Improve Alchemy Radio with create or replace api call

app_alchemy.py

@@ -516,7 +516,7 @@ def run_radio_playlists_endpoint():
     ---
     tags:
       - Alchemy
-    summary: Delete old '_radio' playlists, then create one playlist per enabled radio on the media server.
+    summary: Upsert one playlist per enabled radio (reuses existing playlist by name, preserving its server-side ID).
     responses:
       200:
         description: Run summary.

tasks/radio_manager.py

@@ -1,19 +1,20 @@
 import logging
 
 from .song_alchemy import song_alchemy
-from .mediaserver import create_playlist, delete_playlists_by_suffix
+from .mediaserver import create_or_replace_playlist, create_playlist
 
 logger = logging.getLogger(__name__)
 
-RADIO_PLAYLIST_SUFFIX = '_radio'
-
 
 def run_radio_playlists():
     """Generate one playlist per enabled radio (anchor + temperature + number of results).
 
-    Runs synchronously, like the sonic fingerprint cron flow: compute all
-    playlists first, then delete every existing playlist ending with '_radio',
-    then create the new ones on the media server.
+    Uses create_or_replace_playlist so the same server-side playlist (and ID,
+    where the backend allows) gets reused across runs — avoiding duplicate
+    playlists on online-first sync clients (e.g. Symfonium on Navidrome)
+    that track playlists by ID.
+
+    Falls back to create_playlist for MPD and other unsupported backends.
     """
     from app_helper import get_alchemy_radios
 
@@ -23,7 +24,7 @@ def run_radio_playlists():
     generated = []
     failed = []
     for radio in radios:
-        playlist_name = f"{radio['name']}{RADIO_PLAYLIST_SUFFIX}"
+        playlist_name = radio['name']
         try:
             outcome = song_alchemy(
                 add_items=[{'type': 'anchor', 'id': radio['anchor_id']}],
@@ -40,19 +41,19 @@ def run_radio_playlists():
             failed.append(playlist_name)
             logger.exception(f"Radio '{radio['name']}' failed; skipping playlist creation.")
 
-    try:
-        delete_playlists_by_suffix(RADIO_PLAYLIST_SUFFIX)
-    except Exception:
-        logger.exception(f"Failed to delete old '{RADIO_PLAYLIST_SUFFIX}' playlists; continuing with playlist creation.")
-
     created = 0
     for playlist_name, item_ids in generated:
         try:
-            create_playlist(playlist_name, item_ids)
+            try:
+                create_or_replace_playlist(playlist_name, item_ids)
+            except NotImplementedError:
+                # MPD or unsupported backend: fall back to plain create.
+                create_playlist(playlist_name, item_ids)
             created += 1
+            logger.info(f"Radio playlist '{playlist_name}' upserted with {len(item_ids)} tracks.")
         except Exception:
             failed.append(playlist_name)
-            logger.exception(f"Failed to create playlist '{playlist_name}' on the media server.")
+            logger.exception(f"Failed to upsert playlist '{playlist_name}' on the media server.")
 
     summary = {
         "message": f"Created {created} radio playlist(s) from {len(radios)} enabled radio(s).",

templates/alchemy.html

@@ -97,7 +97,7 @@
 <section>
     <header class="page-header">
         <h1>AudioMuse-AI - Song Alchemy</h1>
-        <p>Select tracks or artists to Include or Exclude — boost favorites with Include and remove unwanted flavors with Exclude.</p>
+        <p>Select tracks or artists to Include or Exclude, boost favorites with Include and remove unwanted flavors with Exclude.</p>
         <div class="alchemy-tabs" style="margin-top:1rem; display:flex; gap:0.5rem; justify-content:flex-end;">
             <button type="button" id="tab-alchemy" class="tab-btn active">Alchemy</button>
             <button type="button" id="tab-anchors" class="tab-btn">Anchors</button>
@@ -214,7 +214,7 @@ <h2>Saved Anchors</h2>
         <h2>Radios</h2>
         <button type="button" id="radio-back-to-alchemy-btn" class="btn btn-ghost btn-sm">← Back to Alchemy</button>
     </div>
-    <p style="font-size:0.9rem; color:var(--text-muted); margin-top:0.3rem;">A radio is a saved anchor plus a temperature and a number of results. "Create Radio Playlists" deletes every old <em>_radio</em> playlist on the media server and creates a fresh one per enabled radio, named after its anchor.</p>
+    <p style="font-size:0.9rem; color:var(--text-muted); margin-top:0.3rem;">A radio is a saved anchor plus a temperature and a number of results.</p>
     <div class="responsive-table-wrapper" style="margin-top: 0.7rem;">
         <table>
             <thead><tr><th style="text-align:center;">Enabled</th><th>Name</th><th>Temp (τ)</th><th title="Number of results">Results</th><th></th></tr></thead>

templates/cron.html

@@ -54,7 +54,7 @@ <h1>AudioMuse-AI - Scheduled Tasks</h1>
                 Radio Playlists
                 <span class="info-tooltip" tabindex="0">
                     <span class="info-icon"></span>
-                    <span class="tooltip-text">Schedule automatic creation of the Radio playlists defined in the Alchemy page (Radio tab). Old "_radio" playlists are deleted and recreated for every enabled radio. Uses cron notation: 5 fields (minute hour day month weekday). Example: "0 3 * * 6" = 3:00 AM every Saturday.</span>
+                    <span class="tooltip-text">Schedule automatic creation of the Radio playlists defined in the Alchemy page (Radio tab). Each radio's existing playlist is updated in-place (preserving its server-side ID) to avoid duplicates on sync clients. Uses cron notation: 5 fields (minute hour day month weekday). Example: "0 3 * * 6" = 3:00 AM every Saturday.</span>
                 </span>
             </label>
             <input id="alchemy-radio-cron" type="text" style="width:100%;" placeholder="cron expression (e.g. 0 3 * * 6)">

tests/unit/test_app_alchemy_radio.py

@@ -166,10 +166,9 @@ def _radio(self, radio_id, anchor_id, name, temperature=1.0, n_results=100, enab
                 'temperature': temperature, 'n_results': n_results, 'enabled': enabled}
 
     @patch('app_helper.get_alchemy_radios')
-    @patch('tasks.radio_manager.create_playlist')
-    @patch('tasks.radio_manager.delete_playlists_by_suffix')
+    @patch('tasks.radio_manager.create_or_replace_playlist')
     @patch('tasks.radio_manager.song_alchemy')
-    def test_creates_playlists_for_enabled_radios_only(self, mock_alchemy, mock_delete, mock_create,
+    def test_creates_playlists_for_enabled_radios_only(self, mock_alchemy, mock_upsert,
                                                        mock_get_radios):
         from tasks.radio_manager import run_radio_playlists
 
@@ -183,36 +182,32 @@ def test_creates_playlists_for_enabled_radios_only(self, mock_alchemy, mock_dele
 
         mock_alchemy.assert_called_once_with(
             add_items=[{'type': 'anchor', 'id': 10}], n_results=30, temperature=0.5)
-        mock_delete.assert_called_once_with('_radio')
-        mock_create.assert_called_once_with('Chill_radio', ['a', 'b'])
+        mock_upsert.assert_called_once_with('Chill', ['a', 'b'])
         assert summary['playlists_created'] == 1
         assert summary['radios_enabled'] == 1
 
     @patch('app_helper.get_alchemy_radios')
-    @patch('tasks.radio_manager.create_playlist')
-    @patch('tasks.radio_manager.delete_playlists_by_suffix')
+    @patch('tasks.radio_manager.create_or_replace_playlist')
     @patch('tasks.radio_manager.song_alchemy')
-    def test_deletes_old_radio_playlists_after_generation(self, mock_alchemy, mock_delete, mock_create,
-                                                          mock_get_radios):
+    def test_upserts_after_generation(self, mock_alchemy, mock_upsert,
+                                       mock_get_radios):
         from tasks.radio_manager import run_radio_playlists
 
         mock_get_radios.return_value = [self._radio(1, 10, 'Chill')]
         mock_alchemy.return_value = {'results': [{'item_id': 'a'}]}
         order_tracker = MagicMock()
         order_tracker.attach_mock(mock_alchemy, 'alchemy')
-        order_tracker.attach_mock(mock_delete, 'delete')
-        order_tracker.attach_mock(mock_create, 'create')
+        order_tracker.attach_mock(mock_upsert, 'upsert')
 
         run_radio_playlists()
 
         names = [c[0] for c in order_tracker.mock_calls]
-        assert names.index('alchemy') < names.index('delete') < names.index('create')
+        assert names.index('alchemy') < names.index('upsert')
 
     @patch('app_helper.get_alchemy_radios')
-    @patch('tasks.radio_manager.create_playlist')
-    @patch('tasks.radio_manager.delete_playlists_by_suffix')
+    @patch('tasks.radio_manager.create_or_replace_playlist')
     @patch('tasks.radio_manager.song_alchemy')
-    def test_one_failing_radio_does_not_block_others(self, mock_alchemy, mock_delete, mock_create,
+    def test_one_failing_radio_does_not_block_others(self, mock_alchemy, mock_upsert,
                                                      mock_get_radios):
         from tasks.radio_manager import run_radio_playlists
 
@@ -224,15 +219,14 @@ def test_one_failing_radio_does_not_block_others(self, mock_alchemy, mock_delete
 
         summary = run_radio_playlists()
 
-        mock_create.assert_called_once_with('Chill_radio', ['x'])
+        mock_upsert.assert_called_once_with('Chill', ['x'])
         assert summary['playlists_created'] == 1
-        assert summary['failed'] == ['Broken_radio']
+        assert summary['failed'] == ['Broken']
 
     @patch('app_helper.get_alchemy_radios')
-    @patch('tasks.radio_manager.create_playlist')
-    @patch('tasks.radio_manager.delete_playlists_by_suffix')
+    @patch('tasks.radio_manager.create_or_replace_playlist')
     @patch('tasks.radio_manager.song_alchemy')
-    def test_radio_with_no_results_creates_no_playlist(self, mock_alchemy, mock_delete, mock_create,
+    def test_radio_with_no_results_creates_no_playlist(self, mock_alchemy, mock_upsert,
                                                        mock_get_radios):
         from tasks.radio_manager import run_radio_playlists
 
@@ -241,10 +235,9 @@ def test_radio_with_no_results_creates_no_playlist(self, mock_alchemy, mock_dele
 
         summary = run_radio_playlists()
 
-        mock_delete.assert_called_once_with('_radio')
-        mock_create.assert_not_called()
+        mock_upsert.assert_not_called()
         assert summary['playlists_created'] == 0
-        assert summary['failed'] == ['Empty_radio']
+        assert summary['failed'] == ['Empty']
 
 
 class TestDeletePlaylistsBySuffix: