using Sirenix.OdinInspector;
using UnityEngine;

public class HomingBehavior : BulletBehavior
{
    public string targetTag = "Player";

    private Rigidbody _rb;
    private Transform _target;
    [SerializeField] private float range = 15;

    [SerializeField] private float redirectSpeed = 5; // How much rotation is allowed to occur within one second
    private Vector3 _storedVelocity;
    private Vector3 _storedNewVelocity;
    // The angle where the projectile starts to tracking between 0-1
    private readonly Vector2 _lockOnFOV = new Vector2(45, 15);

    private void FixedUpdate()
    {
        // Verify target is in front of the projectile velocity.

        // Track Target
        TrackTarget(Vector3.Distance(_rb.position, _target.position));
    }

    private float ValidTargetDirection(Transform target)
    {
        Transform transformProjectile;
        var rigidBody = (transformProjectile = transform).GetComponent<Rigidbody>();
        var targetDirection = target.position - transformProjectile.position;
        var angle = Vector3.Angle(rigidBody.velocity.normalized, targetDirection);
        var normalizedLockOnRatio = Mathf.InverseLerp(_lockOnFOV.x, _lockOnFOV.y, angle);
        return normalizedLockOnRatio;
    }

    private void TrackTarget(float distance)
    {
        if (distance >= range) return;
        var position = _target.position;
        _storedVelocity = _rb.velocity;
        _storedNewVelocity = (position - _rb.position).normalized * _rb.velocity.magnitude;
        _rb.velocity = Vector3.Lerp(_storedVelocity, _storedNewVelocity, Time.deltaTime * redirectSpeed * ValidTargetDirection(_target));

        // Rotate the bullet towards the target's anticipated position
        var targetVelocity = _target.GetComponent<Rigidbody>().velocity;
        var targetFuturePosition = position + targetVelocity;
        var rotation = Quaternion.LookRotation(targetFuturePosition - _rb.position);
        _rb.MoveRotation(rotation);
    }

    private void OnEnable()
    {
        _rb = GetComponent<Rigidbody>();
        _target = GameObject.FindWithTag(targetTag).transform;
    }

    private void OnDrawGizmos()
    {
        if (!Application.isPlaying) return;
        Gizmos.color = Color.green;
        Gizmos.DrawRay(_rb.position, _rb.velocity);
    }
}