using TMPro;
using UnityEngine;
using UnityEngine.UI;

namespace BriarQueen.UI.Components
{
    [ExecuteAlways]
    public class ScrollableTextBox : MonoBehaviour
    {
        [SerializeField] private TextMeshProUGUI                       _text;
        [SerializeField] private RectTransform                         _content;
        [SerializeField] private BriarQueen.UI.Menus.VerticalScrollbar _scrollbar;

        private RectTransform _textRect;
        private LayoutElement _layoutElement;

        private void Awake()
        {
            Init();
        }

        private void OnValidate()
        {
#if UNITY_EDITOR
            UnityEditor.EditorApplication.delayCall += () =>
            {
                if (this == null) return;
                Init();
                if (_text != null && !string.IsNullOrEmpty(_text.text))
                    ApplyTextHeight();
            };
#endif
        }

        private void Init()
        {
            if (_text != null)
            {
                _textRect      = _text.GetComponent<RectTransform>();
                _layoutElement = _text.GetComponent<LayoutElement>();
                
                if (_layoutElement == null)
                    _layoutElement = _text.gameObject.AddComponent<LayoutElement>();
            }
        }

        private void ApplyTextHeight()
        {
            _text.ForceMeshUpdate();
            var height = _text.preferredHeight;

            if (_layoutElement != null)
                _layoutElement.preferredHeight = height;

            if (_textRect != null)
            {
                var delta = _textRect.sizeDelta;
                delta.y = height;
                _textRect.sizeDelta = delta;
            }

            if (_content != null)
            {
                Canvas.ForceUpdateCanvases();
                LayoutRebuilder.ForceRebuildLayoutImmediate(_content);
            }
        }

        public void SetText(string content)
        {
            if (_text == null) return;

            _text.text = content;
            _text.ForceMeshUpdate();

            var height = _text.preferredHeight;

            if (_layoutElement != null)
                _layoutElement.preferredHeight = height;

            if (_textRect != null)
            {
                var delta = _textRect.sizeDelta;
                delta.y = height;
                _textRect.sizeDelta = delta;
            }

            // Also resize Content to match so scrollbar measures correctly
            if (_content != null)
            {
                var delta = _content.sizeDelta;
                delta.y = height;
                _content.sizeDelta = delta;

                var pos = _content.anchoredPosition;
                pos.y   = 0f;
                _content.anchoredPosition = pos;
            }

            if (Application.isPlaying)
                StartCoroutine(RebuildNextFrame());
            else
                _scrollbar?.Rebuild();
        }

        private System.Collections.IEnumerator RebuildNextFrame()
        {
            yield return null;
            Canvas.ForceUpdateCanvases();
            LayoutRebuilder.ForceRebuildLayoutImmediate(_content);
            yield return null;
            _scrollbar?.Rebuild();
            _scrollbar?.SetNormalized(1f);
        }

        public void Clear()
        {
            if (_text == null) return;
            _text.text = string.Empty;

            if (_layoutElement != null)
                _layoutElement.preferredHeight = 0f;

            if (_textRect != null)
            {
                var sd = _textRect.sizeDelta;
                sd.y   = 0f;
                _textRect.sizeDelta = sd;
            }

            if (_content != null)
            {
                var pos = _content.anchoredPosition;
                pos.y   = 0f;
                _content.anchoredPosition = pos;
            }

            _scrollbar?.Rebuild();
        }

        public void ScrollToTop()    => _scrollbar?.SetNormalized(1f);
        public void ScrollToBottom() => _scrollbar?.SetNormalized(0f);
    }
}