3 files changed, 69 insertions, 0 deletions
diff --git a/android/lib/model/src/main/kotlin/net/mullvad/mullvadvpn/lib/model/RedeemVoucherError.kt b/android/lib/model/src/main/kotlin/net/mullvad/mullvadvpn/lib/model/RedeemVoucherError.kt
index d14a2f236b..6df604c4a6 100644
--- a/android/lib/model/src/main/kotlin/net/mullvad/mullvadvpn/lib/model/RedeemVoucherError.kt
+++ b/android/lib/model/src/main/kotlin/net/mullvad/mullvadvpn/lib/model/RedeemVoucherError.kt
@@ -5,6 +5,10 @@ sealed class RedeemVoucherError {
 
     data object VoucherAlreadyUsed : RedeemVoucherError()
 
+    data object TooShortVoucher : RedeemVoucherError()
+
+    data object EnteredAccountNumber : RedeemVoucherError()
+
     data object RpcError : RedeemVoucherError()
 
     data class Unknown(val error: Throwable) : RedeemVoucherError()
diff --git a/android/lib/model/src/main/kotlin/net/mullvad/mullvadvpn/lib/model/VoucherCode.kt b/android/lib/model/src/main/kotlin/net/mullvad/mullvadvpn/lib/model/VoucherCode.kt
new file mode 100644
index 0000000000..9790096d55
--- /dev/null
+++ b/android/lib/model/src/main/kotlin/net/mullvad/mullvadvpn/lib/model/VoucherCode.kt
@@ -0,0 +1,31 @@
+package net.mullvad.mullvadvpn.lib.model
+
+import arrow.core.Either
+import arrow.core.raise.either
+import arrow.core.raise.ensure
+
+@JvmInline
+value class VoucherCode private constructor(val value: String) {
+
+    companion object {
+        // Parsing reference:
+        // <services-repository>/services/docs/adr/0018-distinguish-voucher-codes-from-account-numbers.md
+        fun fromString(value: String): Either<ParseVoucherCodeError, VoucherCode> = either {
+            val trimmedValue = value.trim()
+            ensure(trimmedValue.length >= MIN_VOUCHER_LENGTH) {
+                ParseVoucherCodeError.TooShort(trimmedValue)
+            }
+            ensure(!value.all { it.isDigit() }) { ParseVoucherCodeError.AllDigit(trimmedValue) }
+            VoucherCode(trimmedValue)
+        }
+
+        const val MIN_VOUCHER_LENGTH = 16
+    }
+}
+
+sealed interface ParseVoucherCodeError {
+
+    data class AllDigit(val value: String) : ParseVoucherCodeError
+
+    data class TooShort(val value: String) : ParseVoucherCodeError
+}
diff --git a/android/lib/model/src/test/kotlin/net/mullvad/mullvadvpn/lib/model/VoucherCodeTest.kt b/android/lib/model/src/test/kotlin/net/mullvad/mullvadvpn/lib/model/VoucherCodeTest.kt
new file mode 100644
index 0000000000..270e8b2503
--- /dev/null
+++ b/android/lib/model/src/test/kotlin/net/mullvad/mullvadvpn/lib/model/VoucherCodeTest.kt
@@ -0,0 +1,34 @@
+package net.mullvad.mullvadvpn.lib.model
+
+import kotlin.test.assertEquals
+import kotlin.test.assertTrue
+import org.junit.jupiter.api.Test
+
+class VoucherCodeTest {
+    @Test
+    fun `parsing a too short voucher code should return TooShort`() {
+        val input = "mycode"
+        val result = VoucherCode.fromString(input)
+
+        assertTrue(result.isLeft())
+        assertEquals(ParseVoucherCodeError.TooShort(input), result.leftOrNull())
+    }
+
+    @Test
+    fun `numbers only should not be allowed`() {
+        val input = "1234123412341234"
+        val result = VoucherCode.fromString(input)
+
+        assertTrue(result.isLeft())
+        assertEquals(ParseVoucherCodeError.AllDigit(input), result.leftOrNull())
+    }
+
+    @Test
+    fun `number only input when too short should return TooShort`() {
+        val input = "123412341234"
+        val result = VoucherCode.fromString(input)
+
+        assertTrue(result.isLeft())
+        assertEquals(ParseVoucherCodeError.TooShort(input), result.leftOrNull())
+    }
+}