#nullable enable
using System;
using UnityEngine;
using UnityEngine.UIElements;

namespace UVC.UIToolkit
{
    /// <summary>
    /// String 속성 View 클래스입니다.
    /// UTKInputField를 사용하여 문자열 값을 표시/편집합니다.
    ///
    /// <para><b>사용법 (단독 사용):</b></para>
    /// <code>
    /// // C# 코드에서 생성
    /// var view = new UTKStringPropertyItemView();
    /// view.Label = "이름";
    /// view.Value = "홍길동";
    /// view.IsMultiline = false;
    /// parent.Add(view);
    ///
    /// // UXML에서 사용
    /// &lt;utk:UTKStringPropertyItemView label="이름" value="홍길동" is-multiline="false" /&gt;
    /// </code>
    /// </summary>
    [UxmlElement]
    public partial class UTKStringPropertyItemView : UTKPropertyItemViewBase, IUTKPropertyItemView<string>
    {
        #region Fields
        private UTKInputField? _inputField;

        private string _value = string.Empty;
        private bool _isMultiline = false;
        private int _maxLength = -1;

        private IUTKPropertyItem<string>? _boundData;
        #endregion

        #region Properties
        protected override string ViewTypeName => "UTKStringPropertyItemView";

        /// <summary>현재 값</summary>
        [UxmlAttribute("value")]
        public string Value
        {
            get => _value;
            set
            {
                var newValue = value ?? string.Empty;
                if (_value != newValue)
                {
                    _value = newValue;
                    UpdateValueUI();
                    OnValueChanged?.Invoke(newValue);

                    if (_boundData != null && _boundData.Value != newValue)
                    {
                        _boundData.Value = newValue;
                    }
                }
            }
        }

        /// <summary>멀티라인 모드 여부</summary>
        [UxmlAttribute("is-multiline")]
        public bool IsMultiline
        {
            get => _isMultiline;
            set
            {
                _isMultiline = value;
                if (_inputField != null)
                {
                    _inputField.multiline = value;
                }
            }
        }

        /// <summary>최대 문자 길이 (-1 = 무제한)</summary>
        [UxmlAttribute("max-length")]
        public int MaxLength
        {
            get => _maxLength;
            set
            {
                _maxLength = value;
                if (_inputField != null)
                {
                    _inputField.maxLength = value;
                }
            }
        }
        #endregion

        #region Events
        public event Action<string>? OnValueChanged;
        #endregion

        #region Constructor
        public UTKStringPropertyItemView() : base()
        {
            InitializeUI();
        }

        public UTKStringPropertyItemView(UTKStringPropertyItem item) : base()
        {
            _value = item.Value ?? string.Empty;
            _isMultiline = item.IsMultiline;
            _maxLength = item.MaxLength;
            Label = item.Name;
            _isReadOnly = item.IsReadOnly;
            InitializeUI();
            Bind(item);
        }

        public UTKStringPropertyItemView(string label, string value = "", bool isMultiline = false, int maxLength = -1, bool isReadOnly = false) : base()
        {
            _value = value ?? string.Empty;
            _isMultiline = isMultiline;
            _maxLength = maxLength;
            Label = label;
            _isReadOnly = isReadOnly;
            InitializeUI();
        }
        #endregion

        #region Initialization
        private void InitializeUI()
        {
            AddToClassList("utk-property-item-view");
            AddToClassList("utk-property-item-view--string");

            if (!CreateUIFromUxml())
            {
                CreateUIFallback();
            }

            // UXML에서 요소 가져오기
            QueryUIElements();

            // 이벤트 등록
            RegisterEvents();

            UpdateValueUI();
            UpdateReadOnlyState();
        }

        private void QueryUIElements()
        {
            _inputField = this.Q<UTKInputField>("value-field");

            // Fallback: UXML에서 못 찾으면 생성
            if (_valueContainer != null && _inputField == null)
            {
                _inputField = new UTKInputField { name = "value-field" };
                _inputField.AddToClassList("utk-property-item-view__field");
                _valueContainer.Add(_inputField);
            }

            // 초기 값 설정
            if (_inputField != null)
            {
                _inputField.SetValue(_value, false);
                _inputField.multiline = _isMultiline;
                _inputField.isReadOnly = IsReadOnly;
                if (_maxLength >= 0)
                {
                    _inputField.maxLength = _maxLength;
                }
            }
        }

        private void RegisterEvents()
        {
            if (_inputField != null)
            {
                _inputField.OnValueChanged += OnInputChanged;
            }
        }

        private void UnregisterEvents()
        {
            if (_inputField != null)
            {
                _inputField.OnValueChanged -= OnInputChanged;
            }
        }
        #endregion

        #region Override Methods
        protected override void CreateValueUI(VisualElement container)
        {
            // UXML/QueryUIElements 기반으로 생성하므로 여기서는 생성하지 않음
        }

        public override void RefreshUI()
        {
            UpdateValueUI();
        }

        protected override void OnReadOnlyStateChanged(bool isReadOnly)
        {
            if (_inputField != null)
            {
                _inputField.isReadOnly = isReadOnly;
            }
        }
        #endregion

        #region Event Handling
        private void OnInputChanged(string newValue)
        {
            if (_value != newValue)
            {
                _value = newValue;
                OnValueChanged?.Invoke(newValue);

                if (_boundData != null && _boundData.Value != newValue)
                {
                    _boundData.Value = newValue;
                }
            }
        }
        #endregion

        #region Value Update
        private void UpdateValueUI()
        {
            if (_inputField != null && _inputField.Value != _value)
            {
                _inputField.SetValue(_value, false);
            }
        }
        #endregion

        #region Data Binding
        public void Bind(IUTKPropertyItem data)
        {
            if (data is IUTKPropertyItem<string> stringData)
            {
                Bind(stringData);
            }
            else
            {
                Debug.LogWarning($"[UTKStringPropertyItemView] Cannot bind to non-string data: {data.GetType().Name}");
            }
        }

        public void Bind(IUTKPropertyItem<string> data)
        {
            Unbind();

            _boundData = data;

            Label = data.Name;
            _value = data.Value ?? string.Empty;
            IsReadOnly = data.IsReadOnly;
            IsVisible = data.IsVisible;
            TooltipText = data.Tooltip;
            
            if (data is UTKStringPropertyItem stringItem)
            {
                _isMultiline = stringItem.IsMultiline;
                _maxLength = stringItem.MaxLength;
                if (_inputField != null)
                {
                    _inputField.multiline = _isMultiline;
                    _inputField.maxLength = _maxLength;
                }
            }

            data.OnTypedValueChanged += OnDataValueChanged;

            UpdateValueUI();
            UpdateReadOnlyState();
        }

        public void Unbind()
        {
            if (_boundData != null)
            {
                _boundData.OnTypedValueChanged -= OnDataValueChanged;
                _boundData = null;
            }
        }

        private void OnDataValueChanged(IUTKPropertyItem<string> item, string oldValue, string newValue)
        {
            if (_value != newValue)
            {
                _value = newValue ?? string.Empty;
                UpdateValueUI();
            }
        }
        #endregion

        #region Dispose
        protected override void Dispose(bool disposing)
        {
            if (_disposed) return;

            if (disposing)
            {
                UnregisterEvents();
                Unbind();

                OnValueChanged = null;
                _inputField = null;
            }

            base.Dispose(disposing);
        }
        #endregion
    }
}