using System;
using System.Collections.Generic;
using UnityEngine;

public class UIManager : MonoBehaviour
{
    public static UIManager Instance { get; private set; }

    private Dictionary<string, UIBase> uiDict = new Dictionary<string, UIBase>();

    // 三个层级节点：Low, Mid, High
    public Transform lowLayer;
    public Transform midLayer;
    public Transform highLayer;

    private void Awake()
    {
        Instance = this;
    }

    public T OpenUI<T>(object param = null, int layer = 1) where T : UIBase
    {
        string uiName = typeof(T).Name;

        if (uiDict.TryGetValue(uiName, out var ui))
        {
            ui.gameObject.SetActive(true);
            ui.OnOpen(param);
            return ui as T;
        }

        GameObject prefab = Resources.Load<GameObject>($"UI/{uiName}");
        if (prefab == null)
        {
            Debug.LogError($"UI Prefab not found: {uiName}");
            return null;
        }

        Transform parent = GetLayerParent(layer);
        GameObject go = Instantiate(prefab, parent);
        T uiInstance = go.GetComponent<T>();
        if (uiInstance == null)
        {
            Debug.LogError($"UI Prefab does not have component: {uiName}");
            return null;
        }

        uiDict[uiName] = uiInstance;
        uiInstance.OnOpen(param);
        return uiInstance;
    }

    public void CloseUI(string uiName)
    {
        if (uiDict.TryGetValue(uiName, out var ui))
        {
            ui.OnClose();
            Destroy(ui.gameObject);
            uiDict.Remove(uiName);
        }
    }

    public void CloseAll()
    {
        foreach (var kv in uiDict)
        {
            kv.Value.OnClose();
            Destroy(kv.Value.gameObject);
        }
        uiDict.Clear();
    }

    private Transform GetLayerParent(int layer)
    {
        return layer switch
        {
            0 => lowLayer,
            1 => midLayer,
            2 => highLayer,
            _ => midLayer,
        };
    }
}