using System;
using System.Threading;
using BriarQueen.Framework.Coordinators.Events;
using BriarQueen.Framework.Events.UI;
using BriarQueen.Framework.Managers.Audio;
using BriarQueen.Framework.Managers.Interaction;
using BriarQueen.Framework.Managers.IO;
using BriarQueen.Framework.Managers.Levels;
using BriarQueen.Framework.Managers.UI.Base;
using BriarQueen.Framework.Managers.UI.Events;
using BriarQueen.Framework.Services.Game;
using BriarQueen.UI.Menus.Components;
using Cysharp.Threading.Tasks;
using PrimeTween;
using TMPro;
using UnityEngine;
using UnityEngine.EventSystems;
using UnityEngine.UI;
using VContainer;

namespace BriarQueen.UI.Menus
{
    public class PauseMenuWindow : MonoBehaviour, IUIWindow, IUIOverlayHost
    {
        [Header("Root UI")]
        [SerializeField] private CanvasGroup _canvasGroup;
        [SerializeField] private RectTransform _windowRect;

        [Header("Background")]
        [SerializeField] private CanvasGroup _backgroundGroup;

        [Header("Transient Info")]
        [SerializeField] private TextMeshProUGUI _levelName;

        [Header("Buttons")]
        [SerializeField] private UnderlineButton _resumeButton;
        [SerializeField] private UnderlineButton _saveButton;
        [SerializeField] private UnderlineButton _settingsButton;
        [SerializeField] private UnderlineButton _exitButton;
        [SerializeField] private UnderlineButton _quitToDesktopButton;

        [Header("Layout")]
        [SerializeField] private CanvasGroup _buttonsGroup;

        [Header("Selection")]
        [SerializeField] private Selectable _firstSelectedOnOpen;

        [Header("Tween Settings")]
        [SerializeField] private TweenSettings _backgroundFadeSettings = new()
        {
            duration        = 0.4f,
            ease            = Ease.OutQuad,
            useUnscaledTime = true
        };

        [SerializeField] private TweenSettings _buttonFadeSettings = new()
        {
            duration        = 0.25f,
            ease            = Ease.OutQuad,
            useUnscaledTime = true
        };

        [Header("Scale")]
        [SerializeField] private float _hiddenScale = 0.85f;

        [Header("Internal")]
        [SerializeField] private GraphicRaycaster _graphicRaycaster;

        private AudioManager _audioManager;
        private EventCoordinator _eventCoordinator;
        private GameService _gameService;
        private InteractManager _interactManager;
        private SaveManager _saveManager;
        private LevelManager _levelManager;

        private CancellationTokenSource _cts;
        private Sequence _sequence;
        private bool _raycasterRegistered;

        public bool IsModal => true;
        public WindowType WindowType => WindowType.PauseMenuWindow;
        public UIPauseBehavior PauseBehavior => UIPauseBehavior.TreatAsBackRequest;

        public bool CanSuspendFor(WindowType incomingWindowType)
        {
            return incomingWindowType == WindowType.SettingsWindow;
        }
        
        private void EnsureExclusiveRaycaster()
        {
            if (_interactManager == null || _graphicRaycaster == null)
                return;

            if (!_raycasterRegistered)
            {
                _interactManager.AddUIRaycaster(_graphicRaycaster);
                _raycasterRegistered = true;
            }

            _interactManager.SetExclusiveRaycaster(_graphicRaycaster);
        }
        
        private void TryUnregisterRaycaster()
        {
            if (!_raycasterRegistered)
                return;

            if (_interactManager == null || _graphicRaycaster == null)
                return;

            _interactManager.RemoveUIRaycaster(_graphicRaycaster);
            _interactManager.ReleaseExclusiveRaycaster(_graphicRaycaster);
            _raycasterRegistered = false;
        }

        // ── Unity lifecycle ───────────────────────────────────────────

        private void Awake()
        {
            if (_canvasGroup != null)
            {
                _canvasGroup.alpha          = 0f;
                _canvasGroup.blocksRaycasts = false;
                _canvasGroup.interactable   = false;
            }

            if (_windowRect != null)
                _windowRect.localScale = Vector3.one;

            SetGroupImmediate(_backgroundGroup, 0f);
            HideButtons();
        }

        private void OnEnable()
        {
            BindButtons();
        }

        private void OnDisable()
        {
            UnbindButtons();
        }

        private void OnDestroy()
        {
            StopAndResetCancellation();
            TryUnregisterRaycaster();
        }

        // ── IUIWindow ─────────────────────────────────────────────────

        public async UniTask Show()
        {
            StopAndResetCancellation();

            SetLevelName();
            
            gameObject.SetActive(true);
            EnsureExclusiveRaycaster();
            
            _canvasGroup.blocksRaycasts = false;
            _canvasGroup.interactable   = false;

            SetGroupImmediate(_backgroundGroup, 0f);
            HideButtons();

            try
            {
                var fadeWindowTask = FadeGroup(_canvasGroup, 1f, _backgroundFadeSettings, _cts.Token);
                var fadeBackgroundTask = FadeGroup(_backgroundGroup, 1f, _backgroundFadeSettings, _cts.Token);
                
                await UniTask.WhenAll(fadeWindowTask, fadeBackgroundTask);
                
                _backgroundGroup.blocksRaycasts = true;
                _backgroundGroup.interactable   = true;
                
                _buttonsGroup.blocksRaycasts = true;
                _buttonsGroup.interactable   = true;

                await FadeGroup(_buttonsGroup, 1f, _buttonFadeSettings, _cts.Token);
            }
            catch (OperationCanceledException)
            {
                return;
            }

            _canvasGroup.alpha = 1f;
            _canvasGroup.blocksRaycasts = true;
            _canvasGroup.interactable   = true;
        }

        public async UniTask Hide()
        {
            StopAndResetCancellation();

            _canvasGroup.blocksRaycasts = true;
            _canvasGroup.interactable   = false;

            try
            {
                await FadeGroup(_buttonsGroup, 0f, _buttonFadeSettings, _cts.Token);
                await FadeGroup(_backgroundGroup, 0f, _backgroundFadeSettings, _cts.Token);
            }
            catch (OperationCanceledException)
            {
                return;
            }
            
            _resumeButton.SetSelectedState(false);
            _saveButton.SetSelectedState(false);
            _settingsButton.SetSelectedState(false);
            _exitButton.SetSelectedState(false);
            _quitToDesktopButton.SetSelectedState(false);

            _canvasGroup.alpha          = 0f;
            _canvasGroup.blocksRaycasts = false;
            _canvasGroup.interactable   = false;

            TryUnregisterRaycaster();
            gameObject.SetActive(false);
        }

        public async UniTask SuspendForOverlay()
        {
            StopAndResetCancellation();

            _buttonsGroup.blocksRaycasts = false;
            _buttonsGroup.interactable   = false;

            try
            {
                await FadeGroup(_buttonsGroup, 0f, _buttonFadeSettings, _cts.Token);
            }
            catch (OperationCanceledException)
            {
                return;
            }
        }

        public async UniTask ResumeFromOverlay()
        {
            StopAndResetCancellation();
            EnsureExclusiveRaycaster();

            _buttonsGroup.blocksRaycasts = true;
            _buttonsGroup.interactable   = true;

            try
            {
                await FadeGroup(_buttonsGroup, 1f, _buttonFadeSettings, _cts.Token);
            }
            catch (OperationCanceledException)
            {
                return;
            }

            SelectDefault();
        }

        // ── DI ────────────────────────────────────────────────────────

        [Inject]
        public void Construct(
            EventCoordinator eventCoordinator,
            SaveManager saveManager,
            GameService gameService,
            InteractManager interactManager,
            AudioManager audioManager,
            LevelManager levelManager)
        {
            _eventCoordinator = eventCoordinator;
            _saveManager      = saveManager;
            _gameService      = gameService;
            _interactManager  = interactManager;
            _audioManager     = audioManager;
            _levelManager     = levelManager;
        }

        // ── Level ─────────────────────────────────────────────────────

        private void SetLevelName()
        {
            if (_levelManager == null || _levelName == null)
                return;

            var currentLevel = _levelManager.CurrentLevel;

            if (!string.IsNullOrEmpty(currentLevel.LevelName))
                _levelName.text = currentLevel.LevelName;
        }

        // ── Button binding ────────────────────────────────────────────

        private void BindButtons()
        {
            if (_resumeButton != null)
                _resumeButton.SelectionRequested += OnResumeClicked;

            if (_saveButton != null)
                _saveButton.SelectionRequested += OnSaveClicked;

            if (_settingsButton != null)
                _settingsButton.SelectionRequested += OnSettingsClicked;

            if (_exitButton != null)
                _exitButton.SelectionRequested += OnExitClicked;

            if (_quitToDesktopButton != null)
                _quitToDesktopButton.SelectionRequested += OnQuitToDesktopClicked;
        }

        private void UnbindButtons()
        {
            if (_resumeButton != null)
                _resumeButton.SelectionRequested -= OnResumeClicked;

            if (_saveButton != null)
                _saveButton.SelectionRequested -= OnSaveClicked;

            if (_settingsButton != null)
                _settingsButton.SelectionRequested -= OnSettingsClicked;

            if (_exitButton != null)
                _exitButton.SelectionRequested -= OnExitClicked;

            if (_quitToDesktopButton != null)
                _quitToDesktopButton.SelectionRequested -= OnQuitToDesktopClicked;
        }

        // ── Button callbacks ──────────────────────────────────────────

        private void OnResumeClicked(UnderlineButton _)
        {
            _eventCoordinator?.Publish(new PauseButtonClickedEvent());
        }

        private void OnSaveClicked(UnderlineButton _)
        {
            SaveGame().Forget();
        }

        private void OnSettingsClicked(UnderlineButton _)
        {
            _eventCoordinator?.Publish(new UIToggleSettingsWindow(true, SettingsOpenSource.PauseMenu));
        }

        private void OnExitClicked(UnderlineButton _)
        {
            _eventCoordinator?.Publish(new FadeEvent(false, 1f));
            ExitInternal().Forget();
        }

        private void OnQuitToDesktopClicked(UnderlineButton _)
        {
            QuitInternal().Forget();
        }

        // ── Internal async ────────────────────────────────────────────

        private async UniTask ExitInternal()
        {
            await UniTask.Delay(TimeSpan.FromSeconds(1));

            _audioManager?.StopAllAudio();

            await SaveGame();

            _eventCoordinator?.Publish(new PauseButtonClickedEvent());

            await _gameService.LoadMainMenu();
        }

        private async UniTask QuitInternal()
        {
            _eventCoordinator?.Publish(new FadeEvent(false, 1f));

            await UniTask.Delay(TimeSpan.FromSeconds(1));

            await SaveGame();

            _gameService?.QuitGame();
        }

        private async UniTask SaveGame()
        {
            if (_saveManager == null)
                return;

            await _saveManager.SaveGameDataLatest();
        }

        // ── Layout helpers ────────────────────────────────────────────

        private void HideButtons()
        {
            SetGroupImmediate(_buttonsGroup, 0f);
        }

        private static void SetGroupImmediate(CanvasGroup group, float alpha)
        {
            if (group == null)
                return;

            group.alpha          = alpha;
            group.interactable   = false;
            group.blocksRaycasts = false;
        }

        private async UniTask FadeGroup(
            CanvasGroup group,
            float target,
            TweenSettings settings,
            CancellationToken token)
        {
            if (group == null)
                return;

            await Tween.Alpha(group, new TweenSettings<float>
            {
                startValue = group.alpha,
                endValue   = target,
                settings   = settings
            }).ToUniTask(cancellationToken: token);

            group.alpha = target;
        }

        // ── Selection ─────────────────────────────────────────────────

        private void SelectDefault()
        {
            if (EventSystem.current == null)
                return;

            EventSystem.current.SetSelectedGameObject(null);

            if (_firstSelectedOnOpen != null)
            {
                EventSystem.current.SetSelectedGameObject(
                    _firstSelectedOnOpen.gameObject);
            }
            else if (_resumeButton != null)
            {
                EventSystem.current.SetSelectedGameObject(
                    _resumeButton.gameObject);
            }

            Debug.Log(
                $"[PauseMenuWindow] Selected: {EventSystem.current.currentSelectedGameObject}");
        }

        // ── CTS ───────────────────────────────────────────────────────

        private void StopAndResetCancellation()
        {
            if (_sequence.isAlive)
                _sequence.Stop();

            if (_cts != null)
            {
                try
                {
                    _cts.Cancel();
                }
                catch
                {
                }

                _cts.Dispose();
            }

            _cts = new CancellationTokenSource();
        }
    }
}