jamendo: ship a default client_id so /jamendo works out of the box

The app key identifies the application, not a user, so there is no reason
to make everyone register one before they can play anything. An unset (or
blank) client_id now falls back to DEFAULT_CLIENT_ID, and init writes
whichever key is in force back into jamendo.toml, so the effective value
is always visible and replaceable.

Jamendo rate-limits per key, which the docs say plainly: a shipped
default is a shared budget, and a heavy user should register their own.
A configured key always wins.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

jamendody/src/lib.rs

@@ -22,7 +22,7 @@ use async_trait::async_trait;
 use crabidy_core::proto::crabidy::{Album, LibraryNode, LibraryNodeChild, Track};
 use crabidy_core::{ProviderClient, ProviderError};
 use serde::{Deserialize, Serialize};
-use tracing::warn;
+use tracing::{debug, warn};
 
 pub mod api;
 use api::{Jam, JamAlbum, JamApi, JamTrack};
@@ -42,17 +42,27 @@ pub const DEFAULT_SEARCH_RESULTS: usize = 50;
 pub const DEFAULT_ALBUM_TRACKS: usize = 200;
 /// Default per-request timeout in seconds.
 pub const DEFAULT_CALL_TIMEOUT_SECS: u64 = 30;
+/// The app key crabidy ships with, used when `jamendo.toml` configures none —
+/// so `/jamendo` works out of the box. It identifies the *application*, not a
+/// user, and Jamendo's rate limit is per key: a shared default means a shared
+/// budget, so register your own at <https://devportal.jamendo.com> and set
+/// `client_id` if you use Jamendo heavily. `init` writes whichever key is in
+/// force back to the config file, so the effective value is always visible.
+pub const DEFAULT_CLIENT_ID: &str = "24a50df7";
+
 /// Default requested audio streaming format. `mp31` is Jamendo's freely
 /// streamable MP3; `mp32` (higher bitrate) is *not* reliably provisioned for the
 /// streaming `audio` URL and comes back empty for many tracks, so it is a poor
 /// default (a Pro account can still set it explicitly).
 pub const DEFAULT_AUDIOFORMAT: &str = "mp31";
 
-/// Provider settings, persisted as `jamendo.toml`. `client_id` is **required**:
-/// without it the provider does not mount (D5). The rest have defaults.
+/// Provider settings, persisted as `jamendo.toml`. Every field is optional:
+/// an unset `client_id` falls back to [`DEFAULT_CLIENT_ID`], so the provider
+/// mounts with no configuration at all.
 #[derive(Clone, Default, Deserialize, Serialize)]
 pub struct Settings {
-    /// The registered Jamendo app key from `devportal.jamendo.com`. Required.
+    /// The registered Jamendo app key from `devportal.jamendo.com`. Unset
+    /// falls back to [`DEFAULT_CLIENT_ID`] (and `init` persists what it used).
     /// **Secret**: redacted from `Debug`.
     pub client_id: Option<String>,
     /// Requested audio format. Default [`DEFAULT_AUDIOFORMAT`].
@@ -362,14 +372,22 @@ impl ProviderClient for Client {
             warn!("could not parse jamendo.toml: {err}");
             ProviderError::Config("jamendo.toml is not valid TOML".to_string())
         })?;
-        let client_id = settings
+        // No configured key is the normal first-run case: fall back to the
+        // shipped default so `/jamendo` works out of the box, and record it in
+        // `settings` so the write-back shows which key is in force.
+        let mut settings = settings;
+        let client_id = match settings
             .client_id
             .clone()
             .filter(|id| !id.trim().is_empty())
-            .ok_or_else(|| {
-                warn!("jamendo provider disabled: no client_id configured");
-                ProviderError::Config("jamendo client_id is required".to_string())
-            })?;
+        {
+            Some(id) => id,
+            None => {
+                debug!("no jamendo client_id configured, using the shipped default");
+                settings.client_id = Some(DEFAULT_CLIENT_ID.to_string());
+                DEFAULT_CLIENT_ID.to_string()
+            }
+        };
         let audioformat = settings
             .audioformat
             .clone()

jamendody/src/tests.rs

@@ -71,6 +71,39 @@ fn settings_debug_redacts_client_id() {
     assert!(dumped.contains("<redacted>"));
 }
 
+// --- The shipped default app key -----------------------------------------
+
+/// An empty config must still mount: the shipped `DEFAULT_CLIENT_ID` stands in
+/// for a missing `client_id`, and `init` records it so the write-back shows
+/// which key is in force.
+#[tokio::test]
+async fn an_empty_config_falls_back_to_the_shipped_key() {
+    let client = Client::init("").await.expect("mounts with no config");
+    let written = client.settings();
+    assert!(
+        written.contains(DEFAULT_CLIENT_ID),
+        "init persists the key it used: {written}"
+    );
+}
+
+/// A configured key always wins over the shipped default.
+#[tokio::test]
+async fn a_configured_key_wins_over_the_default() {
+    let client = Client::init("client_id = \"my-own-key\"\n")
+        .await
+        .expect("mounts");
+    let written = client.settings();
+    assert!(written.contains("my-own-key"), "{written}");
+    assert!(!written.contains(DEFAULT_CLIENT_ID), "{written}");
+}
+
+/// A blank key is treated as absent, not as a key that cannot work.
+#[tokio::test]
+async fn a_blank_key_falls_back_too() {
+    let client = Client::init("client_id = \"   \"\n").await.expect("mounts");
+    assert!(client.settings().contains(DEFAULT_CLIENT_ID));
+}
+
 // --- Tree shaping and mapping (T1, T4, T5, T7, T11) -----------------------
 
 #[tokio::test]