Introduce ElementThemeApp to avoid code duplication.

libraries/designsystem/src/main/kotlin/io/element/android/libraries/designsystem/theme/ElementThemeApp.kt

@@ -0,0 +1,46 @@
+/*
+ * Copyright (c) 2024 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
+ *
+ *     https://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.designsystem.theme
+
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.collectAsState
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.remember
+import io.element.android.compound.theme.ElementTheme
+import io.element.android.compound.theme.Theme
+import io.element.android.compound.theme.isDark
+import io.element.android.compound.theme.mapToTheme
+import io.element.android.libraries.preferences.api.store.AppPreferencesStore
+
+/**
+ * Theme to use for all the regular screens of the application.
+ * Will manage the light / dark theme based on the user preference.
+ */
+@Composable
+fun ElementThemeApp(
+    appPreferencesStore: AppPreferencesStore,
+    content: @Composable () -> Unit,
+) {
+    val theme by remember {
+        appPreferencesStore.getThemeFlow().mapToTheme()
+    }
+        .collectAsState(initial = Theme.System)
+    ElementTheme(
+        darkTheme = theme.isDark(),
+        content = content,
+    )
+}