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

namespace UVC.UIToolkit
{
    /// <summary>
    /// 라디오 버튼 컴포넌트.
    /// Unity RadioButton을 래핑하여 커스텀 스타일을 적용합니다.
    /// </summary>
    /// <example>
    /// <para><b>C# 코드에서 사용:</b></para>
    /// <code>
    /// // 라디오 버튼 그룹
    /// var group = new RadioButtonGroup();
    /// var radio1 = new UTKRadioButton { text = "옵션 1" };  // Unity RadioButton의 text 프로퍼티
    /// var radio2 = new UTKRadioButton { text = "옵션 2" };
    /// var radio3 = new UTKRadioButton { text = "옵션 3" };
    /// group.Add(radio1);
    /// group.Add(radio2);
    /// group.Add(radio3);
    /// 
    /// radio1.OnValueChanged += (isSelected) => {
    ///     if (isSelected) Debug.Log("옵션 1 선택됨");
    /// };
    /// </code>
    /// <para><b>UXML에서 사용:</b></para>
    /// <code>
    /// <ui:UXML xmlns:utk="UVC.UIToolkit">
    ///     <ui:RadioButtonGroup>
    ///         <utk:UTKRadioButton label="소형" />
    ///         <utk:UTKRadioButton label="중형" value="true" />
    ///         <utk:UTKRadioButton label="대형" />
    ///     </ui:RadioButtonGroup>
    /// </ui:UXML>
    /// </code>
    /// </example>
    [UxmlElement]
    public partial class UTKRadioButton : RadioButton, IDisposable
    {
        #region Constants
        private const string USS_PATH = "UIToolkit/Button/UTKRadioButton";
        #endregion

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

        #region Events
        /// <summary>체크 상태 변경 이벤트</summary>
        public event Action<bool>? OnValueChanged;
        #endregion

        #region Properties
        /// <summary>라벨 텍스트</summary>
        [UxmlAttribute("text")]
        public string Text
        {
            get => text;
            set => text = value;
        }

        /// <summary>체크 상태</summary>
        [UxmlAttribute("is-checked")]
        public bool IsChecked
        {
            get => value;
            set => SetChecked(value, true);
        }

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

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

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

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

        public UTKRadioButton(string text) : this()
        {
            this.text = text;
        }
        #endregion

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

        private void SetupEvents()
        {
            RegisterCallback<ChangeEvent<bool>>(OnRadioValueChanged);
        }

        private void SubscribeToThemeChanges()
        {
            UTKThemeManager.Instance.OnThemeChanged += OnThemeChanged;
            RegisterCallback<AttachToPanelEvent>(OnAttachToPanelForTheme);
            RegisterCallback<DetachFromPanelEvent>(OnDetachFromPanelForTheme);
        }

        private void OnAttachToPanelForTheme(AttachToPanelEvent evt)
        {
            UTKThemeManager.Instance.OnThemeChanged -= OnThemeChanged;
            UTKThemeManager.Instance.OnThemeChanged += OnThemeChanged;
            UTKThemeManager.Instance.ApplyThemeToElement(this);
        }

        private void OnDetachFromPanelForTheme(DetachFromPanelEvent evt)
        {
            UTKThemeManager.Instance.OnThemeChanged -= OnThemeChanged;
        }

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

        #region Event Handlers
        private void OnRadioValueChanged(ChangeEvent<bool> evt)
        {
            EnableInClassList("utk-radio--checked", evt.newValue);
            OnValueChanged?.Invoke(evt.newValue);
        }
        #endregion

        #region Methods
        /// <summary>
        /// 체크 상태 설정
        /// </summary>
        public void SetChecked(bool checked_, bool notify)
        {
            if (value == checked_) return;

            if (notify)
            {
                value = checked_;
            }
            else
            {
                SetValueWithoutNotify(checked_);
                EnableInClassList("utk-radio--checked", checked_);
            }
        }
        #endregion

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

            UTKThemeManager.Instance.OnThemeChanged -= OnThemeChanged;
            UnregisterCallback<AttachToPanelEvent>(OnAttachToPanelForTheme);
            UnregisterCallback<DetachFromPanelEvent>(OnDetachFromPanelForTheme);
            OnValueChanged = null;
            UnregisterCallback<ChangeEvent<bool>>(OnRadioValueChanged);
        }
        #endregion
    }
}