feat(flipcash): wire SetUsername through the profile service layer

definitions/flipcash/protos/src/main/proto/profile/v1/profile_service.proto

@@ -17,6 +17,10 @@ service Profile {
 
 	rpc SetDisplayName(SetDisplayNameRequest) returns (SetDisplayNameResponse);
 
+	// SetUsername sets the caller's username, replacing any username already
+	// set.
+	rpc SetUsername(SetUsernameRequest) returns (SetUsernameResponse);
+
 	// SetProfilePicture sets the caller's profile picture to a blob they have
 	// already uploaded via BlobStorage, replacing any picture already set.
 	//
@@ -90,6 +94,31 @@ message SetDisplayNameResponse {
     moderation.v1.FlaggedCategory flagged_category = 2;
 }
 
+message SetUsernameRequest {
+	// Username is the new username to set.
+	common.v1.Username username = 1 [(validate.rules).message.required = true];
+
+	common.v1.Auth auth = 10 [(validate.rules).message.required = true];
+}
+
+message SetUsernameResponse {
+	Result result = 1;
+	enum Result {
+		OK                   = 0;
+		INVALID_USERNAME     = 1;
+		DENIED               = 2;
+		ALREADY_TAKEN        = 3;
+		FAILED_MODERATED     = 4;
+		INSUFFICIENT_BALANCE = 5;
+		RESERVED_WORD        = 6;
+	}
+
+	// The best-fit category that tripped moderation, mirroring the Moderation
+	// service's vocabulary. Set only when result == FAILED_MODERATED; NONE
+	// otherwise.
+	moderation.v1.FlaggedCategory flagged_category = 2;
+}
+
 message SetProfilePictureRequest {
 	// The blob holding the ORIGINAL image the caller uploaded. It must be owned
 	// by the caller and READY; the server derives the remaining renditions from

services/flipcash/src/main/kotlin/com/flipcash/services/controllers/ProfileController.kt

@@ -98,6 +98,22 @@ class ProfileController @Inject constructor(
             .onSuccess { mergeLocalProfile { it.copy(displayName = displayName) } }
     }
 
+    /**
+     * Claims [username] as the caller's public Flipcash handle, replacing any
+     * username already set.
+     */
+    suspend fun setUsername(
+        username: String,
+    ): Result<Unit> {
+        val owner = userManager.accountCluster?.authority?.keyPair
+            ?: return Result.failure(Throwable("No account cluster in UserManager"))
+
+        return repository.setUsername(username, owner)
+            // Reflect the change locally so anything observing the profile (e.g. a setup flow
+            // deciding which steps remain) sees it without waiting for a refresh.
+            .onSuccess { mergeLocalProfile { it.copy(username = username) } }
+    }
+
     /**
      * Updates the caller's tip card customization with the given hex color string.
      */

services/flipcash/src/main/kotlin/com/flipcash/services/internal/network/api/ProfileApi.kt

@@ -75,6 +75,25 @@ internal class ProfileApi @Inject constructor(
         }
     }
 
+    /**
+     * Sets the username for a user, replacing any username already set.
+     */
+    suspend fun setUsername(
+        username: String,
+        owner: Ed25519.KeyPair
+    ): ProfileService.SetUsernameResponse {
+        val request = ProfileService.SetUsernameRequest.newBuilder()
+            .setUsername(username.asUsername())
+            .apply { setAuth(authenticate(owner)) }
+            .build()
+
+        request.validate().orThrow()
+
+        return withContext(Dispatchers.IO) {
+            api.setUsername(request)
+        }
+    }
+
     /**
      * Sets the caller's profile picture to a blob they have already uploaded via
      * BlobStorage. The server derives the DISPLAY/THUMBNAIL renditions and returns

services/flipcash/src/main/kotlin/com/flipcash/services/internal/network/services/ProfileService.kt

@@ -10,6 +10,7 @@ import com.flipcash.services.models.LinkSocialAccountError
 import com.flipcash.services.models.ProfileIdentifier
 import com.flipcash.services.models.SetDisplayNameError
 import com.flipcash.services.models.SetProfilePictureError
+import com.flipcash.services.models.SetUsernameError
 import com.flipcash.services.models.SocialAccountLinkRequest
 import com.flipcash.services.models.SocialAccountUnlinkRequest
 import com.flipcash.services.models.UnlinkSocialAccountError
@@ -63,6 +64,31 @@ internal class ProfileService @Inject constructor(
         )
     }
 
+    suspend fun setUsername(
+        username: String,
+        owner: Ed25519.KeyPair,
+    ): Result<Unit> {
+        return runCatching {
+            api.setUsername(username, owner)
+        }.foldWithSuppression(
+            onSuccess = { response ->
+                when (response.result) {
+                    ProfileService.SetUsernameResponse.Result.OK -> Result.success(Unit)
+                    ProfileService.SetUsernameResponse.Result.INVALID_USERNAME -> Result.failure(SetUsernameError.InvalidUsername())
+                    ProfileService.SetUsernameResponse.Result.DENIED -> Result.failure(SetUsernameError.Denied())
+                    ProfileService.SetUsernameResponse.Result.ALREADY_TAKEN -> Result.failure(SetUsernameError.AlreadyTaken())
+                    ProfileService.SetUsernameResponse.Result.FAILED_MODERATED ->
+                        Result.failure(SetUsernameError.FailedModerated(response.flaggedCategory.toFlaggedCategory()))
+                    ProfileService.SetUsernameResponse.Result.INSUFFICIENT_BALANCE -> Result.failure(SetUsernameError.InsufficientBalance())
+                    ProfileService.SetUsernameResponse.Result.RESERVED_WORD -> Result.failure(SetUsernameError.ReservedWord())
+                    ProfileService.SetUsernameResponse.Result.UNRECOGNIZED -> Result.failure(SetUsernameError.Unrecognized())
+                    null -> Result.failure(SetUsernameError.Unrecognized())
+                }
+            },
+            onFailure = { Result.failure(it.toValidationOrElse { cause -> SetUsernameError.Other(cause) }) }
+        )
+    }
+
     suspend fun setProfilePicture(
         blobId: BlobId,
         owner: Ed25519.KeyPair,

services/flipcash/src/main/kotlin/com/flipcash/services/internal/repositories/InternalProfileRepository.kt

@@ -5,6 +5,8 @@ import com.flipcash.services.internal.domain.UserProfileMapper
 import com.flipcash.services.internal.network.services.ProfileService
 import com.flipcash.services.models.GetUserProfileError
 import com.flipcash.services.models.ProfileIdentifier
+import com.flipcash.services.models.SetDisplayNameError
+import com.flipcash.services.models.SetUsernameError
 import com.flipcash.services.models.SocialAccount
 import com.flipcash.services.models.SocialAccountLinkRequest
 import com.flipcash.services.models.SocialAccountUnlinkRequest
@@ -38,7 +40,34 @@ internal class InternalProfileRepository(
         owner: Ed25519.KeyPair
     ): Result<Unit> {
         return service.setDisplayName(displayName, owner)
-            .onFailure { ErrorUtils.handleError(it) }
+            .onFailure {
+                // The rejections below are the server answering a user's choice of
+                // display name, not a fault worth reporting.
+                val expected = it is SetDisplayNameError.InvalidDisplayName ||
+                        it is SetDisplayNameError.FailedModerated
+                if (!expected) {
+                    ErrorUtils.handleError(it)
+                }
+            }
+    }
+
+    override suspend fun setUsername(
+        username: String,
+        owner: Ed25519.KeyPair
+    ): Result<Unit> {
+        return service.setUsername(username, owner)
+            .onFailure {
+                // The rejections below are the server answering a user's choice of
+                // username, not a fault worth reporting.
+                val expected = it is SetUsernameError.InvalidUsername ||
+                        it is SetUsernameError.AlreadyTaken ||
+                        it is SetUsernameError.ReservedWord ||
+                        it is SetUsernameError.FailedModerated ||
+                        it is SetUsernameError.InsufficientBalance
+                if (!expected) {
+                    ErrorUtils.handleError(it)
+                }
+            }
     }
 
     override suspend fun setProfilePicture(

services/flipcash/src/main/kotlin/com/flipcash/services/models/Errors.kt

@@ -206,6 +206,23 @@ sealed class SetDisplayNameError(
     data class Other(override val cause: Throwable? = null) : SetDisplayNameError(message = cause?.message, cause = cause), NotifiableError
 }
 
+sealed class SetUsernameError(
+    override val message: String? = null,
+    override val cause: Throwable? = null
+): CodeServerError(message, cause) {
+    class InvalidUsername: SetUsernameError("Invalid username")
+    class Denied: SetUsernameError("Denied")
+    // Another user already holds this username.
+    class AlreadyTaken: SetUsernameError("Username already taken")
+    class FailedModerated(val category: ModerationResult.FlaggedCategory) : SetUsernameError("Content flagged: $category")
+    // Claiming this username costs more than the caller can pay.
+    class InsufficientBalance: SetUsernameError("Insufficient balance")
+    // The username is on the server's reserved list and cannot be claimed.
+    class ReservedWord: SetUsernameError("Reserved word")
+    class Unrecognized : SetUsernameError("Unrecognized"), NotifiableError
+    data class Other(override val cause: Throwable? = null) : SetUsernameError(message = cause?.message, cause = cause), NotifiableError
+}
+
 sealed class SetProfilePictureError(
     override val message: String? = null,
     override val cause: Throwable? = null

services/flipcash/src/main/kotlin/com/flipcash/services/repository/ProfileRepository.kt

@@ -12,6 +12,7 @@ import com.getcode.ed25519.Ed25519
 interface ProfileRepository {
     suspend fun getProfile(identifier: ProfileIdentifier, owner: Ed25519.KeyPair): Result<UserProfile>
     suspend fun setDisplayName(displayName: String, owner: Ed25519.KeyPair): Result<Unit>
+    suspend fun setUsername(username: String, owner: Ed25519.KeyPair): Result<Unit>
     suspend fun setProfilePicture(blobId: BlobId, owner: Ed25519.KeyPair): Result<MediaItem>
     suspend fun updateTipCard(owner: Ed25519.KeyPair, hexColor: String): Result<Unit>
     suspend fun linkSocialAccount(request: SocialAccountLinkRequest, owner: Ed25519.KeyPair): Result<SocialAccount>

services/flipcash/src/test/kotlin/com/flipcash/services/controllers/ProfileControllerTest.kt

@@ -302,13 +302,15 @@ class ProfileControllerTest {
 private class FakeProfileRepository : ProfileRepository {
     var getProfileResult: Result<UserProfile> = Result.failure(RuntimeException("not configured"))
     var setDisplayNameResult: Result<Unit> = Result.success(Unit)
+    var setUsernameResult: Result<Unit> = Result.success(Unit)
     var setProfilePictureResult: Result<MediaItem> = Result.failure(RuntimeException("not configured"))
     var updateTipCardResult: Result<Unit> = Result.success(Unit)
     var linkSocialAccountResult: Result<SocialAccount> = Result.failure(RuntimeException("not configured"))
     var unlinkSocialAccountResult: Result<Unit> = Result.success(Unit)
 
     override suspend fun getProfile(identifier: ProfileIdentifier, owner: Ed25519.KeyPair) = getProfileResult
     override suspend fun setDisplayName(displayName: String, owner: Ed25519.KeyPair) = setDisplayNameResult
+    override suspend fun setUsername(username: String, owner: Ed25519.KeyPair) = setUsernameResult
     override suspend fun setProfilePicture(blobId: BlobId, owner: Ed25519.KeyPair) = setProfilePictureResult
     override suspend fun updateTipCard(owner: Ed25519.KeyPair, hexColor: String) = updateTipCardResult
     override suspend fun linkSocialAccount(request: SocialAccountLinkRequest, owner: Ed25519.KeyPair) =