Added helper for checking minimal volume size

README.md

@@ -75,6 +75,36 @@ class BalanceConstroller extends Controller {
 }
 ```
 
+### Checking minimal volume size
+
+See https://support.kraken.com/hc/en-us/articles/205893708-What-is-the-minimum-order-size-
+
+#### Check minimal order size for pair
+```php
+$orderVolume = new \Butschster\Kraken\OrderVolume;
+$pair = $client->getAssetPairs('EOSETH')->first();
+$isValidSize = $orderVolume->checkMinimalSizeForPair($pair, 1.1);
+```
+
+#### Check minimal order size for currency
+```php
+$orderVolume = new \Butschster\Kraken\OrderVolume;
+$isValidSize = $orderVolume->checkMinimalSizeForPair('EOS', 1.1);
+```
+
+#### Get minimal order size
+```php
+$orderVolume = new \Butschster\Kraken\OrderVolume;
+
+// Pair
+$pair = $client->getAssetPairs('EOSETH')->first();
+$minimalsize = $orderVolume->getMinimalSizeForPair($pair);
+
+// Currency
+$minimalsize = $orderVolume->getMinimalSize('EOS');
+```
+
+
 ### API methods
 
 #### Make request

config/kraken.php

@@ -9,4 +9,24 @@
 
     // Two-factor password (if two-factor enabled, otherwise not required)
     'otp' => env('KRAKEN_OTP'),
+
+    'minimal_volumes' => [
+        'XREP' => 0.3,
+        'XXBT' => 0.002,
+        'BCH' => 0.002,
+        'DASH' => 0.03,
+        'DOGE' => 3000,
+        'EOS' => 3,
+        'XETH' => 0.2,
+        'XETC' => 0.3,
+        'GNO' => 0.03,
+        'XICN' => 2,
+        'XLTC' => 0.1,
+        'XMLN' => 0.1,
+        'XXMR' => 0.1,
+        'XXRP' => 30,
+        'XXLM' => 30,
+        'XZEC' => 0.03,
+        'USDT' => 5
+    ]
 ];

src/Exceptions/MinimalVolumeSizeNotFound.php

@@ -0,0 +1,8 @@
+<?php
+
+namespace Butschster\Kraken\Exceptions;
+
+class MinimalVolumeSizeNotFound extends \Exception
+{
+
+}

src/OrderVolume.php

@@ -0,0 +1,65 @@
+<?php
+
+namespace Butschster\Kraken;
+
+use Butschster\Kraken\Exceptions\MinimalVolumeSizeNotFound;
+use Butschster\Kraken\Objects\Pair;
+
+class OrderVolume
+{
+    /**
+     * Check minimal volume size for selected pair
+     *
+     * @param Pair $pair
+     * @param float $volume
+     * @return bool
+     * @throws MinimalVolumeSizeNotFound
+     */
+    public function checkMinimalSizeForPair(Pair $pair, float $volume): bool
+    {
+        return $this->getMinimalSizeForPair($pair) < $volume;
+    }
+
+    /**
+     * Check minimal volume size for selected currency
+     *
+     * @param string $currency
+     * @param float $volume
+     * @return bool
+     * @throws MinimalVolumeSizeNotFound
+     */
+    public function checkMinimalSize(string $currency, float $volume): bool
+    {
+        return $this->getMinimalSize($currency) < $volume;
+    }
+
+    /**
+     * Get minimal volume size for selected pair
+     *
+     * @param Pair $pair
+     * @return mixed
+     * @throws MinimalVolumeSizeNotFound
+     */
+    public function getMinimalSizeForPair(Pair $pair)
+    {
+        return $this->getMinimalSize($pair->base());
+    }
+
+    /**
+     * Get minimal volume size for selected currency
+     *
+     * @param string $currency
+     * @return mixed
+     * @throws MinimalVolumeSizeNotFound
+     */
+    public function getMinimalSize(string $currency)
+    {
+        $minimalSize = config('kraken.minimal_volumes.'.$currency);
+
+        if (is_null($minimalSize)) {
+            throw new MinimalVolumeSizeNotFound("Minimal volume size for currency [{$currency}] not found.");
+        }
+
+        return $minimalSize;
+    }
+}