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;
    }
}