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

namespace UVC.UIToolkit
{
    /// <summary>
    /// 모달 창 컴포넌트.
    /// 사용자 정의 콘텐츠를 포함할 수 있는 모달 대화상자입니다.
    /// </summary>
    /// <example>
    /// <para><b>C# 코드에서 사용:</b></para>
    /// <code>
    /// // 모달 생성 및 표시
    /// var modal = new UTKModal();
    /// modal.Title = "설정";
    /// modal.Size = UTKModal.ModalSize.Medium;
    /// modal.OnClosed += () => Debug.Log("모달 닫힘");
    /// 
    /// // 콘텐츠 추가
    /// var content = new Label("모달 내용");
    /// modal.AddContent(content);
    /// 
    /// // 푸터 버튼 추가
    /// modal.AddFooterButton("확인", UTKButton.ButtonVariant.Primary, () => modal.Close());
    /// modal.AddFooterButton("취소", UTKButton.ButtonVariant.Normal, () => modal.Close());
    /// 
    /// // 표시
    /// modal.Show(rootElement);
    /// </code>
    /// <para><b>UXML에서 사용:</b></para>
    /// <code>
    /// <ui:UXML xmlns:utk="UVC.UIToolkit">
    ///     <utk:UTKModal title="설정" size="Medium" show-close-button="true">
    ///         <ui:Label text="모달 내용을 여기에 추가하세요" />
    ///     </utk:UTKModal>
    /// </ui:UXML>
    /// </code>
    /// </example>
    [UxmlElement]
    public partial class UTKModal : VisualElement, IDisposable
    {
        #region Constants
        private const string USS_PATH = "UIToolkit/Modal/UTKModal";
        #endregion

        #region Fields
        private bool _disposed;
        private UTKModalBlocker? _blocker;
        private VisualElement? _header;
        private Label? _titleLabel;
        private Button? _closeButton;
        private VisualElement? _content;
        private VisualElement? _footer;

        private string _title = "Modal";
        private bool _showCloseButton = true;
        private bool _closeOnBackdropClick = true;
        private ModalSize _size = ModalSize.Medium;
        #endregion

        #region Events
        /// <summary>닫힘 이벤트</summary>
        public event Action? OnClosed;
        #endregion

        #region Properties
        /// <summary>모달 제목</summary>
        [UxmlAttribute("title")]
        public string Title
        {
            get => _title;
            set
            {
                _title = value;
                if (_titleLabel != null) _titleLabel.text = value;
            }
        }

        /// <summary>닫기 버튼 표시 여부</summary>
        [UxmlAttribute("show-close-button")]
        public bool ShowCloseButton
        {
            get => _showCloseButton;
            set
            {
                _showCloseButton = value;
                if (_closeButton != null)
                {
                    _closeButton.style.display = value ? DisplayStyle.Flex : DisplayStyle.None;
                }
            }
        }

        /// <summary>배경 클릭 시 닫기 여부</summary>
        [UxmlAttribute("close-on-backdrop-click")]
        public bool CloseOnBackdropClick
        {
            get => _closeOnBackdropClick;
            set => _closeOnBackdropClick = value;
        }

        /// <summary>모달 크기</summary>
        [UxmlAttribute("size")]
        public ModalSize Size
        {
            get => _size;
            set
            {
                _size = value;
                UpdateSize();
            }
        }

        /// <summary>콘텐츠 컨테이너</summary>
        public VisualElement? ContentContainer => _content;

        /// <summary>푸터 컨테이너</summary>
        public VisualElement? FooterContainer => _footer;
        #endregion

        #region Enums
        public enum ModalSize
        {
            Small,
            Medium,
            Large,
            FullScreen
        }
        #endregion

        #region Constructor
        public UTKModal()
        {
            UTKThemeManager.Instance.ApplyThemeToElement(this);

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

            CreateUI();
            SetupEvents();
            SubscribeToThemeChanges();
        }

        public UTKModal(string title, ModalSize size = ModalSize.Medium) : this()
        {
            Title = title;
            Size = size;
        }
        #endregion

        #region Static Factory
        /// <summary>
        /// 모달 표시
        /// </summary>
        public static UTKModal Show(VisualElement parent, string title, ModalSize size = ModalSize.Medium)
        {
            var modal = new UTKModal(title, size);

            modal._blocker = UTKModalBlocker.Show(parent, 0.5f, false);
            if (modal._closeOnBackdropClick)
            {
                modal._blocker.OnBlockerClicked += modal.Close;
            }
            modal._blocker.Add(modal);

            // 중앙 정렬
            modal.style.position = Position.Absolute;
            modal.style.left = Length.Percent(50);
            modal.style.top = Length.Percent(50);
            modal.style.translate = new Translate(Length.Percent(-50), Length.Percent(-50));

            return modal;
        }
        #endregion

        #region UI Creation
        private void CreateUI()
        {
            AddToClassList("utk-modal");

            // Header
            _header = new VisualElement { name = "header" };
            _header.AddToClassList("utk-modal__header");
            hierarchy.Add(_header);

            _titleLabel = new Label { name = "title", text = _title };
            _titleLabel.AddToClassList("utk-modal__title");
            _header.Add(_titleLabel);

            _closeButton = new Button { name = "close-btn", text = "✕" };
            _closeButton.AddToClassList("utk-modal__close-btn");
            _header.Add(_closeButton);

            // Content
            _content = new VisualElement { name = "content" };
            _content.AddToClassList("utk-modal__content");
            hierarchy.Add(_content);

            // Footer
            _footer = new VisualElement { name = "footer" };
            _footer.AddToClassList("utk-modal__footer");
            hierarchy.Add(_footer);

            UpdateSize();
        }

        private void SetupEvents()
        {
            _closeButton?.RegisterCallback<ClickEvent>(_ => Close());

            RegisterCallback<KeyDownEvent>(evt =>
            {
                if (evt.keyCode == KeyCode.Escape)
                {
                    Close();
                    evt.StopPropagation();
                }
            }, TrickleDown.TrickleDown);
        }

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

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

        #region Methods
        private void UpdateSize()
        {
            RemoveFromClassList("utk-modal--small");
            RemoveFromClassList("utk-modal--medium");
            RemoveFromClassList("utk-modal--large");
            RemoveFromClassList("utk-modal--fullscreen");

            var sizeClass = _size switch
            {
                ModalSize.Small => "utk-modal--small",
                ModalSize.Large => "utk-modal--large",
                ModalSize.FullScreen => "utk-modal--fullscreen",
                _ => "utk-modal--medium"
            };
            AddToClassList(sizeClass);
        }

        /// <summary>
        /// 콘텐츠 추가
        /// </summary>
        public new void Add(VisualElement element)
        {
            _content?.Add(element);
        }

        /// <summary>
        /// 푸터에 요소 추가
        /// </summary>
        public void AddToFooter(VisualElement element)
        {
            _footer?.Add(element);
        }

        /// <summary>
        /// 푸터 표시/숨김
        /// </summary>
        public void SetFooterVisible(bool visible)
        {
            if (_footer != null)
            {
                _footer.style.display = visible ? DisplayStyle.Flex : DisplayStyle.None;
            }
        }

        /// <summary>
        /// 모달 닫기
        /// </summary>
        public void Close()
        {
            OnClosed?.Invoke();
            if (_blocker != null)
            {
                _blocker.OnBlockerClicked -= Close;
                _blocker.Hide();
            }
            _blocker = null;
        }
        #endregion

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

            UTKThemeManager.Instance.OnThemeChanged -= OnThemeChanged;
            OnClosed = null;
            _blocker = null;
        }
        #endregion
    }
}