using UnityEngine;
using UnityEngine.InputSystem;
using Unheimlich.Data;
using Unheimlich.Managers;

namespace Unheimlich.Gameplay.Player
{
    /// <summary>
    /// Handles camera effects: aim assist and shake.
    /// </summary>
    public class CameraEffects : MonoBehaviour
    {
        [Header("Settings")]
        public CameraEffectsSettings Settings;

        private float _shakeTimer = 0f;
        private float _shakeInterval;
        private Vector3 _shakeTarget;
        private Vector3 _shakeOriginalPos;
        private float _shakeSmoothness;
        private Vector3 _pendingAimAssistTarget;
        private bool _hasAimAssistTarget;

        public bool IsAimLocked { get; private set; }
        public bool HasActiveLookInput { get; private set; }
        public bool IsUsingGamepad { get; private set; }

        void Start()
        {
            if (Settings != null)
                _shakeInterval = 1f / Settings.shakeFrequency;
        }

        void Update()
        {
            DetectInputDevice();
        }

        void LateUpdate()
        {
            if (_hasAimAssistTarget)
            {
                ApplyAimAssistInternal(_pendingAimAssistTarget);
            }
        }

        private void DetectInputDevice()
        {
            Vector2 lookInput = InputManager.GetLookInput();
            HasActiveLookInput = lookInput.magnitude > 0.1f;

            if (Gamepad.current != null && Gamepad.current.rightStick.ReadValue().magnitude > 0.1f)
                IsUsingGamepad = true;
            else if (Mouse.current != null && Mouse.current.delta.ReadValue().magnitude > 0.1f)
                IsUsingGamepad = false;
        }

        public void ShakeCamera(float amplitude, float smoothness = 0f)
        {
            if (PlayerController.Instance == null || PlayerController.Instance.CameraPivot == null || Settings == null) 
                return;

            _shakeSmoothness = smoothness;
            _shakeTimer -= Time.deltaTime;

            if (_shakeTimer <= 0f)
            {
                _shakeTimer = _shakeInterval * amplitude;
                _shakeOriginalPos = PlayerController.Instance.CameraPivot.position;

                float x = Random.Range(-1f, 1f) * amplitude;
                float y = Random.Range(-1f, 1f) * amplitude;

                _shakeTarget = _shakeOriginalPos + new Vector3(x, y, 0f);
            }

            if (_shakeSmoothness > 0f)
            {
                PlayerController.Instance.CameraPivot.position = Vector3.Lerp(
                    PlayerController.Instance.CameraPivot.position, 
                    _shakeTarget, 
                    Time.deltaTime * _shakeSmoothness);
            }
            else
            {
                PlayerController.Instance.CameraPivot.position = _shakeTarget;
            }
        }

        public void ApplyAimAssist(Vector3 targetCenter)
        {
            _pendingAimAssistTarget = targetCenter;
            _hasAimAssistTarget = true;
        }

        private void ApplyAimAssistInternal(Vector3 targetCenter)
        {
            if (PlayerController.Instance == null || PlayerController.Instance.CameraTransform == null || Settings == null) 
                return;
            
            if (PlayerController.Instance.Movement == null)
                return;

            if (IsAimLocked && HasActiveLookInput)
                IsAimLocked = false;

            Vector3 directionToTarget = (targetCenter - PlayerController.Instance.CameraTransform.position).normalized;
            float angleError = Vector3.Angle(PlayerController.Instance.CameraTransform.forward, directionToTarget);

            if (IsAimLocked || angleError < Settings.aimAssistMaxAngle)
            {
                Vector3 targetDirection = directionToTarget;
                float targetYaw = Mathf.Atan2(targetDirection.x, targetDirection.z) * Mathf.Rad2Deg;
                float targetPitch = -Mathf.Asin(targetDirection.y) * Mathf.Rad2Deg;
                
                float currentYaw = PlayerController.Instance.Movement.Yaw;
                float currentPitch = PlayerController.Instance.Movement.Pitch;
                
                float newYaw = Mathf.LerpAngle(currentYaw, targetYaw, Settings.aimAssistStrength * Time.deltaTime);
                float newPitch = Mathf.Lerp(currentPitch, targetPitch, Settings.aimAssistStrength * Time.deltaTime);
                
                PlayerController.Instance.Movement.Yaw = newYaw;
                PlayerController.Instance.Movement.Pitch = newPitch;
            }
            
            _hasAimAssistTarget = false;
        }

        public void LockAim(bool locked)
        {
            IsAimLocked = locked;
        }
    }
}