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

namespace Core
{
    public enum UILayer
    {
        Background,
        Normal,
        Popup,
        Top
    }

    /// <summary>
    /// 单例UI管理者，控制UI的层级关系，UI的开关
    /// </summary>
    public class UIManager : MonoSingleton<UIManager>
    {
        public bool IsHasNonBackgroundUIActive
        {
            get
            { return openedUIs.Values.Any(ui => ui.gameObject.activeSelf && ui.transform.parent != layerRoots[UILayer.Background]); }
        }

        private Dictionary<UILayer, Transform> layerRoots = new Dictionary<UILayer, Transform>();
        private Dictionary<string, UIBase> openedUIs = new Dictionary<string, UIBase>();
        
        private IInputManager inputManager;
        
        public void RegisterInputManager(IInputManager inputMgr)
        {
            inputManager = inputMgr;
        }

        public void RegisterLayer(UILayer layer, Transform root)
        {
            if (!layerRoots.ContainsKey(layer))
            {
                layerRoots[layer] = root;

                // 注册场景中已存在的UI
                // 遍历子对象
                foreach (Transform child in root)
                {
                    var uiName = child.gameObject.name;
                    UIBase uiBase = child.GetComponent<UIBase>();
                    if (uiBase != null && !openedUIs.ContainsKey(uiName))
                    {
                        openedUIs[uiName] = uiBase;
                        uiBase.Hide(); // 默认关闭
                        if (uiBase.IsOpenOnFirstLoad)
                        {
                            uiBase.Show();
                        }
                    }
                }
            }
        }

        public T OpenUI<T>(UILayer layer = UILayer.Normal) where T : Component
        {
            string uiName = typeof(T).Name;
            if (openedUIs.ContainsKey(uiName))
            {
                openedUIs[uiName].Show();
                UpdateCursorState();
                return openedUIs[uiName] as T;
            }
            // 加载UI预制体
            GameObject prefab = Resources.Load<GameObject>("UI/" + uiName); // 从 Resources/UI 文件夹加载UI预制体
            if (prefab == null)
            {
                Debug.LogError("UI Prefab not found: " + uiName);
                return null;
            }

            GameObject uiObj = Instantiate(prefab, layerRoots[layer]); // 实例化并设置父对象
            UIBase uiBase = uiObj.GetComponent<UIBase>(); // 获取UIBase组件
            openedUIs[uiName] = uiBase; // 注册到字典中
            uiBase.Show(); // 显示UI
            UpdateCursorState(); // 更新鼠标状态
            return uiBase as T;
        }

        public void CloseUI<T>() where T : Component
        {
            string uiName = typeof(T).Name;
            if (openedUIs.ContainsKey(uiName))
            {
                openedUIs[uiName].Hide();
                UpdateCursorState();
            }
        }

        // 来回切换UI状态，按同一个键实现UI的开关
        public void SwitchUI<T>(UILayer layer = UILayer.Normal) where T : Component
        {
            string uiName = typeof(T).Name;
            if (openedUIs.ContainsKey(uiName) && openedUIs[uiName].gameObject.activeSelf)
            {
                CloseUI<T>();
            }
            else
            {
                OpenUI<T>(layer);
            }
        }

        public Dictionary<UILayer, List<GameObject>> GetExistingUIsByLayer()
        {
            var result = new Dictionary<UILayer, List<GameObject>>();
            foreach (var kvp in layerRoots)
            {
                var layer = kvp.Key;
                var root = kvp.Value;
                var uiList = new List<GameObject>();
                foreach (Transform child in root)
                {
                    UIBase uiBase = child.GetComponent<UIBase>();
                    if (uiBase != null)
                        uiList.Add(uiBase.gameObject);
                }
                result[layer] = uiList;
            }
            return result;
        }


        private void UpdateCursorState()
        {
            if(inputManager == null) return;
            bool shouldLockCursor = !IsHasNonBackgroundUIActive; //&& !isInMainMenu; // 仅在没有非Background UI且不在主菜单时锁定鼠标
            if (shouldLockCursor)
            {
                inputManager.SetCursorState(false, CursorLockMode.Locked);
            }
            else
            {
                inputManager.SetCursorState(true, CursorLockMode.None);
                
            }
            inputManager.SetInputForLook(shouldLockCursor);
            inputManager.SetInputForMove(shouldLockCursor);
        }
    }
}