Add Session Verification flow (#197)

libraries/matrix/api/src/main/kotlin/io/element/android/libraries/matrix/api/MatrixClient.kt

@@ -21,6 +21,7 @@ import io.element.android.libraries.matrix.api.core.SessionId
 import io.element.android.libraries.matrix.api.media.MediaResolver
 import io.element.android.libraries.matrix.api.room.MatrixRoom
 import io.element.android.libraries.matrix.api.room.RoomSummaryDataSource
+import io.element.android.libraries.matrix.api.verification.SessionVerificationService
 
 interface MatrixClient {
     val sessionId: SessionId
@@ -29,6 +30,7 @@ interface MatrixClient {
     fun startSync()
     fun stopSync()
     fun mediaResolver(): MediaResolver
+    fun sessionVerificationService(): SessionVerificationService
     suspend fun logout()
     suspend fun loadUserDisplayName(): Result<String>
     suspend fun loadUserAvatarURLString(): Result<String>
@@ -38,4 +40,6 @@ interface MatrixClient {
         width: Long,
         height: Long
     ): Result<ByteArray>
+
+    fun onSlidingSyncUpdate()
 }

libraries/matrix/api/src/main/kotlin/io/element/android/libraries/matrix/api/verification/SessionVerificationService.kt

@@ -0,0 +1,105 @@
+/*
+ * Copyright (c) 2023 New Vector Ltd
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package io.element.android.libraries.matrix.api.verification
+
+import kotlinx.coroutines.flow.StateFlow
+
+interface SessionVerificationService {
+
+    /**
+     * State of the current verification flow ([VerificationFlowState.Initial] if not started).
+     */
+    val verificationFlowState : StateFlow<VerificationFlowState>
+
+    /**
+     * The internal service that checks verification can only run after the initial sync.
+     * This [StateFlow] will notify consumers when the service is ready to be used.
+     */
+    val isReady: StateFlow<Boolean>
+
+    /**
+     * Returns whether the current verification status is either: [SessionVerifiedStatus.Unknown], [SessionVerifiedStatus.NotVerified]
+     * or [SessionVerifiedStatus.Verified].
+     */
+    val sessionVerifiedStatus: StateFlow<SessionVerifiedStatus>
+
+    /**
+     * Request verification of the current session.
+     */
+    fun requestVerification()
+
+    /**
+     * Cancels the current verification attempt.
+     */
+    fun cancelVerification()
+
+    /**
+     * Approves the current verification. This must happen on both devices to successfully verify a session.
+     */
+    fun approveVerification()
+
+    /**
+     * Declines the verification attempt because the user could not verify or does not trust the other side of the verification.
+     */
+    fun declineVerification()
+
+    /**
+     * Starts the verification of the unverified session from another device.
+     */
+    fun startVerification()
+
+    /**
+     * Returns the verification service state to the initial step.
+     */
+    fun reset()
+}
+
+/** Verification status of the current session. */
+sealed interface SessionVerifiedStatus {
+    /** Unknown status, we couldn't read the actual value from the SDK. */
+    object Unknown : SessionVerifiedStatus
+
+    /** Not verified session status. */
+    object NotVerified : SessionVerifiedStatus
+
+    /** Verified session status. */
+    object Verified : SessionVerifiedStatus
+}
+
+/** States produced by the [SessionVerificationService]. */
+sealed interface VerificationFlowState {
+    /** Initial state. */
+    object Initial : VerificationFlowState
+
+    /** Session verification request was accepted by another device. */
+    object AcceptedVerificationRequest : VerificationFlowState
+
+    /** Short Authentication String (SAS) verification started between the 2 devices. */
+    object StartedSasVerification : VerificationFlowState
+
+    /** Verification data for the SAS verification (emojis) received. */
+    data class ReceivedVerificationData(val emoji: List<VerificationEmoji>) : VerificationFlowState
+
+    /** Verification completed successfully. */
+    object Finished : VerificationFlowState
+
+    /** Verification was cancelled by either device. */
+    object Canceled : VerificationFlowState
+
+    /** Verification failed with an error. */
+    object Failed : VerificationFlowState
+}

libraries/matrix/api/src/main/kotlin/io/element/android/libraries/matrix/api/verification/VerificationEmoji.kt

@@ -0,0 +1,22 @@
+/*
+ * Copyright (c) 2023 New Vector Ltd
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package io.element.android.libraries.matrix.api.verification
+
+data class VerificationEmoji(
+    val code: String,
+    val name: String,
+)