using OpenAI;
using OpenAI.Chat;
using System;
using System.ClientModel;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Text;
using System.Threading;
using System.Threading.Tasks;

namespace MCI18n.AI
{
    internal class I18nChatClient
    {
        /// <summary>
        /// 火山方舟API Key
        /// </summary>
        private string API_KEY = "API_KEY";
        private string API_ENDPOINT = "https://ark.cn-beijing.volces.com/api/v3";
        private readonly ChatClient _client;

        // 使用信号量限制并发请求数
        private static readonly SemaphoreSlim _semaphore = new SemaphoreSlim(2, 3); // 最多2个并发请求，可根据API限制调整

        // 重试次数和延迟
        private const int MaxRetries = 3;
        private static readonly TimeSpan InitialRetryDelay = TimeSpan.FromSeconds(1);

        public I18nChatClient(string modelName)
        {
            _client = new ChatClient(modelName, new ApiKeyCredential(API_KEY), new OpenAIClientOptions
            {
                Endpoint = new Uri(API_ENDPOINT),
                NetworkTimeout = TimeSpan.FromSeconds(20d)
            });
        }

        private string SystemPrompt = @"
你是一个minecraft相关的语言翻译机器人。

你需要翻译用户提供的文本到指定的目标语言。

源语言通常是英文。

你只需要翻译文本，禁止解释或提供额外信息。

如果存在多种解释或是含义，只需要给出最贴近Minecraft与社区Mod相关语言的一个。

被{}包裹的内容保留原文与位置。
";
        private string Prompt = @"

目标语言：{0}

用户提供的文本:
{1}
";

        public string Translate(string text, string targetLanguage)
        {
            try
            {
                _semaphore.Wait(); // 获取信号量
                try
                {
                    var quest = string.Format(Prompt, targetLanguage, text);

                    var response = _client.CompleteChat(
                         ChatMessage.CreateSystemMessage(SystemPrompt),
                         ChatMessage.CreateUserMessage($"{quest}")
                         );
                    if (!string.IsNullOrWhiteSpace(response.Value.Content[0].Text))
                    {
                        return response.Value.Content[0].Text;
                    }
                    else
                    {
                        throw new Exception("No response from translation model.");
                    }
                }
                finally
                {
                    _semaphore.Release(); // 释放信号量
                }
            }
            catch (Exception ex)
            {
                throw;
            }
        }

        public async Task<string> TranslateAsync(string text, string targetLanguage)
        {
            int retries = 0;
            TimeSpan delay = InitialRetryDelay;

            while (true)
            {
                try
                {
                    await _semaphore.WaitAsync(); // 异步获取信号量
                    try
                    {
                        var quest = string.Format(Prompt, targetLanguage, text);

                        var response = await _client.CompleteChatAsync(
                            ChatMessage.CreateSystemMessage(SystemPrompt),
                            ChatMessage.CreateUserMessage($"{quest}")
                        );

                        if (!string.IsNullOrWhiteSpace(response.Value.Content[0].Text))
                        {
                            return response.Value.Content[0].Text;
                        }
                        else
                        {
                            throw new Exception("No response from translation model.");
                        }
                    }
                    finally
                    {
                        _semaphore.Release(); // 释放信号量
                    }
                }
                catch (ClientResultException ex) when (ex.Status ==  429 && retries < MaxRetries)
                {
                    // 针对429错误特殊处理，采用退避策略
                    retries++;
                    await Task.Delay(delay);
                    delay = TimeSpan.FromMilliseconds(delay.TotalMilliseconds * 2); // 指数退避
                    continue; // 重试请求
                }
                catch (Exception ex)
                {
                    throw;
                }

                break; // 如果成功或者非429错误，退出循环
            }

            // 这里不会被执行到，只是为了满足编译器要求
            throw new Exception("Unexpected code path");
        }
    } 
}