import { defHttp } from '/@/utils/http/axios';

enum Api {
  unified = '/ventAI/api/chat',
  getHistoryList = '/ventAI/api/sessions',
  getDetail = '/ventAI/api/chat/history/',
  deleteSession = '/ventAI/api/sessions/',
}

/**
 * 历史会话接口
 */
export const getHistoryList = (params) => defHttp.get({ url: Api.getHistoryList, params }, { joinParamsToUrl: true, isTransformResponse: false });

/**
 * 获取历史会话详情
 * @param session_id - 会话ID
 */
export const getDetail = (session_id: string) => defHttp.get({ url: Api.getDetail + session_id }, { isTransformResponse: false });

/**
 * 删除会话
 * @param session_id - 会话ID
 */
export const deleteSession = (session_id: string) => defHttp.delete({ url: Api.deleteSession + session_id }, { isTransformResponse: false });

/**
 * 统一对话接口（SSE流式响应）
 * @param params.message - 用户输入的文本，必填
 * @param params.session_id - 会话唯一标识ID，不传参时服务端自动生成全新会话ID
 * @param params.file - 上传的PDF文件，可选
 * @param onChunk - 流式数据回调函数
 * @returns Promise<{ session_id: string }>
 */
export const unifiedStream = async (
  params: { message: string; session_id?: string; file?: File },
  onChunk: (chunk: string) => void
): Promise<{ session_id: string }> => {
  try {
    const formData = new FormData();
    formData.append('message', params.message);
    if (params.session_id) {
      formData.append('session_id', params.session_id);
    }
    if (params.file) {
      formData.append('file', params.file);
    }

    const response = await fetch(Api.unified, {
      method: 'POST',
      body: formData,
    });

    if (!response.ok) {
      throw new Error(`HTTP错误: ${response.status}`);
    }

    const reader = response.body!.getReader();
    const decoder = new TextDecoder();
    let buffer = '';
    let sessionId = '';
    let isDone = false;

    // eslint-disable-next-line no-constant-condition
    while (true) {
      const { done, value } = await reader.read();
      if (done || isDone) break;

      buffer += decoder.decode(value, { stream: true });
      const lines = buffer.split('\n');
      buffer = lines.pop() || '';

      for (const line of lines) {
        if (line.trim() === '') continue;

        if (line.startsWith('data: ')) {
          const dataStr = line.replace(/^data: /, '');

          try {
            const data = JSON.parse(dataStr);

            onChunk(line);

            if (data.type === 'done' || data.type === 'error') {
              if (data.session_id) {
                sessionId = data.session_id;
              }
              isDone = true;
              break;
            }
          } catch (e) {
            console.warn('SSE数据解析失败:', dataStr);
          }
        }
      }

      if (isDone) break;
    }

    return { session_id: sessionId };
  } catch (error) {
    console.error('统一对话流式请求失败:', error);
    throw error;
  }
};