shootismoke/common

import { aqicn, openaq, waqi } from '@shootismoke/dataproviders';
import retry, { Options } from 'async-retry';

import type { Api } from './api';
import { createApi } from './api';

const AllProviders = ['aqicn', 'openaq', 'waqi'] as const;
type AllProviders = 'aqicn' | 'openaq' | 'waqi';

/**
 * Given some normalized data points, filter out the first one that contains
 * pm25 data. Returns a TaskEither left is none is found, or format the data
 * into the Api interface
 *
 */
async function providerFetch(
    provider: AllProviders,
    station: string
): Promise<Api> {
    const results =
        provider === 'aqicn'
            ? aqicn.normalize(
                    await aqicn.fetchByStation(station, {
                        token: process.env.BACKEND_AQICN_TOKEN as string,
                    })
              )
            : provider === 'waqi'
            ? waqi.normalize(await waqi.fetchByStation(station))
            : openaq.normalize(
                    await openaq.fetchByStation(station, {
                        limit: 1,
                        parameter: ['pm25'],
                    })
              );

    // Gps coordinates are irrelevant for expo report.
    return createApi({ latitude: 0, longitude: 0 }, results);
}

function assertKnownProvider(
    provider: string,
    stationId: string
): asserts provider is AllProviders {
    if (!AllProviders.includes(provider as AllProviders)) {
        throw new Error(`Unrecognized stationId "${stationId}".`);
    }
}

/**
 * Fetch data from correct provider, based on stationId.
 *
 * @param stationId - The stationId of the station
 */
export function fetchStationId(
    stationId: string,
    options?: Options
): Promise<Api> {
    const [provider, station] = stationId.split('|');
    assertKnownProvider(provider, stationId);

    // Find the cigarettes at the user's last known station (stationId)
    // If anything throws, we retry, up to 5 times.
    return retry(async () => providerFetch(provider, station), options);
}