using UnityEngine;
using UnityEngine.UI;
using UnityEngine.SceneManagement;

public class gTransBlack : MonoBehaviour
{
    [SerializeField] private Canvas b_Canvas;
    [SerializeField] private CanvasGroup b_CG;
    [SerializeField] private Text nowLoadingText;

    public Canvas Canvas => b_Canvas;
    public CanvasGroup CanvasGroup => b_CG;

    private void Awake()
    {
        EnsureReferences();
        ApplySceneCamera();
    }

    private void OnEnable()
    {
        SceneManager.sceneLoaded -= HandleSceneLoaded;
        SceneManager.sceneLoaded += HandleSceneLoaded;
        ApplySceneCamera();
    }

    private void OnDisable()
    {
        SceneManager.sceneLoaded -= HandleSceneLoaded;
    }

    private void HandleSceneLoaded(Scene scene, LoadSceneMode mode)
    {
        ApplySceneCamera();
    }

    public void RefreshCanvasCamera()
    {
        ApplySceneCamera();
    }

    public void SetNowLoadingText(string text)
    {
        if (nowLoadingText != null)
        {
            nowLoadingText.text = text;
        }
    }

    private void EnsureReferences()
    {
        if (b_Canvas == null)
        {
            b_Canvas = GetComponentInChildren<Canvas>(true);
        }

        if (b_CG == null)
        {
            b_CG = GetComponent<CanvasGroup>();
            if (b_CG == null)
            {
                b_CG = GetComponentInChildren<CanvasGroup>(true);
            }
        }
    }

    private void ApplySceneCamera()
    {
        EnsureReferences();

        if (b_Canvas == null)
        {
            return;
        }

        if (b_Canvas.renderMode == RenderMode.ScreenSpaceOverlay)
        {
            b_Canvas.worldCamera = null;
            return;
        }

        if (b_Canvas.transform.localScale == Vector3.zero)
        {
            b_Canvas.transform.localScale = Vector3.one;
        }

        Camera targetCamera = ResolveFirstSceneCamera();
        if (targetCamera == null)
        {
            return;
        }

        b_Canvas.worldCamera = targetCamera;
    }

    private static Camera ResolveFirstSceneCamera()
    {
        Camera mainCam = Camera.main;
        if (mainCam != null && mainCam.gameObject.scene.IsValid() && mainCam.gameObject.scene.isLoaded)
        {
            return mainCam;
        }

        Camera[] cameras = Object.FindObjectsByType<Camera>(FindObjectsInactive.Exclude, FindObjectsSortMode.None);
        for (int i = 0; i < cameras.Length; i++)
        {
            Camera camera = cameras[i];
            if (camera == null || !camera.isActiveAndEnabled)
            {
                continue;
            }

            if (!camera.gameObject.scene.IsValid() || !camera.gameObject.scene.isLoaded)
            {
                continue;
            }

            return camera;
        }

        return null;
    }
}