feat(setup): bootstrap Android plugin and web UI

This initial commit adds a multi-part scaffold for Wechselbild, including a web UI and an Android plugin.
It introduces frontend assets and a package.json-based dev setup, plus plugin scaffolding for Android with Kotlin sources and Cargo.toml for the Tauri plugin.

- Adds Android wallpaper plugin with Kotlin sources and manifest
- Includes web UI scaffold with index.html and package.json
- Adds Tauri plugin scaffold with Cargo.toml and build config

plugins/src/commands.rs

@@ -0,0 +1,10 @@
+use tauri::{AppHandle, command, Runtime};
+
+use crate::models::*;
+use crate::Result;
+use crate::WallpaperExt;
+
+#[command] pub(crate) async fn get_state<R: Runtime>(app: AppHandle<R>) -> Result<WallpaperState> { app.wallpaper().get_state() }
+#[command] pub(crate) async fn select_images<R: Runtime>(app: AppHandle<R>) -> Result<WallpaperState> { app.wallpaper().select_images() }
+#[command] pub(crate) async fn set_setting<R: Runtime>(app: AppHandle<R>, name: String, value: bool) -> Result<WallpaperState> { app.wallpaper().set_setting(SettingRequest { name, value }) }
+#[command] pub(crate) async fn next_wallpaper<R: Runtime>(app: AppHandle<R>) -> Result<WallpaperState> { app.wallpaper().next_wallpaper() }

plugins/src/desktop.rs

@@ -0,0 +1,22 @@
+use serde::de::DeserializeOwned;
+use tauri::{plugin::PluginApi, AppHandle, Runtime};
+
+use crate::models::*;
+
+pub fn init<R: Runtime, C: DeserializeOwned>(
+  app: &AppHandle<R>,
+  _api: PluginApi<R, C>,
+) -> crate::Result<Wallpaper<R>> {
+  Ok(Wallpaper(app.clone()))
+}
+
+/// Access to the wallpaper APIs.
+pub struct Wallpaper<R: Runtime>(AppHandle<R>);
+
+impl<R: Runtime> Wallpaper<R> {
+  fn demo() -> WallpaperState { WallpaperState { image_count: 3, enabled: true, shuffle: true, lock_screen_only: true, current_index: 0, image_urls: vec!["/wallpapers/alpine.png".into(), "/wallpapers/waterfall.png".into(), "/wallpapers/coast.png".into()] } }
+  pub fn get_state(&self) -> crate::Result<WallpaperState> { Ok(Self::demo()) }
+  pub fn select_images(&self) -> crate::Result<WallpaperState> { Ok(Self::demo()) }
+  pub fn set_setting(&self, payload: SettingRequest) -> crate::Result<WallpaperState> { let mut state = Self::demo(); match payload.name.as_str() { "enabled" => state.enabled = payload.value, "shuffle" => state.shuffle = payload.value, "lockScreenOnly" => state.lock_screen_only = payload.value, _ => {} }; Ok(state) }
+  pub fn next_wallpaper(&self) -> crate::Result<WallpaperState> { let mut state = Self::demo(); state.current_index = 1; Ok(state) }
+}

plugins/src/error.rs

@@ -0,0 +1,21 @@
+use serde::{ser::Serializer, Serialize};
+
+pub type Result<T> = std::result::Result<T, Error>;
+
+#[derive(Debug, thiserror::Error)]
+pub enum Error {
+  #[error(transparent)]
+  Io(#[from] std::io::Error),
+  #[cfg(mobile)]
+  #[error(transparent)]
+  PluginInvoke(#[from] tauri::plugin::mobile::PluginInvokeError),
+}
+
+impl Serialize for Error {
+  fn serialize<S>(&self, serializer: S) -> std::result::Result<S::Ok, S::Error>
+  where
+    S: Serializer,
+  {
+    serializer.serialize_str(self.to_string().as_ref())
+  }
+}

plugins/src/lib.rs

@@ -0,0 +1,48 @@
+use tauri::{
+  plugin::{Builder, TauriPlugin},
+  Manager, Runtime,
+};
+
+pub use models::*;
+
+#[cfg(desktop)]
+mod desktop;
+#[cfg(mobile)]
+mod mobile;
+
+mod commands;
+mod error;
+mod models;
+
+pub use error::{Error, Result};
+
+#[cfg(desktop)]
+use desktop::Wallpaper;
+#[cfg(mobile)]
+use mobile::Wallpaper;
+
+/// Extensions to [`tauri::App`], [`tauri::AppHandle`] and [`tauri::Window`] to access the wallpaper APIs.
+pub trait WallpaperExt<R: Runtime> {
+  fn wallpaper(&self) -> &Wallpaper<R>;
+}
+
+impl<R: Runtime, T: Manager<R>> crate::WallpaperExt<R> for T {
+  fn wallpaper(&self) -> &Wallpaper<R> {
+    self.state::<Wallpaper<R>>().inner()
+  }
+}
+
+/// Initializes the plugin.
+pub fn init<R: Runtime>() -> TauriPlugin<R> {
+  Builder::new("wallpaper")
+    .invoke_handler(tauri::generate_handler![commands::get_state, commands::select_images, commands::set_setting, commands::next_wallpaper])
+    .setup(|app, api| {
+      #[cfg(mobile)]
+      let wallpaper = mobile::init(app, api)?;
+      #[cfg(desktop)]
+      let wallpaper = desktop::init(app, api)?;
+      app.manage(wallpaper);
+      Ok(())
+    })
+    .build()
+}

plugins/src/mobile.rs

@@ -0,0 +1,32 @@
+use serde::de::DeserializeOwned;
+use tauri::{
+  plugin::{PluginApi, PluginHandle},
+  AppHandle, Runtime,
+};
+
+use crate::models::*;
+
+#[cfg(target_os = "ios")]
+tauri::ios_plugin_binding!(init_plugin_wallpaper);
+
+// initializes the Kotlin or Swift plugin classes
+pub fn init<R: Runtime, C: DeserializeOwned>(
+  _app: &AppHandle<R>,
+  api: PluginApi<R, C>,
+) -> crate::Result<Wallpaper<R>> {
+  #[cfg(target_os = "android")]
+  let handle = api.register_android_plugin("de.wechselbild.wallpaper", "WallpaperPlugin")?;
+  #[cfg(target_os = "ios")]
+  let handle = api.register_ios_plugin(init_plugin_wallpaper)?;
+  Ok(Wallpaper(handle))
+}
+
+/// Access to the wallpaper APIs.
+pub struct Wallpaper<R: Runtime>(PluginHandle<R>);
+
+impl<R: Runtime> Wallpaper<R> {
+  pub fn get_state(&self) -> crate::Result<WallpaperState> { self.0.run_mobile_plugin("getState", ()).map_err(Into::into) }
+  pub fn select_images(&self) -> crate::Result<WallpaperState> { self.0.run_mobile_plugin("selectImages", ()).map_err(Into::into) }
+  pub fn set_setting(&self, payload: SettingRequest) -> crate::Result<WallpaperState> { self.0.run_mobile_plugin("setSetting", payload).map_err(Into::into) }
+  pub fn next_wallpaper(&self) -> crate::Result<WallpaperState> { self.0.run_mobile_plugin("nextWallpaper", ()).map_err(Into::into) }
+}

plugins/src/models.rs

@@ -0,0 +1,16 @@
+use serde::{Deserialize, Serialize};
+
+#[derive(Debug, Clone, Default, Deserialize, Serialize)]
+#[serde(rename_all = "camelCase")]
+pub struct WallpaperState {
+  pub image_count: usize,
+  pub enabled: bool,
+  pub shuffle: bool,
+  pub lock_screen_only: bool,
+  pub current_index: usize,
+  pub image_urls: Vec<String>,
+}
+
+#[derive(Debug, Clone, Deserialize, Serialize)]
+#[serde(rename_all = "camelCase")]
+pub struct SettingRequest { pub name: String, pub value: bool }