import { QueryService } from './base';
import { Datasource, DatasourceQuery } from '../../connectors';
import { TsdbKitError, DatasourceUnavailable } from '../../types';

import axios, { AxiosResponse } from 'axios';
import * as _ from 'lodash';


export class GrafanaUnavailable extends TsdbKitError { };

export class GrafanaQueryService extends QueryService {
  constructor(datasource: Datasource) {
    super(datasource);
  }

  async query(query: DatasourceQuery, apiKey: string): Promise<AxiosResponse<any>> {
    let headers = { Authorization: `Bearer ${apiKey}` };

    if(query.headers !== undefined) {
      _.merge(headers, query.headers);
    }

    let axiosQuery = {
      headers,
      url: query.url,
      method: query.method,
    };

    _.defaults(axiosQuery, query.schema);

    try {
      const resp = await axios(axiosQuery);
      return resp;
    } catch (e) {
      // TODO: seems like this error handler can be used for both Grafana and Direct queries
      const msg = `TSDB-kit: fail while request data: ${e.message}`;
      const parsedUrl = new URL(query.url);
      const queryUrl = `query url: ${JSON.stringify(parsedUrl.pathname)}`;
      console.error(`${msg} ${queryUrl}`);
      if(e.errno === 'ECONNREFUSED') {
        throw new GrafanaUnavailable(e.message);
      }
      if(e.response !== undefined) {
        console.error(`Response: \
          status: ${e.response.status}, \
          response data: ${JSON.stringify(e.response.data)}, \
          headers: ${JSON.stringify(e.response.headers)}
        `);
        if(e.response.status === 401) {
          throw new Error(`Unauthorized. Check the API_KEY. ${e.message}`);
        }
        if(e.response.status === 502) {
          let datasourceError = new DatasourceUnavailable(
            `datasource ${parsedUrl.pathname} unavailable, message: ${e.message}`,
            this._datasource.type,
            query.url
          );
          throw datasourceError;
        }
      }
      throw new Error(msg);
    }
  }
}