feat(downloads): WiFi-only network-type-aware download gating

Add a metered/cellular network detector so downloads honour a "WiFi
only" preference. Android reports network type via NetworkTypeMonitor;
Rust exposes it through download/network.rs and holds the queue pump when
on a metered connection, emitting a queue-wide waitingForNetwork event.
The frontend surfaces this via the networkType service and a
waitingForNetwork store flag.

TRACES: UR-053 | DR-074

src-tauri/src/commands/download/mod.rs

@@ -8,6 +8,7 @@ use std::sync::{Arc, Mutex};
 use tauri::{Manager, State};
 
 use super::{DatabaseWrapper, SmartCacheWrapper};
+use crate::download::network::{NetworkState, NetworkStateHandle, NetworkType};
 use crate::download::{DownloadInfo, DownloadManager};
 use crate::storage::db_service::{DatabaseService, Query, QueryParam};
 
@@ -21,6 +22,80 @@ pub use smart_cache::*;
 /// Wrapper for DownloadManager to be used as Tauri state
 pub struct DownloadManagerWrapper(pub Mutex<DownloadManager>);
 
+/// Wrapper for the current network transport, used by the WiFi-only gate.
+///
+/// TRACES: UR-053 | DR-074
+pub struct NetworkStateWrapper(pub NetworkStateHandle);
+
+/// Report the device's current network transport (Android → Rust).
+///
+/// The frontend calls this on startup and whenever the native network callback
+/// fires. Updating to an acceptable network re-pumps the download queue, so a
+/// queue parked on "waiting for WiFi" drains itself without user action.
+///
+/// TRACES: UR-053 | DR-074
+#[tauri::command]
+#[specta::specta]
+pub async fn set_network_state(
+    app: tauri::AppHandle,
+    network: NetworkStateWrapperArg,
+    db: State<'_, DatabaseWrapper>,
+    download_manager: State<'_, DownloadManagerWrapper>,
+) -> Result<(), String> {
+    let new_state = NetworkState {
+        network_type: network.network_type,
+        unmetered: network.unmetered,
+    };
+
+    let handle = app.state::<NetworkStateWrapper>().0.clone();
+    let previous = handle.get().await;
+    handle.set(new_state).await;
+
+    if previous != new_state {
+        info!(
+            "[network] Transport changed: {:?} (unmetered={}) -> {:?} (unmetered={})",
+            previous.network_type, previous.unmetered, new_state.network_type, new_state.unmetered
+        );
+    }
+
+    // If the new network unblocks the gate, drain whatever was waiting.
+    if downloads_allowed_on_current_network(&app).await {
+        let db_service = {
+            let database = db.0.lock().map_err(|e| e.to_string())?;
+            Arc::new(database.service())
+        };
+        let active = {
+            let manager = download_manager.0.lock().map_err(|e| e.to_string())?;
+            manager.get_active_downloads()
+        };
+        pump_download_queue(app.clone(), db_service, active).await;
+    }
+
+    Ok(())
+}
+
+/// Argument struct for [`set_network_state`].
+///
+/// TRACES: UR-053 | DR-074
+#[derive(specta::Type, Debug, Clone, serde::Serialize, serde::Deserialize)]
+#[serde(rename_all = "camelCase")]
+pub struct NetworkStateWrapperArg {
+    pub network_type: NetworkType,
+    pub unmetered: bool,
+}
+
+/// Whether downloads are currently permitted by the WiFi-only gate.
+///
+/// The downloads UI uses this to render "Waiting for WiFi" on pending rows
+/// rather than leaving them looking silently stuck.
+///
+/// TRACES: UR-053 | DR-074
+#[tauri::command]
+#[specta::specta]
+pub async fn get_downloads_allowed(app: tauri::AppHandle) -> Result<bool, String> {
+    Ok(downloads_allowed_on_current_network(&app).await)
+}
+
 /// Download statistics computed server-side
 #[allow(dead_code)]
 #[derive(specta::Type, Debug, Clone, serde::Serialize, serde::Deserialize)]
@@ -1213,6 +1288,37 @@ pub async fn enqueue_video_downloads(
     Ok(())
 }
 
+/// Whether the current network permits downloads, given the user's WiFi-only
+/// preference.
+///
+/// Reads `wifi_only` from the SmartCache config (the single home of the
+/// setting) and checks it against the transport reported by the platform. On
+/// desktop the transport defaults to unmetered ethernet, so this is always
+/// true there.
+///
+/// TRACES: UR-053 | DR-074
+pub(crate) async fn downloads_allowed_on_current_network(app: &tauri::AppHandle) -> bool {
+    let wifi_only = {
+        let smart_cache = app.state::<SmartCacheWrapper>();
+        let cache = match smart_cache.0.lock() {
+            Ok(c) => c,
+            Err(e) => {
+                error!("[pump] Failed to lock smart cache: {}", e);
+                // Fail open: a lock problem must not silently wedge downloads.
+                return true;
+            }
+        };
+        cache.get_config().map(|c| c.wifi_only).unwrap_or(false)
+    };
+
+    if !wifi_only {
+        return true;
+    }
+
+    let network = app.state::<NetworkStateWrapper>();
+    network.0.allows_download(true).await
+}
+
 /// Start as many pending downloads as there are free concurrency slots.
 ///
 /// Picks the highest-priority `pending` rows that have a persisted `stream_url`
@@ -1227,6 +1333,16 @@ pub(crate) async fn pump_download_queue(
     use crate::download::events::DownloadEvent;
     use tauri::Emitter;
 
+    // WiFi-only gate (UR-053): when the user has restricted downloads to
+    // unmetered networks and we're on cellular (or can't tell), leave every
+    // pending row exactly as it is. They stay 'pending' and the Android
+    // network callback re-pumps us as soon as an acceptable network appears.
+    if !downloads_allowed_on_current_network(&app).await {
+        info!("[pump] Downloads paused: waiting for an unmetered network (WiFi-only enabled)");
+        let _ = app.emit("download-event", DownloadEvent::WaitingForNetwork);
+        return;
+    }
+
     let max_concurrent = {
         let manager = app.state::<DownloadManagerWrapper>();
         let manager = match manager.0.lock() {
@@ -1799,6 +1915,76 @@ pub async fn delete_album_downloads(
     Ok(deleted_count as i64)
 }
 
+/// Remove every completed download at or under a container item.
+///
+/// Works at any level of the Downloaded browse: a leaf (removes just that
+/// download), an album/season/series (removes all downloaded descendants linked
+/// via album_id/season_id/series_id/parent_id). Deletes the DB rows and the
+/// on-disk files. Returns the number of downloads removed. Idempotent.
+///
+/// TRACES: UR-055 | DR-083
+#[tauri::command]
+#[specta::specta]
+pub async fn delete_downloads_under(
+    db: State<'_, DatabaseWrapper>,
+    item_id: String,
+    user_id: String,
+) -> Result<i64, String> {
+    let db_service = {
+        let database = db.0.lock().map_err(|e| e.to_string())?;
+        Arc::new(database.service())
+    };
+
+    // The item itself, or any child linked to it by container id.
+    const SCOPE: &str = "d.user_id = ? AND d.status = 'completed'
+         AND (
+             d.item_id = ?
+             OR d.item_id IN (
+                 SELECT c.id FROM items c
+                 WHERE c.album_id = ? OR c.season_id = ? OR c.series_id = ? OR c.parent_id = ?
+             )
+         )";
+
+    let file_query = Query::with_params(
+        &format!("SELECT d.file_path FROM downloads d WHERE {SCOPE}"),
+        vec![
+            QueryParam::String(user_id.clone()),
+            QueryParam::String(item_id.clone()),
+            QueryParam::String(item_id.clone()),
+            QueryParam::String(item_id.clone()),
+            QueryParam::String(item_id.clone()),
+            QueryParam::String(item_id.clone()),
+        ],
+    );
+    let file_paths: Vec<String> = db_service
+        .query_many(file_query, |row| row.get(0))
+        .await
+        .map_err(|e| e.to_string())?;
+
+    let delete_query = Query::with_params(
+        &format!("DELETE FROM downloads WHERE id IN (SELECT d.id FROM downloads d WHERE {SCOPE})"),
+        vec![
+            QueryParam::String(user_id),
+            QueryParam::String(item_id.clone()),
+            QueryParam::String(item_id.clone()),
+            QueryParam::String(item_id.clone()),
+            QueryParam::String(item_id.clone()),
+            QueryParam::String(item_id),
+        ],
+    );
+    let deleted_count = db_service
+        .execute(delete_query)
+        .await
+        .map_err(|e| e.to_string())?;
+
+    for path in file_paths {
+        let _ = std::fs::remove_file(&path);
+        let _ = std::fs::remove_file(format!("{}.part", path));
+    }
+
+    Ok(deleted_count as i64)
+}
+
 /// Download manager statistics
 #[derive(specta::Type, Debug, Clone, serde::Serialize)]
 pub struct DownloadManagerStats {

src-tauri/src/download/cache.rs

@@ -64,11 +64,20 @@ impl SmartCache {
         }
     }
 
-    /// Check if should pre-cache queue items
+    /// Check if should pre-cache queue items.
+    ///
+    /// Note this deliberately does NOT consult `wifi_only`. It used to return
+    /// `queue_precache_enabled && !wifi_only`, which disabled precaching
+    /// outright whenever the user enabled WiFi-only — regardless of the network
+    /// actually in use. The network check now lives in the download queue pump
+    /// (`downloads_allowed_on_current_network`), which is the single gate for
+    /// all download traffic, so this only answers "is precaching enabled?".
+    ///
+    /// TRACES: UR-053 | DR-074
     pub fn should_precache_queue(&self) -> bool {
         self.config
             .lock()
-            .map(|cfg| cfg.queue_precache_enabled && !cfg.wifi_only)
+            .map(|cfg| cfg.queue_precache_enabled)
             .unwrap_or(false)
     }
 
@@ -282,6 +291,19 @@ mod tests {
         assert!(cache.should_precache_queue());
     }
 
+    #[test]
+    fn test_wifi_only_does_not_disable_precaching() {
+        // wifi_only must not short-circuit precaching: the network gate lives in
+        // the download pump, which checks the *actual* transport. Enabling
+        // WiFi-only while on WiFi should still precache.
+        let mut config = CacheConfig::default();
+        config.queue_precache_enabled = true;
+        config.wifi_only = true;
+
+        let cache = SmartCache::new(config);
+        assert!(cache.should_precache_queue());
+    }
+
     #[tokio::test]
     async fn test_storage_limit_check() {
         use crate::storage::db_service::RusqliteService;

src-tauri/src/download/events.rs

@@ -41,6 +41,11 @@ pub enum DownloadEvent {
     /// Download cancelled
     #[serde(rename_all = "camelCase")]
     Cancelled { download_id: i64, item_id: String },
+    /// The queue is holding: WiFi-only is enabled and the current network is
+    /// metered/cellular. Pending rows stay pending and resume on network change.
+    ///
+    /// TRACES: UR-053 | DR-074
+    WaitingForNetwork,
 }
 
 #[cfg(test)]

src-tauri/src/download/mod.rs

@@ -8,6 +8,7 @@
 
 pub mod cache;
 pub mod events;
+pub mod network;
 pub mod worker;
 
 use crate::utils::lock::MutexSafe;

src-tauri/src/download/network.rs

@@ -0,0 +1,196 @@
+//! Network transport classification for the WiFi-only download gate.
+//!
+//! This answers "what kind of connection are we on?", which is orthogonal to
+//! the `ConnectivityMonitor`'s "is the server reachable?". The download queue
+//! pump consults this before starting pending rows when the user has enabled
+//! WiFi-only downloads.
+//!
+//! On Android the real transport is read from `NetworkCapabilities` in
+//! `NetworkTypeMonitor.kt` and pushed in from the frontend. On desktop there is
+//! no metered-connection concept worth enforcing, so we report `Ethernet`,
+//! which is always acceptable — gating desktop downloads would be a regression.
+
+use serde::{Deserialize, Serialize};
+use std::sync::Arc;
+use tokio::sync::RwLock;
+
+/// Kind of network transport currently active.
+///
+/// Mirrors the string constants in `NetworkTypeMonitor.kt`; the two must stay
+/// in sync (the serde rename below is what the frontend sends).
+///
+/// TRACES: UR-053 | DR-074
+#[derive(specta::Type, Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize)]
+#[serde(rename_all = "lowercase")]
+pub enum NetworkType {
+    /// No active network.
+    None,
+    /// WiFi (may still be metered — check `unmetered`).
+    Wifi,
+    /// Wired ethernet, typical on Android TV and desktop.
+    Ethernet,
+    /// Mobile data — never acceptable when wifi-only is enabled.
+    Cellular,
+    /// Some other transport (VPN over unknown carrier, Bluetooth tethering, …).
+    Other,
+    /// Could not determine the transport.
+    Unknown,
+}
+
+/// Current network transport plus whether it is metered.
+///
+/// TRACES: UR-053 | DR-074
+#[derive(specta::Type, Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize)]
+#[serde(rename_all = "camelCase")]
+pub struct NetworkState {
+    pub network_type: NetworkType,
+    /// Whether the active network is unmetered (Android `NET_CAPABILITY_NOT_METERED`).
+    pub unmetered: bool,
+}
+
+impl Default for NetworkState {
+    fn default() -> Self {
+        // Desktop default: wired and unmetered, so the gate never blocks there.
+        // Android overwrites this as soon as the frontend reports the real state.
+        Self {
+            network_type: NetworkType::Ethernet,
+            unmetered: true,
+        }
+    }
+}
+
+impl NetworkState {
+    /// Whether downloads may run right now given the wifi-only preference.
+    ///
+    /// Ethernet counts as acceptable — it is unmetered in practice and is what
+    /// Android TV devices use. Cellular never does. `None`/`Unknown` fail
+    /// closed: if we cannot tell what we are on, we do not spend the user's
+    /// mobile data to find out.
+    ///
+    /// TRACES: UR-053 | DR-074
+    pub fn allows_download(&self, wifi_only: bool) -> bool {
+        if !wifi_only {
+            return true;
+        }
+        match self.network_type {
+            NetworkType::Cellular | NetworkType::None | NetworkType::Unknown => false,
+            // Require unmetered so metered WiFi hotspots (backed by the very
+            // cellular data this setting protects) are excluded too.
+            NetworkType::Wifi | NetworkType::Ethernet | NetworkType::Other => self.unmetered,
+        }
+    }
+}
+
+/// Shared, mutable view of the current network transport.
+///
+/// Cheap to clone; the frontend updates it via `set_network_state` whenever
+/// Android reports a network change.
+#[derive(Clone, Default)]
+pub struct NetworkStateHandle {
+    state: Arc<RwLock<NetworkState>>,
+}
+
+impl NetworkStateHandle {
+    pub fn new() -> Self {
+        Self {
+            state: Arc::new(RwLock::new(NetworkState::default())),
+        }
+    }
+
+    pub async fn get(&self) -> NetworkState {
+        *self.state.read().await
+    }
+
+    pub async fn set(&self, new_state: NetworkState) {
+        *self.state.write().await = new_state;
+    }
+
+    /// Whether downloads may run right now given the wifi-only preference.
+    pub async fn allows_download(&self, wifi_only: bool) -> bool {
+        self.state.read().await.allows_download(wifi_only)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn state(network_type: NetworkType, unmetered: bool) -> NetworkState {
+        NetworkState {
+            network_type,
+            unmetered,
+        }
+    }
+
+    #[test]
+    fn wifi_only_off_allows_every_transport() {
+        for t in [
+            NetworkType::None,
+            NetworkType::Wifi,
+            NetworkType::Ethernet,
+            NetworkType::Cellular,
+            NetworkType::Other,
+            NetworkType::Unknown,
+        ] {
+            assert!(
+                state(t, false).allows_download(false),
+                "{t:?} should be allowed when wifi_only is off"
+            );
+        }
+    }
+
+    #[test]
+    fn cellular_is_blocked_when_wifi_only() {
+        // Even if somehow flagged unmetered, cellular is never acceptable.
+        assert!(!state(NetworkType::Cellular, true).allows_download(true));
+        assert!(!state(NetworkType::Cellular, false).allows_download(true));
+    }
+
+    #[test]
+    fn unmetered_wifi_and_ethernet_are_allowed() {
+        assert!(state(NetworkType::Wifi, true).allows_download(true));
+        assert!(state(NetworkType::Ethernet, true).allows_download(true));
+    }
+
+    #[test]
+    fn metered_wifi_is_blocked() {
+        // A phone hotspot reports as WiFi but is metered — blocking it is the
+        // whole point of checking NOT_METERED rather than the transport alone.
+        assert!(!state(NetworkType::Wifi, false).allows_download(true));
+    }
+
+    #[test]
+    fn unknown_and_none_fail_closed() {
+        assert!(!state(NetworkType::Unknown, true).allows_download(true));
+        assert!(!state(NetworkType::None, true).allows_download(true));
+    }
+
+    #[test]
+    fn desktop_default_is_never_gated() {
+        assert!(NetworkState::default().allows_download(true));
+    }
+
+    #[tokio::test]
+    async fn handle_roundtrips_state() {
+        let handle = NetworkStateHandle::new();
+        assert!(handle.allows_download(true).await);
+
+        handle.set(state(NetworkType::Cellular, false)).await;
+        assert!(!handle.allows_download(true).await);
+        assert!(handle.allows_download(false).await);
+        assert_eq!(handle.get().await.network_type, NetworkType::Cellular);
+    }
+
+    #[test]
+    fn network_type_serializes_lowercase() {
+        // Must match the string constants in NetworkTypeMonitor.kt.
+        assert_eq!(
+            serde_json::to_string(&NetworkType::Wifi).unwrap(),
+            "\"wifi\""
+        );
+        assert_eq!(
+            serde_json::to_string(&NetworkType::Cellular).unwrap(),
+            "\"cellular\""
+        );
+    }
+}

src-tauri/src/lib.rs

@@ -52,6 +52,7 @@ use commands::{
     delete_album_downloads,
     delete_all_downloads,
     delete_download,
+    delete_downloads_under,
     // Device commands
     device_get_id,
     device_set_id,
@@ -71,6 +72,7 @@ use commands::{
     get_download_manager_stats,
     get_download_storage_stats,
     get_downloads,
+    get_downloads_allowed,
     get_smart_cache_config,
     get_smart_cache_stats,
     image_get_url,
@@ -179,6 +181,9 @@ use commands::{
     repository_get_audio_only_stream_url_for_video,
     repository_get_audio_stream_url,
     repository_get_channels,
+    repository_get_download_disk_usage,
+    repository_get_downloaded_items,
+    repository_get_downloaded_libraries,
     repository_get_genres,
     repository_get_image_url,
     repository_get_item,
@@ -212,6 +217,7 @@ use commands::{
     // Session polling commands
     sessions_set_polling_hint,
     set_max_concurrent_downloads,
+    set_network_state,
     set_show_server_catalog,
     start_download,
     // Storage commands
@@ -770,6 +776,7 @@ fn specta_builder() -> Builder<tauri::Wry> {
             delete_download,
             delete_all_downloads,
             delete_album_downloads,
+            delete_downloads_under,
             clear_stale_downloads,
             get_download_storage_stats,
             mark_download_completed,
@@ -786,6 +793,9 @@ fn specta_builder() -> Builder<tauri::Wry> {
             get_smart_cache_stats,
             update_smart_cache_config,
             get_smart_cache_config,
+            // WiFi-only download gate (UR-053)
+            set_network_state,
+            get_downloads_allowed,
             get_album_recommendations,
             get_album_affinity_status,
             // Pinning commands
@@ -835,6 +845,9 @@ fn specta_builder() -> Builder<tauri::Wry> {
             repository_get_libraries,
             repository_get_items,
             repository_get_item,
+            repository_get_downloaded_libraries,
+            repository_get_downloaded_items,
+            repository_get_download_disk_usage,
             repository_jray_actors_at,
             repository_get_latest_items,
             repository_get_resume_items,
@@ -1196,6 +1209,13 @@ pub fn run() {
             let download_manager_wrapper = DownloadManagerWrapper(Mutex::new(download_manager));
             app.manage(download_manager_wrapper);
 
+            // Current network transport, for the WiFi-only download gate (UR-053).
+            // Defaults to unmetered ethernet so desktop is never gated; Android
+            // overwrites it via set_network_state as soon as the UI starts.
+            app.manage(commands::download::NetworkStateWrapper(
+                download::network::NetworkStateHandle::new(),
+            ));
+
             // Initialize connectivity monitor
             info!("[INIT] Initializing connectivity monitor...");
             let http_config = HttpConfig::default();