using UnityEngine;
using UnityEngine.UI;
using UnityEngine.EventSystems;
using BaseGames.Core.Events;
using BaseGames.UI.Theme;

namespace BaseGames.UI
{
    /// <summary>按钮视觉变体（驱动从主题派生的 <see cref="ColorBlock"/>）。</summary>
    public enum UIButtonVariant { Primary, Secondary, Accent, Danger, Ghost }

    /// <summary>
    /// 主题化按钮变体 + 交互反馈。薄封装在 uGUI <see cref="Button"/> 之上：
    /// - 按变体从 <see cref="UIThemeSO"/> 取基色，派生 normal/highlighted/pressed/disabled 并写入 Button.colors。
    /// - 选中/悬停时缩放反馈（走 <see cref="UITween.Scale"/>）。
    /// - 可选点击/悬停音效（事件频道驱动，不直接耦合 Audio 程序集）。
    ///
    /// 主题来源：优先 Inspector 直接赋的 <see cref="_theme"/>，否则就近向上找 <see cref="UIThemeApplier"/>。
    /// </summary>
    [RequireComponent(typeof(Button))]
    [DisallowMultipleComponent]
    public class UIButton : MonoBehaviour,
        ISelectHandler, IDeselectHandler, IPointerEnterHandler, IPointerExitHandler
    {
        [Header("变体")]
        [SerializeField] private UIButtonVariant _variant = UIButtonVariant.Primary;
        [Tooltip("主题资产；为空则就近向上查找 UIThemeApplier。")]
        [SerializeField] private UIThemeSO _theme;

        [Header("反馈")]
        [Tooltip("选中/悬停时的缩放反馈。")]
        [SerializeField] private bool _scaleFeedback = true;
        [SerializeField] private float _selectedScale = 1.06f;
        [SerializeField] private float _scaleDuration = 0.08f;

        [Header("音效（可选，事件频道驱动）")]
        [SerializeField] private VoidEventChannelSO _onClickSfx;
        [SerializeField] private VoidEventChannelSO _onHoverSfx;

        private Button _button;
        private Coroutine _scaleRoutine;
        private Vector3 _baseScale = Vector3.one;

        private void Awake()
        {
            _button = GetComponent<Button>();
            _baseScale = transform.localScale;
            _button.onClick.AddListener(RaiseClickSfx);
        }

        private void OnEnable()
        {
            ApplyTheme();
            transform.localScale = _baseScale;
        }

        private void OnDisable()
        {
            if (_scaleRoutine != null) { StopCoroutine(_scaleRoutine); _scaleRoutine = null; }
            transform.localScale = _baseScale;
        }

        // ── 主题应用 ──────────────────────────────────────────────────────────
        /// <summary>按当前变体与主题刷新 Button 配色。</summary>
        public void ApplyTheme()
        {
            var theme = ResolveTheme();
            if (theme == null) return;
            if (_button == null) _button = GetComponent<Button>();
            if (_button == null) return;

            Color baseColor = VariantBaseColor(theme, _variant);
            var cb = _button.colors;
            cb.colorMultiplier = 1f;
            cb.fadeDuration    = 0.1f;
            cb.disabledColor   = theme.ButtonDisabled;

            if (_variant == UIButtonVariant.Ghost)
            {
                cb.normalColor      = new Color(baseColor.r, baseColor.g, baseColor.b, 0f);
                cb.highlightedColor = new Color(baseColor.r, baseColor.g, baseColor.b, 0.25f);
                cb.pressedColor     = new Color(baseColor.r, baseColor.g, baseColor.b, 0.40f);
                cb.selectedColor    = cb.highlightedColor;
            }
            else
            {
                cb.normalColor      = baseColor;
                cb.highlightedColor = Color.Lerp(baseColor, Color.white, 0.12f);
                cb.pressedColor     = Color.Lerp(baseColor, Color.black, 0.15f);
                cb.selectedColor    = cb.highlightedColor;
            }
            _button.colors = cb;
        }

        private static Color VariantBaseColor(UIThemeSO t, UIButtonVariant v) => v switch
        {
            UIButtonVariant.Primary   => t.Primary,
            UIButtonVariant.Secondary => t.Secondary,
            UIButtonVariant.Accent    => t.Accent,
            UIButtonVariant.Danger    => t.Danger,
            UIButtonVariant.Ghost     => t.TextPrimary,
            _                         => t.Primary,
        };

        private UIThemeSO ResolveTheme()
        {
            if (_theme != null) return _theme;
            var applier = GetComponentInParent<UIThemeApplier>(includeInactive: true);
            return applier != null ? applier.Theme : null;
        }

        // ── 交互反馈 ──────────────────────────────────────────────────────────
        public void OnSelect(BaseEventData e)   { PlayScale(_selectedScale); RaiseHoverSfx(); }
        public void OnDeselect(BaseEventData e)  { PlayScale(1f); }
        public void OnPointerEnter(PointerEventData e) { PlayScale(_selectedScale); RaiseHoverSfx(); }
        public void OnPointerExit(PointerEventData e)
        {
            // 仍为当前选中项则保持放大
            if (EventSystem.current != null && EventSystem.current.currentSelectedGameObject == gameObject) return;
            PlayScale(1f);
        }

        private void PlayScale(float factor)
        {
            if (!_scaleFeedback || !isActiveAndEnabled) return;
            if (_scaleRoutine != null) StopCoroutine(_scaleRoutine);
            _scaleRoutine = StartCoroutine(UITween.Scale(transform, _baseScale * factor, _scaleDuration));
        }

        private void RaiseClickSfx() => _onClickSfx?.Raise();
        private void RaiseHoverSfx() => _onHoverSfx?.Raise();

#if UNITY_EDITOR
        private void OnValidate()
        {
            if (Application.isPlaying) return;
            _button = GetComponent<Button>();
            ApplyTheme();
        }
#endif
    }
}