firefly-iii/app/Support/Http/Api/ExchangeRateConverter.php

311 lines
11 KiB
PHP

<?php
/*
* ExchangeRateConverter.php
* Copyright (c) 2023 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\Support\Http\Api;
use Carbon\Carbon;
use FireflyIII\Exceptions\FireflyException;
use FireflyIII\Models\CurrencyExchangeRate;
use FireflyIII\Models\TransactionCurrency;
use FireflyIII\Support\CacheProperties;
use Illuminate\Support\Facades\Log;
/**
* Class ExchangeRateConverter
*/
class ExchangeRateConverter
{
// use ConvertsExchangeRates;
private array $fallback = [];
private bool $isPrepared = false;
private bool $noPreparedRates = false;
private array $prepared = [];
private int $queryCount = 0;
/**
* @throws FireflyException
*/
public function convert(TransactionCurrency $from, TransactionCurrency $to, Carbon $date, string $amount): string
{
Log::debug('convert()');
$rate = $this->getCurrencyRate($from, $to, $date);
return bcmul($amount, $rate);
}
/**
* @throws FireflyException
*/
public function getCurrencyRate(TransactionCurrency $from, TransactionCurrency $to, Carbon $date): string
{
Log::debug('getCurrencyRate()');
$rate = $this->getRate($from, $to, $date);
return '0' === $rate ? '1' : $rate;
}
/**
* @throws FireflyException
*/
private function getRate(TransactionCurrency $from, TransactionCurrency $to, Carbon $date): string
{
Log::debug('getRate()');
if ($this->isPrepared && $this->noPreparedRates) {
$fallback = $this->fallback[$from->id][$to->id] ?? '0';
Log::debug(sprintf('Return fallback rate from #%d to #%d on %s: %s', $from->id, $to->id, $date->format('Y-m-d'), $fallback));
return $fallback;
}
// first attempt:
$rate = $this->getFromDB($from->id, $to->id, $date->format('Y-m-d'));
if (null !== $rate) {
return $rate;
}
// no result. perhaps the other way around?
$rate = $this->getFromDB($to->id, $from->id, $date->format('Y-m-d'));
if (null !== $rate) {
return bcdiv('1', $rate);
}
// if nothing in place, fall back on the rate for $from to EUR
$first = $this->getEuroRate($from, $date);
$second = $this->getEuroRate($to, $date);
// combined (if present), they can be used to calculate the necessary conversion rate.
if (0 === bccomp('0', $first) || 0 === bccomp('0', $second)) {
Log::warning(sprintf('$first is "%s" and $second is "%s"', $first, $second));
return '0';
}
$second = bcdiv('1', $second);
return bcmul($first, $second);
}
private function getFromDB(int $from, int $to, string $date): ?string
{
Log::debug('getFromDB()');
if ($from === $to) {
return '1';
}
$key = sprintf('cer-%d-%d-%s', $from, $to, $date);
// perhaps the rate has been cached during this particular run
$preparedRate = $this->prepared[$date][$from][$to] ?? null;
if (null !== $preparedRate && 0 !== bccomp('0', $preparedRate)) {
Log::debug(sprintf('Found prepared rate from #%d to #%d on %s.', $from, $to, $date));
return $preparedRate;
}
$cache = new CacheProperties();
$cache->addProperty($key);
if ($cache->has()) {
$rate = $cache->get();
if ('' === $rate) {
return null;
}
Log::debug(sprintf('Found cached rate from #%d to #%d on %s.', $from, $to, $date));
return $rate;
}
/** @var null|CurrencyExchangeRate $result */
$result = auth()->user()
->currencyExchangeRates()
->where('from_currency_id', $from)
->where('to_currency_id', $to)
->where('date', '<=', $date)
->orderBy('date', 'DESC')
->first()
;
++$this->queryCount;
$rate = (string)$result?->rate;
if ('' === $rate) {
app('log')->debug(sprintf('Found no rate for #%d->#%d (%s) in the DB.', $from, $to, $date));
return null;
}
if (0 === bccomp('0', $rate)) {
app('log')->debug(sprintf('Found rate for #%d->#%d (%s) in the DB, but it\'s zero.', $from, $to, $date));
return null;
}
app('log')->debug(sprintf('Found rate for #%d->#%d (%s) in the DB: %s.', $from, $to, $date, $rate));
$cache->store($rate);
// if the rate has not been cached during this particular run, save it
$this->prepared[$date] ??= [
$from => [
$to => $rate,
],
];
// also save the exchange rate the other way around:
$this->prepared[$date] ??= [
$to => [
$from => bcdiv('1', $rate),
],
];
return $rate;
}
/**
* @throws FireflyException
*/
private function getEuroRate(TransactionCurrency $currency, Carbon $date): string
{
Log::debug('getEuroRate()');
$euroId = $this->getEuroId();
if ($euroId === $currency->id) {
return '1';
}
$rate = $this->getFromDB($currency->id, $euroId, $date->format('Y-m-d'));
if (null !== $rate) {
// app('log')->debug(sprintf('Rate for %s to EUR is %s.', $currency->code, $rate));
return $rate;
}
$rate = $this->getFromDB($euroId, $currency->id, $date->format('Y-m-d'));
if (null !== $rate) {
return bcdiv('1', $rate);
// app('log')->debug(sprintf('Inverted rate for %s to EUR is %s.', $currency->code, $rate));
// return $rate;
}
// grab backup values from config file:
$backup = config(sprintf('cer.rates.%s', $currency->code));
if (null !== $backup) {
return bcdiv('1', (string)$backup);
// app('log')->debug(sprintf('Backup rate for %s to EUR is %s.', $currency->code, $backup));
// return $backup;
}
// app('log')->debug(sprintf('No rate for %s to EUR.', $currency->code));
return '0';
}
/**
* @throws FireflyException
*/
private function getEuroId(): int
{
Log::debug('getEuroId()');
$cache = new CacheProperties();
$cache->addProperty('cer-euro-id');
if ($cache->has()) {
return (int)$cache->get();
}
$euro = TransactionCurrency::whereCode('EUR')->first();
++$this->queryCount;
if (null === $euro) {
throw new FireflyException('Cannot find EUR in system, cannot do currency conversion.');
}
$cache->store($euro->id);
return $euro->id;
}
/**
* @throws FireflyException
*/
public function prepare(TransactionCurrency $from, TransactionCurrency $to, Carbon $start, Carbon $end): void
{
Log::debug('prepare()');
$start->startOfDay();
$end->endOfDay();
Log::debug(sprintf('Preparing for %s to %s between %s and %s', $from->code, $to->code, $start->format('Y-m-d'), $end->format('Y-m-d')));
$set = auth()->user()
->currencyExchangeRates()
->where('from_currency_id', $from->id)
->where('to_currency_id', $to->id)
->where('date', '<=', $end->format('Y-m-d'))
->where('date', '>=', $start->format('Y-m-d'))
->orderBy('date', 'DESC')->get()
;
++$this->queryCount;
if (0 === $set->count()) {
Log::debug('No prepared rates found in this period, use the fallback');
$this->fallback($from, $to, $start);
$this->noPreparedRates = true;
$this->isPrepared = true;
Log::debug('prepare DONE()');
return;
}
$this->isPrepared = true;
// so there is a fallback just in case. Now loop the set of rates we DO have.
$temp = [];
$count = 0;
foreach ($set as $rate) {
$date = $rate->date->format('Y-m-d');
$temp[$date] ??= [
$from->id => [
$to->id => $rate->rate,
],
];
++$count;
}
Log::debug(sprintf('Found %d rates in this period.', $count));
$currentStart = clone $start;
while ($currentStart->lte($end)) {
$currentDate = $currentStart->format('Y-m-d');
$this->prepared[$currentDate] ??= [];
$fallback = $temp[$currentDate][$from->id][$to->id] ?? $this->fallback[$from->id][$to->id] ?? '0';
if (0 === count($this->prepared[$currentDate]) && 0 !== bccomp('0', $fallback)) {
// fill from temp or fallback or from temp (see before)
$this->prepared[$currentDate][$from->id][$to->id] = $fallback;
}
$currentStart->addDay();
}
}
/**
* If there are no exchange rate in the "prepare" array, future searches for any exchange rate
* will result in nothing: otherwise the preparation had been unnecessary. So, to fix this Firefly III
* will set two fallback currency exchange rates, A > B and B > A using the regular getCurrencyRate method.
*
* This method in turn will fall back on the default exchange rate (if present) or on "1" if necessary.
*
* @throws FireflyException
*/
private function fallback(TransactionCurrency $from, TransactionCurrency $to, Carbon $date): void
{
Log::debug('fallback()');
$fallback = $this->getRate($from, $to, $date);
$fallback = 0 === bccomp('0', $fallback) ? '1' : $fallback;
$this->fallback[$from->id][$to->id] = $fallback;
$this->fallback[$to->id][$from->id] = bcdiv('1', $fallback);
Log::debug(sprintf('Fallback rate %s > %s = %s', $from->code, $to->code, $fallback));
Log::debug(sprintf('Fallback rate %s > %s = %s', $to->code, $from->code, bcdiv('1', $fallback)));
}
public function summarize(): void
{
Log::debug(sprintf('ExchangeRateConverter ran %d queries.', $this->queryCount));
}
}