using UnityEngine;
using UnityEngine.SceneManagement;
using System.IO.Ports;

public class HardwareSceneSwitch : MonoBehaviour
{
    [Header("填写你的Arduino COM口号")]
    public string comPort = "COM3";
    public int baudRate = 9600;

    private SerialPort serial;

    void Start()
    {
        // 打开串口
        serial = new SerialPort(comPort, baudRate);
        serial.ReadTimeout = 10;
        try
        {
            serial.Open();
            Debug.Log("串口已连接，按下硬件按键切换下一场景");
        }
        catch
        {
            Debug.LogError("串口打开失败，检查COM口、关闭Arduino串口监视器");
        }
    }

    void Update()
    {
        if (!serial.IsOpen || serial.BytesToRead <= 0) return;

        string rec = serial.ReadLine().Trim();
        // 收到Arduino的切换指令
        if (rec == "NEXT")
        {
            serial.Close();
            LoadNextScene();
        }
    }

    // 加载下一个场景，末尾循环回第一个场景
    void LoadNextScene()
    {
        int currentIndex = SceneManager.GetActiveScene().buildIndex;
        int totalScenes = SceneManager.sceneCountInBuildSettings;
        int nextIndex = currentIndex + 1;

        // 到达最后一个场景，切回第一个场景
        if (nextIndex >= totalScenes) nextIndex = 0;

        SceneManager.LoadScene(nextIndex);
    }

    // 切换场景/退出时关闭串口，防止占用
    void OnDestroy()
    {
        if (serial != null && serial.IsOpen)
            serial.Close();
    }
}