using UnityEngine;

namespace Funique
{
    /// <summary>
    /// Facing direction reflection <br />
    /// Dynamically copy a rotation to another object <br />
    /// This could apply offset, multiple with eularangle, and with ignore direction flag <br />
    /// ------------------------------------------------ <br />
    /// 面向方向映射 <br />
    /// 動態的映射一個物件的旋轉至另一個物件 <br />
    /// 可以套用位移, 乘積到歐拉角, 還有忽略座標軸
    /// </summary>
    [AddComponentMenu("Funique/Core/Dynamic Direction")]
    public class DynamicDirection : MonoBehaviour
    {
        // 欄位
        #region Field
        [SerializeField] Transform Player;
        [SerializeField] Transform Center;
        [SerializeField] Transform Target;
        [SerializeField] Vector3 Offset;
        [SerializeField] Vector3 Multiple = Vector3.one;
        [SerializeField] DirectionFlag Ignore;
        Vector3 dir;
        Quaternion qb;
        #endregion


        // 屬性
        #region Property
        /// <summary>
        /// A vector that player pointing to center <br />
        /// ------------------------------------------------ <br />
        /// 玩家指向中心的向量
        /// </summary>
        public Vector3 Dir => dir;
        /// <summary>
        /// The quaternion of the direction vector <br />
        /// ------------------------------------------------ <br />
        /// 方向向量的四元數換算
        /// </summary>
        public Quaternion QB => qb;
        #endregion


        // Unity 事件
        #region Unity Event
        private void Update()
        {
            if (Player == null || Center == null || Target == null) return;

            dir = (Center.position - Player.position).normalized;
            if (Ignore.HasFlag(DirectionFlag.X)) dir.x = 0;
            if (Ignore.HasFlag(DirectionFlag.Y)) dir.y = 0;
            if (Ignore.HasFlag(DirectionFlag.Z)) dir.z = 0;
            dir = new Vector3(dir.x * Multiple.x, dir.y * Multiple.y, dir.z * Multiple.z);

            qb = Quaternion.LookRotation(dir);
            Target.rotation = qb;
            Target.localEulerAngles += Offset;
        }
        #endregion
    }
}