using UnityEngine;
using UnityEngine.InputSystem;
using Unheimlich.Core;
using Unheimlich.Features.Player.Data;
using Unheimlich.Features.Dialogue;
using InputManager = Unheimlich.Core.Input.InputManager;

namespace Unheimlich.Features.Player
{
    /// <summary>
    /// Handles camera effects: aim assist, shake, and FOV kick on sprint.
    /// </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;

        // FOV kick
        private float _baseFov = -1f;
        private float _currentFovOffset = 0f;

        // External FOV override — when >= 0, UpdateFovKick uses this as the base FOV
        // instead of the locally cached snapshot. Set by HouseOfLeavesController each frame.
        // Consumed once per frame — caller must re-submit every Update.
        private float _externalBaseFov = -1f;

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

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

            if (PlayerController.Instance?.PlayerCamera != null)
                _baseFov = PlayerController.Instance.PlayerCamera.fieldOfView;
        }

        private void Update()
        {
            DetectInputDevice();
            UpdateFovKick();
        }

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

        // ── FOV Kick ──────────────────────────────────────────────────────────────

        private void UpdateFovKick()
        {
            if (Settings == null || PlayerController.Instance?.PlayerCamera == null) return;

            // Use the external override if submitted this frame, otherwise fall back
            // to the locally cached base FOV.
            float effectiveBase = _externalBaseFov >= 0f ? _externalBaseFov : _baseFov;

            if (effectiveBase < 0f)
            {
                effectiveBase = PlayerController.Instance.PlayerCamera.fieldOfView;
                _baseFov      = effectiveBase;
            }

            float targetOffset    = PlayerController.Instance.IsRunning ? Settings.fovKickAmount : 0f;
            _currentFovOffset     = Mathf.Lerp(_currentFovOffset, targetOffset, Time.deltaTime * Settings.fovKickSpeed);

            PlayerController.Instance.PlayerCamera.fieldOfView = effectiveBase + _currentFovOffset;

            // Consume the override — must be re-submitted next frame by the caller.
            _externalBaseFov = -1f;
        }

        /// <summary>
        /// Overrides the base FOV used by the sprint kick for this frame.
        /// Call every Update from HouseOfLeavesController — consumed automatically after use.
        /// Must be called before CameraEffects.Update runs (use Script Execution Order -10).
        /// </summary>
        public void SetBaseFovOverride(float fov) => _externalBaseFov = fov;

        /// <summary>
        /// Resets the locally cached base FOV to the camera's current fieldOfView.
        /// </summary>
        public void ResetBaseFov()
        {
            if (PlayerController.Instance?.PlayerCamera != null)
                _baseFov = PlayerController.Instance.PlayerCamera.fieldOfView;
        }

        // ── Input device detection ────────────────────────────────────────────────

        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;
        }

        // ── Camera Shake ──────────────────────────────────────────────────────────

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

            PlayerEvents.TriggerCameraShake(amplitude);

            _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;
            }
        }

        // ── Aim Assist ────────────────────────────────────────────────────────────

        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.State.Yaw;
                float currentPitch = PlayerController.Instance.Movement.State.Pitch;

                float newYaw   = Mathf.LerpAngle(currentYaw,   targetYaw,   Settings.aimAssistStrength * Time.deltaTime);
                float newPitch = Mathf.Lerp(currentPitch,       targetPitch, Settings.aimAssistStrength * Time.deltaTime);

                PlayerController.Instance.Movement.State.Yaw   = newYaw;
                PlayerController.Instance.Movement.State.Pitch = newPitch;
            }

            _hasAimAssistTarget = false;
        }

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