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

namespace Ichni.Menu.UI
{
    /// <summary>
    /// 通用多选弹窗。
    /// 标题、正文与按钮均在播放前完成最终布局；入退场只改变 Background、两处文本 Mask 和 Rail，
    /// 因而不会在动画期间触发 TMP 重新换行或按钮布局抖动。
    /// </summary>
    public sealed class SelectionBox : MonoBehaviour
    {
        [Header("Base")]
        [SerializeField] private CanvasGroup canvasGroup;
        [SerializeField] private CanvasGroup optionCanvasGroup;

        [Header("Text & Options")]
        [SerializeField] private TMP_Text titleText;
        [SerializeField] private TMP_Text contentText;
        [SerializeField] private RectTransform optionContainer;
        [SerializeField] private SelectionBoxButton optionButtonPrefab;

        [Header("Layout References")]
        [SerializeField] private RectTransform messageBody;
        [SerializeField] private RectTransform backgroundVisual;
        [SerializeField] private RectMask2D titleTextMask;
        [SerializeField] private RectTransform contentLayoutRoot;
        [SerializeField] private RectMask2D contentTextMask;
        [SerializeField] private RectTransform railRoot;
        [SerializeField] private RectTransform leftRail;
        [SerializeField] private RectTransform rightRail;

        [Header("Animation")]
        [SerializeField, Min(0f)] private float bodyOpenDelay = 0.1f;
        [SerializeField, Min(0f)] private float bodyOpenDuration = 0.5f;
        [SerializeField, Min(0f)] private float railOpenDelay;
        [SerializeField, Min(0f)] private float railOpenDuration = 0.5f;
        [SerializeField, Min(0f)] private float bodyCloseDelay;
        [SerializeField, Min(0f)] private float bodyCloseDuration = 0.5f;
        [SerializeField, Min(0f)] private float railCloseDelay = 0.1f;
        [SerializeField, Min(0f)] private float railCloseDuration = 0.5f;
        [SerializeField, Min(0f)] private float closedMaskHorizontalPadding = 600f;
        [SerializeField] private Ease bodyEase = Ease.OutCubic;
        [SerializeField] private Ease railEase = Ease.OutQuart;

        /// <summary>
        /// 玩家选择任一选项、弹窗完成退场后触发。MessageUIPage 使用它继续共享 FIFO 队列。
        /// </summary>
        public event Action<SelectionBox> Closed;

        private readonly List<SelectionBoxButton> generatedButtons = new();
        private Sequence transitionSequence;
        private CanvasGroup leftRailCanvasGroup;
        private CanvasGroup rightRailCanvasGroup;
        private Vector2 backgroundOpenSizeDelta;
        private Vector2 leftRailOpenPosition;
        private Vector2 rightRailOpenPosition;
        private bool isResolved;

        private void Awake()
        {
            backgroundOpenSizeDelta = backgroundVisual.sizeDelta;
            leftRailOpenPosition = leftRail.anchoredPosition;
            rightRailOpenPosition = rightRail.anchoredPosition;
            leftRailCanvasGroup = leftRail.GetComponent<CanvasGroup>();
            rightRailCanvasGroup = rightRail.GetComponent<CanvasGroup>();
        }

        private void OnDestroy()
        {
            transitionSequence?.Kill();
            ClearGeneratedButtons();
        }

        /// <summary>
        /// 创建本次选择所需的按钮并播放入场动画。空选项没有可执行的玩家选择，因此返回 false。
        /// </summary>
        public bool SetUp(string title, string content, IReadOnlyList<SelectionBoxOption> options)
        {
            if (options == null || options.Count == 0)
            {
                Debug.LogWarning("[SelectionBox] 未提供任何 SelectionBoxOption，忽略空选项框。", this);
                return false;
            }

            ClearGeneratedButtons();
            isResolved = false;
            titleText.text = title ?? string.Empty;
            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);
            RefreshFinalLayout();
            Open();
            return true;
        }

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

            // 先阻断输入，再执行可能触发存档、跳转或新 UI 的业务回调。
            canvasGroup.interactable = false;
            canvasGroup.blocksRaycasts = false;
            foreach (SelectionBoxButton button in generatedButtons)
            {
                button.button.interactable = false;
            }

            action?.Invoke();
            Close();
        }

        /// <summary>
        /// 在最终尺寸下重建正文、主体和按钮行的布局。后续动画不再改变这些布局节点的尺寸。
        /// </summary>
        private void RefreshFinalLayout()
        {
            SetOpenVisualState();
            Canvas.ForceUpdateCanvases();
            LayoutRebuilder.ForceRebuildLayoutImmediate(contentLayoutRoot);
            LayoutRebuilder.ForceRebuildLayoutImmediate(messageBody);
            LayoutRebuilder.ForceRebuildLayoutImmediate(optionContainer);
            Canvas.ForceUpdateCanvases();
        }

        private void SetOpenVisualState()
        {
            backgroundVisual.sizeDelta = backgroundOpenSizeDelta;
            titleTextMask.padding = Vector4.zero;
            contentTextMask.padding = Vector4.zero;
            optionContainer.localScale = new Vector3(1f, optionContainer.localScale.y, optionContainer.localScale.z);
            optionCanvasGroup.alpha = 1f;
            optionCanvasGroup.interactable = true;
            optionCanvasGroup.blocksRaycasts = true;
            leftRail.anchoredPosition = leftRailOpenPosition;
            rightRail.anchoredPosition = rightRailOpenPosition;
            leftRailCanvasGroup.alpha = 1f;
            rightRailCanvasGroup.alpha = 1f;
        }

        private void SetClosedVisualState()
        {
            backgroundVisual.sizeDelta = GetClosedBackgroundSizeDelta();
            titleTextMask.padding = ClosedMaskPadding;
            contentTextMask.padding = ClosedMaskPadding;
            optionCanvasGroup.alpha = 0f;
            optionCanvasGroup.interactable = false;
            optionCanvasGroup.blocksRaycasts = false;

            float halfRootWidth = railRoot.rect.width * 0.5f;
            leftRail.anchoredPosition = new Vector2(halfRootWidth, leftRailOpenPosition.y);
            rightRail.anchoredPosition = new Vector2(-halfRootWidth, rightRailOpenPosition.y);
            leftRailCanvasGroup.alpha = 0f;
            rightRailCanvasGroup.alpha = 0f;
        }

        private Vector4 ClosedMaskPadding =>
            new(closedMaskHorizontalPadding, 0f, closedMaskHorizontalPadding, 0f);

        private Vector2 GetClosedBackgroundSizeDelta() =>
            new(backgroundOpenSizeDelta.x - backgroundVisual.rect.width, backgroundOpenSizeDelta.y);

        private static Tween CreateMaskPaddingTween(RectMask2D mask, Vector4 targetPadding, float duration, Ease ease) =>
            DOTween.To(() => mask.padding, value => mask.padding = value, targetPadding, duration).SetEase(ease);

        private static void AddRailTransition(
            Sequence sequence,
            RectTransform rail,
            CanvasGroup railCanvasGroup,
            Vector2 targetPosition,
            float targetAlpha,
            float delay,
            float duration,
            Ease positionEase)
        {
            sequence.Insert(delay, rail.DOAnchorPos(targetPosition, duration).SetEase(positionEase));
            sequence.Insert(delay, railCanvasGroup.DOFade(targetAlpha, duration).SetEase(Ease.Linear));
        }

        private void Open()
        {
            transitionSequence?.Kill();
            canvasGroup.gameObject.SetActive(true);
            canvasGroup.alpha = 1f;
            canvasGroup.interactable = false;
            canvasGroup.blocksRaycasts = false;
            SetClosedVisualState();

            transitionSequence = DOTween.Sequence().SetAutoKill(true).Pause();
            transitionSequence.Insert(
                bodyOpenDelay,
                backgroundVisual.DOSizeDelta(backgroundOpenSizeDelta, bodyOpenDuration).SetEase(bodyEase));
            transitionSequence.Insert(
                bodyOpenDelay,
                CreateMaskPaddingTween(titleTextMask, Vector4.zero, bodyOpenDuration, bodyEase));
            transitionSequence.Insert(
                bodyOpenDelay,
                CreateMaskPaddingTween(contentTextMask, Vector4.zero, bodyOpenDuration, bodyEase));
            AddRailTransition(
                transitionSequence,
                leftRail,
                leftRailCanvasGroup,
                leftRailOpenPosition,
                1f,
                railOpenDelay,
                railOpenDuration,
                railEase);
            AddRailTransition(
                transitionSequence,
                rightRail,
                rightRailCanvasGroup,
                rightRailOpenPosition,
                1f,
                railOpenDelay,
                railOpenDuration,
                railEase);

            float optionRevealTime = bodyOpenDelay + bodyOpenDuration;
            transitionSequence.Insert(
                optionRevealTime,
                optionCanvasGroup.DOFade(1f, 0.4f).From(0f).SetEase(Ease.Linear));
            transitionSequence.Insert(
                optionRevealTime,
                optionContainer.DOAnchorPos(Vector2.zero, 0.4f).From(new Vector2(0f, 100f)).SetEase(Ease.OutQuad));
            transitionSequence.OnComplete(() =>
            {
                canvasGroup.interactable = true;
                canvasGroup.blocksRaycasts = true;
                optionCanvasGroup.interactable = true;
                optionCanvasGroup.blocksRaycasts = true;
            });
            // 项目约定：DOTween 动画必须由代码显式触发 Play。
            transitionSequence.Play();
        }

        private void Close()
        {
            transitionSequence?.Kill();
            canvasGroup.interactable = false;
            canvasGroup.blocksRaycasts = false;
            optionCanvasGroup.interactable = false;
            optionCanvasGroup.blocksRaycasts = false;

            float halfRootWidth = railRoot.rect.width * 0.5f;
            transitionSequence = DOTween.Sequence().SetAutoKill(true).Pause();
            transitionSequence.Insert(
                bodyCloseDelay,
                backgroundVisual.DOSizeDelta(GetClosedBackgroundSizeDelta(), bodyCloseDuration).SetEase(Ease.InCubic));
            transitionSequence.Insert(
                bodyCloseDelay,
                CreateMaskPaddingTween(titleTextMask, ClosedMaskPadding, bodyCloseDuration, Ease.InCubic));
            transitionSequence.Insert(
                bodyCloseDelay,
                CreateMaskPaddingTween(contentTextMask, ClosedMaskPadding, bodyCloseDuration, Ease.InCubic));
            transitionSequence.Insert(
                bodyCloseDelay,
                optionContainer.DOScaleX(0f, bodyCloseDuration).SetEase(Ease.InCubic));
            AddRailTransition(
                transitionSequence,
                leftRail,
                leftRailCanvasGroup,
                new Vector2(halfRootWidth, leftRailOpenPosition.y),
                0f,
                railCloseDelay,
                railCloseDuration,
                Ease.InQuart);
            AddRailTransition(
                transitionSequence,
                rightRail,
                rightRailCanvasGroup,
                new Vector2(-halfRootWidth, rightRailOpenPosition.y),
                0f,
                railCloseDelay,
                railCloseDuration,
                Ease.InQuart);

            transitionSequence.OnComplete(() =>
            {
                canvasGroup.gameObject.SetActive(false);
                Closed?.Invoke(this);
            });
            // 项目约定：DOTween 动画必须由代码显式触发 Play。
            transitionSequence.Play();
        }

        private void ClearGeneratedButtons()
        {
            foreach (SelectionBoxButton button in generatedButtons)
            {
                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;
        }
    }
}