nextcloud-autocurrency/lib/Service/FetchCurrenciesService.php

<?php
declare(strict_types=1);
// SPDX-FileCopyrightText: Chen Asraf <contact@casraf.dev>
// SPDX-License-Identifier: AGPL-3.0-or-later

namespace OCA\AutoCurrency\Service;

use Exception;

use OCA\AutoCurrency\Service\CurrencyNotFound;
use OCA\AutoCurrency\Db\CospendProjectMapper;
use OCP\AppFramework\Db\DoesNotExistException;
use OCP\AppFramework\Db\MultipleObjectsReturnedException;

use OCA\AutoCurrency\Db\Currency;
use OCA\AutoCurrency\Db\CurrencyMapper;
use OCP\ILogger;

class FetchCurrenciesService {
  private static $EXCHANGE_URL = 'https://api.exchangerate.host/latest?base={base}';
  private CurrencyMapper $currencyMapper;
  private CospendProjectMapper $projectMapper;
  private ILogger $logger;

  public function __construct(CurrencyMapper $currencyMapper, CospendProjectMapper $projectMapper, ILogger $logger) {
    $this->currencyMapper = $currencyMapper;
    $this->projectMapper = $projectMapper;
    $this->logger = $logger;
  }

  public function doCron(): void {
    $projects = $this->projectMapper->findAll();
    $currencyMap = [];

    foreach ($projects as $project) {
      $base = $this->getCurrencyName($project->getCurrencyname());

      if (isset($currencyMap[$base])) {
        $json = $currencyMap[$base];
      } else {
        // request currency exchange rates from the API
        $this->logger->info('Fetching exchange rates for base currency ' . $base);
        $fp = fopen(str_replace('{base}', $base, FetchCurrenciesService::$EXCHANGE_URL), 'r');
        $data = stream_get_contents($fp);
        fclose($fp);
        $json = json_decode($data, true);
        $this->logger->info('Fetched exchange rates for base currency: ' . json_encode($json));
        if ($json['success'] == false) {
          $this->logger->error(new \Error('Failed to fetch exchange rates for base currency ' . $base));
          continue;
        }
        $currencyMap[$base] = $json;
      }

      $currencies = $this->findAll($project->id);

      foreach ($currencies as $currency) {
        $cur = $this->getCurrencyName($currency->getName());
        $newRate = floatval(number_format(1 / $json['rates'][$cur], 2));
        $currency->setExchangeRate($newRate);
        $this->logger->info('Setting exchange rate for currency ' . $cur . ' to ' . $newRate);
        $this->currencyMapper->update($currency);
      }
    }
  }

  private function getCurrencyName(string $name): string {
    // find 3-letter currency code for the base currency
    preg_match('/([A-Z]{3})/', $name, $matches);

    $this->logger->info('Matches: ' . json_encode($matches));

    if (count($matches) === 2) {
      $name = $matches[1];
    }

    return $name;
  }

  /**
   * @return list<Currency>
   */
  public function findAll(string $projectId): array {
    return $this->currencyMapper->findAll($projectId);
  }

  /**
   * @return never
   */
  private function handleException(Exception $e) {
    if ($e instanceof DoesNotExistException ||
      $e instanceof MultipleObjectsReturnedException) {
      throw new CurrencyNotFound($e->getMessage());
    } else {
      throw $e;
    }
  }
}