using System;
using System.Threading;
using Cysharp.Threading.Tasks;
using Newtonsoft.Json;
using UnityEngine;

namespace Stary.Evo.StoryEditor
{
    /// <summary>
    /// 剧本播放器
    /// </summary>
    public static class ScriptPlayer
    {
        /// <summary>
        /// 资源加载工具
        /// </summary>
        private static IResource _loader;

        /// <summary>
        /// 动画单次时长
        /// </summary>
        private const float AnimationTime = 0.2f;
        /// <summary>
        /// 刷新帧率
        /// </summary>
        private const float UpdateInterval = 0.02f;
        
        /// <summary>
        /// 字幕组件
        /// </summary>
        private static SpriteRenderer _caption;
        /// <summary>
        /// 音频组件
        /// </summary>
        private static AudioSource _audio;
        
        /// <summary>
        /// 当前执行的剧本
        /// </summary>
        private static GraphPlayer _graph;

        /// <summary>
        /// 初始化剧本播放器
        /// </summary>
        /// <param name="loader">资源加载工具</param>
        /// <param name="audio">音频组件</param>
        /// <param name="caption">字幕组件</param>
        public static void Init(IResource loader, AudioSource audio = null, SpriteRenderer caption = null)
        {
            _loader = loader;
            _caption = caption;
            _audio = audio;
        }

        /// <summary>
        /// 释放资源
        /// </summary>
        public static void Release()
        {
            _loader = null;
            _caption = null;
            _audio = null;
            Resources.UnloadUnusedAssets();
        }
        
        /// <summary>
        /// 播放剧本
        /// </summary>
        /// <param name="packageID">包体ID</param>
        /// <param name="scriptName">剧本名称（不用加_txt后缀）</param>
        public static async UniTask Play(string packageID, string scriptName)
        {
            // 资源加载工具排空
            if (_loader == null)
            {
                Debug.LogError("资源加载工具未准备好");
                return;
            }

            // 加载剧本
            ResourcePathData path = new(packageID,scriptName);
            var json = await _loader.Load<TextAsset>(path);
            var scriptData = JsonConvert.DeserializeObject<GraphData>(json.text, new JsonSerializerSettings() { TypeNameHandling = TypeNameHandling.All });
            if (scriptData == null)
            {
                Debug.LogError($"剧本加载失败：[{path.packageID}]{path.path}");
                return;
            }
            
            // 解析并执行剧本
            _graph = new(scriptData, _loader);
            await _graph.Execute();
        }

        /// <summary>
        /// 播放剧本段落
        /// </summary>
        /// <param name="para">段落数据</param>
        /// <param name="ct">CT</param>
        public static async UniTask PlayScriptPara(ScriptParagraphNodePlayer para, CancellationToken ct)
        {
            // 设置变量
            if (_caption)
                _caption.sprite = await _loader.Load<Sprite>(para.CaptionPath);
            if (_audio)
                _audio.clip = await _loader.Load<AudioClip>(para.AudioPath);
            
            // 淡入
            await SetCaptionColor(1,ct);

            // 等音频播放完
            if (_audio)
            {
                _audio.Play();
                await UniTask.Delay(TimeSpan.FromSeconds(_audio.clip.length), cancellationToken:ct);
            }

            // 淡出
            await SetCaptionColor(0, ct);
            await UniTask.Delay(TimeSpan.FromSeconds(AnimationTime), cancellationToken:ct);
        }

        /// <summary>
        /// 停止剧本
        /// </summary>
        public static async UniTask Stop()
        {
           _graph.Stop();

           await SetCaptionColor(0, CancellationToken.None);

           ReleaseGraph();
        }

        public static void ReleaseGraph() => _graph = null;

        private static async UniTask DoAnim(Action animAction, CancellationToken ct)
        {
            float time = 0;
            while (time < AnimationTime)
            {
                animAction?.Invoke();
                await UniTask.Delay(TimeSpan.FromSeconds(UpdateInterval), cancellationToken: ct);
                time+=UpdateInterval;
            }
        }

        private static async UniTask SetCaptionColor(int alpha, CancellationToken ct)
        {
            var isAdd = alpha > _caption.color.a;

            var speed = Mathf.Abs(_caption.color.a - alpha) / AnimationTime * UpdateInterval;
            if (speed == 0)
                return;
            
            await DoAnim(() =>
            {
                _caption.color = new(1, 1, 1, _caption.color.a + (isAdd ? speed : -speed));
            }, ct);
        }
    }
}