import { sseResponseEventEnum } from '@/constants/chat';
import { getErrText } from '@/utils/tools';
import { parseStreamChunk } from '@/utils/adapt';
import { QuoteItemType } from '@/pages/api/app/modules/kb/search';
import { rawSearchKey } from '@/constants/chat';

interface StreamFetchProps {
  url?: string;
  data: Record<string, any>;
  onMessage: (text: string) => void;
  abortSignal: AbortController;
}
export const streamFetch = ({
  url = '/api/openapi/v1/chat/completions',
  data,
  onMessage,
  abortSignal
}: StreamFetchProps) =>
  new Promise<{
    responseText: string;
    errMsg: string;
    newHistoryId: string | null;
    [rawSearchKey]: QuoteItemType[];
  }>(async (resolve, reject) => {
    try {
      const response = await window.fetch(url, {
        method: 'POST',
        headers: {
          'Content-Type': 'application/json'
        },
        signal: abortSignal.signal,
        body: JSON.stringify({
          ...data,
          stream: true
        })
      });

      if (!response?.body) {
        throw new Error('Request Error');
      }

      const reader = response.body?.getReader();

      // response data
      let responseText = '';
      let rawSearch: QuoteItemType[] = [];
      let errMsg = '';
      const newHistoryId = response.headers.get('newHistoryId');

      const read = async () => {
        try {
          const { done, value } = await reader.read();
          if (done) {
            if (response.status === 200 && !errMsg) {
              return resolve({
                responseText,
                errMsg,
                newHistoryId,
                rawSearch
              });
            } else {
              return reject({
                message: errMsg || '响应过程出现异常~',
                responseText
              });
            }
          }
          const chunkResponse = parseStreamChunk(value);

          chunkResponse.forEach((item) => {
            // parse json data
            const data = (() => {
              try {
                return JSON.parse(item.data);
              } catch (error) {
                return item.data;
              }
            })();

            if (item.event === sseResponseEventEnum.answer && data !== '[DONE]') {
              const answer: string = data?.choices?.[0].delta.content || '';
              onMessage(answer);
              responseText += answer;
            } else if (item.event === sseResponseEventEnum.appStreamResponse) {
              rawSearch = data?.[rawSearchKey] ? data[rawSearchKey] : rawSearch;
            } else if (item.event === sseResponseEventEnum.error) {
              errMsg = getErrText(data, '流响应错误');
            }
          });
          read();
        } catch (err: any) {
          console.log(111111111111111111);

          if (err?.message === 'The user aborted a request.') {
            return resolve({
              responseText,
              errMsg,
              newHistoryId,
              rawSearch
            });
          }
          reject(getErrText(err, '请求异常'));
        }
      };
      read();
    } catch (err: any) {
      console.log(err, 'fetch error');

      reject(getErrText(err, '请求异常'));
    }
  });