import { PassThrough } from "stream";
import path from 'path';
import _ from 'lodash';
import mime from 'mime';
import FormData from "form-data";
import axios, { AxiosResponse } from 'axios';

import APIException from "@/lib/exceptions/APIException.ts";
import EX from "@/api/consts/exceptions.ts";
import { createParser } from 'eventsource-parser'
import logger from '@/lib/logger.ts';
import util from '@/lib/util.ts';

// 模型名称
const MODEL_NAME = 'glm';
// 默认的智能体ID，GLM4
const DEFAULT_ASSISTANT_ID = '65940acff94777010aa6b796';
// access_token有效期
const ACCESS_TOKEN_EXPIRES = 3600;
// 最大重试次数
const MAX_RETRY_COUNT = 3;
// 重试延迟
const RETRY_DELAY = 5000;
// 伪装headers
const FAKE_HEADERS = {
  'Accept': '*/*',
  'App-Name': 'chatglm',
  'Platform': 'pc',
  'Origin': 'https://chatglm.cn',
  'Sec-Ch-Ua': '"Chromium";v="122", "Not(A:Brand";v="24", "Google Chrome";v="122"',
  'Sec-Ch-Ua-Mobile': '?0',
  'Sec-Ch-Ua-Platform': '"Windows"',
  'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/122.0.0.0 Safari/537.36',
  'Version': '0.0.1'
};
// 文件最大大小
const FILE_MAX_SIZE = 100 * 1024 * 1024;
// access_token映射
const accessTokenMap = new Map();
// access_token请求队列映射
const accessTokenRequestQueueMap: Record<string, Function[]> = {};

/**
 * 请求access_token
 * 
 * 使用refresh_token去刷新获得access_token
 * 
 * @param refreshToken 用于刷新access_token的refresh_token
 */
async function requestToken(refreshToken: string) {
  if (accessTokenRequestQueueMap[refreshToken])
    return new Promise(resolve => accessTokenRequestQueueMap[refreshToken].push(resolve));
  accessTokenRequestQueueMap[refreshToken] = [];
  logger.info(`Refresh token: ${refreshToken}`);
  const result = await (async () => {
    const result = await axios.post('https://chatglm.cn/chatglm/backend-api/v1/user/refresh', {}, {
      headers: {
        Authorization: `Bearer ${refreshToken}`,
        Referer: 'https://chatglm.cn/main/alltoolsdetail',
        'X-Device-Id': util.uuid(false),
        'X-Request-Id': util.uuid(false),
        ...FAKE_HEADERS
      },
      timeout: 15000,
      validateStatus: () => true
    });
    const { result: _result } = checkResult(result, refreshToken);
    const { accessToken } = _result;
    return {
      accessToken,
      refreshToken,
      refreshTime: util.unixTimestamp() + ACCESS_TOKEN_EXPIRES
    }
  })()
    .then(result => {
      if(accessTokenRequestQueueMap[refreshToken]) {
        accessTokenRequestQueueMap[refreshToken].forEach(resolve => resolve(result));
        delete accessTokenRequestQueueMap[refreshToken];
      }
      logger.success(`Refresh successful`);
      return result;
    })
    .catch(err => {
      if(accessTokenRequestQueueMap[refreshToken]) {
        accessTokenRequestQueueMap[refreshToken].forEach(resolve => resolve(err));
        delete accessTokenRequestQueueMap[refreshToken];
      }
      return err;
    });
  if(_.isError(result))
    throw result;
  return result;
}

/**
 * 获取缓存中的access_token
 * 
 * 避免短时间大量刷新token，未加锁，如果有并发要求还需加锁
 * 
 * @param refreshToken 用于刷新access_token的refresh_token
 */
async function acquireToken(refreshToken: string): Promise<string> {
  let result = accessTokenMap.get(refreshToken);
  if (!result) {
    result = await requestToken(refreshToken);
    accessTokenMap.set(refreshToken, result);
  }
  if (util.unixTimestamp() > result.refreshTime) {
    result = await requestToken(refreshToken);
    accessTokenMap.set(refreshToken, result);
  }
  return result.accessToken;
}

/**
 * 移除会话
 * 
 * 在对话流传输完毕后移除会话，避免创建的会话出现在用户的对话列表中
 * 
 * @param refreshToken 用于刷新access_token的refresh_token
 */
async function removeConversation(convId: string, refreshToken: string, assistantId = DEFAULT_ASSISTANT_ID) {
  const token = await acquireToken(refreshToken);

  const result = await axios.post('https://chatglm.cn/chatglm/backend-api/assistant/conversation/delete', {
    assistant_id: assistantId,
    conversation_id: convId
  }, {
    headers: {
      Authorization: `Bearer ${token}`,
      Referer: `https://chatglm.cn/main/alltoolsdetail`,
      'X-Device-Id': util.uuid(false),
      'X-Request-Id': util.uuid(false),
      ...FAKE_HEADERS
    },
    timeout: 15000,
    validateStatus: () => true
  });
  checkResult(result, refreshToken);
}

/**
 * 同步对话补全
 * 
 * @param messages 参考gpt系列消息格式，多轮对话请完整提供上下文
 * @param refreshToken 用于刷新access_token的refresh_token
 * @param assistantId 智能体ID，默认使用GLM4原版
 * @param retryCount 重试次数
 */
async function createCompletion(messages: any[], refreshToken: string, assistantId = DEFAULT_ASSISTANT_ID, retryCount = 0) {
  return (async () => {
    logger.info(messages);

    // 提取引用文件URL并上传获得引用的文件ID列表
    const refFileUrls = extractRefFileUrls(messages);
    const refs = refFileUrls.length ? await Promise.all(refFileUrls.map(fileUrl => uploadFile(fileUrl, refreshToken))) : [];

    // 请求流
    const token = await acquireToken(refreshToken);
    const result = await axios.post('https://chatglm.cn/chatglm/backend-api/assistant/stream', {
      assistant_id: assistantId,
      conversation_id: '',
      messages: messagesPrepare(messages, refs),
      meta_data: {
        channel: '',
        draft_id: '',
        input_question_type: 'xxxx',
        is_test: false
      }
    }, {
      headers: {
        Authorization: `Bearer ${token}`,
        Referer: assistantId == DEFAULT_ASSISTANT_ID ? 'https://chatglm.cn/main/alltoolsdetail' : `https://chatglm.cn/main/gdetail/${assistantId}`,
        'X-Device-Id': util.uuid(false),
        'X-Request-Id': util.uuid(false),
        ...FAKE_HEADERS
      },
      // 120秒超时
      timeout: 120000,
      validateStatus: () => true,
      responseType: 'stream'
    });

    if(result.headers['content-type'].indexOf('text/event-stream') == -1)
      throw new APIException(EX.API_REQUEST_FAILED, `Stream response Content-Type invalid: ${result.headers['content-type']}`);

    const streamStartTime = util.timestamp();
    // 接收流为输出文本
    const answer = await receiveStream(result.data);
    logger.success(`Stream has completed transfer ${util.timestamp() - streamStartTime}ms`);

    // 异步移除会话
    removeConversation(answer.id, refreshToken, assistantId)
      .catch(err => console.error(err));

    return answer;
  })()
    .catch(err => {
      if(retryCount < MAX_RETRY_COUNT) {
        logger.error(`Stream response error: ${err.stack}`);
        logger.warn(`Try again after ${RETRY_DELAY / 1000}s...`);
        return (async () => {
          await new Promise(resolve => setTimeout(resolve, RETRY_DELAY));
          return createCompletion(messages, refreshToken, assistantId, retryCount + 1);
        })();
      }
      throw err;
    });
}

/**
 * 流式对话补全
 * 
 * @param messages 参考gpt系列消息格式，多轮对话请完整提供上下文
 * @param refreshToken 用于刷新access_token的refresh_token
 * @param assistantId 智能体ID，默认使用GLM4原版
 * @param retryCount 重试次数
 */
async function createCompletionStream(messages: any[], refreshToken: string, assistantId = DEFAULT_ASSISTANT_ID, retryCount = 0) {
  return (async () => {
    logger.info(messages);

    // 提取引用文件URL并上传获得引用的文件ID列表
    const refFileUrls = extractRefFileUrls(messages);
    const refs = refFileUrls.length ? await Promise.all(refFileUrls.map(fileUrl => uploadFile(fileUrl, refreshToken))) : [];

    // 请求流
    const token = await acquireToken(refreshToken);
    const result = await axios.post(`https://chatglm.cn/chatglm/backend-api/assistant/stream`, {
      assistant_id: assistantId,
      conversation_id: '',
      messages: messagesPrepare(messages, refs),
      meta_data: {
        channel: '',
        draft_id: '',
        input_question_type: 'xxxx',
        is_test: false
      }
    }, {
      headers: {
        Authorization: `Bearer ${token}`,
        Referer: assistantId == DEFAULT_ASSISTANT_ID ? 'https://chatglm.cn/main/alltoolsdetail' : `https://chatglm.cn/main/gdetail/${assistantId}`,
        'X-Device-Id': util.uuid(false),
        'X-Request-Id': util.uuid(false),
        ...FAKE_HEADERS
      },
      // 120秒超时
      timeout: 120000,
      validateStatus: () => true,
      responseType: 'stream'
    });

    if(result.headers['content-type'].indexOf('text/event-stream') == -1) {
      logger.error(`Invalid response Content-Type:`, result.headers['content-type']);
      const transStream = new PassThrough();
      transStream.end(`data: ${JSON.stringify({
        id: '',
        model: MODEL_NAME,
        object: 'chat.completion.chunk',
        choices: [
          {
            index: 0, delta: { role: 'assistant', content: '服务暂时不可用，第三方响应错误' }, finish_reason: 'stop'
          }
        ],
        usage: { prompt_tokens: 1, completion_tokens: 1, total_tokens: 2 },
        created: util.unixTimestamp()
      })}\n\n`);
      return transStream;
    }

    const streamStartTime = util.timestamp();
    // 创建转换流将消息格式转换为gpt兼容格式
    return createTransStream(result.data, (convId: string) => {
      logger.success(`Stream has completed transfer ${util.timestamp() - streamStartTime}ms`);
      // 流传输结束后异步移除会话，如果消息不合规，此操作可能会抛出数据库错误异常，请忽略
      removeConversation(convId, refreshToken, assistantId)
        .catch(err => console.error(err));
    });
  })()
    .catch(err => {
      if(retryCount < MAX_RETRY_COUNT) {
        logger.error(`Stream response error: ${err.stack}`);
        logger.warn(`Try again after ${RETRY_DELAY / 1000}s...`);
        return (async () => {
          await new Promise(resolve => setTimeout(resolve, RETRY_DELAY));
          return createCompletionStream(messages, refreshToken, assistantId, retryCount + 1);
        })();
      }
      throw err;
    });
}

/**
 * 提取消息中引用的文件URL
 * 
 * @param messages 参考gpt系列消息格式，多轮对话请完整提供上下文
 */
function extractRefFileUrls(messages: any[]) {
  return messages.reduce((urls, message) => {
    if (_.isArray(message.content)) {
      message.content.forEach(v => {
        if (!_.isObject(v) || !['file', 'image_url'].includes(v['type']))
          return;
        // glm-free-api支持格式
        if (v['type'] == 'file' && _.isObject(v['file_url']) && _.isString(v['file_url']['url']))
          urls.push(v['file_url']['url']);
        // 兼容gpt-4-vision-preview API格式
        else if (v['type'] == 'image_url' && _.isObject(v['image_url']) && _.isString(v['image_url']['url']))
          urls.push(v['image_url']['url']);
      });
    }
    return urls;
  }, []);
}

/**
 * 消息预处理
 * 
 * 由于接口只取第一条消息，此处会将多条消息合并为一条，实现多轮对话效果
 * 使用”你“这个角色回复”我“这个角色，以第一人称对话\n
 * 我:旧消息1
 * 你:旧消息2
 * 我:新消息
 * 
 * @param messages 参考gpt系列消息格式，多轮对话请完整提供上下文
 */
function messagesPrepare(messages: any[], refs: any[]) {
  const content = messages.reduce((content, message) => {
    if (_.isArray(message.content)) {
      return message.content.reduce((_content, v) => {
        if (!_.isObject(v) || v['type'] != 'text')
          return _content;
        return _content + (v['text'] || '');
      }, content) + '\n';
    }
    return content += `${message.role.replace('sytstem', '<|sytstem|>').replace('assistant', '<|assistant|>').replace('user', '<|user|>')}\n${message.content}\n`;
  }, '') + '<|assistant|>\n';
  const fileRefs = refs.filter(ref => !ref.width && !ref.height);
  const imageRefs = refs.filter(ref => ref.width || ref.height).map(ref => {
    ref.image_url = ref.file_url;
    return ref;
  });
  return [
    {
      role: 'user',
      content: [
        { type: 'text', text: content.replace(/\!\[.+\]\(.+\)/g, '') },
        ...(fileRefs.length == 0 ? [] : [{
          type: 'file',
          file: fileRefs
        }]),
        ...(imageRefs.length == 0 ? [] : [{
          type: 'image',
          image: imageRefs
        }])
      ]
    }
  ]
}

/**
 * 预检查文件URL有效性
 * 
 * @param fileUrl 文件URL
 */
async function checkFileUrl(fileUrl: string) {
  if (util.isBASE64Data(fileUrl))
    return;
  const result = await axios.head(fileUrl, {
    timeout: 15000,
    validateStatus: () => true
  });
  if (result.status >= 400)
    throw new APIException(EX.API_FILE_URL_INVALID, `File ${fileUrl} is not valid: [${result.status}] ${result.statusText}`);
  // 检查文件大小
  if (result.headers && result.headers['content-length']) {
    const fileSize = parseInt(result.headers['content-length'], 10);
    if (fileSize > FILE_MAX_SIZE)
      throw new APIException(EX.API_FILE_EXECEEDS_SIZE, `File ${fileUrl} is not valid`);
  }
}

/**
 * 上传文件
 * 
 * @param fileUrl 文件URL
 * @param refreshToken 用于刷新access_token的refresh_token
 */
async function uploadFile(fileUrl: string, refreshToken: string) {
  // 预检查远程文件URL可用性
  await checkFileUrl(fileUrl);

  let filename, fileData, mimeType;
  // 如果是BASE64数据则直接转换为Buffer
  if (util.isBASE64Data(fileUrl)) {
    mimeType = util.extractBASE64DataFormat(fileUrl);
    const ext = mime.getExtension(mimeType);
    filename = `${util.uuid()}.${ext}`;
    fileData = Buffer.from(util.removeBASE64DataHeader(fileUrl), 'base64');
  }
  // 下载文件到内存，如果您的服务器内存很小，建议考虑改造为流直传到下一个接口上，避免停留占用内存
  else {
    filename = path.basename(fileUrl);
    ({ data: fileData } = await axios.get(fileUrl, {
      responseType: 'arraybuffer',
      // 100M限制
      maxContentLength: FILE_MAX_SIZE,
      // 60秒超时
      timeout: 60000
    }));
  }

  // 获取文件的MIME类型
  mimeType = mimeType || mime.getType(filename);

  const formData = new FormData();
  formData.append('file', fileData, {
    filename,
    contentType: mimeType
  });

  // 上传文件到目标OSS
  const token = await acquireToken(refreshToken);
  let result = await axios.request({
    method: 'POST',
    url: 'https://chatglm.cn/chatglm/backend-api/assistant/file_upload',
    data: formData,
    // 100M限制
    maxBodyLength: FILE_MAX_SIZE,
    // 60秒超时
    timeout: 60000,
    headers: {
      Authorization: `Bearer ${token}`,
      Referer: `https://chatglm.cn/`,
      ...FAKE_HEADERS,
      ...formData.getHeaders()
    },
    validateStatus: () => true
  });
  const { result: uploadResult } = checkResult(result, refreshToken);

  return uploadResult;
}

/**
 * 检查请求结果
 * 
 * @param result 结果
 */
function checkResult(result: AxiosResponse, refreshToken: string) {
  if (!result.data)
    return null;
  const { code, status, message } = result.data;
  if (!_.isFinite(code) && !_.isFinite(status))
    return result.data;
  if (code === 0 || status === 0)
    return result.data;
  if (code == 401)
    accessTokenMap.delete(refreshToken);
  throw new APIException(EX.API_REQUEST_FAILED, `[请求glm失败]: ${message}`);
}

/**
 * 从流接收完整的消息内容
 * 
 * @param stream 消息流
 */
async function receiveStream(stream: any): Promise<any> {
  return new Promise((resolve, reject) => {
    // 消息初始化
    const data = {
      id: '',
      model: MODEL_NAME,
      object: 'chat.completion',
      choices: [
        { index: 0, message: { role: 'assistant', content: '' }, finish_reason: 'stop' }
      ],
      usage: { prompt_tokens: 1, completion_tokens: 1, total_tokens: 2 },
      created: util.unixTimestamp()
    };
    let toolCall = false;
    let textOffset = 0;
    const parser = createParser(event => {
      try {
        if (event.type !== "event") return;
        // 解析JSON
        const result = _.attempt(() => JSON.parse(event.data));
        if (_.isError(result))
          throw new Error(`Stream response invalid: ${event.data}`);
        if(!data.id && result.conversation_id)
          data.id = result.conversation_id;
        if(result.status != 'finish') {
          const text = result.parts.reduce((str, part) => {
            const { status, content, meta_data } = part;
            if(!_.isArray(content))
              return str;
            const partText = content.reduce((innerStr, value) => {
              const { type, text, image } = value;
              if(type == 'text') {
                if(toolCall) {
                  innerStr += '\n';
                  textOffset++;
                  toolCall = false;
                }
                return innerStr + text;
              }
              else if(type == 'quote_result' && status == 'finish' && meta_data && _.isArray(meta_data.metadata_list)) {
                const searchText = meta_data.metadata_list.reduce((meta, v) => meta + `检索 ${v.title}(${v.url}) ...`, '') + '\n';
                textOffset += searchText.length;
                toolCall = true;
                return innerStr + searchText;
              }
              else if(type == 'image' && _.isArray(image) && status == 'finish') {
                const imageText = image.reduce((imgs, v) => imgs + (/^(http|https):\/\//.test(v.image_url) ? `![图像](${v.image_url || ''})` : ''), '') + '\n';
                textOffset += imageText.length;
                toolCall = true;
                return innerStr + imageText;
              }
              return innerStr;
            }, '');
            return str + partText;
          }, '');
          const chunk = text.substring(data.choices[0].message.content.length - textOffset, text.length);
          data.choices[0].message.content += chunk;
        }
        else {
          data.choices[0].message.content = data.choices[0].message.content.replace(/【\d+†source】/g, '');
          resolve(data);
        }
      }
      catch (err) {
        logger.error(err);
        reject(err);
      }
    });
    // 将流数据喂给SSE转换器
    stream.on("data", buffer => parser.feed(buffer.toString()));
    stream.once("error", err => reject(err));
    stream.once("close", () => resolve(data));
  });
}

/**
 * 创建转换流
 * 
 * 将流格式转换为gpt兼容流格式
 * 
 * @param stream 消息流
 * @param endCallback 传输结束回调
 */
function createTransStream(stream: any, endCallback?: Function) {
  // 消息创建时间
  const created = util.unixTimestamp();
  // 创建转换流
  const transStream = new PassThrough();
  let content = '';
  let toolCall = false;
  let textOffset = 0;
  !transStream.closed && transStream.write(`data: ${JSON.stringify({
    id: '',
    model: MODEL_NAME,
    object: 'chat.completion.chunk',
    choices: [
      { index: 0, delta: { role: 'assistant', content: '' }, finish_reason: null }
    ],
    created
  })}\n\n`);
  const parser = createParser(event => {
    try {
      if (event.type !== "event") return;
      // 解析JSON
      const result = _.attempt(() => JSON.parse(event.data));
      if (_.isError(result))
        throw new Error(`Stream response invalid: ${event.data}`);
      if(result.status != 'finish' && result.status != 'intervene') {
        const text = result.parts.reduce((str, part) => {
          const { status, content, meta_data } = part;
          if(!_.isArray(content))
            return str;
          const partText = content.reduce((innerStr, value) => {
            const { type, text, image } = value;
            if(type == 'text') {
              if(toolCall) {
                innerStr += '\n';
                textOffset++;
                toolCall = false;
              }
              return innerStr + text.replace(/【\d+†source】/g, '');
            }
            else if(type == 'quote_result' && status == 'finish' && meta_data && _.isArray(meta_data.metadata_list)) {
              const searchText = meta_data.metadata_list.reduce((meta, v) => meta + `检索 ${v.title}(${v.url}) ...`, '') + '\n';
              textOffset += searchText.length;
              toolCall = true;
              return innerStr + searchText;
            }
            else if(type == 'image' && _.isArray(image) && status == 'finish') {
              const imageText = image.reduce((imgs, v) => imgs + (/^(http|https):\/\//.test(v.image_url) ? `![图像](${v.image_url || ''})` : ''), '') + '\n';
              textOffset += imageText.length;
              toolCall = true;
              return innerStr + imageText;
            }
            return innerStr;
          }, '');
          return str + partText;
        }, '');
        const chunk = text.substring(content.length - textOffset, text.length);
        if(chunk) {
          content += chunk;
          const data = `data: ${JSON.stringify({
            id: result.conversation_id,
            model: MODEL_NAME,
            object: 'chat.completion.chunk',
            choices: [
              { index: 0, delta: { content: chunk }, finish_reason: null }
            ],
            created
          })}\n\n`;
          !transStream.closed && transStream.write(data);
        }
      }
      else {
        const data = `data: ${JSON.stringify({
          id: result.conversation_id,
          model: MODEL_NAME,
          object: 'chat.completion.chunk',
          choices: [
            {
              index: 0,
              delta: result.status == 'intervene' && result.last_error && result.last_error.intervene_text ? { content: `\n\n${result.last_error.intervene_text}` } :  {},
              finish_reason: 'stop'
            }
          ],
          usage: { prompt_tokens: 1, completion_tokens: 1, total_tokens: 2 },
          created
        })}\n\n`;
        !transStream.closed && transStream.write(data);
        !transStream.closed && transStream.end('data: [DONE]\n\n');
        content = '';
        endCallback && endCallback();
      }
    }
    catch (err) {
      logger.error(err);
      !transStream.closed && transStream.end('\n\n');
    }
  });
  // 将流数据喂给SSE转换器
  stream.on("data", buffer => parser.feed(buffer.toString()));
  stream.once("error", () => !transStream.closed && transStream.end('data: [DONE]\n\n'));
  stream.once("close", () => !transStream.closed && transStream.end('data: [DONE]\n\n'));
  return transStream;
}

/**
 * Token切分
 * 
 * @param authorization 认证字符串
 */
function tokenSplit(authorization: string) {
  return authorization.replace('Bearer ', '').split(',');
}

/**
 * 备用生成cookie
 * 
 * 暂时还不需要
 * 
 * @param refreshToken 
 * @param token 
 */
function generateCookie(refreshToken: string, token: string) {
  const timestamp = util.unixTimestamp();
  const gsTimestamp = timestamp - Math.round(Math.random() * 2592000);
  return {
    chatglm_refresh_token: refreshToken,
    // chatglm_user_id: '',
    _ga_PMD05MS2V9: `GS1.1.${gsTimestamp}.18.0.${gsTimestamp}.0.0.0`,
    chatglm_token: token,
    chatglm_token_expires: util.getDateString('yyyy-MM-dd HH:mm:ss'),
    abtestid: 'a',
    // acw_tc: ''
  }
}

export default {
  createCompletion,
  createCompletionStream,
  tokenSplit
};