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

namespace HotUpdate.UI
{
    /// <summary>
    /// 竖屏 UI 页面栈：加载 Prefab、打开/关闭、按名查找。
    /// </summary>
    public sealed class UiManager : MonoBehaviour
    {
        public static UiManager Instance { get; private set; }

        readonly Dictionary<string, GameObject> _opened = new Dictionary<string, GameObject>(StringComparer.Ordinal);
        Transform _root;
        UiPrefabLoader _loader;

        public void Init(Transform root, UiPrefabLoader loader)
        {
            Instance = this;
            _root = root;
            _loader = loader ?? new UiPrefabLoader();
        }

        public GameObject Open(string prefabName, int siblingIndex = -1)
        {
            if (string.IsNullOrEmpty(prefabName)) return null;
            if (_opened.TryGetValue(prefabName, out var existing) && existing != null)
            {
                existing.SetActive(true);
                return existing;
            }

            var prefab = _loader.Load(prefabName);
            if (prefab == null)
            {
                Debug.LogError($"[UiManager] prefab not found: {prefabName}");
                return null;
            }

            var go = Instantiate(prefab, _root, false);
            go.name = prefabName;
            if (siblingIndex >= 0)
                go.transform.SetSiblingIndex(siblingIndex);
            _opened[prefabName] = go;
            return go;
        }

        public T Open<T>(string prefabName) where T : Component
        {
            var go = Open(prefabName);
            return go != null ? go.GetComponentInChildren<T>(true) : null;
        }

        public void Close(string prefabName, bool destroy = false)
        {
            if (!_opened.TryGetValue(prefabName, out var go) || go == null)
                return;
            if (destroy)
            {
                Destroy(go);
                _opened.Remove(prefabName);
            }
            else go.SetActive(false);
        }

        public GameObject Get(string prefabName)
        {
            _opened.TryGetValue(prefabName, out var go);
            return go;
        }

        void OnDestroy()
        {
            if (Instance == this) Instance = null;
        }
    }
}