BABA_YAGA/Assets/Scripts/UI/UIManager.cs

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

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

        [System.Serializable]
        public class ScreenData
        {
            public string screenName;
            public UIDocument document;
            public bool isOverlay;
            public Texture2D customCursor;
            public bool isActive; // For Editor and Initial state
        }

        public List<ScreenData> screens = new List<ScreenData>();
        
        [Header("Settings")]
        public string initialScreen = "MainMenu";
        public float focusRadius = 300f;
        [Range(0f, 1f)]
        public float globalOpacity = 1f;

        private Stack<string> _navigationStack = new Stack<string>();
        private string _currentScreenName;
        private VisualElement _lastHoveredElement;

        private void Awake()
        {
            if (Instance == null) Instance = this;
            else { Destroy(gameObject); return; }

            // Initialize all screens based on isActive or hidden
            foreach (var screen in screens)
            {
                if (screen.document != null)
                {
                    // Ensure the root has the screen-root class for transitions
                    var root = screen.document.rootVisualElement;
                    if (root != null)
                    {
                        root.AddToClassList("screen-root");
                        root.style.display = DisplayStyle.None;
                    }
                }
            }

            ShowScreen(initialScreen);
        }

        private void Update()
        {
            HandleGlobalInputs();
            HandleCursorlessFocus();
        }

        // --- Editor Support Methods ---

        public void SyncScreens()
        {
            foreach (var screen in screens)
            {
                if (screen.document != null && screen.document.rootVisualElement != null)
                {
                    screen.document.rootVisualElement.style.display = 
                        screen.isActive ? DisplayStyle.Flex : DisplayStyle.None;
                    screen.document.rootVisualElement.style.opacity = globalOpacity;
                }
            }
        }

        public void ShowOnly(string name)
        {
            foreach (var screen in screens)
            {
                screen.isActive = (screen.screenName == name);
            }
            SyncScreens();
        }

        // --- Runtime Logic ---

        private void HandleGlobalInputs()
        {
            if ((Input.GetKey(KeyCode.LeftControl) || Input.GetKey(KeyCode.RightControl)) && Input.GetKeyDown(KeyCode.O))
            {
                ToggleSettings();
            }

            if (Input.GetKeyDown(KeyCode.Escape))
            {
                if (_navigationStack.Count > 1)
                {
                    GoBack();
                }
            }
        }

        private void HandleCursorlessFocus()
        {
            if (string.IsNullOrEmpty(_currentScreenName)) return;

            var screen = screens.Find(s => s.screenName == _currentScreenName);
            if (screen == null || screen.document == null) return;

            Vector2 mousePos = Input.mousePosition;
            Vector2 uiMousePos = new Vector2(mousePos.x, Screen.height - mousePos.y);

            VisualElement bestElement = null;
            float minDistance = float.MaxValue;

            var interactiveElements = screen.document.rootVisualElement.Query<VisualElement>()
                .Where(e => e.focusable && e.pickingMode == PickingMode.Position).ToList();

            foreach (var element in interactiveElements)
            {
                Rect worldBounds = element.worldBound;
                Vector2 center = worldBounds.center;
                float dist = Vector2.Distance(uiMousePos, center);

                if (dist < minDistance && dist < focusRadius)
                {
                    minDistance = dist;
                    bestElement = element;
                }
            }

            if (bestElement != _lastHoveredElement)
            {
                _lastHoveredElement?.RemoveFromClassList("hover");
                bestElement?.AddToClassList("hover");
                _lastHoveredElement = bestElement;
            }

            if (Input.GetMouseButtonDown(0) && _lastHoveredElement != null)
            {
                using (var clickEvent = ClickEvent.GetPooled())
                {
                    clickEvent.target = _lastHoveredElement;
                    _lastHoveredElement.SendEvent(clickEvent);
                }
            }
        }

        public void ShowScreen(string name)
        {
            var nextData = screens.Find(s => s.screenName == name);
            if (nextData == null) return;

            // Hide all first for a clean state at runtime
            foreach (var s in screens)
            {
                if (s.document != null) s.document.rootVisualElement.style.display = DisplayStyle.None;
                s.isActive = false;
            }

            _navigationStack.Push(name);
            _currentScreenName = name;
            nextData.isActive = true;
            
            nextData.document.rootVisualElement.style.display = DisplayStyle.Flex;
            nextData.document.rootVisualElement.style.opacity = globalOpacity;
            ApplyCursorSettings(nextData);
        }

        public void GoBack()
        {
            if (_navigationStack.Count <= 1) return;

            string current = _navigationStack.Pop();
            var currentData = screens.Find(s => s.screenName == current);
            if (currentData != null) currentData.document.rootVisualElement.style.display = DisplayStyle.None;

            _currentScreenName = _navigationStack.Peek();
            var prevData = screens.Find(s => s.screenName == _currentScreenName);
            if (prevData != null)
            {
                prevData.document.rootVisualElement.style.display = DisplayStyle.Flex;
                ApplyCursorSettings(prevData);
            }
        }

        public void ToggleSettings()
        {
            var settings = screens.Find(s => s.screenName == "Settings");
            if (settings == null) return;

            bool isShowing = settings.document.rootVisualElement.style.display == DisplayStyle.Flex;
            settings.document.rootVisualElement.style.display = isShowing ? DisplayStyle.None : DisplayStyle.Flex;
            
            if (!isShowing)
            {
                settings.document.sortingOrder = 999;
            }
        }

        private void ApplyCursorSettings(ScreenData data)
        {
            if (data.screenName == "HUD")
            {
                UnityEngine.Cursor.visible = false;
                UnityEngine.Cursor.lockState = CursorLockMode.Locked;
            }
            else
            {
                UnityEngine.Cursor.visible = false;
                UnityEngine.Cursor.lockState = CursorLockMode.None;
            }
        }
    }
}