Move some mystery numbers to constants.

These are parameters (market place and device type) that come up time
and time again across gateways, but have different values for each
gateway, e.g. 0, 1, 2 vs E, M, R. A mapping should be standardised.

src/Message/AIMAuthorizeRequest.php

@@ -10,6 +10,21 @@
  */
 class AIMAuthorizeRequest extends AIMAbstractRequest
 {
+    const MARKET_TYPE_ECOMMERCE  = '0';
+    const MARKET_TYPE_MOTO       = '1';
+    const MARKET_TYPE_RETAIL     = '2';
+
+    const DEVICE_TYPE_UNKNOWN = '1';
+    const DEVICE_TYPE_UNATTENDED_TERMINAL = '2';
+    const DEVICE_TYPE_SELF_SERVICE_TERMINAL = '3';
+    const DEVICE_TYPE_ELECTRONIC_CASH_REGISTER = '4';
+    const DEVICE_TYPE_PC_BASED_TERMINAL = '5';
+    const DEVICE_TYPE_AIRPAY = '6';
+    const DEVICE_TYPE_WIRELESS_POS = '7';
+    const DEVICE_TYPE_WEBSITE = '8';
+    const DEVICE_TYPE_DIAL_TERMINAL = '9';
+    const DEVICE_TYPE_VIRTUAL_TERMINAL = '10';
+
     protected $action = 'authOnlyTransaction';
 
     public function getData()
@@ -71,14 +86,29 @@ protected function addRetail(\SimpleXMLElement $data)
         }
 
         if (isset($deviceType) && !isset($marketType)) {
-            $marketType = "2";
+            $marketType = static::MARKET_TYPE_RETAIL;
         }
 
-        if (!in_array($deviceType, [ "1", "2", "3", "4", "5", "6", "7", "8", "9", "10" ])) {
+        if (!in_array($deviceType, [
+            static::DEVICE_TYPE_UNKNOWN,
+            static::DEVICE_TYPE_UNATTENDED_TERMINAL,
+            static::DEVICE_TYPE_SELF_SERVICE_TERMINAL,
+            static::DEVICE_TYPE_ELECTRONIC_CASH_REGISTER,
+            static::DEVICE_TYPE_PC_BASED_TERMINAL,
+            static::DEVICE_TYPE_AIRPAY,
+            static::DEVICE_TYPE_WIRELESS_POS,
+            static::DEVICE_TYPE_WEBSITE,
+            static::DEVICE_TYPE_DIAL_TERMINAL,
+            static::DEVICE_TYPE_VIRTUAL_TERMINAL,
+        ])) {
             throw new InvalidRequestException("deviceType `{$deviceType}` is invalid");
         }
 
-        if (!in_array($marketType, [ "0", "1", "2" ])) {
+        if (!in_array($marketType, [
+            static::MARKET_TYPE_ECOMMERCE,
+            static::MARKET_TYPE_MOTO,
+            static::MARKET_TYPE_RETAIL,
+        ])) {
             throw new InvalidRequestException("marketType `{$marketType}` is invalid");
         }