Fix false "Plex fallback" banner during the first scan

history_coverage is only written at the end of an ingest, but
has_completion_data was reading from it. During the first scan the coverage
table is empty while watch_event already holds tens of thousands of Tautulli
rows, so the dashboard announced a fallback that had not happened and claimed
the rejection component was disabled when it was not.

The flag now comes from the events themselves — does any row carry a
percent_complete — which is true the moment Tautulli rows land and false for
Plex-only history. history_source falls back to the scan record when coverage
is absent, so it reads "tautulli" mid-scan instead of null.

Also: the banner named Plex as the source without checking, and now reports
whichever source is actually active, and stays quiet while a scan is running
since the counts are still moving.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01GVbG48GAXfCZatcmX123Ra

mediashelf/api.py

@@ -212,7 +212,7 @@ def sources():
     return jsonify({
         "plex": {"configured": c.plex_configured, "base_url": c.plex_base_url},
         "tautulli": {"configured": c.tautulli_configured, "base_url": c.tautulli_base_url},
-        "history_source": (cov[0]["source"] if cov else None),
+        "history_source": queries.active_history_source(d),
         "has_completion_data": queries.history_has_completion(d),
         "coverage": cov,
         "providers": [dict(r) for r in d.query("SELECT * FROM provider")],

mediashelf/queries.py

@@ -34,11 +34,26 @@ def _score_ctx(db, cfg, has_completion_data: bool) -> scoring.ScoreContext:
 
 
 def history_has_completion(db) -> bool:
-    """True when the active history source records percent_complete (§4.11)."""
+    """True when the ingested history actually carries percent_complete (§4.11).
-    row = db.one(
+
-        "SELECT source FROM history_coverage ORDER BY event_count DESC LIMIT 1"
+    Read from the events themselves, not from history_coverage: that row is only
-    )
+    written at the END of an ingest, so during the first scan the coverage table
-    return bool(row and row["source"] == "tautulli")
+    is empty while watch_event is already full of Tautulli rows. Deriving the
+    flag from the table made the UI announce a Plex fallback that had not
+    happened, mid-scan, on every fresh database.
+    """
+    return bool(db.scalar(
+        "SELECT 1 FROM watch_event WHERE percent_complete IS NOT NULL LIMIT 1"))
+
+
+def active_history_source(db) -> str | None:
+    """Which source history came from — coverage if it exists, else the scan."""
+    row = db.one("SELECT source FROM history_coverage ORDER BY event_count DESC LIMIT 1")
+    if row:
+        return row["source"]
+    row = db.one("SELECT history_source FROM scan WHERE history_source IS NOT NULL "
+                 "ORDER BY id DESC LIMIT 1")
+    return row["history_source"] if row else None
 
 
 BASE_COLUMNS = """
@@ -273,7 +288,7 @@ def overview(db, cfg) -> dict:
         "episodes": s("SELECT COUNT(*) FROM episode WHERE status='present'"),
         "watch_events": s("SELECT COUNT(*) FROM watch_event"),
         "accounts": s("SELECT COUNT(*) FROM account"),
-        "history_source": cov["source"] if cov else None,
+        "history_source": active_history_source(db),
         "history_since": cov["earliest_event_at"] if cov else None,
         "history_until": cov["latest_event_at"] if cov else None,
         "has_completion_data": history_has_completion(db),

mediashelf/static/app.js

@@ -19,6 +19,7 @@ const state = {
   views: [],
   lastPage: null,
   hasCompletion: true,
+  scanning: false,
 };
 
 /* ── helpers ──────────────────────────────────────────────────────── */
@@ -162,9 +163,11 @@ async function loadDashboard() {
       ? 'Completion data available — the rejection component is active'
       : 'No completion data — running degraded, rejection component disabled';
   }
-  if (!ov.has_completion_data && ov.watch_events > 0) {
+  // Only a finished scan can tell us this; mid-scan the counts are still moving.
-    banner('warn', 'Watch history has no completion data (Plex fallback). ' +
+  if (!ov.has_completion_data && ov.watch_events > 0 && !state.scanning) {
-      'The score is running degraded: the “rejection” component is disabled.');
+    banner('warn', `Watch history has no completion data (source: ` +
+      `${ov.history_source || 'unknown'}). The score is running degraded: ` +
+      `the “rejection” component is disabled.`);
   }
 
   // size by library
@@ -727,6 +730,7 @@ $('#scan-now').addEventListener('click', async () => {
 async function pollScan() {
   const btn = $('#scan-now');
   btn.disabled = true;
+  state.scanning = true;
   const tick = async () => {
     const s = await api('/scans/current');
     if (s) {
@@ -735,6 +739,7 @@ async function pollScan() {
     } else {
       btn.textContent = 'Scan now';
       btn.disabled = false;
+      state.scanning = false;
       $('#banner-area').replaceChildren();
       show(state.view);
     }

tests/test_rules_and_api.py

@@ -182,3 +182,28 @@ def test_bulk_keep(client, scanned):
     assert r.status_code == 200
     assert r.get_json()["created"] == len(ids)
     assert client.get("/api/v1/keeps").get_json()["kept_items"] >= len(ids)
+
+
+def test_completion_flag_comes_from_events_not_the_coverage_table(client, scanned):
+    """history_coverage is written at the END of an ingest. Reading the flag from
+    it made the UI announce a Plex fallback mid-scan on every fresh database."""
+    from mediashelf import queries
+
+    assert queries.history_has_completion(scanned) is True
+
+    # simulate mid-scan: events present, coverage not yet written
+    scanned.execute("DELETE FROM history_coverage")
+    assert queries.history_has_completion(scanned) is True, \
+        "flag went false with events already ingested"
+    assert queries.active_history_source(scanned) == "tautulli", \
+        "source should fall back to the scan record when coverage is absent"
+
+    ov = client.get("/api/v1/stats/overview").get_json()
+    assert ov["has_completion_data"] is True
+    assert ov["history_source"] == "tautulli"
+
+
+def test_completion_flag_is_false_for_plex_only_history(scanned):
+    from mediashelf import queries
+    scanned.execute("UPDATE watch_event SET percent_complete = NULL")
+    assert queries.history_has_completion(scanned) is False