using System;
using JetBrains.Annotations;
using UnityEngine;

namespace Camera
{
    public class CameraFollow : MonoBehaviour
    {
        [CanBeNull] public static CameraFollow Current;
        private Transform _followTarget;
        
        private float _defaultYaw;
        private bool _enableMove;
        private float _height;
        
        [CanBeNull]
        public Transform followTarget
        {
            get => _followTarget;
            set {
                if (_followTarget == value) return;
                
                _followTarget = value;
        
                if (_followTarget != null)
                    OnFollowTargetChanged(value);
                else
                    OnFollowTargetLost();
            }
        }
        
        private void Awake()
        {
            _defaultYaw = rotationYaw.eulerAngles.y;
            
            if (Current != null)
                Debug.LogWarning("Duplicate CameraFollow Found!");
            Current = this;
            followTarget = defaultFollowTarget;
        }

        [Header("Parameters")] 
        [SerializeField] private bool enableYaw;
        [SerializeField] private Transform defaultFollowTarget;
        [SerializeField] [Range(0.015f, 1f)] private float yawRotationLerp;
        [SerializeField] [Range(0.015f, 1f)] private float positionLerp;
        [SerializeField] [Range(0.015f, 1f)] private float heightLerp;
        [SerializeField] private LayerMask heightCheckLayerMask;

        [Header("Bindings")] 
        [SerializeField] private Transform rotationYaw;
        [SerializeField] private Transform rotationPitch;
        [SerializeField] private Transform positionCamera;
        [SerializeField] private Transform positionHeight;

        private void OnFollowTargetChanged([CanBeNull] Transform target)
        {
            Debug.Log($"Follow target: {target?.name}");
            _enableMove = target != null;
        }
        
        private void OnFollowTargetLost()
        {
            Debug.Log("Follow target lost");
            _enableMove = false;
        }
        
        private void FixedUpdate()
        {
            FixedUpdateHeight();
            
            if (_enableMove)
            {
                try
                {
                    FixedUpdateMoveCamera();
                }
                catch (NullReferenceException)
                {
                    OnFollowTargetLost();
                }
            }
        }

        private void FixedUpdateMoveCamera()
        {
            var transformYaw = _followTarget.rotation.eulerAngles.y;
            var transformPosition = _followTarget.position;

            var targetYaw = transformYaw;
            var targetYawRotation = Quaternion.Euler(0, enableYaw ? targetYaw : _defaultYaw, 0);
            var targetPosition = new Vector3(transformPosition.x, 0, transformPosition.z);
            
            transform.position = Vector3.Lerp(transform.position, targetPosition, positionLerp);
            rotationYaw.rotation = Quaternion.Lerp(rotationYaw.rotation, targetYawRotation, yawRotationLerp);
            positionHeight.position = new Vector3(
                transformPosition.x,
                Mathf.Lerp(positionHeight.position.y, _height, heightLerp),
                transformPosition.z
                );
        }

        private void FixedUpdateHeight()
        {
            var transformPosition = transform.position;
            var start = transformPosition + Vector3.up * 100;
            var end = transformPosition + Vector3.down * 100;
            Physics.Linecast(start, end, out RaycastHit hit, heightCheckLayerMask);
            if (hit.collider == null)
                _height = transformPosition.y;
            else
                _height = hit.point.y;
        }
        
        private void OnDestroy()
        {
            if (Current == this)
                Current = null;
        }
    }
}