using System;
using System.Collections.Generic;
using DG.Tweening;
using TMPro;
using UnityEngine;
using UnityEngine.Events;

namespace Ichni.Menu.UI
{
    /// <summary>
    /// 可复用的多选弹窗元素。调用方提供标题、内容与任意数量的 <see cref="SelectionBoxOption"/>，
    /// 本类动态实例化对应按钮，并确保一次显示最多只会执行一个选项回调。
    /// </summary>
    public class SelectionBox : MonoBehaviour
    {
        [Header("Selection Box")]
        public CanvasGroup canvasGroup;
        public TMP_Text titleText;
        public TMP_Text contentText;
        public RectTransform optionContainer;
        public SelectionBoxButton optionButtonPrefab;

        private readonly List<SelectionBoxButton> _generatedButtons = new();
        private bool _isResolved;

        /// <summary>
        /// 选项被选择并且自身淡出结束后触发。页面容器使用它销毁本次生成的 SelectionBox。
        /// </summary>
        public event Action<SelectionBox> Closed;

        private void Awake()
        {
            canvasGroup ??= GetComponent<CanvasGroup>();
        }

        /// <summary>
        /// 根据运行时选项初始化弹窗。至少需要一个选项；失败时返回 false，且不会显示半配置的弹窗。
        /// </summary>
        public bool SetUp(string title, string content, IReadOnlyList<SelectionBoxOption> options)
        {
            if (canvasGroup == null || optionContainer == null || optionButtonPrefab == null ||
                options == null || options.Count == 0)
            {
                Debug.LogWarning("[SelectionBox] 缺少 CanvasGroup、选项容器、选项按钮预制体，或未提供任何选项。");
                return false;
            }

            ClearGeneratedButtons();
            _isResolved = false;

            if (titleText != null) titleText.text = title ?? string.Empty;
            if (contentText != null) contentText.text = content ?? string.Empty;

            foreach (SelectionBoxOption option in options)
            {
                SelectionBoxButton button = Instantiate(optionButtonPrefab, optionContainer);
                _generatedButtons.Add(button);
                button.SetUp(option.label, () => Select(option.action));
            }

            gameObject.SetActive(true);
            canvasGroup.alpha = 0f;
            canvasGroup.interactable = true;
            canvasGroup.blocksRaycasts = true;
            canvasGroup.DOFade(1f, 0.2f).Play();
            return true;
        }

        private void Select(UnityAction action)
        {
            if (_isResolved) return;
            _isResolved = true;

            // 先禁用所有输入，再执行回调。回调可以触发存档、场景切换或打开下一层 UI，
            // 因而不能让同一帧内的其它按钮再次触发。
            canvasGroup.interactable = false;
            canvasGroup.blocksRaycasts = false;
            foreach (SelectionBoxButton button in _generatedButtons)
            {
                if (button?.button != null)
                    button.button.interactable = false;
            }

            action?.Invoke();
            canvasGroup.DOFade(0f, 0.2f).OnComplete(() => Closed?.Invoke(this)).Play();
        }

        private void ClearGeneratedButtons()
        {
            foreach (SelectionBoxButton button in _generatedButtons)
            {
                if (button != null)
                    Destroy(button.gameObject);
            }

            _generatedButtons.Clear();
        }
    }

    /// <summary>
    /// SelectionBox 的单个运行时选项。它不序列化到场景或存档；显示时由调用方临时创建。
    /// </summary>
    public readonly struct SelectionBoxOption
    {
        public readonly string label;
        public readonly UnityAction action;

        public SelectionBoxOption(string label, UnityAction action)
        {
            this.label = label;
            this.action = action;
        }
    }
}