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

namespace UVC.UIToolkit
{
    /// <summary>
    /// Vector3(3D 벡터) 입력 필드 컴포넌트.
    /// Unity Vector3Field를 래핑하여 커스텀 스타일을 적용합니다.
    /// 3D 공간의 좌표(X, Y, Z)를 입력받습니다.
    /// </summary>
    /// <remarks>
    /// <para><b>Vector3란?</b></para>
    /// <para>Vector3는 3차원 공간에서 위치, 방향, 크기 등을 나타내는 구조체입니다.</para>
    /// <list type="bullet">
    ///   <item><description><b>위치 (Position)</b>: 3D 공간에서 오브젝트의 좌표</description></item>
    ///   <item><description><b>회전 (Euler Angles)</b>: X, Y, Z 축 기준 회전 각도</description></item>
    ///   <item><description><b>크기 (Scale)</b>: 오브젝트의 3축 스케일</description></item>
    ///   <item><description><b>방향 (Direction)</b>: 정규화된 방향 벡터</description></item>
    /// </list>
    /// <para>Unity의 Transform 컴포넌트에서 position, eulerAngles, localScale이 모두 Vector3입니다.</para>
    /// </remarks>
    /// <example>
    /// <para><b>C# 코드에서 사용:</b></para>
    /// <code>
    /// // 기본 Vector3 필드 생성
    /// var vec3Field = new UTKVector3Field();
    /// vec3Field.label = "위치";
    /// vec3Field.Value = new Vector3(1, 2, 3);
    ///
    /// // 값 변경 이벤트
    /// vec3Field.OnValueChanged += (vec) => {
    ///     Debug.Log($"위치: ({vec.x}, {vec.y}, {vec.z})");
    /// };
    ///
    /// // 라벨 생성자 사용
    /// var positionField = new UTKVector3Field("Position");
    ///
    /// // 축 라벨 커스터마이징
    /// vec3Field.XLabel = "X (좌우)";
    /// vec3Field.YLabel = "Y (상하)";
    /// vec3Field.ZLabel = "Z (앞뒤)";
    ///
    /// // Transform과 연동
    /// var posField = new UTKVector3Field("위치");
    /// posField.Value = transform.position;
    /// posField.OnValueChanged += (pos) => transform.position = pos;
    ///
    /// // 읽기 전용 (사용자가 수정할 수 없음)
    /// var readOnlyField = new UTKVector3Field("고정 위치");
    /// readOnlyField.Value = new Vector3(1, 2, 3);
    /// readOnlyField.IsReadOnly = true;
    /// </code>
    /// <para><b>Validation (입력 검증):</b></para>
    /// <code>
    /// // 검증 함수 설정 (Func<bool>)
    /// var posField = new UTKVector3Field("위치");
    /// posField.ErrorMessage = "Y값은 0 이상이어야 합니다.";
    /// posField.Validation = () => posField.Value.y >= 0;
    /// // → FocusOut 시 자동으로 검증
    /// // → 실패 시 붉은 외곽선 + 에러 메시지 표시, 통과 시 자동 해제
    ///
    /// // 강제 검증 호출 (예: 폼 제출 버튼 클릭 시)
    /// bool isValid = posField.Validate();
    /// if (!isValid) return; // 검증 실패
    ///
    /// // 에러 수동 해제
    /// posField.ClearError();
    ///
    /// // 에러 메시지 직접 설정 (Validation 없이, 서버 오류 등)
    /// posField.ErrorMessage = "유효하지 않은 좌표입니다.";
    /// posField.ErrorMessage = "";  // 오류 제거
    /// </code>
    /// <para><b>UXML에서 사용:</b></para>
    /// <code><![CDATA[
    /// <!-- 기본 Vector3 필드 -->
    /// <utk:UTKVector3Field label="위치" />
    ///
    /// <!-- 커스텀 축 라벨 -->
    /// <utk:UTKVector3Field label="크기"
    ///                      x-label="Width" y-label="Height" z-label="Depth" />
    ///
    /// <!-- 비활성화 상태 -->
    /// <utk:UTKVector3Field label="비활성화" is-enabled="false" />
    ///
    /// <!-- 읽기 전용 -->
    /// <utk:UTKVector3Field label="고정 위치" is-readonly="true" />
    ///
    /// <!-- 에러 메시지 (C#에서 Validation 설정 권장) -->
    /// <utk:UTKVector3Field label="위치" error-message="유효하지 않은 좌표입니다." />
    ///
    /// <!-- label min-width 설정 -->
    /// <utk:UTKVector3Field label="위치" label-min-width="120" />
    /// ]]></code>
    /// <para><b>Label Min-Width 설정:</b></para>
    /// <code>
    /// // label이 있을 때 .unity-label의 min-width를 설정
    /// var vec3Field = new UTKVector3Field("위치");
    /// vec3Field.LabelMinWidth = 120f; // 120px
    /// </code>
    /// <para><b>실제 활용 예시 (Transform 편집기):</b></para>
    /// <code>
    /// // GameObject Transform 편집
    /// var posField = new UTKVector3Field("Position");
    /// var rotField = new UTKVector3Field("Rotation");
    /// var scaleField = new UTKVector3Field("Scale");
    ///
    /// posField.Value = selectedObject.transform.position;
    /// rotField.Value = selectedObject.transform.eulerAngles;
    /// scaleField.Value = selectedObject.transform.localScale;
    ///
    /// posField.OnValueChanged += (v) => selectedObject.transform.position = v;
    /// rotField.OnValueChanged += (v) => selectedObject.transform.eulerAngles = v;
    /// scaleField.OnValueChanged += (v) => selectedObject.transform.localScale = v;
    /// </code>
    /// </example>
    [UxmlElement]
    public partial class UTKVector3Field : Vector3Field, IDisposable
    {
        #region Constants
        private const string USS_PATH = "UIToolkit/Input/UTKVector3Field";
        #endregion

        #region Fields
        private bool _disposed;
        private bool _isEnabled = true;
        private bool _isReadOnly = false;
        private string _xLabel = "X";
        private string _yLabel = "Y";
        private string _zLabel = "Z";
        private string _errorMessage = "";
        private float _labelMinWidth = -1f;
        private Func<bool>? _validation;
        private Label? _errorLabel;
        #endregion

        #region Events
        /// <summary>값 변경 이벤트</summary>
        public event Action<Vector3>? OnValueChanged;
        #endregion

        #region Properties
        /// <summary>현재 값</summary>
        public Vector3 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-vector3-field--disabled", !value);
            }
        }

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

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

        /// <summary>Z축 라벨</summary>
        [UxmlAttribute("z-label")]
        public string ZLabel
        {
            get => _zLabel;
            set
            {
                _zLabel = value;
                UpdateAxisLabels();
            }
        }

        /// <summary>읽기 전용 상태</summary>
        [UxmlAttribute("is-readonly")]
        public bool IsReadOnly
        {
            get => _isReadOnly;
            set
            {
                _isReadOnly = value;
                UpdateReadOnlyState();
                EnableInClassList("utk-vector3-field--readonly", value);
            }
        }

        /// <summary>에러 메시지. 비어있지 않으면 에러 상태로 표시</summary>
        [UxmlAttribute("error-message")]
        public string ErrorMessage
        {
            get => _errorMessage;
            set
            {
                _errorMessage = value;
                var hasError = !string.IsNullOrEmpty(value);
                EnableInClassList("utk-vector3-field--error", hasError);
                UpdateErrorLabel(hasError ? value : null);
            }
        }

        /// <summary>
        /// 검증 함수. FocusOut 시 호출되어 false 반환 시 ErrorMessage 표시.
        /// </summary>
        /// <example>
        /// <code>
        /// var posField = new UTKVector3Field("위치");
        /// posField.ErrorMessage = "Y값은 0 이상이어야 합니다.";
        /// posField.Validation = () => posField.Value.y >= 0;
        /// </code>
        /// </example>
        public Func<bool>? Validation
        {
            get => _validation;
            set => _validation = value;
        }

        /// <summary>label이 있을 때 .unity-label의 min-width (px). -1이면 미설정</summary>
        [UxmlAttribute("label-min-width")]
        public float LabelMinWidth
        {
            get => _labelMinWidth;
            set
            {
                _labelMinWidth = value;
                ApplyLabelMinWidth();
            }
        }
        #endregion

        #region Constructor
        public UTKVector3Field() : base()
        {
            UTKThemeManager.Instance.ApplyThemeToElement(this);

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

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

        public UTKVector3Field(bool isReadOnly) : this()
        {
            _isReadOnly = isReadOnly;
            UpdateReadOnlyState();
        }

        public UTKVector3Field(string label, bool isReadOnly = false) : this()
        {
            this.label = label;
            _isReadOnly = isReadOnly;
            UpdateReadOnlyState();
        }
        #endregion

        #region Setup
        private void SetupStyles()
        {
            AddToClassList("utk-vector3-field");

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

        private void SetupEvents()
        {
            RegisterCallback<ChangeEvent<Vector3>>(OnFieldValueChanged);
            RegisterCallback<FocusOutEvent>(OnFocusOut);
        }

        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()
        {
            // Vector3Field의 내부 FloatField들을 찾아서 라벨 변경
            var floatFields = this.Query<FloatField>().ToList();
            if (floatFields.Count >= 3)
            {
                floatFields[0].label = _xLabel;
                floatFields[1].label = _yLabel;
                floatFields[2].label = _zLabel;
            }
        }

        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;
            }
        }

        private void ApplyLabelMinWidth()
        {
            if (string.IsNullOrEmpty(label)) return;
            var labelElement = this.Q<Label>(className: "unity-label");
            if (labelElement == null) return;

            if (_labelMinWidth >= 0)
            {
                labelElement.style.minWidth = _labelMinWidth;
            }
            else
            {
                labelElement.style.minWidth = StyleKeyword.Null;
            }
        }
        #endregion

        #region Event Handlers
        private void OnFieldValueChanged(ChangeEvent<Vector3> evt)
        {
            OnValueChanged?.Invoke(evt.newValue);
        }

        private void OnFocusOut(FocusOutEvent evt)
        {
            RunValidation();
        }
        #endregion

        #region Methods
        /// <summary>
        /// 강제로 Validation을 실행하여 에러 상태를 업데이트합니다.
        /// </summary>
        /// <returns>Validation이 null이면 true, 아니면 Validation 결과</returns>
        public bool Validate()
        {
            return RunValidation();
        }

        /// <summary>에러 상태를 수동으로 해제합니다.</summary>
        public void ClearError()
        {
            ErrorMessage = "";
        }

        private bool RunValidation()
        {
            if (_validation == null) return true;

            var isValid = _validation.Invoke();
            if (isValid)
            {
                // 검증 통과 시 에러 상태 해제
                EnableInClassList("utk-vector3-field--error", false);
                UpdateErrorLabel(null);
            }
            else
            {
                // 검증 실패 시 에러 상태 표시
                EnableInClassList("utk-vector3-field--error", true);
                UpdateErrorLabel(_errorMessage);
            }
            return isValid;
        }

        private void UpdateErrorLabel(string? message)
        {
            if (string.IsNullOrEmpty(message))
            {
                // 에러 라벨 숨기기 (존재하면)
                if (_errorLabel != null)
                {
                    _errorLabel.style.display = DisplayStyle.None;
                }
                return;
            }

            // 에러 라벨 생성 (지연 생성 - 필요할 때만)
            if (_errorLabel == null)
            {
                _errorLabel = new Label();
                _errorLabel.AddToClassList("utk-vector3-field__error-message");
                _errorLabel.style.display = DisplayStyle.None;
                Add(_errorLabel);
            }

            _errorLabel.text = message;
            _errorLabel.style.display = DisplayStyle.Flex;
        }
        #endregion

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

            UTKThemeManager.Instance.OnThemeChanged -= OnThemeChanged;
            UnregisterCallback<AttachToPanelEvent>(OnAttachToPanelForTheme);
            UnregisterCallback<DetachFromPanelEvent>(OnDetachFromPanelForTheme);
            UnregisterCallback<ChangeEvent<Vector3>>(OnFieldValueChanged);
            UnregisterCallback<FocusOutEvent>(OnFocusOut);
            OnValueChanged = null;
            _validation = null;
            _errorLabel = null;
        }
        #endregion
    }
}