using System;
using System.Threading;
using System.Threading.Tasks;
using AibisDream.Kit;
using AibisDream.Utility;
using UnityEngine;
using Yarn.Unity;

namespace AibisDream
{
    public class LineSyncToken
    {
        private Action _nextStep;
        private readonly ITextShown _textShown;
        
        public LineInfo lineInfo;
        public LineSyncState state;
        public CancellationTokenSource AdvanceDelayToken { get; private set; }

        public event Action SkipTextAnima;
        public event Action OnAdvance;

        public LineSyncToken(LocalizedLine lineInfo, Action nextStep, bool isAutoSkip = false)
        {
            this.lineInfo = LineInfo.Generate(lineInfo);
            _nextStep = nextStep;
            state = LineSyncState.PlayText;
            if (this.lineInfo.isAutoSkip && isAutoSkip)
            {
                _textShown = new AutoNextTextShown();
            }
            else
            {
                _textShown = new DefaultTextShown();
            }
        }

        public void TrySkip()
        {
            if (state == LineSyncState.PlayText)
            {
                SkipTextAnima?.Invoke();
                SkipTextAnima = null;
            }
            else
            {
                Debug.Log($"line{lineInfo.lineId} 状态为{state.ToString()}, 不能跳过文本");
            }
        }

        public void TryAdvance()
        {
            if (state == LineSyncState.WaitForAdvance)
            {
                Advance();
                Dispose();
            }
            else
            {
                Debug.Log($"line{lineInfo.lineId} 状态为{state.ToString()}, 不能向前推进");
            }
        }

        public void ForceAdvance()
        {
            // 先中断延时
            AdvanceDelayToken?.Cancel();
            // 推进
            Advance();
            Dispose();
        }

        private void Advance()
        {
            OnAdvance?.Invoke();
            OnAdvance = null;
            _nextStep?.Invoke();
            state = LineSyncState.Advanced;
        }

        private void Dispose()
        {
            _nextStep = null;
            SkipTextAnima = null;
        }
        
        public async void TextShown()
        {
            AdvanceDelayToken = new CancellationTokenSource();
            await _textShown.OnTextShown(this);
        }
    }

    public struct LineInfo
    {
        public string lineId;
        public string lineText;
        public CharacterVo character;
        public bool isAutoSkip;
        
        public static LineInfo Generate(LocalizedLine dialogueLine)
        {
            return new LineInfo
            {
                lineId = dialogueLine.TextID,
                lineText = dialogueLine.TextWithoutCharacterName.Text,
                character = dialogueLine.GetCharacterVo(),
                isAutoSkip = dialogueLine.IsAutoSkipLine()
            };
        }

        public int CalcDelayTime()
        {
            var delayTime = lineText.RemoveRichTextTags().Length * ConstRef.CharacterDelayTime;
            return CommonUtil.Limit(delayTime, ConstRef.LineMaxDelay, ConstRef.LineMinDelay);
        }
    }

    public interface ITextShown
    {
        Task OnTextShown(LineSyncToken token);
    }

    public class DefaultTextShown : ITextShown
    {
        public async Task OnTextShown(LineSyncToken token)
        {
            token.state = LineSyncState.AdvanceDelay;
            await Task.Delay(token.lineInfo.CalcDelayTime(), token.AdvanceDelayToken.Token);
            token.state = LineSyncState.WaitForAdvance;
        }
    }

    public class AutoNextTextShown : ITextShown
    {
        public async Task OnTextShown(LineSyncToken token)
        {
            token.state = LineSyncState.AdvanceDelay;
            await Task.Delay(token.lineInfo.CalcDelayTime(), token.AdvanceDelayToken.Token);
            token.state = LineSyncState.WaitForAdvance;
            token.TryAdvance();
        }
    }

    public enum LineSyncState
    {
        Default,
        PlayText,
        AdvanceDelay,
        WaitForAdvance,
        Advanced
    }
}