firefly-iii/app/Http/Controllers/Json/ExchangeController.php

<?php
/**
 * ExchangeController.php
 * Copyright (c) 2019 james@firefly-iii.org
 *
 * This file is part of Firefly III (https://github.com/firefly-iii).
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as
 * published by the Free Software Foundation, either version 3 of the
 * License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */
declare(strict_types=1);

namespace FireflyIII\Http\Controllers\Json;

use Carbon\Carbon;
use FireflyIII\Http\Controllers\Controller;
use FireflyIII\Models\TransactionCurrency;
use FireflyIII\Repositories\Currency\CurrencyRepositoryInterface;
use FireflyIII\Services\Currency\ExchangeRateInterface;
use FireflyIII\User;
use Illuminate\Http\JsonResponse;
use Illuminate\Http\Request;
use Log;

/**
 * Class ExchangeController.
 */
class ExchangeController extends Controller
{

    /**
     * Returns an exchange rate.
     *
     * @param Request             $request
     * @param TransactionCurrency $fromCurrency
     * @param TransactionCurrency $toCurrency
     * @param Carbon              $date
     *
     * @return JsonResponse
     */
    public function getRate(Request $request, TransactionCurrency $fromCurrency, TransactionCurrency $toCurrency, Carbon $date): JsonResponse
    {
        /** @var CurrencyRepositoryInterface $repository */
        $repository = app(CurrencyRepositoryInterface::class);
        $rate       = $repository->getExchangeRate($fromCurrency, $toCurrency, $date);


        if (null === $rate) {
            Log::debug(sprintf('No cached exchange rate in database for %s to %s on %s', $fromCurrency->code, $toCurrency->code, $date->format('Y-m-d')));

            // create service:
            /** @var User $user */
            $user = auth()->user();
            /** @var ExchangeRateInterface $service */
            $service = app(ExchangeRateInterface::class);
            $service->setUser($user);

            // get rate:
            $rate = $service->getRate($fromCurrency, $toCurrency, $date);
        }

        $return           = $rate->toArray();
        $return['amount'] = null;
        if (null !== $request->get('amount')) {
            // assume amount is in "from" currency:
            $return['amount'] = bcmul($request->get('amount'), (string) $rate->rate, 12);
            // round to toCurrency decimal places:
            $return['amount'] = round($return['amount'], $toCurrency->decimal_places);
        }

        return response()->json($return);
    }
}