs

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+using GameCore.ECS;
+using GameCore.ECS.Interfaces;
+using GameCore.Input;
+using GameCore.Math;
+using GameCore.Physics;
+using GameCore.Player;
+
+namespace GameCore.AI;
+
+public class AIPathfindingSystem : ISystem
+{
+    private const float WaypointReachThreshold = 0.5f;
+
+    public void Update(World world, float deltaTime)
+    {
+        var entities = world.GetEntitiesWith<AIComponent>();
+        foreach (var entity in entities)
+        {
+            if (world.GetComponent<PlayerComponent>(entity) != null) continue;
+
+            var ai = world.GetComponent<AIComponent>(entity);
+            var input = world.GetComponent<InputStateComponent>(entity);
+            var pos = world.GetComponent<PositionComponent>(entity);
+            if (ai == null || input == null || pos == null) continue;
+
+            input.MoveDirection = Vector3.Zero;
+            Vector3? targetPosition = null;
+
+            switch (ai.CurrentState)
+            {
+                case AIState.Chase:
+                    targetPosition = ai.LastKnownTargetPosition;
+                    world.Logger.Debug($"AI Entity {entity.Id} chasing target at {targetPosition}");
+                    break;
+                case AIState.Patrol:
+                    var patrol = world.GetComponent<PatrolComponent>(entity);
+                    if (patrol == null || patrol.PatrolPoints.Count == 0)
+                    {
+                        ai.CurrentState = AIState.Idle;
+                        world.Logger.Debug($"AI Entity {entity.Id} has no patrol points, switching to Idle state.");
+                        continue;
+                    }
+
+                    targetPosition = patrol.PatrolPoints[patrol.CurrentPatrolIndex];
+                    var horizontalDiff = new Vector3(targetPosition.Value.X - pos.Position.X, 0f,
+                        targetPosition.Value.Z - pos.Position.Z);
+                    var distanceToPatrolPoint = horizontalDiff.Length();
+
+                    if (distanceToPatrolPoint < WaypointReachThreshold)
+                    {
+                        patrol.CurrentPatrolIndex++;
+                        if (patrol.CurrentPatrolIndex >= patrol.PatrolPoints.Count)
+                            patrol.CurrentPatrolIndex = patrol.IsLooping ? 0 : patrol.PatrolPoints.Count - 1;
+                        targetPosition = patrol.PatrolPoints[patrol.CurrentPatrolIndex];
+                        world.Logger.Debug(
+                            $"AI Entity {entity.Id} reached patrol point, moving to next point at {targetPosition}");
+                    }
+
+                    break;
+                case AIState.Idle:
+                case AIState.Attack:
+                    world.Logger.Debug($"AI Entity {entity.Id} is in state {ai.CurrentState}, not moving.");
+                    continue;
+            }
+
+            if (targetPosition == null)
+            {
+                world.Logger.Debug($"AI Entity {entity.Id} has no target position.");
+                continue;
+            }
+
+            var path = world.WorldQuery.GetPath(pos.Position, targetPosition.Value);
+            world.Logger.Debug($"Path for AI Entity {entity.Id}: {string.Join(" -> ", path)}");
+
+            if (path.Count > 0)
+            {
+                var nextWaypoint = path[0];
+                var horizontalDiffToWaypoint =
+                    new Vector3(nextWaypoint.X - pos.Position.X, 0f, nextWaypoint.Z - pos.Position.Z);
+                if (horizontalDiffToWaypoint.Length() < 0.1f && path.Count > 1)
+                {
+                    nextWaypoint = path[1];
+                    world.Logger.Debug($"AI Entity {entity.Id} skipping first waypoint, moving to {nextWaypoint}");
+                }
+
+                var directionVector = nextWaypoint - pos.Position;
+                input.MoveDirection = new Vector3(directionVector.X, 0f, directionVector.Z).Normalize();
+                world.Logger.Debug(
+                    $"AI Entity {entity.Id} moving towards waypoint at {nextWaypoint} with direction {input.MoveDirection}");
+            }
+            else
+            {
+                world.Logger.Debug($"AI Entity {entity.Id} has no path.");
+            }
+        }
+    }
+}

GameCore/AI/AIPerceptionSystem.cs

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+using GameCore.ECS;
+using GameCore.ECS.Interfaces;
+using GameCore.Math;
+using GameCore.Movement;
+using GameCore.Physics;
+using GameCore.Player;
+
+namespace GameCore.AI;
+
+public class AIPerceptionSystem : ISystem
+{
+    private readonly Vector3 _aiEyeOffset = new(0f, 1.5f, 0f);
+    private readonly Vector3 _playerCenterOffset = new(0f, 1.0f, 0f);
+
+    public void Update(World world, float deltaTime)
+    {
+        var playerEntities = world.GetEntitiesWith<PlayerComponent>().ToList();
+        if (!playerEntities.Any())
+        {
+            world.Logger.Warn("No player entity found for AI perception.");
+            return;
+        }
+
+        var playerEntity = playerEntities.First();
+        var playerPos = world.GetComponent<PositionComponent>(playerEntity);
+        if (playerPos == null)
+        {
+            world.Logger.Warn("No player position found for AI perception.");
+            return;
+        }
+
+        var aiEntities = world.GetEntitiesWith<AIComponent>();
+        foreach (var entity in aiEntities)
+        {
+            if (world.GetComponent<PlayerComponent>(entity) != null)
+            {
+                world.Logger.Warn("AI Perception System: Skipping player entity.");
+                continue;
+            }
+
+            var ai = world.GetComponent<AIComponent>(entity);
+            var aiPos = world.GetComponent<PositionComponent>(entity);
+            var aiRot = world.GetComponent<RotationComponent>(entity);
+            if (ai == null || aiPos == null || aiRot == null)
+            {
+                world.Logger.Warn("AI Perception System: Skipping AI perception. Missing components.");
+                continue;
+            }
+
+            ai.StateTimer += deltaTime;
+
+            var aiEyePos = aiPos.Position + _aiEyeOffset;
+            var playerCenterPos = playerPos.Position + _playerCenterOffset;
+
+            var vectorToPlayer = playerCenterPos - aiEyePos;
+            var distanceToPlayer = vectorToPlayer.Length();
+            var directionToPlayer = vectorToPlayer.Normalize();
+
+            if (distanceToPlayer < ai.SightRange &&
+                IsInFieldOfView(world, ai, aiRot, directionToPlayer) &&
+                HasLineOfSight(world, aiEyePos, playerCenterPos, entity))
+            {
+                ai.Target = playerEntity;
+                ai.LastKnownTargetPosition = playerPos.Position;
+                ai.StateTimer = 0.0f;
+
+                var attackRangeBuffer = ai.AttackRange * ai.AttackRangeBufferPercent;
+                if (distanceToPlayer <= ai.AttackRange)
+                {
+                    if (ai.CurrentState != AIState.Attack)
+                    {
+                        ai.CurrentState = AIState.Attack;
+                        world.Logger.Debug($"AI Entity {entity.Id} switching to Attack state.");
+                    }
+                }
+                else if (distanceToPlayer > ai.AttackRange + attackRangeBuffer)
+                {
+                    if (ai.CurrentState != AIState.Chase)
+                    {
+                        ai.CurrentState = AIState.Chase;
+                        world.Logger.Debug($"AI Entity {entity.Id} switching to Chase state.");
+                    }
+                }
+            }
+            else
+            {
+                if (ai.Target != null)
+                {
+                    if (ai.StateTimer > ai.ChaseGiveUpTime)
+                    {
+                        ai.Target = null;
+                        ai.CurrentState = world.GetComponent<PatrolComponent>(entity) != null
+                            ? AIState.Patrol
+                            : AIState.Idle;
+                        world.Logger.Debug($"AI Entity {entity.Id} lost target, switching to {ai.CurrentState} state.");
+                    }
+                    else
+                    {
+                        ai.CurrentState = AIState.Chase;
+                        world.Logger.Debug($"AI Entity {entity.Id} continuing to chase last known target position.");
+                    }
+                }
+                else
+                {
+                    ai.CurrentState = world.GetComponent<PatrolComponent>(entity) != null
+                        ? AIState.Patrol
+                        : AIState.Idle;
+                    world.Logger.Debug($"AI Entity {entity.Id} has no target, switching to {ai.CurrentState} state.");
+                }
+            }
+        }
+    }
+
+    private bool HasLineOfSight(World world, Vector3 from, Vector3 to, Entity owner)
+    {
+        var hit = world.WorldQuery.Raycast(from, to, owner);
+        return hit.DidHit && hit.HitEntity.HasValue && world.GetComponent<PlayerComponent>(hit.HitEntity.Value) != null;
+    }
+
+    private bool IsInFieldOfView(World world, AIComponent ai, RotationComponent aiRot, Vector3 directionToPlayer)
+    {
+        var aiForward = world.WorldQuery.RotateVectorByYaw(new Vector3(0f, 0f, 1f), aiRot.Rotation.Y);
+
+        var dotProduct = Vector3.Dot(aiForward, directionToPlayer);
+        var fovRadians = ai.FieldOfView * (float)System.Math.PI / 180f;
+        var fovThreshold = (float)System.Math.Cos(fovRadians / 2f);
+
+        return dotProduct >= fovThreshold;
+    }
+}

GameCore/AI/AIState.cs

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+namespace GameCore.AI;
+
+public enum AIState
+{
+    Idle,
+    Patrol,
+    Chase,
+    Attack
+}

GameCore/AI/PatrolComponent.cs

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+using GameCore.ECS.Interfaces;
+using GameCore.Math;
+
+namespace GameCore.AI;
+
+public class PatrolComponent : IComponent
+{
+    public List<Vector3> PatrolPoints { get; set; } = [];
+    public int CurrentPatrolIndex { get; set; } = 0;
+    public bool IsLooping { get; set; } = false;
+}