Integrate Element Call with widget API (#1581)

* Integrate Element Call with widget API.

- Add `appconfig` module and extract constants that can be overridden in forks there.
- Add an Element Call feature flag, disabled by default.
- Refactor the whole `ElementCallActivity`, move most logic out of it.
- Integrate with the Rust Widget Driver API (note the Rust SDK version used in this PR lacks some needed changes to make the calls actually work).
- Handle calls differently based on `CallType`.
- Add UI to create/join a call.

---------

Co-authored-by: ElementBot <benoitm+elementbot@element.io>

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

@@ -17,7 +17,7 @@
 package io.element.android.libraries.matrix.api.permalink
 
 import android.net.Uri
-import io.element.android.libraries.matrix.api.config.MatrixConfiguration
+import io.element.android.appconfig.MatrixConfiguration
 
 /**
  * Mapping of an input URI to a matrix.to compliant URI.

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

@@ -16,7 +16,7 @@
 
 package io.element.android.libraries.matrix.api.permalink
 
-import io.element.android.libraries.matrix.api.config.MatrixConfiguration
+import io.element.android.appconfig.MatrixConfiguration
 import io.element.android.libraries.matrix.api.core.MatrixPatterns
 import io.element.android.libraries.matrix.api.core.RoomId
 import io.element.android.libraries.matrix.api.core.UserId

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

@@ -30,6 +30,8 @@ import io.element.android.libraries.matrix.api.media.VideoInfo
 import io.element.android.libraries.matrix.api.poll.PollKind
 import io.element.android.libraries.matrix.api.room.location.AssetType
 import io.element.android.libraries.matrix.api.timeline.MatrixTimeline
+import io.element.android.libraries.matrix.api.widget.MatrixWidgetDriver
+import io.element.android.libraries.matrix.api.widget.MatrixWidgetSettings
 import kotlinx.coroutines.flow.StateFlow
 import java.io.Closeable
 import java.io.File
@@ -192,5 +194,27 @@ interface MatrixRoom : Closeable {
         progressCallback: ProgressCallback?
     ): Result<MediaUploadHandler>
 
+    /**
+     * Generates a Widget url to display in a [android.webkit.WebView] given the provided parameters.
+     * @param widgetSettings The widget settings to use.
+     * @param clientId The client id to use. It should be unique per app install.
+     * @param languageTag The language tag to use. If null, the default language will be used.
+     * @param theme The theme to use. If null, the default theme will be used.
+     * @return The resulting url, or a failure.
+     */
+    suspend fun generateWidgetWebViewUrl(
+        widgetSettings: MatrixWidgetSettings,
+        clientId: String,
+        languageTag: String? = null,
+        theme: String? = null,
+    ): Result<String>
+
+    /**
+     * Get a [MatrixWidgetDriver] for the provided [widgetSettings].
+     * @param widgetSettings The widget settings to use.
+     * @return The resulting [MatrixWidgetDriver], or a failure.
+     */
+    fun getWidgetDriver(widgetSettings: MatrixWidgetSettings): Result<MatrixWidgetDriver>
+
     override fun close() = destroy()
 }

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

@@ -14,9 +14,13 @@
  * limitations under the License.
  */
 
-package io.element.android.libraries.matrix.api.config
+package io.element.android.libraries.matrix.api.widget
 
-object MatrixConfiguration {
-    const val matrixToPermalinkBaseUrl: String = "https://matrix.to/#/"
-    val clientPermalinkBaseUrl: String? = null
+import java.util.UUID
+
+interface CallWidgetSettingsProvider {
+    fun provide(
+        baseUrl: String,
+        widgetId: String = UUID.randomUUID().toString()
+    ): MatrixWidgetSettings
 }

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

@@ -0,0 +1,27 @@
+/*
+ * 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.widget
+
+import kotlinx.coroutines.flow.Flow
+
+interface MatrixWidgetDriver : AutoCloseable {
+    val id: String
+    val incomingMessages: Flow<String>
+
+    suspend fun run()
+    suspend fun send(message: String)
+}

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

@@ -0,0 +1,29 @@
+/*
+ * 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.widget
+
+import android.os.Parcelable
+import kotlinx.parcelize.Parcelize
+
+@Parcelize
+class MatrixWidgetSettings(
+    val id: String,
+    val initAfterContentLoad: Boolean,
+    val rawUrl: String,
+) : Parcelable {
+    companion object
+}