feat(stars): sync implement unified purchase flow

internal/compat/android/stars.go

@@ -0,0 +1,24 @@
+package android
+
+import "encoding/json"
+
+// DirectInvoiceCurrencies are the Google Play billing currencies for which
+// DrKLO's official client must use Telegram's invoice flow. telesrv does not
+// publish or verify Google Play products, so this prevents Stars options with
+// no store_product from entering the Play Billing branch once it is ready.
+var directInvoiceCurrencies = []string{
+	"AED", "AUD", "BRL", "CAD", "CHF", "CLP", "CNY", "COP", "CZK", "DKK",
+	"EGP", "EUR", "GBP", "HKD", "HUF", "IDR", "ILS", "INR", "JPY", "KRW",
+	"KZT", "MXN", "MYR", "NGN", "NOK", "NZD", "PEN", "PHP", "PKR", "PLN",
+	"QAR", "RON", "RUB", "SAR", "SEK", "SGD", "THB", "TRY", "TWD", "UAH",
+	"USD", "VND", "ZAR",
+}
+
+func DirectInvoiceCurrencies() []string {
+	return append([]string(nil), directInvoiceCurrencies...)
+}
+
+func DirectInvoiceCurrenciesJSON() string {
+	body, _ := json.Marshal(directInvoiceCurrencies)
+	return string(body)
+}

internal/compat/android/stars_test.go

@@ -0,0 +1,30 @@
+package android
+
+import (
+	"encoding/json"
+	"testing"
+)
+
+func TestDirectInvoiceCurrenciesAreStableAndContainUSD(t *testing.T) {
+	values := DirectInvoiceCurrencies()
+	if len(values) == 0 {
+		t.Fatal("direct invoice currency list is empty")
+	}
+	foundUSD := false
+	for _, value := range values {
+		if value == "USD" {
+			foundUSD = true
+		}
+	}
+	if !foundUSD {
+		t.Fatalf("direct invoice currencies = %v, want USD", values)
+	}
+	values[0] = "MUTATED"
+	if DirectInvoiceCurrencies()[0] == "MUTATED" {
+		t.Fatal("DirectInvoiceCurrencies returned mutable package storage")
+	}
+	var decoded []string
+	if err := json.Unmarshal([]byte(DirectInvoiceCurrenciesJSON()), &decoded); err != nil || len(decoded) != len(values) {
+		t.Fatalf("currency JSON = %q decoded=%v err=%v", DirectInvoiceCurrenciesJSON(), decoded, err)
+	}
+}