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

import axios from 'axios';
import * as _ from 'lodash';


export class GrafanaUnavailable extends TsdbKitError { };

// TODO: move to class and inherit from QueryService abstract class
export async function queryGrafana(query: DatasourceQuery, apiKey: string, datasource: Datasource) {
  let headers = { Authorization: `Bearer ${apiKey}` };

  const grafanaUrl = getGrafanaUrl(query.url);
  query.url = `${grafanaUrl}/${query.url}`;

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

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

  _.defaults(axiosQuery, query.schema);

  try {
    return axios(axiosQuery);
  } 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}`,
          datasource.type,
          query.url
        );
        throw datasourceError;
      }
    }
    throw new Error(msg);
  }
}

function getGrafanaUrl(url: string): string {
  const parsedUrl = new URL(url);
  const path = parsedUrl.pathname;
  const panelUrl = path.match(/^\/*([^\/]*)\/d\//);
  if(panelUrl === null) {
    return url;
  }

  const origin = parsedUrl.origin;
  const grafanaSubPath = panelUrl[1];
  if(grafanaSubPath.length > 0) {
    return `${origin}/${grafanaSubPath}`;
  }

  return origin;
}