using System;
using DG.Tweening;
using SLSUtilities.WwiseAssistance;
using TMPro;
using UnityEngine;
using UnityEngine.UI;

namespace Ichni.Menu.UI
{
    /// <summary>
    /// 单条文本提示框。
    /// 多条弹窗的 FIFO 顺序由 MessageUIPage 统一管理；本类只负责当前一条消息的布局、
    /// 入退场视觉和确认输入，避免与 UIPage 的队列职责重复。
    /// </summary>
    public sealed class MessageBox : MonoBehaviour
    {
        [Header("Base")]
        [SerializeField] private CanvasGroup canvasGroup;
        [SerializeField] private Button receiveButton;

        [Header("Text")]
        [SerializeField] private TMP_Text titleText;
        [SerializeField] private TMP_Text contentText;

        [Header("Layout References")]
        [Tooltip("可变高度的最终布局节点。动画期间不会修改它、Title 或 Content 的 RectTransform。")]
        [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("Content Height Limit")]
        [SerializeField, Min(0f)] private float maximumBodyHeight = 600f;
        [SerializeField, Min(1f)] private float minimumContentFontSize = 18f;

        [Header("Animation")]
        [Tooltip("背景与文本 Mask 从中心展开前的延迟；Rail 的默认延迟为 0，因此会先行动。")]
        [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 = 520f;
        [SerializeField] private Ease bodyEase = Ease.OutCubic;
        [SerializeField] private Ease railEase = Ease.OutQuart;

        /// <summary>
        /// 退场动画结束后触发。MessageUIPage 订阅它以销毁当前实例并继续 FIFO 队列。
        /// </summary>
        public event Action<MessageBox> Closed;

        private Sequence transitionSequence;
        private CanvasGroup leftRailCanvasGroup;
        private CanvasGroup rightRailCanvasGroup;
        private Vector2 backgroundOpenSizeDelta;
        private Vector2 leftRailOpenPosition;
        private Vector2 rightRailOpenPosition;
        private float contentMaximumFontSize;

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

            receiveButton.onClick.AddListener(HandleReceiveButtonClicked);
        }

        private void OnDestroy()
        {
            transitionSequence?.Kill();
            receiveButton.onClick.RemoveListener(HandleReceiveButtonClicked);
        }

        /// <summary>
        /// 写入唯一一条待显示文本，并播放入场动画。
        /// 多条提示请分别提交给 MessageUIPage，而不要在一个 MessageBox 中追加消息。
        /// </summary>
        public void SetUp(string title, string content)
        {
            titleText.text = title ?? string.Empty;
            contentText.text = content ?? string.Empty;

            RefreshLayoutAndFitContentText();
            Open();
        }

        private void HandleReceiveButtonClicked()
        {
            AudioManager.Post(AK.EVENTS.CONFIRM);
            Close();
        }

        /// <summary>
        /// 使用最终宽度计算文字换行与内容高度。正文超过 maximumBodyHeight 时，
        /// 通过二分查找缩小至可容纳的最大字号；不会引入滚动或截断内容。
        /// </summary>
        private void RefreshLayoutAndFitContentText()
        {
            SetOpenVisualState();
            ForceRebuildLayout();

            if (maximumBodyHeight <= 0f)
            {
                return;
            }

            contentText.enableAutoSizing = false;
            contentText.fontSize = contentMaximumFontSize;
            ForceRebuildLayout();

            if (messageBody.rect.height <= maximumBodyHeight)
            {
                return;
            }

            float minimumFontSize = Mathf.Min(minimumContentFontSize, contentMaximumFontSize);
            float lowerBound = minimumFontSize;
            float upperBound = contentMaximumFontSize;
            float bestFontSize = minimumFontSize;

            // 字号与内容高度单调相关；六次二分已足够平滑且只在弹窗创建时执行。
            for (int iteration = 0; iteration < 6; iteration++)
            {
                float candidate = (lowerBound + upperBound) * 0.5f;
                contentText.fontSize = candidate;
                ForceRebuildLayout();

                if (messageBody.rect.height <= maximumBodyHeight)
                {
                    bestFontSize = candidate;
                    lowerBound = candidate;
                }
                else
                {
                    upperBound = candidate;
                }
            }

            contentText.fontSize = bestFontSize;
            ForceRebuildLayout();

            if (messageBody.rect.height > maximumBodyHeight)
            {
                Debug.LogWarning(
                    $"[MessageBox] 正文在最小字号 {minimumFontSize:F1} 下仍超过最大高度 {maximumBodyHeight:F1}；" +
                    "已保留完整内容并允许消息框继续增高。",
                    this);
            }
        }

        private void ForceRebuildLayout()
        {
            Canvas.ForceUpdateCanvases();
            LayoutRebuilder.ForceRebuildLayoutImmediate(contentLayoutRoot);
            LayoutRebuilder.ForceRebuildLayoutImmediate(messageBody);
            Canvas.ForceUpdateCanvases();
        }

        /// <summary>
        /// 恢复最终视觉尺寸以完成布局。这里不会改变 MessageBox、Title 或 Content 的尺寸，
        /// 因此 TMP 在展开和收拢全过程都不会重新换行。
        /// </summary>
        private void SetOpenVisualState()
        {
            backgroundVisual.sizeDelta = backgroundOpenSizeDelta;
            titleTextMask.padding = Vector4.zero;
            contentTextMask.padding = Vector4.zero;
            leftRail.anchoredPosition = leftRailOpenPosition;
            rightRail.anchoredPosition = rightRailOpenPosition;
            leftRailCanvasGroup.alpha = 1f;
            rightRailCanvasGroup.alpha = 1f;
        }

        private void SetClosedVisualState()
        {
            backgroundVisual.sizeDelta = GetClosedBackgroundSizeDelta();
            titleTextMask.padding = ClosedMaskPadding;
            contentTextMask.padding = ClosedMaskPadding;

            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);

        /// <summary>
        /// Background 使用左右 Stretch 锚点。以最终实际宽度抵消它的 SizeDelta X，
        /// 可将图像视觉收拢到中心而不改变 MessageBox 的布局宽度。
        /// </summary>
        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));
        }

        /// <summary>
        /// 只展开 Background 与两个文字 Mask；MessageBox、标题、正文均已是最终布局尺寸。
        /// 每个 Sequence 都先 Pause，再在结尾显式调用 Play，符合项目的 DOTween 使用约定。
        /// </summary>
        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);

            transitionSequence.OnComplete(() =>
            {
                canvasGroup.interactable = true;
                canvasGroup.blocksRaycasts = true;
            });
            transitionSequence.Play();
        }

        /// <summary>
        /// 反向收拢 Background、文字 Mask 和两侧 Rail；完成后通知 MessageUIPage 显示下一项。
        /// </summary>
        private void Close()
        {
            transitionSequence?.Kill();
            canvasGroup.interactable = false;
            canvasGroup.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));
            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);
            });
            transitionSequence.Play();
        }
    }
}