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

namespace UVC.UIToolkit
{
    /// <summary>
    /// 프로그레스 바 컴포넌트.
    /// Unity ProgressBar를 래핑하여 커스텀 스타일을 적용합니다.
    /// </summary>
    /// <example>
    /// <para><b>C# 코드에서 사용:</b></para>
    /// <code>
    /// // 기본 프로그레스 바
    /// var progressBar = new UTKProgressBar();
    /// progressBar.title = "다운로드 중...";
    /// progressBar.MinValue = 0;
    /// progressBar.MaxValue = 100;
    /// progressBar.Value = 50;
    /// 
    /// // 값 표시 설정
    /// progressBar.ShowValue = true;
    /// progressBar.ShowPercentage = true;
    /// 
    /// // 무한 로딩 (불확정 상태)
    /// progressBar.IsIndeterminate = true;
    /// 
    /// // 변형 스타일
    /// progressBar.Variant = UTKProgressBar.ProgressBarVariant.Success;
    /// </code>
    /// <para><b>UXML에서 사용:</b></para>
    /// <code>
    /// <ui:UXML xmlns:utk="UVC.UIToolkit">
    ///     <!-- 기본 프로그레스 바 -->
    ///     <utk:UTKProgressBar title="진행률" low-value="0" high-value="100" value="30" />
    ///     
    ///     <!-- 퍼센트 표시 -->
    ///     <utk:UTKProgressBar ShowPercentage="true" value="75" />
    ///     
    ///     <!-- 성공 스타일 -->
    ///     <utk:UTKProgressBar Variant="Success" value="100" />
    /// </ui:UXML>
    /// </code>
    /// </example>
    [UxmlElement]
    public partial class UTKProgressBar : ProgressBar, IDisposable
    {
        #region Constants
        private const string USS_PATH = "UIToolkit/Slider/UTKProgressBar";
        #endregion

        #region Fields
        private bool _disposed;
        private bool _showValue = true;
        private bool _showPercentage = true;
        private bool _isIndeterminate;
        private ProgressBarVariant _variant = ProgressBarVariant.Default;
        #endregion

        #region Properties
        /// <summary>현재 값</summary>
        public float Value
        {
            get => value;
            set => SetValue(value);
        }

        /// <summary>최소값</summary>
        public float MinValue
        {
            get => lowValue;
            set
            {
                lowValue = value;
                UpdateValueLabel();
            }
        }

        /// <summary>최대값</summary>
        public float MaxValue
        {
            get => highValue;
            set
            {
                highValue = value;
                UpdateValueLabel();
            }
        }

        /// <summary>값 표시 여부</summary>
        [UxmlAttribute("show-value")]
        public bool ShowValue
        {
            get => _showValue;
            set
            {
                _showValue = value;
                UpdateValueLabel();
            }
        }

        /// <summary>퍼센트로 표시 여부</summary>
        [UxmlAttribute("show-percentage")]
        public bool ShowPercentage
        {
            get => _showPercentage;
            set
            {
                _showPercentage = value;
                UpdateValueLabel();
            }
        }

        /// <summary>불확정 상태 (애니메이션)</summary>
        [UxmlAttribute("is-indeterminate")]
        public bool IsIndeterminate
        {
            get => _isIndeterminate;
            set
            {
                _isIndeterminate = value;
                EnableInClassList("utk-progress--indeterminate", value);
                UpdateValueLabel();
            }
        }

        /// <summary>스타일 변형</summary>
        [UxmlAttribute("variant")]
        public ProgressBarVariant Variant
        {
            get => _variant;
            set
            {
                _variant = value;
                UpdateVariant();
            }
        }
        #endregion

        #region Enums
        public enum ProgressBarVariant
        {
            Default,
            Success,
            Warning,
            Error
        }
        #endregion

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

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

            SetupStyles();
            SubscribeToThemeChanges();
        }

        public UTKProgressBar(string text, float value = 0f, float maxValue = 100f) : this()
        {
            title = text;
            highValue = maxValue;
            SetValue(value);
        }
        #endregion

        #region Setup
        private void SetupStyles()
        {
            AddToClassList("utk-progress");
            UpdateVariant();
            UpdateValueLabel();
        }

        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
        /// <summary>
        /// 값 설정
        /// </summary>
        public void SetValue(float newValue)
        {
            value = Mathf.Clamp(newValue, lowValue, highValue);
            UpdateValueLabel();
        }

        private void UpdateValueLabel()
        {
            if (_isIndeterminate || !_showValue)
            {
                title = title?.Split(' ')[0] ?? "";
                return;
            }

            string baseTitle = title?.Split(' ')[0] ?? "";

            if (_showPercentage)
            {
                float range = highValue - lowValue;
                float percent = range > 0 ? (value - lowValue) / range * 100 : 0;
                title = string.IsNullOrEmpty(baseTitle) ? $"{percent:F0}%" : $"{baseTitle} {percent:F0}%";
            }
            else
            {
                title = string.IsNullOrEmpty(baseTitle) ? $"{value:F0}/{highValue:F0}" : $"{baseTitle} {value:F0}/{highValue:F0}";
            }
        }

        private void UpdateVariant()
        {
            RemoveFromClassList("utk-progress--default");
            RemoveFromClassList("utk-progress--success");
            RemoveFromClassList("utk-progress--warning");
            RemoveFromClassList("utk-progress--error");

            var variantClass = _variant switch
            {
                ProgressBarVariant.Success => "utk-progress--success",
                ProgressBarVariant.Warning => "utk-progress--warning",
                ProgressBarVariant.Error => "utk-progress--error",
                _ => "utk-progress--default"
            };
            AddToClassList(variantClass);
        }
        #endregion

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

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