feat(plex): full-library cast backfill via a batched rich re-sync (S1b)

Lazy enrichment only covers viewed titles, so an actor's count/results were
partial. Add a background backfill: each plex_sync rich-fetches a bounded batch
(60) of not-yet-enriched movies/shows and persists their FULL cast, stamping
people_enriched_at so each is fetched once — the whole library is covered over
successive runs (migration 0057 adds the marker). Extracted the enrichment into a
shared app/plex/people.py (cast_from_meta / enrich_row_people / prune_orphan_people
+ the person-image host/proxy) so the info-page lazy path and the batch share ONE
implementation — no duplication; the info page also stamps the marker so the batch
skips it. Verified: an 8-item batch grows those movies' cast_names 3->24 and fills
plex_people (32->224); the info-page cast is intact after the _rich_meta refactor.
(Plex cast-explore S1b)

backend/app/models.py

@@ -1027,6 +1027,8 @@ class PlexShow(Base, TimestampMixin, UpdatedAtMixin):
     directors: Mapped[list | None] = mapped_column(JSONB)
     cast_names: Mapped[list | None] = mapped_column(JSONB)
     people_text: Mapped[str | None] = mapped_column(Text)  # cast+directors, folded into search_vector
+    # Set once the show's FULL cast has been rich-fetched by the backfill; NULL = still the listing top-3.
+    people_enriched_at: Mapped[datetime | None] = mapped_column(DateTime(timezone=True))
     search_vector: Mapped[object | None] = mapped_column(
         TSVECTOR,
         Computed(
@@ -1118,6 +1120,8 @@ class PlexItem(Base, TimestampMixin, UpdatedAtMixin):
     # Cast + director names, space-joined — folded into search_vector (weight B) so the search box
     # finds titles by a person's name (and ranks them above summary-only mentions).
     people_text: Mapped[str | None] = mapped_column(Text)
+    # Set once the movie's FULL cast has been rich-fetched by the backfill; NULL = still the listing top-3.
+    people_enriched_at: Mapped[datetime | None] = mapped_column(DateTime(timezone=True))
     search_vector: Mapped[object | None] = mapped_column(
         TSVECTOR,
         Computed(

backend/app/plex/people.py

@@ -0,0 +1,97 @@
+"""Shared Plex people helpers: parse cast/crew from rich metadata, persist the full cast onto a movie
+or show (cast_names + the people_text search blob + the plex_people headshot cache), and prune
+orphaned people. Used by BOTH the info-page lazy enrichment (routes.plex) and the background rich
+re-sync (plex.sync), so the two paths never diverge."""
+
+from urllib.parse import quote
+
+from sqlalchemy import text
+from sqlalchemy.orm import Session
+
+from app.models import PlexPerson
+
+# Cast/crew photos come from Plex's PUBLIC metadata CDN (no token). We proxy them (host-whitelisted)
+# so the user's browser makes no third-party request (privacy + self-host CSP friendliness).
+PERSON_IMG_HOST = "https://metadata-static.plex.tv/"
+
+
+def person_thumb_url(thumb: str | None) -> str | None:
+    """Proxied /person-image URL for a Plex CDN headshot, or None when it's missing / off-CDN."""
+    t = str(thumb or "")
+    return f"/api/plex/person-image?u={quote(t, safe='')}" if t.startswith(PERSON_IMG_HOST) else None
+
+
+def cast_from_meta(meta: dict, limit: int = 24) -> list[dict]:
+    """[{name, role, thumb}] for the cast (Role tags) in a full Plex metadata dict — thumb is the
+    proxied person-image URL or None. Shared by the info-page response, the lazy enrichment, and the
+    re-sync so the parsing lives in one place."""
+    out: list[dict] = []
+    for role in (meta.get("Role") or [])[:limit]:
+        name = role.get("tag")
+        if not name:
+            continue
+        out.append(
+            {"name": name, "role": role.get("role"), "thumb": person_thumb_url(role.get("thumb"))}
+        )
+    return out
+
+
+def enrich_row_people(db: Session, row, cast: list[dict]) -> bool:
+    """Persist the FULLER cast onto the row's `cast_names` + `people_text`, and cache each cast
+    member's headshot in plex_people. The cheap section listing that drives the main sync only carries
+    the top ~3 cast, so this — run whenever a rich fetch happens (info-page view + the rich re-sync) —
+    is what makes the full displayed cast filterable. Returns True if anything was written (the caller
+    commits). Best-effort by contract: never the reason a read 500s."""
+    names = list(dict.fromkeys(c["name"] for c in cast if c.get("name")))[:24]
+    if not names:
+        return False
+    dirty = False
+    # Grow/refresh cast_names only when the rich set adds names the stored (listing top-3) set lacks —
+    # avoid churn and never downgrade a fuller set back to the thin listing.
+    if set(names) - set(row.cast_names or []):
+        row.cast_names = names
+        row.people_text = " ".join(dict.fromkeys(list(row.directors or []) + names)) or None
+        dirty = True
+    # Headshot cache: upsert name -> proxied thumb (a later fetch fills a prior NULL; names without a
+    # whitelisted photo still get a row so a card can show a placeholder).
+    existing = {p.name: p for p in db.query(PlexPerson).filter(PlexPerson.name.in_(names))}
+    for c in cast:
+        nm, th = c.get("name"), c.get("thumb")
+        if not nm:
+            continue
+        p = existing.get(nm)
+        if p is None:
+            p = PlexPerson(name=nm, photo_thumb=th)
+            db.add(p)
+            existing[nm] = p
+            dirty = True
+        elif th and not p.photo_thumb:
+            p.photo_thumb = th
+            dirty = True
+    return dirty
+
+
+# The person names still referenced by ANY movie/show (cast OR directors). plex_people rows outside
+# this set are orphans left by a library removal.
+_REFERENCED_PEOPLE_SQL = """
+    SELECT jsonb_array_elements_text(cast_names) FROM plex_items WHERE jsonb_typeof(cast_names) = 'array'
+    UNION SELECT jsonb_array_elements_text(directors) FROM plex_items WHERE jsonb_typeof(directors) = 'array'
+    UNION SELECT jsonb_array_elements_text(cast_names) FROM plex_shows WHERE jsonb_typeof(cast_names) = 'array'
+    UNION SELECT jsonb_array_elements_text(directors) FROM plex_shows WHERE jsonb_typeof(directors) = 'array'
+"""
+
+
+def prune_orphan_people(db: Session) -> int:
+    """Delete plex_people (headshot cache) rows whose name no longer appears in any movie/show cast or
+    directors — orphaned by a library removal. Returns the number pruned. Commits its own work."""
+    # `WHERE ref IS NOT NULL` matters: a JSON-null array element surfaces as a SQL NULL in the
+    # referenced set, and `name NOT IN (…, NULL)` is NULL (never TRUE) for every row — the classic
+    # NOT IN trap that would silently prune nothing. Filtering NULLs out keeps the delete correct.
+    res = db.execute(
+        text(
+            "DELETE FROM plex_people WHERE name NOT IN "
+            f"(SELECT ref FROM ({_REFERENCED_PEOPLE_SQL}) AS refs(ref) WHERE ref IS NOT NULL)"
+        )
+    )
+    db.commit()
+    return res.rowcount or 0

backend/app/plex/sync.py

@@ -12,11 +12,11 @@ Cast + intro/credit markers are fetched lazily on the item-detail/player path (P
 import logging
 from datetime import datetime, timezone
 
-from sqlalchemy import text
 from sqlalchemy.orm import Session
 
 from app import sysconfig
 from app.models import PlexCollection, PlexItem, PlexLibrary, PlexSeason, PlexShow
+from app.plex import people
 from app.plex.client import PlexClient, PlexError, PlexNotConfigured
 
 log = logging.getLogger("siftlode.plex")
@@ -130,6 +130,12 @@ def sync(db: Session) -> dict:
                     _sync_shows(db, plex, lib, stats)
                 _sync_collections(db, plex, lib, stats)
             db.commit()
+            # Rich-fetch a bounded batch of not-yet-enriched titles' FULL cast, so the whole library
+            # becomes filterable over successive runs (the cheap listing above only stored the top ~3).
+            try:
+                stats["people_enriched"] = _enrich_people_batch(db, plex)
+            except Exception as e:  # best-effort — never fail the sync over the backfill
+                log.warning("Plex people enrich batch failed: %s", e)
     except PlexNotConfigured as e:
         return {"skipped": str(e)}
     except PlexError as e:
@@ -139,37 +145,53 @@ def sync(db: Session) -> dict:
     # Prune the headshot cache: a reconcile may have removed titles, orphaning people who no longer
     # appear in ANY item's cast/directors — drop those rows, mirroring how Plex drops orphaned metadata.
     try:
-        stats["people_pruned"] = prune_orphan_people(db)
+        stats["people_pruned"] = people.prune_orphan_people(db)
     except Exception as e:  # best-effort housekeeping — never fail the sync over it
         log.warning("Plex people prune failed: %s", e)
     log.info("Plex sync done: %s", stats)
     return stats
 
 
-# The person names still referenced by ANY movie/show (cast OR directors). plex_people rows outside
-# this set are orphans left by a library removal.
-_REFERENCED_PEOPLE_SQL = """
-    SELECT jsonb_array_elements_text(cast_names) FROM plex_items WHERE jsonb_typeof(cast_names) = 'array'
-    UNION SELECT jsonb_array_elements_text(directors) FROM plex_items WHERE jsonb_typeof(directors) = 'array'
-    UNION SELECT jsonb_array_elements_text(cast_names) FROM plex_shows WHERE jsonb_typeof(cast_names) = 'array'
-    UNION SELECT jsonb_array_elements_text(directors) FROM plex_shows WHERE jsonb_typeof(directors) = 'array'
-"""
+# How many titles to rich-fetch per sync run for the cast backfill — bounds the extra Plex load; the
+# whole library is covered over successive runs (each fetched item is stamped people_enriched_at once).
+_ENRICH_BATCH = 60
 
 
-def prune_orphan_people(db: Session) -> int:
-    """Delete plex_people (headshot cache) rows whose name no longer appears in any movie/show cast or
-    directors — orphaned by a library removal. Returns the number pruned. Commits its own work."""
-    # `WHERE ref IS NOT NULL` matters: a JSON-null array element would surface as a SQL NULL in the
-    # referenced set, and `name NOT IN (…, NULL)` is NULL (never TRUE) for every row — the classic
-    # NOT IN trap that would silently prune nothing. Filtering NULLs out keeps the delete correct.
-    res = db.execute(
-        text(
-            "DELETE FROM plex_people WHERE name NOT IN "
-            f"(SELECT ref FROM ({_REFERENCED_PEOPLE_SQL}) AS refs(ref) WHERE ref IS NOT NULL)"
-        )
+def _enrich_people_batch(db: Session, plex: PlexClient, limit: int = _ENRICH_BATCH) -> int:
+    """Rich-fetch the FULL cast of up to `limit` not-yet-enriched movies/shows and persist it (via the
+    shared enrich_row_people). Oldest-id first, movies before shows. Stamps people_enriched_at only on
+    a SUCCESSFUL fetch, so a transient per-item failure retries next run rather than being lost.
+    Returns how many items were enriched this run."""
+    movies = (
+        db.query(PlexItem)
+        .filter(PlexItem.kind == "movie", PlexItem.people_enriched_at.is_(None))
+        .order_by(PlexItem.id)
+        .limit(limit)
+        .all()
     )
+    remaining = limit - len(movies)
+    shows = (
+        db.query(PlexShow)
+        .filter(PlexShow.people_enriched_at.is_(None))
+        .order_by(PlexShow.id)
+        .limit(remaining)
+        .all()
+        if remaining > 0
+        else []
+    )
+    now = datetime.now(timezone.utc)
+    n = 0
+    for row in [*movies, *shows]:
+        try:
+            meta = plex.metadata(row.rating_key) or {}
+        except Exception as e:
+            log.debug("Plex people enrich fetch failed for %s: %s", row.rating_key, e)
+            continue  # leave people_enriched_at NULL so it's retried on a later run
+        people.enrich_row_people(db, row, people.cast_from_meta(meta))
+        row.people_enriched_at = now
+        n += 1
     db.commit()
-    return res.rowcount or 0
+    return n
 
 
 def _upsert_library(db: Session, key: str, title: str, kind: str) -> PlexLibrary:

backend/app/routes/plex.py

@@ -17,7 +17,6 @@ from concurrent.futures import ThreadPoolExecutor
 from dataclasses import dataclass
 from datetime import datetime, timedelta, timezone
 from pathlib import Path
-from urllib.parse import quote
 
 import httpx
 from fastapi import APIRouter, BackgroundTasks, Depends, HTTPException, Query, Request, Response
@@ -43,6 +42,7 @@ from app.models import (
     User,
 )
 from app.plex import paths as plex_paths
+from app.plex import people as plex_people
 from app.plex import stream as plex_stream
 from app.plex import sync as plex_sync
 from app.plex import watch_sync as plex_watch
@@ -1227,8 +1227,11 @@ def show_detail(
         pass
 
     # Lazy enrichment: persist the show's full cast so its cast members become filterable (same as the
-    # movie info page — the sync only stored the listing's top ~3). Best-effort.
-    if _enrich_people_from_rich(db, sh, rich):
+    # movie info page — the sync only stored the listing's top ~3), and stamp people_enriched_at so the
+    # backfill skips it. Best-effort.
+    if rich.get("cast"):
+        plex_people.enrich_row_people(db, sh, rich["cast"])
+        sh.people_enriched_at = datetime.now(timezone.utc)
         try:
             db.commit()
         except Exception:
@@ -1582,11 +1585,6 @@ _PROGRESS_MIN_S = 5
 _FINISH_MARGIN_S = 30
 
 
-# Cast/crew photos come from Plex's PUBLIC metadata CDN (no token). We proxy them (host-whitelisted)
-# so the user's browser makes no third-party request (privacy + self-host CSP friendliness).
-_PERSON_IMG_HOST = "https://metadata-static.plex.tv/"
-
-
 def _rich_meta(meta: dict) -> dict:
     """Pull the "info page" extras out of a full Plex metadata dict: an IMDb score + link, content
     rating, genres, director(s), studio, tagline, and cast (name/role/photo). Best-effort — any
@@ -1612,21 +1610,6 @@ def _rich_meta(meta: dict) -> dict:
         if gid.startswith("imdb://"):
             imdb_id = gid.split("imdb://", 1)[1]
             break
-    cast = []
-    for role in (meta.get("Role") or [])[:24]:
-        name = role.get("tag")
-        if not name:
-            continue
-        thumb = str(role.get("thumb") or "")
-        cast.append(
-            {
-                "name": name,
-                "role": role.get("role"),
-                "thumb": f"/api/plex/person-image?u={quote(thumb, safe='')}"
-                if thumb.startswith(_PERSON_IMG_HOST)
-                else None,
-            }
-        )
     return {
         "imdb_rating": imdb_rating,
         "imdb_id": imdb_id,
@@ -1636,47 +1619,10 @@ def _rich_meta(meta: dict) -> dict:
         "directors": [d.get("tag") for d in (meta.get("Director") or []) if d.get("tag")][:4],
         "studio": meta.get("studio"),
         "tagline": meta.get("tagline"),
-        "cast": cast,
+        "cast": plex_people.cast_from_meta(meta),
     }
 
 
-def _enrich_people_from_rich(db: Session, row, rich: dict) -> bool:
-    """Persist the FULLER cast (from an item's rich metadata) onto the row's `cast_names` + the
-    `people_text` search blob, and cache each cast member's headshot in plex_people. The cheap section
-    listing that drives the main sync only carries the top ~3 cast, so this — run when a rich fetch
-    happens (info-page view + the rich re-sync) — is what makes the full displayed cast filterable.
-    Returns True if anything was written (the caller commits). Best-effort: never the reason a read
-    500s (the caller wraps the commit)."""
-    cast = rich.get("cast") or []
-    names = list(dict.fromkeys(c["name"] for c in cast if c.get("name")))[:24]
-    if not names:
-        return False
-    dirty = False
-    # Grow/refresh cast_names only when the rich set adds names the stored (listing top-3) set lacks —
-    # avoid churn and never downgrade a fuller set back to the thin listing.
-    if set(names) - set(row.cast_names or []):
-        row.cast_names = names
-        row.people_text = " ".join(dict.fromkeys(list(row.directors or []) + names)) or None
-        dirty = True
-    # Headshot cache: upsert name -> proxied thumb (a later fetch fills a prior NULL; names without a
-    # whitelisted photo still get a row so a card can show a placeholder).
-    existing = {p.name: p for p in db.query(PlexPerson).filter(PlexPerson.name.in_(names))}
-    for c in cast:
-        nm, th = c.get("name"), c.get("thumb")
-        if not nm:
-            continue
-        p = existing.get(nm)
-        if p is None:
-            p = PlexPerson(name=nm, photo_thumb=th)
-            db.add(p)
-            existing[nm] = p
-            dirty = True
-        elif th and not p.photo_thumb:
-            p.photo_thumb = th
-            dirty = True
-    return dirty
-
-
 @router.get("/people/cards")
 def people_cards(
     names: str,
@@ -1727,7 +1673,7 @@ def person_image(u: str, request: Request) -> Response:
     """Proxy a cast/crew photo from Plex's public metadata CDN (host-whitelisted; no token needed).
     Signed-session auth (no DB) so it, like /image, never holds a pool connection during the fetch."""
     _require_session(request)
-    if not u.startswith(_PERSON_IMG_HOST):
+    if not u.startswith(plex_people.PERSON_IMG_HOST):
         raise HTTPException(status_code=400, detail="Unsupported image host")
     cache_key = "person_" + hashlib.sha1(u.encode()).hexdigest()
     hit = _img_cache_read(cache_key)
@@ -1875,9 +1821,12 @@ def item_detail(
         pass  # metadata extras are best-effort; any live-Plex failure must degrade, not 500 — playback works without them
 
     # Lazy enrichment: the rich fetch above carries the FULL cast (the sync only stored the listing's
-    # top ~3), so persist it onto this movie so every cast member shown here becomes filterable. A
-    # movie only — episodes aren't in the grid; their show's cast is enriched from /show. Best-effort.
-    if it.kind == "movie" and _enrich_people_from_rich(db, it, rich):
+    # top ~3), so persist it onto this movie so every cast member shown here becomes filterable, and
+    # stamp people_enriched_at so the backfill skips it. Movie only — episodes aren't in the grid; a
+    # show's cast is enriched from /show. Best-effort.
+    if it.kind == "movie" and rich.get("cast"):
+        plex_people.enrich_row_people(db, it, rich["cast"])
+        it.people_enriched_at = datetime.now(timezone.utc)
         try:
             db.commit()
         except Exception: