Use central banks of czechia, turkey and romania as a free provider for their currencies exchange rates

config/packages/swap.yaml

@@ -5,6 +5,9 @@ florianv_swap:
 
   providers:
     european_central_bank: ~                      # European Central Bank (only works for EUR base currency)
-    fixer:                                        # Fixer.io (needs an API key)
+    central_bank_of_czech_republic: ~
-      access_key: "%env(string:settings:exchange_rate:fixerApiKey)%"
+    central_bank_of_republic_turkey: ~
-    #exchange_rates_api: ~
+    national_bank_of_romania: ~
+
+    fixer: # Fixer.io (needs an API key)
+        access_key: "%env(string:settings:exchange_rate:fixerApiKey)%"

src/Services/Tools/ExchangeRateUpdater.php

@@ -26,6 +26,8 @@ use App\Entity\PriceInformations\Currency;
 use App\Settings\SystemSettings\LocalizationSettings;
 use Brick\Math\BigDecimal;
 use Brick\Math\RoundingMode;
+use Exchanger\Exception\UnsupportedCurrencyPairException;
+use Exchanger\Exception\UnsupportedExchangeQueryException;
 use Swap\Swap;
 
 class ExchangeRateUpdater
@@ -39,15 +41,21 @@ class ExchangeRateUpdater
      */
     public function update(Currency $currency): Currency
     {
-        //Currency pairs are always in the format "BASE/QUOTE"
+        try {
-        $rate = $this->swap->latest($this->localizationSettings->baseCurrency.'/'.$currency->getIsoCode());
+            //Try it in the direction QUOTE/BASE first, as most providers provide rates in this direction
-        //The rate says how many quote units are worth one base unit
+            $rate = $this->swap->latest($currency->getIsoCode().'/'.$this->localizationSettings->baseCurrency);
-        //So we need to invert it to get the exchange rate
+            $effective_rate = BigDecimal::of($rate->getValue());
+        } catch (UnsupportedCurrencyPairException|UnsupportedExchangeQueryException $exception) {
+            //Otherwise try to get it inverse and calculate it ourselfes, from the format "BASE/QUOTE"
+            $rate = $this->swap->latest($this->localizationSettings->baseCurrency.'/'.$currency->getIsoCode());
+            //The rate says how many quote units are worth one base unit
+            //So we need to invert it to get the exchange rate
 
-        $rate_bd = BigDecimal::of($rate->getValue());
+            $rate_bd = BigDecimal::of($rate->getValue());
-        $rate_inverted = BigDecimal::one()->dividedBy($rate_bd, Currency::PRICE_SCALE, RoundingMode::HALF_UP);
+            $effective_rate = BigDecimal::one()->dividedBy($rate_bd, Currency::PRICE_SCALE, RoundingMode::HALF_UP);
+        }
 
-        $currency->setExchangeRate($rate_inverted);
+        $currency->setExchangeRate($effective_rate);
 
         return $currency;
     }