status: spotify_error, the last Spotify session error and when it happened

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

components/spotify/include/spotify.h

@@ -58,6 +58,8 @@ typedef struct {
 bool spotify_now_playing(spotify_track_t *t);
 // Current state for status.spotify_state.
 const char *spotify_state(void);
+// Last session error (exception text and uptime) for status.spotify_error. False if none yet.
+bool spotify_last_error(char *out, size_t len);
 
 #ifdef __cplusplus
 }

components/spotify/spotify.cpp

@@ -16,6 +16,7 @@
 #include "SpircHandler.h"
 #include "TrackPlayer.h"
 #include "esp_log.h"
+#include "esp_timer.h"
 #include "freertos/FreeRTOS.h"
 #include "freertos/task.h"
 #include "mdns.h"
@@ -39,6 +40,8 @@ static std::atomic<bool> s_got_blob{false};
 static std::atomic<bool> s_in_session{false};           // session() running (its tasks may exist)
 static std::atomic<int> s_volume{65535};                // player volume in Spotify units (0..65535)
 static std::atomic<const char *> s_state{"disabled"};
+static std::mutex s_error_mutex;
+static std::string s_error;                             // last session error, kept for the status
 static std::atomic<uint64_t> s_pcm_bytes{0};
 static std::shared_ptr<cspot::SpircHandler> s_handler;    // running session, else null
 static spotify_pcm_cb_t s_pcm_cb;
@@ -230,6 +233,13 @@ const char *spotify_state(void)
     return s_state.load();
 }
 
+bool spotify_last_error(char *out, size_t len)
+{
+    std::lock_guard<std::mutex> lock(s_error_mutex);
+    snprintf(out, len, "%s", s_error.c_str());
+    return !s_error.empty();
+}
+
 /* ----- cspot/bell logging -> esp_log (UART + syslog) ----- */
 
 // cspot logs through bell::bellGlobalLogger; without one, CSPOT_LOG dereferences NULL.
@@ -494,6 +504,8 @@ static void spotify_task(void *arg)
         } catch (const std::exception &e) {
             s_state = "error";
             ESP_LOGE(TAG, "session ended: %s", e.what());
+            std::lock_guard<std::mutex> lock(s_error_mutex);
+            s_error = std::string(e.what()) + " (at " + std::to_string(esp_timer_get_time() / 1000000) + " s)";
         }
         s_handler.reset();
         s_in_session = false;