Add amount helper with auto adjusting decimal points

README.md

@@ -49,11 +49,15 @@ instance := adyen.New(
   os.Getenv("ADYEN_PASSWORD"),
 )
 
-req := &adyen.AuthoriseEncrypted{
-  Amount: &adyen.Amount{
+amount := &adyen.Amount{
     Value:    1000, // amount * 100, f.e. 10,30 EUR = 1030
     Currency: "EUR" // or use instance.Currency
-  },
+}
+
+// or amount := adyen.NewAmount("EUR", 10), in this case decimal points would be adjusted automatically
+
+req := &adyen.AuthoriseEncrypted{
+  Amount: amount,
   MerchantAccount: os.Getenv("ADYEN_ACCOUNT"), // your merchant account in Adyen
   AdditionalData:  &adyen.AdditionalData{Content: "encryptedData"}, // encrypted data from a form
   Reference:       "your-order-number",
@@ -95,10 +99,7 @@ instance.MerchantAccount = "TEST_MERCHANT_ACCOUNT"
 
 // futher, information could be retrieved to populate request 
 req := &adyen.AuthoriseEncrypted{
-  Amount: &adyen.Amount{
-    Value:    1000,
-    Currency: instance.Currency
-  },
+  Amount: adyen.NewAmount(instance.Currency, 10.00),
   MerchantAccount: instance.MerchantAccount,
   AdditionalData:  &adyen.AdditionalData{Content: "encryptedData"}, // encrypted data from a form
   Reference:       "your-order-number",

amount.go

@@ -0,0 +1,65 @@
+package adyen
+
+import "math"
+
+// Amount value/currency representation
+type Amount struct {
+	Value    float32 `json:"value"`
+	Currency string  `json:"currency"`
+}
+
+var (
+	// DefaultCurrencyDecimals - default currency decimals
+	DefaultCurrencyDecimals uint = 2
+
+	// CurrencyDecimals - https://docs.adyen.com/developers/currency-codes
+	// currencies with 2 decimals stripped out
+	CurrencyDecimals = map[string]uint{
+		"BHD": 3,
+		"CVE": 0,
+		"DJF": 0,
+		"GNF": 0,
+		"IDR": 0,
+		"JOD": 3,
+		"JPY": 0,
+		"KMF": 0,
+		"KRW": 0,
+		"KWD": 3,
+		"LYD": 3,
+		"OMR": 3,
+		"PYG": 0,
+		"RWF": 0,
+		"TND": 3,
+		"UGX": 0,
+		"VND": 0,
+		"VUV": 0,
+		"XAF": 0,
+		"XOF": 0,
+		"XPF": 0,
+	}
+)
+
+// NewAmount - creates Amount instance
+//
+// Automatically adjust decimal points for the float value
+// Link - https://docs.adyen.com/developers/development-resources/currency-codes
+func NewAmount(currency string, amount float32) *Amount {
+	decimals, ok := CurrencyDecimals[currency]
+	if !ok {
+		decimals = DefaultCurrencyDecimals
+	}
+
+	if decimals == 0 {
+		return &Amount{
+			Currency: currency,
+			Value:    amount,
+		}
+	}
+
+	coef := float32(math.Pow(10, float64(decimals)))
+
+	return &Amount{
+		Currency: currency,
+		Value:    amount * coef,
+	}
+}

amount_test.go

@@ -0,0 +1,53 @@
+package adyen
+
+import (
+	"testing"
+)
+
+func TestNewAmount(t *testing.T) {
+	cases := []struct {
+		name     string
+		currency string
+		amount   float32
+		expected Amount
+	}{
+		{
+			name:     "Test EUR currency",
+			currency: "EUR",
+			amount:   10.50,
+			expected: Amount{Currency: "EUR", Value: 1050},
+		},
+		{
+			name:     "Test EUR currency, zero case",
+			currency: "EUR",
+			amount:   0,
+			expected: Amount{Currency: "EUR", Value: 0},
+		},
+		{
+			name:     "Test unknown (UKN) currency, default should be used",
+			currency: "UKN",
+			amount:   10.60,
+			expected: Amount{Currency: "UKN", Value: 1060},
+		},
+		{
+			name:     "Test CVE currency with zero decimal adjustment",
+			currency: "CVE",
+			amount:   150,
+			expected: Amount{Currency: "CVE", Value: 150},
+		},
+		{
+			name:     "Test BHD currency with 3 decimal adjustment points",
+			currency: "BHD",
+			amount:   150.050,
+			expected: Amount{Currency: "BHD", Value: 150050},
+		},
+	}
+
+	for _, c := range cases {
+		t.Run(c.name, func(t *testing.T) {
+			a := NewAmount(c.currency, c.amount)
+
+			equals(t, c.expected, *a)
+		})
+	}
+}

types.go

@@ -25,16 +25,6 @@ type Address struct {
 	Street            string `json:"street"`
 }
 
-/*********
-* Amount *
-*********/
-
-// Amount value/currency representation
-type Amount struct {
-	Value    float32 `json:"value"`
-	Currency string  `json:"currency"`
-}
-
 /*******
 * Card *
 *******/