feat(chat): record video messages from the message input

app/build.gradle.kts

@@ -41,6 +41,7 @@ val androidxTestVersion = "1.5.0"
 val media3Version = "1.11.0"
 val coroutinesVersion = "1.11.0"
 val mockitoKotlinVersion = "6.3.0"
+val cameraXVersion = "1.6.1"
 
 android {
     compileSdk = 37
@@ -244,6 +245,12 @@ dependencies {
     implementation("androidx.lifecycle:lifecycle-common:$lifecycleVersion")
     implementation("androidx.lifecycle:lifecycle-viewmodel-compose:$lifecycleVersion")
 
+    implementation("androidx.camera:camera-core:$cameraXVersion")
+    implementation("androidx.camera:camera-camera2:$cameraXVersion")
+    implementation("androidx.camera:camera-lifecycle:$cameraXVersion")
+    implementation("androidx.camera:camera-video:$cameraXVersion")
+    implementation("androidx.camera:camera-view:$cameraXVersion")
+
     implementation("androidx.biometric:biometric:1.1.0")
 
     implementation("io.reactivex.rxjava2:rxandroid:2.1.1")

app/src/main/java/com/nextcloud/talk/chat/CameraLens.kt

@@ -0,0 +1,60 @@
+/*
+ * Nextcloud Talk - Android Client
+ *
+ * SPDX-FileCopyrightText: 2026 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: GPL-3.0-or-later
+ */
+package com.nextcloud.talk.chat
+
+import android.content.Context
+import android.util.Log
+import androidx.camera.core.Camera
+import androidx.camera.core.CameraSelector
+import androidx.camera.core.UseCase
+import androidx.camera.lifecycle.ProcessCameraProvider
+import androidx.core.content.ContextCompat
+import androidx.lifecycle.LifecycleOwner
+import java.util.concurrent.ExecutionException
+
+private const val TAG = "CameraLens"
+
+internal fun cameraSelectorFor(lens: Int): CameraSelector = CameraSelector.Builder().requireLensFacing(lens).build()
+
+internal fun oppositeLens(lens: Int): Int =
+    if (lens == CameraSelector.LENS_FACING_FRONT) CameraSelector.LENS_FACING_BACK else CameraSelector.LENS_FACING_FRONT
+
+/**
+ * The lens to bind: [preferred] when the device has it, otherwise the other one.
+ */
+internal fun resolveLens(provider: ProcessCameraProvider, preferred: Int): Int =
+    if (provider.hasCamera(cameraSelectorFor(preferred))) preferred else oppositeLens(preferred)
+
+/**
+ * Calls [onResult] on the main thread with the camera provider, or with null when it is not available.
+ */
+internal fun whenCameraProviderReady(context: Context, onResult: (ProcessCameraProvider?) -> Unit) {
+    val providerFuture = ProcessCameraProvider.getInstance(context)
+    providerFuture.addListener({
+        val provider = try {
+            providerFuture.get()
+        } catch (e: ExecutionException) {
+            Log.w(TAG, "camera provider is not available", e)
+            null
+        }
+        onResult(provider)
+    }, ContextCompat.getMainExecutor(context))
+}
+
+/**
+ * Binds [useCases] to the camera with [lens]. Returns null when the camera cannot be bound.
+ */
+internal fun ProcessCameraProvider.bindSafely(owner: LifecycleOwner, lens: Int, vararg useCases: UseCase): Camera? =
+    try {
+        bindToLifecycle(owner, cameraSelectorFor(lens), *useCases)
+    } catch (e: IllegalArgumentException) {
+        Log.w(TAG, "cannot bind camera use cases", e)
+        null
+    } catch (e: IllegalStateException) {
+        Log.w(TAG, "cannot bind camera use cases", e)
+        null
+    }