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

namespace UVC.UIToolkit
{
    /// <summary>
    /// Rect(사각형) 입력 필드 컴포넌트.
    /// Unity RectField를 래핑하여 커스텀 스타일을 적용합니다.
    /// 2D 공간에서 사각형의 위치(X, Y)와 크기(Width, Height)를 입력받습니다.
    /// </summary>
    /// <remarks>
    /// <para><b>Rect란?</b></para>
    /// <para>Rect는 2D 공간에서 직사각형 영역을 나타내는 구조체입니다.</para>
    /// <list type="bullet">
    ///   <item><description><b>X, Y</b>: 사각형의 왼쪽 상단 모서리 위치</description></item>
    ///   <item><description><b>Width</b>: 사각형의 너비</description></item>
    ///   <item><description><b>Height</b>: 사각형의 높이</description></item>
    /// </list>
    /// <para>주로 UI 요소의 위치/크기, 스프라이트 영역, 화면 좌표 등에 사용됩니다.</para>
    /// </remarks>
    /// <example>
    /// <para><b>C# 코드에서 사용:</b></para>
    /// <code>
    /// // 기본 Rect 필드 생성
    /// var rectField = new UTKRectField();
    /// rectField.label = "UI 영역";
    /// rectField.Value = new Rect(0, 0, 100, 50);
    ///
    /// // 값 변경 이벤트
    /// rectField.OnValueChanged += (rect) => {
    ///     Debug.Log($"위치: ({rect.x}, {rect.y}), 크기: {rect.width} x {rect.height}");
    /// };
    ///
    /// // 라벨 생성자 사용
    /// var namedField = new UTKRectField("클리핑 영역");
    ///
    /// // 축 라벨 커스터마이징
    /// rectField.XLabel = "Left";
    /// rectField.YLabel = "Top";
    /// rectField.WLabel = "Width";
    /// rectField.HLabel = "Height";
    ///
    /// // 읽기 전용 (사용자가 수정할 수 없음)
    /// var readOnlyField = new UTKRectField("고정 영역");
    /// readOnlyField.Value = new Rect(10, 10, 200, 100);
    /// readOnlyField.IsReadOnly = true;
    /// </code>
    /// <para><b>UXML에서 사용:</b></para>
    /// <code><![CDATA[
    /// <!-- 기본 Rect 필드 -->
    /// <utk:UTKRectField label="영역" />
    ///
    /// <!-- 커스텀 라벨 -->
    /// <utk:UTKRectField label="스프라이트 영역"
    ///                   x-label="Left" y-label="Top"
    ///                   w-label="W" h-label="H" />
    ///
    /// <!-- 비활성화 상태 -->
    /// <utk:UTKRectField label="비활성화" is-enabled="false" />
    ///
    /// <!-- 읽기 전용 -->
    /// <utk:UTKRectField label="고정 영역" is-readonly="true" />
    /// ]]></code>
    /// <para><b>실제 활용 예시 (스프라이트 영역 편집):</b></para>
    /// <code>
    /// // 스프라이트 UV 영역 편집기
    /// var uvField = new UTKRectField("UV 영역");
    /// uvField.Value = sprite.rect;
    /// uvField.OnValueChanged += (newRect) => {
    ///     // 스프라이트 영역 업데이트
    ///     UpdateSpriteRect(sprite, newRect);
    /// };
    /// </code>
    /// </example>
    [UxmlElement]
    public partial class UTKRectField : RectField, IDisposable
    {
        #region Constants
        private const string USS_PATH = "UIToolkit/Input/UTKRectField";
        #endregion

        #region Fields
        private bool _disposed;
        private bool _isEnabled = true;
        private bool _isReadOnly;
        private string _xLabel = "X";
        private string _yLabel = "Y";
        private string _wLabel = "W";
        private string _hLabel = "H";
        #endregion

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

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

        /// <summary>현재 값</summary>
        public Rect Value
        {
            get => value;
            set => this.value = value;
        }

        /// <summary>X 라벨</summary>
        [UxmlAttribute("x-label")]
        public string XLabel
        {
            get => _xLabel;
            set
            {
                _xLabel = value;
                UpdateAxisLabels();
            }
        }

        /// <summary>Y 라벨</summary>
        [UxmlAttribute("y-label")]
        public string YLabel
        {
            get => _yLabel;
            set
            {
                _yLabel = value;
                UpdateAxisLabels();
            }
        }

        /// <summary>W 라벨</summary>
        [UxmlAttribute("w-label")]
        public string WLabel
        {
            get => _wLabel;
            set
            {
                _wLabel = value;
                UpdateAxisLabels();
            }
        }

        /// <summary>H 라벨</summary>
        [UxmlAttribute("h-label")]
        public string HLabel
        {
            get => _hLabel;
            set
            {
                _hLabel = value;
                UpdateAxisLabels();
            }
        }

        /// <summary>읽기 전용 상태</summary>
        [UxmlAttribute("is-readonly")]
        public bool IsReadOnly
        {
            get => _isReadOnly;
            set
            {
                _isReadOnly = value;
                UpdateReadOnlyState();
                EnableInClassList("utk-rectfield--readonly", value);
            }
        }
        #endregion

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

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

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

        public UTKRectField(bool isReadOnly) : this()
        {
            _isReadOnly = isReadOnly;
            UpdateReadOnlyState();
        }

        public UTKRectField(string label, bool isReadOnly = false) : this()
        {
            this.label = label;
            _isReadOnly = isReadOnly;
            UpdateReadOnlyState();
        }
        #endregion

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

            // 초기 라벨 설정
            schedule.Execute(() => UpdateAxisLabels());
        }

        private void SetupEvents()
        {
            RegisterCallback<ChangeEvent<Rect>>(OnFieldValueChanged);
        }

        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);
        }

        private void UpdateAxisLabels()
        {
            // RectField의 내부 FloatField들을 찾아서 라벨 변경 (X, Y, W, H 순서)
            var floatFields = this.Query<FloatField>().ToList();
            if (floatFields.Count >= 4)
            {
                floatFields[0].label = _xLabel;
                floatFields[1].label = _yLabel;
                floatFields[2].label = _wLabel;
                floatFields[3].label = _hLabel;
            }
        }

        private void UpdateReadOnlyState()
        {
            // 내부 FloatField들의 TextInput을 찾아서 읽기 전용 설정
            var textInputs = this.Query<TextInputBaseField<float>>().ToList();
            foreach (var textInput in textInputs)
            {
                textInput.isReadOnly = _isReadOnly;
            }
        }
        #endregion

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