Really use euro as base currency when querying exchange rates, so we can use the configuration-free ECB provider

This should fixes issue #154.

config/packages/swap.yaml

@@ -1,4 +1,8 @@
 florianv_swap:
+  cache:
+    ttl: 3600 # 1 hour
+
+
   providers:
     european_central_bank: ~                      # European Central Bank (only works for EUR base currency)
     fixer:                                        # Fixer.io (needs an API key)

src/Services/ExchangeRateUpdater.php

@@ -22,6 +22,7 @@ namespace App\Services;
 
 use App\Entity\PriceInformations\Currency;
 use Brick\Math\BigDecimal;
+use Brick\Math\RoundingMode;
 use Swap\Swap;
 
 class ExchangeRateUpdater
@@ -40,8 +41,15 @@ class ExchangeRateUpdater
      */
     public function update(Currency $currency): Currency
     {
-        $rate = $this->swap->latest($currency->getIsoCode().'/'.$this->base_currency);
-        $currency->setExchangeRate(BigDecimal::of($rate->getValue()));
+        //Currency pairs are always in the format "BASE/QUOTE"
+        $rate = $this->swap->latest($this->base_currency.'/'.$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());
+        $rate_inverted = BigDecimal::one()->dividedBy($rate_bd, Currency::PRICE_SCALE, RoundingMode::HALF_UP);
+
+        $currency->setExchangeRate($rate_inverted);
 
         return $currency;
     }

templates/AdminPages/CurrencyAdmin.html.twig

@@ -18,15 +18,19 @@
     {% endif %}
 
     {{ form_row(form.exchange_rate) }}
+    {% if entity.inverseExchangeRate %}
+        <p class="form-text text-muted offset-3 col-9">
+        {{ '1'|format_currency(default_currency) }} = {{ entity.inverseExchangeRate.tofloat | format_currency(entity.isoCode, {fraction_digit: 5}) }}<br>
+        {{ '1'|format_currency(entity.isoCode) }} = {{ entity.exchangeRate.tofloat | format_currency(default_currency, {fraction_digit: 5}) }}
+        </p>
+    {% endif %}
+
 
     {% if form.update_exchange_rate is defined %}
         {{ form_row(form.update_exchange_rate, {attr: {class: 'btn-info'}}) }}
     {% endif %}
-    {% if entity.inverseExchangeRate %}
-        <span class="form-text text-muted offset-3 col-9">
-        {{ '1'|format_currency(default_currency) }} = {{ entity.inverseExchangeRate.tofloat | format_currency(entity.isoCode, {fraction_digit: 5}) }}
-    </span>
-    {% endif %}
+
+
 {% endblock %}
 
 {% block edit_title %}

translations/messages.en.xlf

@@ -9941,5 +9941,11 @@ Element 3</target>
         <target>Unable to retrieve the exchange rate. Check your exchange rate provider configuration.</target>
       </segment>
     </unit>
+    <unit id="E_M7mZ5" name="currency.edit.exchange_rate_updated.success">
+      <segment>
+        <source>currency.edit.exchange_rate_updated.success</source>
+        <target>Retrieved the exchange rate successfully.</target>
+      </segment>
+    </unit>
   </file>
 </xliff>