using System.Collections.Concurrent;
using System.Runtime.CompilerServices;
using System.Text;
using Microsoft.AspNetCore.Http;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging;
using Newtonsoft.Json;
using Newtonsoft.Json.Serialization;
using OpenAI.Chat;
using Volo.Abp.Domain.Services;
using Yi.Framework.AiHub.Application.Contracts.Dtos;
using Yi.Framework.AiHub.Domain.AiChat;
using Yi.Framework.AiHub.Domain.Entities;
using Yi.Framework.AiHub.Domain.Entities.Model;
using Yi.Framework.AiHub.Domain.Shared.Dtos;
using Yi.Framework.SqlSugarCore.Abstractions;

namespace Yi.Framework.AiHub.Domain.Managers;

public class AiGateWayManager : DomainService
{
    private readonly ISqlSugarRepository<AiAppAggregateRoot> _aiAppRepository;
    private readonly ILogger<AiGateWayManager> _logger;
    private readonly AiMessageManager _aiMessageManager;
    private readonly UsageStatisticsManager _usageStatisticsManager;

    public AiGateWayManager(ISqlSugarRepository<AiAppAggregateRoot> aiAppRepository, ILogger<AiGateWayManager> logger,
        AiMessageManager aiMessageManager, UsageStatisticsManager usageStatisticsManager)
    {
        _aiAppRepository = aiAppRepository;
        _logger = logger;
        _aiMessageManager = aiMessageManager;
        _usageStatisticsManager = usageStatisticsManager;
    }

    /// <summary>
    /// 获取模型
    /// </summary>
    /// <param name="modelId"></param>
    /// <returns></returns>
    private async Task<AiModelDescribe> GetModelAsync(string modelId)
    {
        var allApp = await _aiAppRepository._DbQueryable.Includes(x => x.AiModels).ToListAsync();
        foreach (var app in allApp)
        {
            var model = app.AiModels.FirstOrDefault(x => x.ModelId == modelId);
            if (model is not null)
            {
                return new AiModelDescribe
                {
                    AppId = app.Id,
                    AppName = app.Name,
                    Endpoint = app.Endpoint,
                    ApiKey = app.ApiKey,
                    OrderNum = model.OrderNum,
                    HandlerName = model.HandlerName,
                    ModelId = model.ModelId,
                    ModelName = model.Name,
                    Description = model.Description
                };
            }
        }

        throw new UserFriendlyException($"{modelId}模型当前版本不支持");
    }


    /// <summary>
    /// 聊天完成
    /// </summary>
    /// <param name="modelId"></param>
    /// <param name="messages"></param>
    /// <param name="cancellationToken"></param>
    /// <returns></returns>
    public async IAsyncEnumerable<CompleteChatResponse> CompleteChatAsync(string modelId, List<ChatMessage> messages,
        [EnumeratorCancellation] CancellationToken cancellationToken)
    {
        var modelDescribe = await GetModelAsync(modelId);
        var chatService = LazyServiceProvider.GetRequiredKeyedService<IChatService>(modelDescribe.HandlerName);
        await foreach (var result in chatService.CompleteChatAsync(modelDescribe, messages, cancellationToken))
        {
            yield return result;
        }
    }

    /// <summary>
    /// 聊天完成-缓存处理
    /// </summary>
    /// <param name="httpContext"></param>
    /// <param name="modelId"></param>
    /// <param name="messages"></param>
    /// <param name="sessionId"></param>
    /// <param name="cancellationToken"></param>
    /// <param name="userId"></param>
    /// <returns></returns>
    public async Task CompleteChatForHttpContextAsync(
        HttpContext httpContext,
        string modelId,
        List<ChatMessage> messages,
        Guid? userId = null,
        Guid? sessionId = null,
        CancellationToken cancellationToken = default)
    {
        var response = httpContext.Response;
        // 设置响应头，声明是 SSE 流
        response.ContentType = "text/event-stream";
        response.Headers.Append("Cache-Control", "no-cache");
        response.Headers.Append("Connection", "keep-alive");


        var gateWay = LazyServiceProvider.GetRequiredService<AiGateWayManager>();
        var completeChatResponse = gateWay.CompleteChatAsync(modelId, messages, cancellationToken);
        var tokenUsage = new TokenUsage();
        await using var writer = new StreamWriter(response.Body, Encoding.UTF8, leaveOpen: true);

        //缓存队列算法
        // 创建一个队列来缓存消息
        var messageQueue = new ConcurrentQueue<string>();

        StringBuilder backupSystemContent = new StringBuilder();
        // 设置输出速率（例如每50毫秒输出一次）
        var outputInterval = TimeSpan.FromMilliseconds(75);
        // 标记是否完成接收
        var isComplete = false;
        // 启动一个后台任务来消费队列
        var outputTask = Task.Run(async () =>
        {
            while (!(isComplete && messageQueue.IsEmpty))
            {
                if (messageQueue.TryDequeue(out var message))
                {
                    await writer.WriteLineAsync(message);
                    await writer.FlushAsync(cancellationToken);
                }

                if (!isComplete)
                {
                    // 如果没有完成，才等待，已完成，全部输出
                    await Task.Delay(outputInterval, cancellationToken);
                }
            }
        }, cancellationToken);


        //IAsyncEnumerable 只能在最外层捕获异常（如果你有其他办法的话...）
        try
        {
            await foreach (var data in completeChatResponse)
            {
                if (data.IsFinish)
                {
                    tokenUsage = data.TokenUsage;
                }

                var model = MapToMessage(modelId, data.Content);
                var message = JsonConvert.SerializeObject(model, new JsonSerializerSettings
                {
                    ContractResolver = new CamelCasePropertyNamesContractResolver()
                });
                backupSystemContent.Append(data.Content);
                // 将消息加入队列而不是直接写入
                messageQueue.Enqueue($"data: {message}\n");
            }
        }
        catch (Exception e)
        {
            _logger.LogError(e, $"Ai对话异常");
            var errorContent = $"Ai对话异常，异常信息：\n{e.Message}";
            var model = MapToMessage(modelId, errorContent);
            var message = JsonConvert.SerializeObject(model, new JsonSerializerSettings
            {
                ContractResolver = new CamelCasePropertyNamesContractResolver()
            });
            backupSystemContent.Append(errorContent);
            messageQueue.Enqueue($"data: {message}\n");
        }

        //断开连接
        messageQueue.Enqueue("data: [DONE]\n");
        // 标记完成并发送结束标记
        isComplete = true;

        await outputTask;

        if (userId is not null)
        {
            await _aiMessageManager.CreateUserMessageAsync(userId.Value, sessionId,
                new MessageInputDto
                {
                    Content = messages.LastOrDefault().Content.FirstOrDefault()?.Text ?? string.Empty,
                    ModelId = modelId,
                    TokenUsage = tokenUsage,
                });

            await _aiMessageManager.CreateSystemMessageAsync(userId.Value, sessionId,
                new MessageInputDto
                {
                    Content = backupSystemContent.ToString(),
                    ModelId = modelId,
                    TokenUsage = tokenUsage
                });

            await _usageStatisticsManager.SetUsageAsync(userId.Value, modelId, tokenUsage.InputTokenCount,
                tokenUsage.OutputTokenCount);
        }
    }


    private SendMessageOutputDto MapToMessage(string modelId, string content)
    {
        var output = new SendMessageOutputDto
        {
            Id = "chatcmpl-BotYP3BlN5T4g9YPnW0fBSBvKzXdd",
            Object = "chat.completion.chunk",
            Created = 1750336171,
            Model = modelId,
            Choices = new()
            {
                new Choice
                {
                    Index = 0,
                    Delta = new Delta
                    {
                        Content = content,
                        Role = "assistant"
                    },
                    FinishReason = null,
                    ContentFilterResults = new()
                    {
                        Hate = new()
                        {
                            Filtered = false,
                            Detected = null
                        },
                        SelfHarm = new()
                        {
                            Filtered = false,
                            Detected = null
                        },
                        Sexual = new()
                        {
                            Filtered = false,
                            Detected = null
                        },
                        Violence = new()
                        {
                            Filtered = false,
                            Detected = null
                        },
                        Jailbreak = new()
                        {
                            Filtered = false,
                            Detected = false
                        },
                        Profanity = new()
                        {
                            Filtered = false,
                            Detected = false
                        },
                    }
                }
            },
            SystemFingerprint = "",
            Usage = new Usage
            {
                PromptTokens = 0,
                CompletionTokens = 0,
                TotalTokens = 0,
                PromptTokensDetails = new()
                {
                    AudioTokens = 0,
                    CachedTokens = 0
                },
                CompletionTokensDetails = new()
                {
                    AudioTokens = 0,
                    ReasoningTokens = 0,
                    AcceptedPredictionTokens = 0,
                    RejectedPredictionTokens = 0
                }
            }
        };

        return output;
    }
}