using System;
using UnityEngine;

[Serializable]
public class EnemyChasePlayer : State<Character>
{
    StatData moveSpeedPerSecStat;
    float moveSpeedPerSec => moveSpeedPerSecStat != null ? moveSpeedPerSecStat.Value : 0;

    Entity target;
    float sqrtTargetDist;

    protected override void OnInitialize()
    {
        Owner.Excutor.Data.TryGetStat(StatID.MoveSpeedPerSec, out moveSpeedPerSecStat);
    }

    public override void Enter()
    {
        if(target is null)
        {
            Owner.ChangeState<EnemyIdle>();
            return;
        }

        Debug.Assert(Owner.Excutor.SkeletonAnimation.TryGetAnimation("move", out Spine.Animation _), "move animation not exist");
        Owner.Excutor.SkeletonAnimation.AnimationState.SetAnimation(0, "move", true);
    }

    public override void Excute()
    {
        if(target is null)
        {
            Owner.ChangeState<EnemyIdle>();
        }
        else
        {
            Owner.Excutor.ChangeLookDirection(target.transform);
            Vector2 to = target.Position - Owner.Excutor.Position;

            if (to.sqrMagnitude <= sqrtTargetDist)
            {
                Owner.ChangeState<EnemyIdle>();
            }
            else
            {
                Vector3 newPosition = Owner.transform.position + (Vector3)(to.normalized * moveSpeedPerSec * Time.fixedDeltaTime);
                Owner.transform.position = newPosition;
            }
        }
    }

    public override void Exit()
    {
        target = null;
        sqrtTargetDist = 0;
    }

    public void SetTarget(Entity target, float targetDist)
    {
        this.target = target;
        sqrtTargetDist = targetDist * targetDist;
    }
}