using UnityEngine;
using System.Collections.Generic;
using TMPro;
using Unheimlich.Data.Dialogues;
using Unheimlich.Gameplay.Player;
using Unheimlich.Interactions.FloatingWords;
using Unheimlich.Utility;

namespace Unheimlich.UI
{
    /// <summary>
    /// Manages dialogue UI display and choice button spawning with configurable animations.
    /// Supports multiple spawn modes, distance scaling, player following, and visual effects.
    /// </summary>
    public class DialogueUI : MonoBehaviour
{
    [Header("Panels - World Mode")]
    [SerializeField] private GameObject _dialoguePanel;
    public GameObject ChoiceContainer;
    
    [Header("Text Fields - World Mode")]
    [SerializeField] private TextMeshProUGUI _speakerText;
    [SerializeField] private TextMeshProUGUI _contentText;

    [Header("Prefabs")]
    public ChoiceFocusHandler ChoiceButtonPrefab; 

    [Header("Default Animation Settings")] 
    [SerializeField] private float _defaultRotationSpeed = 36f;

    [Header("Fade Settings")]
    [SerializeField] private float _fadeOutDuration = 0.5f;
    [SerializeField] private CanvasGroup _dialogueCanvasGroup;

    private DialogueAnimationSettings _currentAnimationSettings;
    private Vector3 _currentRotationAxis = Vector3.forward;
    private bool _shouldFollowPlayerPosition = false;
    private bool _shouldFollowPlayerRotation = false;
    private Transform _currentAnchor;
    private Vector3 _baseScale;
    private List<ChoiceFocusHandler> _activeChoices = new List<ChoiceFocusHandler>();
    private float _sortTimer = 0f;
    private const float SORT_INTERVAL = 0.1f;
    
    private DialogueDisplayMode _currentDisplayMode = DialogueDisplayMode.World;
    
    private int _fadeCanvasTweenId = -1;
    private int _rotationTweenId = -1;
    private List<int> _floatingTweenIds = new List<int>();
    
    private static readonly Vector3 ViewportCenter = new Vector3(0.5f, 0.5f, 0f);

    private void Awake()
    {
        if (_dialogueCanvasGroup == null && _dialoguePanel != null)
        {
            _dialogueCanvasGroup = _dialoguePanel.GetComponent<CanvasGroup>();
            
            if (_dialogueCanvasGroup == null)
                _dialogueCanvasGroup = _dialoguePanel.AddComponent<CanvasGroup>();
        }
    }

    private void Update()
    {
        if (Player.Instance == null || !ChoiceContainer.activeInHierarchy)
            return;

        if (_shouldFollowPlayerPosition)
            ChoiceContainer.transform.position = Player.Instance.transform.position;
        
        if (_shouldFollowPlayerRotation)
        {
            float playerYRotation = Player.Instance.transform.eulerAngles.y;
            ChoiceContainer.transform.rotation = Quaternion.Euler(0f, playerYRotation, 0f);
        }
        
        if (_currentAnimationSettings != null && _currentAnimationSettings.EnableDistanceScaling && !_shouldFollowPlayerPosition)
            ApplyDistanceScaling();

        SortChoicesByDistance();
    }

    public void ShowDialogueBox(string speaker, string content, DialogueDisplayMode displayMode = DialogueDisplayMode.World)
    {
        _currentDisplayMode = displayMode;
        
        if (displayMode == DialogueDisplayMode.World)
        {
            if (DialogueScreenUI.Instance != null)
                DialogueScreenUI.Instance.Hide();
            
            _speakerText.text = speaker;
            _contentText.text = content;
            _dialoguePanel.SetActive(true);
            
            if (_dialogueCanvasGroup != null)
            {
                TweenHelper.CancelTween(ref _fadeCanvasTweenId);
                _dialogueCanvasGroup.alpha = 1f;
            }
        }
        else
        {
            if (_dialoguePanel != null)
                _dialoguePanel.SetActive(false);
            
            if (DialogueScreenUI.Instance != null)
                DialogueScreenUI.Instance.Show(speaker, content);
            else
                Debug.LogWarning("[DialogueUI] DialogueScreenUI.Instance is null! Make sure DialogueScreenUI component exists in the scene.");
        }
    }

    public void HideDialogueBox()
    {
        if (_dialoguePanel != null)
            _dialoguePanel.SetActive(false);
        
        if (DialogueScreenUI.Instance != null)
            DialogueScreenUI.Instance.Hide();
        
        ChoiceContainer.SetActive(false);
        HideChoices();
    }

    public void FadeOutAndHide(System.Action onComplete = null)
    {
        if (_currentDisplayMode == DialogueDisplayMode.World)
        {
            if (_dialogueCanvasGroup != null && _dialoguePanel != null)
            {
                TweenHelper.CancelTween(ref _fadeCanvasTweenId);
                _fadeCanvasTweenId = TweenHelper.FadeCanvasGroup(
                    _dialogueCanvasGroup, 
                    0f, 
                    _fadeOutDuration,
                    () =>
                    {
                        HideDialogueBox();
                        onComplete?.Invoke();
                    });
            }
            else
            {
                HideDialogueBox();
                onComplete?.Invoke();
            }
        }
        else
        {
            if (DialogueScreenUI.Instance != null)
            {
                DialogueScreenUI.Instance.FadeOutAndHide(() =>
                {
                    HideChoices();
                    ChoiceContainer.SetActive(false);
                    onComplete?.Invoke();
                });
            }
            else
            {
                HideDialogueBox();
                onComplete?.Invoke();
            }
        }
    }
    
    public bool AreChoicesVisible()
    {
        return ChoiceContainer.transform.childCount > 0;
    }

    public void ShowChoices(List<DialogueChoiceData> nodeChoices, Transform anchorTransform, DialogueAnimationSettings animationSettings = null)
    {
        HideChoices();

        _currentAnimationSettings = animationSettings;
        _currentAnchor = anchorTransform;

        if (anchorTransform != null)
        {
            ChoiceContainer.transform.SetParent(anchorTransform);
            
            bool followPosition = animationSettings != null && animationSettings.FollowPlayerPosition;
            bool followRotation = animationSettings != null && animationSettings.FollowPlayerRotation;
            
            _shouldFollowPlayerPosition = followPosition;
            _shouldFollowPlayerRotation = followRotation;
            
            if (followPosition && Player.Instance != null)
            {
                Vector3 playerWorldPos = Player.Instance.transform.position;
                ChoiceContainer.transform.position = playerWorldPos;
            }
            else
                ChoiceContainer.transform.localPosition = Vector3.zero;
            
            if (followRotation && Player.Instance != null)
            {
                float playerYRotation = Player.Instance.transform.eulerAngles.y;
                ChoiceContainer.transform.rotation = Quaternion.Euler(0f, playerYRotation, 0f);
            }
            else
                ChoiceContainer.transform.localRotation = Quaternion.identity;
        }

        ChoiceContainer.SetActive(true);
        ChoiceContainer.transform.localScale = Vector3.one;
        _baseScale = Vector3.one;

        int numChoices = nodeChoices.Count;
        if (numChoices == 0) return;

        SpawnChoices(nodeChoices, animationSettings);
        
        if (animationSettings != null && animationSettings.EnableDistanceScaling && !_shouldFollowPlayerPosition)
            ApplyDistanceScaling();
        
        bool shouldRotate = animationSettings == null || animationSettings.EnableRotation;
        if (shouldRotate)
        {
            float rotationSpeed = animationSettings != null ? animationSettings.NormalRotationSpeed : _defaultRotationSpeed;
            RotationAnimation(rotationSpeed);
        }
    }
    
    private void SpawnChoices(List<DialogueChoiceData> nodeChoices, DialogueAnimationSettings settings)
    {
        _currentRotationAxis = GetRotationAxisVector(settings != null ? settings.RotationAxis : RotationAxis.Forward);
        
        if (settings == null) return;
        
        Vector3[] originalPositions;
        List<ChoiceFocusHandler> spawnedChoices = FloatingWordsSpawner.SpawnByMode(
            nodeChoices,
            ChoiceButtonPrefab,
            ChoiceContainer.transform,
            settings,
            out originalPositions
        );
        
        for (int i = 0; i < spawnedChoices.Count; i++)
        {
            _activeChoices.Add(spawnedChoices[i]);
            
            if (settings.EnableFloating)
                StartFloatingAnimation(spawnedChoices[i].gameObject, i);
        }
    }
    
    private void StartFloatingAnimation(GameObject choice, int index)
    {
        if (_currentAnimationSettings == null) return;

        float amplitude = _currentAnimationSettings.FloatingAmplitude;
        float duration = _currentAnimationSettings.FloatingDuration;
        float delay = index * 0.2f;

        Vector3 startPos = choice.transform.localPosition;

        int tweenId = TweenHelper.FloatAnimation(choice, startPos, amplitude, duration, delay, Axis.Y);
        _floatingTweenIds.Add(tweenId);
    }

    public void RotationAnimation(float degreesPerSecond = 60f)
    {
        TweenHelper.CancelTween(ref _rotationTweenId);
        _rotationTweenId = TweenHelper.RotateAround(ChoiceContainer, _currentRotationAxis, degreesPerSecond);
    }

    /// <summary>
    /// Dynamically scales the choice container based on distance from player to anchor.
    /// Provides visual feedback for spatial awareness in 3D dialogue interactions.
    /// </summary>
    private void ApplyDistanceScaling()
    {
        if (_currentAnchor == null || Player.Instance == null)
            return;

        float distance = Vector3.Distance(_currentAnchor.position, Player.Instance.transform.position);
        
        float normalizedDistance = Mathf.InverseLerp(_currentAnimationSettings.MinDistance, _currentAnimationSettings.MaxDistance, distance);
        
        float finalScale = Mathf.Lerp(_currentAnimationSettings.MinScaleMultiplier, _currentAnimationSettings.MaxScaleMultiplier, normalizedDistance);
        
        ChoiceContainer.transform.localScale = _baseScale * finalScale;
    }

    private Vector3 GetRotationAxisVector(RotationAxis axis)
    {
        switch (axis)
        {
            case RotationAxis.Forward:
                return Vector3.forward;
            case RotationAxis.Up:
                return Vector3.up;
            case RotationAxis.Right:
                return Vector3.right;
            default:
                return Vector3.forward;
        }
    }

    public void HideChoices()
    {
        _shouldFollowPlayerPosition = false;
        _shouldFollowPlayerRotation = false;
        _currentAnchor = null;
        _currentAnimationSettings = null;
        _activeChoices.Clear();
        
        TweenHelper.CancelTween(ref _rotationTweenId);
        foreach (int tweenId in _floatingTweenIds)
        {
            int id = tweenId;
            TweenHelper.CancelTween(ref id);
        }
        _floatingTweenIds.Clear();
        
        foreach (Transform child in ChoiceContainer.transform)
        {
            Destroy(child.gameObject);
        }
    }

    /// <summary>
    /// Sorts choice buttons by distance to player camera.
    /// Closer choices are rendered on top by being placed last in hierarchy (higher sibling index).
    /// Uses interval-based sorting to reduce performance overhead.
    /// </summary>
    private void SortChoicesByDistance()
    {
        if (_activeChoices.Count <= 1 || Player.Instance == null)
            return;

        _sortTimer += Time.deltaTime;
        if (_sortTimer < SORT_INTERVAL)
            return;

        _sortTimer = 0f;

        Camera mainCamera = Camera.main;
        if (mainCamera == null)
            return;

        Vector3 cameraPosition = mainCamera.transform.position;

        _activeChoices.Sort((a, b) =>
        {
            if (a == null || b == null)
                return 0;

            float distanceA = Vector3.Distance(cameraPosition, a.transform.position);
            float distanceB = Vector3.Distance(cameraPosition, b.transform.position);

            return distanceB.CompareTo(distanceA);
        });

        for (int i = 0; i < _activeChoices.Count; i++)
        {
            if (_activeChoices[i] != null)
                _activeChoices[i].transform.SetSiblingIndex(i);
        }
    }
}
}