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

namespace UVC.UIToolkit
{
    /// <summary>
    /// DateTime 속성 View 클래스입니다.
    /// UTKInputField + UTKDatePicker (DateAndTime 모드)를 사용하여 날짜시간을 표시/편집합니다.
    /// </summary>
    [UxmlElement]
    public partial class UTKDateTimePropertyItemView : UTKPropertyItemViewBase, IUTKPropertyItemView<DateTime>
    {
        #region Fields
        private UTKInputField? _dateTimeField;
        private UTKButton? _pickerButton;
        private UTKDatePicker? _currentPicker;

        private DateTime _value = DateTime.Now;
        private string _dateTimeFormat = "yyyy-MM-dd HH:mm";

        private IUTKPropertyItem<DateTime>? _boundData;
        #endregion

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

        /// <summary>현재 값</summary>
        public DateTime Value
        {
            get => _value;
            set
            {
                if (_value != value)
                {
                    _value = value;
                    UpdateValueUI();
                    OnValueChanged?.Invoke(value);

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

        /// <summary>날짜시간 표시 형식</summary>
        [UxmlAttribute("datetime-format")]
        public string DateTimeFormat
        {
            get => _dateTimeFormat;
            set
            {
                _dateTimeFormat = value ?? "yyyy-MM-dd HH:mm";
                UpdateValueUI();
            }
        }
        #endregion

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

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

        public UTKDateTimePropertyItemView(string label, DateTime value = default) : base()
        {
            _value = value == default ? DateTime.Now : value;
            Label = label;
            InitializeUI();
        }
        #endregion

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

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

            // UXML에서 요소 가져오기
            QueryUIElements();

            // 이벤트 등록
            RegisterEvents();

            UpdateValueUI();
            UpdateReadOnlyState();
        }

        private void QueryUIElements()
        {
            _dateTimeField = this.Q<UTKInputField>("datetime-field");
            _pickerButton = this.Q<UTKButton>("picker-btn");

            // Fallback: UXML에서 못 찾으면 생성
            if (_valueContainer != null)
            {
                if (_dateTimeField == null)
                {
                    _dateTimeField = new UTKInputField { name = "datetime-field" };
                    _dateTimeField.style.flexGrow = 1;
                    _dateTimeField.AddToClassList("utk-property-item-view__field");
                    _valueContainer.Add(_dateTimeField);
                }

                if (_pickerButton == null)
                {
                    _pickerButton = new UTKButton("...", "", UTKButton.ButtonVariant.Secondary)
                    {
                        name = "picker-btn"
                    };
                    _pickerButton.AddToClassList("utk-property-item-view__picker-btn");
                    _valueContainer.Add(_pickerButton);
                }
            }

            // 초기 값 설정
            if (_dateTimeField != null)
            {
                _dateTimeField.SetValue(_value.ToString(_dateTimeFormat), false);
                _dateTimeField.isReadOnly = true;//IsReadOnly와 상관 없이 편집 불가
            }
            if (_pickerButton != null)
            {
                _pickerButton.IsEnabled = !IsReadOnly;
            }
        }

        private void RegisterEvents()
        {
            if (_dateTimeField != null)
            {
                _dateTimeField.OnValueChanged += OnDateTimeTextChanged;
            }
            if (_pickerButton != null)
            {
                _pickerButton.OnClicked += OnPickerButtonClicked;
            }
        }

        private void UnregisterEvents()
        {
            if (_dateTimeField != null)
            {
                _dateTimeField.OnValueChanged -= OnDateTimeTextChanged;
            }
            if (_pickerButton != null)
            {
                _pickerButton.OnClicked -= OnPickerButtonClicked;
            }
        }
        #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 (_dateTimeField != null) _dateTimeField.isReadOnly = isReadOnly;
            if (_pickerButton != null) _pickerButton.style.display = isReadOnly ? DisplayStyle.None : DisplayStyle.Flex;
        }
        #endregion

        #region Event Handling
        private void OnPickerButtonClicked()
        {
            OpenPicker();
        }

        private void OnDateTimeTextChanged(string newValue)
        {
            if (DateTime.TryParse(newValue, out DateTime dateTime))
            {
                if (_value != dateTime)
                {
                    _value = dateTime;
                    OnValueChanged?.Invoke(_value);

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

        private void OpenPicker()
        {
            if (_currentPicker != null) return;

            var root = this as VisualElement;
            while (root.parent != null)
            {
                root = root.parent;
            }

            _currentPicker = UTKDatePicker.Show(root, _value, UTKDatePicker.PickerMode.DateAndTime, Label);
            _currentPicker.OnDateSelected += OnPickerDateSelected;
            _currentPicker.OnClosed += OnPickerClosed;
        }

        private void ClosePicker()
        {
            if (_currentPicker != null)
            {
                _currentPicker.OnDateSelected -= OnPickerDateSelected;
                _currentPicker.OnClosed -= OnPickerClosed;
                _currentPicker.Close();
                _currentPicker = null;
            }
        }

        private void OnPickerDateSelected(DateTime dateTime)
        {
            Value = dateTime;
            ClosePicker();
        }

        private void OnPickerClosed()
        {
            _currentPicker = null;
        }
        #endregion

        #region Value Update
        private void UpdateValueUI()
        {
            if (_dateTimeField != null)
            {
                var formatted = _value.ToString(_dateTimeFormat);
                if (_dateTimeField.Value != formatted)
                {
                    _dateTimeField.SetValue(formatted, false);
                }
            }
        }
        #endregion

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

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

            _boundData = data;

            Label = data.Name;
            _value = data.Value;
            IsReadOnly = data.IsReadOnly;
            IsVisible = data.IsVisible;
            TooltipText = data.Tooltip;

            if (data is UTKDateTimePropertyItem dateTimeItem)
            {
                _dateTimeFormat = dateTimeItem.DateTimeFormat;
            }

            data.OnTypedValueChanged += OnDataValueChanged;

            UpdateValueUI();
            UpdateReadOnlyState();
        }

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

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

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

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

                OnValueChanged = null;
                _dateTimeField = null;
                _pickerButton = null;
            }

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