using System;
using DG.Tweening;
using TMPro;
using UnityEngine;

namespace Ichni.Story
{
    /// <summary>
    /// 由 <see cref="StoryHelperController"/> 按需实例化的 Helper 专属对话气泡。
    /// <para>每个实例只显示一条文本：淡入、停留、淡出后自动销毁，因此场景中不需要常驻气泡，
    /// 也不会与通用 MessageBox 队列产生耦合。</para>
    /// </summary>
    [RequireComponent(typeof(CanvasGroup))]
    public class StoryHelperTalk : MonoBehaviour
    {
        [SerializeField, Tooltip("显示 Helper 名称的文本。")]
        private TMP_Text speakerText;

        [SerializeField, Tooltip("显示随机 Helper 对话的文本。")]
        private TMP_Text contentText;

        [Header("Animation")]
        [SerializeField, Min(0.01f), Tooltip("淡入与缩放入场时间。")]
        private float showDuration = 0.18f;

        [SerializeField, Min(0f), Tooltip("气泡完整显示后的停留时间。")]
        private float visibleDuration = 4.5f;

        [SerializeField, Min(0.01f), Tooltip("淡出与缩放退场时间。")]
        private float hideDuration = 0.16f;

        [SerializeField, Range(0.5f, 1f), Tooltip("入场与退场时相对原始大小的缩放比例。")]
        private float initialScaleMultiplier = 0.92f;

        /// <summary>气泡结束显示并准备销毁时触发，供创建者清理当前实例引用。</summary>
        public event Action<StoryHelperTalk> Closed;

        private CanvasGroup _canvasGroup;
        private RectTransform _rectTransform;
        private Sequence _sequence;
        private Vector3 _baseScale;
        private bool _isClosed;

        private void Awake()
        {
            _canvasGroup = GetComponent<CanvasGroup>();
            _rectTransform = transform as RectTransform;
            _baseScale = _rectTransform != null ? _rectTransform.localScale : Vector3.one;
        }

        /// <summary>
        /// 写入文本并播放完整的出现、停留与收回流程。
        /// 所有 DOTween Sequence 均先 Pause，再手动调用 Play，符合项目约定。
        /// </summary>
        public void Show(string speaker, string content)
        {
            if (speakerText == null || contentText == null || _rectTransform == null)
            {
                Debug.LogWarning("[StoryHelperTalk] Prefab 未配置 Speaker Text、Content Text 或 RectTransform，已取消显示。", this);
                CloseImmediately();
                return;
            }

            speakerText.text = speaker;
            contentText.text = content;
            _canvasGroup.alpha = 0f;
            _rectTransform.localScale = _baseScale * initialScaleMultiplier;

            _sequence?.Kill();
            _sequence = DOTween.Sequence()
                .Pause()
                .SetUpdate(true)
                .Append(_canvasGroup.DOFade(1f, showDuration))
                .Join(_rectTransform.DOScale(_baseScale, showDuration).SetEase(Ease.OutBack))
                .AppendInterval(visibleDuration)
                .Append(_canvasGroup.DOFade(0f, hideDuration))
                .Join(_rectTransform.DOScale(_baseScale * initialScaleMultiplier, hideDuration).SetEase(Ease.InQuad))
                .OnComplete(CloseImmediately);
            _sequence.Play();
        }

        /// <summary>
        /// 立即关闭并销毁该运行时实例。再次点击 Helper 时会调用它，使旧文本不会与新文本叠加。
        /// </summary>
        public void CloseImmediately()
        {
            if (_isClosed)
                return;

            _isClosed = true;
            _sequence?.Kill();
            _sequence = null;
            Closed?.Invoke(this);
            Destroy(gameObject);
        }

        private void OnDestroy()
        {
            _sequence?.Kill();
        }
    }
}