[PM-33508] feat: Add AuthenticatedBillingApi and BillingService network layer

network/src/main/kotlin/com/bitwarden/network/BitwardenServiceClient.kt

@@ -9,6 +9,7 @@ import com.bitwarden.network.provider.RefreshTokenProvider
 import com.bitwarden.network.provider.TokenProvider
 import com.bitwarden.network.service.AccountsService
 import com.bitwarden.network.service.AuthRequestsService
+import com.bitwarden.network.service.BillingService
 import com.bitwarden.network.service.CiphersService
 import com.bitwarden.network.service.ConfigService
 import com.bitwarden.network.service.DevicesService
@@ -70,6 +71,11 @@ interface BitwardenServiceClient {
      */
     val authRequestsService: AuthRequestsService
 
+    /**
+     * Provides access to the Billing service.
+     */
+    val billingService: BillingService
+
     /**
      * Provides access to the Ciphers service.
      */

network/src/main/kotlin/com/bitwarden/network/BitwardenServiceClientImpl.kt

@@ -15,6 +15,8 @@ import com.bitwarden.network.retrofit.RetrofitsImpl
 import com.bitwarden.network.service.AccountsServiceImpl
 import com.bitwarden.network.service.AuthRequestsService
 import com.bitwarden.network.service.AuthRequestsServiceImpl
+import com.bitwarden.network.service.BillingService
+import com.bitwarden.network.service.BillingServiceImpl
 import com.bitwarden.network.service.CiphersService
 import com.bitwarden.network.service.CiphersServiceImpl
 import com.bitwarden.network.service.ConfigService
@@ -115,6 +117,12 @@ internal class BitwardenServiceClientImpl(
         )
     }
 
+    override val billingService: BillingService by lazy {
+        BillingServiceImpl(
+            authenticatedBillingApi = retrofits.authenticatedApiRetrofit.create(),
+        )
+    }
+
     override val ciphersService: CiphersService by lazy {
         CiphersServiceImpl(
             azureApi = retrofits.createStaticRetrofit().create(),

network/src/main/kotlin/com/bitwarden/network/api/AuthenticatedBillingApi.kt

@@ -0,0 +1,28 @@
+package com.bitwarden.network.api
+
+import com.bitwarden.network.model.CheckoutSessionRequestJson
+import com.bitwarden.network.model.CheckoutSessionResponseJson
+import com.bitwarden.network.model.NetworkResult
+import com.bitwarden.network.model.PortalUrlResponseJson
+import retrofit2.http.Body
+import retrofit2.http.POST
+
+/**
+ * Defines raw calls under the /account/billing API with authentication applied.
+ */
+internal interface AuthenticatedBillingApi {
+
+    /**
+     * Creates a Stripe checkout session for premium upgrade.
+     */
+    @POST("/account/billing/vnext/premium/checkout")
+    suspend fun createCheckoutSession(
+        @Body body: CheckoutSessionRequestJson,
+    ): NetworkResult<CheckoutSessionResponseJson>
+
+    /**
+     * Creates a Stripe customer portal session for managing the premium subscription.
+     */
+    @POST("/account/billing/vnext/portal-session")
+    suspend fun getPortalUrl(): NetworkResult<PortalUrlResponseJson>
+}

network/src/main/kotlin/com/bitwarden/network/model/CheckoutSessionRequestJson.kt

@@ -0,0 +1,15 @@
+package com.bitwarden.network.model
+
+import kotlinx.serialization.SerialName
+import kotlinx.serialization.Serializable
+
+/**
+ * Request object for creating a Stripe checkout session for premium upgrade.
+ *
+ * @property platform The platform identifier (e.g., "android" or "ios").
+ */
+@Serializable
+data class CheckoutSessionRequestJson(
+    @SerialName("platform")
+    val platform: String,
+)

network/src/main/kotlin/com/bitwarden/network/model/CheckoutSessionResponseJson.kt

@@ -0,0 +1,15 @@
+package com.bitwarden.network.model
+
+import kotlinx.serialization.SerialName
+import kotlinx.serialization.Serializable
+
+/**
+ * Response object returned when creating a premium checkout session.
+ *
+ * @property checkoutSessionUrl The Stripe checkout URL for premium upgrade.
+ */
+@Serializable
+data class CheckoutSessionResponseJson(
+    @SerialName("checkoutSessionUrl")
+    val checkoutSessionUrl: String,
+)

network/src/main/kotlin/com/bitwarden/network/model/PortalUrlResponseJson.kt

@@ -0,0 +1,15 @@
+package com.bitwarden.network.model
+
+import kotlinx.serialization.SerialName
+import kotlinx.serialization.Serializable
+
+/**
+ * Response object returned when requesting a Stripe customer portal session.
+ *
+ * @property url The Stripe customer portal URL.
+ */
+@Serializable
+data class PortalUrlResponseJson(
+    @SerialName("url")
+    val url: String,
+)

network/src/main/kotlin/com/bitwarden/network/service/BillingService.kt

@@ -0,0 +1,20 @@
+package com.bitwarden.network.service
+
+import com.bitwarden.network.model.CheckoutSessionResponseJson
+import com.bitwarden.network.model.PortalUrlResponseJson
+
+/**
+ * Provides an API for interacting with the billing endpoints.
+ */
+interface BillingService {
+
+    /**
+     * Creates a Stripe checkout session for premium upgrade.
+     */
+    suspend fun createCheckoutSession(): Result<CheckoutSessionResponseJson>
+
+    /**
+     * Creates a Stripe customer portal session for managing the premium subscription.
+     */
+    suspend fun getPortalUrl(): Result<PortalUrlResponseJson>
+}

network/src/main/kotlin/com/bitwarden/network/service/BillingServiceImpl.kt

@@ -0,0 +1,29 @@
+package com.bitwarden.network.service
+
+import com.bitwarden.network.api.AuthenticatedBillingApi
+import com.bitwarden.network.model.CheckoutSessionRequestJson
+import com.bitwarden.network.model.CheckoutSessionResponseJson
+import com.bitwarden.network.model.PortalUrlResponseJson
+import com.bitwarden.network.util.toResult
+
+private const val PLATFORM = "android"
+
+/**
+ * The default implementation of the [BillingService].
+ */
+internal class BillingServiceImpl(
+    private val authenticatedBillingApi: AuthenticatedBillingApi,
+) : BillingService {
+
+    override suspend fun createCheckoutSession(): Result<CheckoutSessionResponseJson> =
+        authenticatedBillingApi
+            .createCheckoutSession(
+                body = CheckoutSessionRequestJson(platform = PLATFORM),
+            )
+            .toResult()
+
+    override suspend fun getPortalUrl(): Result<PortalUrlResponseJson> =
+        authenticatedBillingApi
+            .getPortalUrl()
+            .toResult()
+}

network/src/test/kotlin/com/bitwarden/network/service/BillingServiceTest.kt

@@ -0,0 +1,79 @@
+package com.bitwarden.network.service
+
+import com.bitwarden.core.data.util.asSuccess
+import com.bitwarden.network.api.AuthenticatedBillingApi
+import com.bitwarden.network.base.BaseServiceTest
+import com.bitwarden.network.model.CheckoutSessionResponseJson
+import com.bitwarden.network.model.PortalUrlResponseJson
+import kotlinx.coroutines.test.runTest
+import okhttp3.mockwebserver.MockResponse
+import org.junit.jupiter.api.Assertions.assertEquals
+import org.junit.jupiter.api.Assertions.assertTrue
+import org.junit.jupiter.api.Test
+import retrofit2.create
+
+class BillingServiceTest : BaseServiceTest() {
+
+    private val billingApi: AuthenticatedBillingApi = retrofit.create()
+    private val service = BillingServiceImpl(
+        authenticatedBillingApi = billingApi,
+    )
+
+    @Test
+    fun `createCheckoutSession when response is Failure should return Failure`() =
+        runTest {
+            val response = MockResponse().setResponseCode(400)
+            server.enqueue(response)
+            val actual = service.createCheckoutSession()
+            assertTrue(actual.isFailure)
+        }
+
+    @Test
+    fun `createCheckoutSession when response is Success should return Success`() =
+        runTest {
+            val response = MockResponse()
+                .setBody(CHECKOUT_SESSION_RESPONSE_JSON)
+                .setResponseCode(200)
+            server.enqueue(response)
+            val actual = service.createCheckoutSession()
+            assertEquals(CHECKOUT_SESSION_RESPONSE.asSuccess(), actual)
+        }
+
+    @Test
+    fun `getPortalUrl when response is Failure should return Failure`() = runTest {
+        val response = MockResponse().setResponseCode(400)
+        server.enqueue(response)
+        val actual = service.getPortalUrl()
+        assertTrue(actual.isFailure)
+    }
+
+    @Test
+    fun `getPortalUrl when response is Success should return Success`() = runTest {
+        val response = MockResponse()
+            .setBody(PORTAL_URL_RESPONSE_JSON)
+            .setResponseCode(200)
+        server.enqueue(response)
+        val actual = service.getPortalUrl()
+        assertEquals(PORTAL_URL_RESPONSE.asSuccess(), actual)
+    }
+}
+
+private const val CHECKOUT_SESSION_RESPONSE_JSON = """
+{
+  "checkoutSessionUrl": "https://checkout.stripe.com/c/pay/test_session_123"
+}
+"""
+
+private val CHECKOUT_SESSION_RESPONSE = CheckoutSessionResponseJson(
+    checkoutSessionUrl = "https://checkout.stripe.com/c/pay/test_session_123",
+)
+
+private const val PORTAL_URL_RESPONSE_JSON = """
+{
+  "url": "https://billing.stripe.com/p/session/test_portal_456"
+}
+"""
+
+private val PORTAL_URL_RESPONSE = PortalUrlResponseJson(
+    url = "https://billing.stripe.com/p/session/test_portal_456",
+)