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

namespace UVC.UIToolkit
{
    /// <summary>
    /// Long 정수 입력 필드 컴포넌트.
    /// Unity LongField를 래핑하여 커스텀 스타일을 적용합니다.
    /// </summary>
    [UxmlElement]
    public partial class UTKLongField : LongField, IDisposable
    {
        #region Constants
        private const string USS_PATH = "UIToolkit/Input/UTKLongField";
        #endregion

        #region Fields
        private bool _disposed;
        private bool _isEnabled = true;
        #endregion

        #region Events
        /// <summary>값 변경 이벤트</summary>
        public event Action<long>? OnValueChanged;
        #endregion

        #region Properties
        /// <summary>현재 값</summary>
        public long Value
        {
            get => value;
            set => this.value = value;
        }

        /// <summary>활성화 상태</summary>
        [UxmlAttribute("is-enabled")]
        public bool IsEnabled
        {
            get => _isEnabled;
            set
            {
                _isEnabled = value;
                SetEnabled(value);
                EnableInClassList("utk-long-field--disabled", !value);
            }
        }
        #endregion

        #region Constructor
        public UTKLongField() : base()
        {
            UTKThemeManager.Instance.ApplyThemeToElement(this);

            var uss = Resources.Load<StyleSheet>(USS_PATH);
            if (uss != null)
            {
                styleSheets.Add(uss);
            }

            SetupStyles();
            SetupEvents();
            SubscribeToThemeChanges();
        }

        public UTKLongField(string label, long defaultValue = 0) : this()
        {
            this.label = label;
            value = defaultValue;
        }
        #endregion

        #region Setup
        private void SetupStyles()
        {
            AddToClassList("utk-long-field");
        }

        private void SetupEvents()
        {
            this.RegisterValueChangedCallback(OnFieldValueChanged);
        }

        private void SubscribeToThemeChanges()
        {
            UTKThemeManager.Instance.OnThemeChanged += OnThemeChanged;
            RegisterCallback<DetachFromPanelEvent>(_ =>
            {
                UTKThemeManager.Instance.OnThemeChanged -= OnThemeChanged;
            });
        }

        private void OnThemeChanged(UTKTheme theme)
        {
            UTKThemeManager.Instance.ApplyThemeToElement(this);
        }
        #endregion

        #region Event Handlers
        private void OnFieldValueChanged(ChangeEvent<long> evt)
        {
            OnValueChanged?.Invoke(evt.newValue);
        }
        #endregion

        #region IDisposable
        public void Dispose()
        {
            if (_disposed) return;
            _disposed = true;

            UTKThemeManager.Instance.OnThemeChanged -= OnThemeChanged;
            OnValueChanged = null;
        }
        #endregion
    }
}