feat(db): add M6a rediscover queries (albums + artists, with fallbacks)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
2026-05-01 09:00:20 -04:00
parent 10c84a536e
commit 5ed3c20b74
2 changed files with 350 additions and 0 deletions
@@ -253,3 +253,95 @@ LEFT JOIN LATERAL (
 ) cnt ON true
 ORDER BY max_started.started_at DESC, a.id
 LIMIT $2;
+
+-- name: ListRediscoverAlbumsForUser :many
+-- M6a: albums liked >30 days ago AND not played in the last 14 days,
+-- ordered by longest-since-last-play first. The HAVING clause uses an
+-- epoch sentinel so albums with NO plays count as eligible (their
+-- "last play" is treated as 1970, which is always >14 days ago).
+WITH eligible AS (
+    SELECT al.id        AS album_id,
+           gla.liked_at,
+           max(pe.started_at) AS last_played
+    FROM general_likes_albums gla
+    JOIN albums al ON al.id = gla.album_id
+    LEFT JOIN tracks t       ON t.album_id = al.id
+    LEFT JOIN play_events pe ON pe.track_id = t.id AND pe.user_id = $1
+    WHERE gla.user_id = $1
+      AND gla.liked_at < now() - interval '30 days'
+    GROUP BY al.id, gla.liked_at
+    HAVING COALESCE(max(pe.started_at), '1970-01-01'::timestamptz)
+           < now() - interval '14 days'
+)
+SELECT sqlc.embed(albums), artists.name AS artist_name
+FROM eligible e
+JOIN albums  ON albums.id = e.album_id
+JOIN artists ON artists.id = albums.artist_id
+ORDER BY (now() - COALESCE(e.last_played, e.liked_at)) DESC, albums.id
+LIMIT $2;
+
+-- name: ListRediscoverAlbumsFallbackForUser :many
+-- M6a: random sample of liked albums for the user. The Go service uses
+-- this to top up the rediscover row when ListRediscoverAlbumsForUser
+-- returns fewer than `limit` rows.
+SELECT sqlc.embed(albums), artists.name AS artist_name
+FROM general_likes_albums gla
+JOIN albums  ON albums.id = gla.album_id
+JOIN artists ON artists.id = albums.artist_id
+WHERE gla.user_id = $1
+ORDER BY random()
+LIMIT $2;
+
+-- name: ListRediscoverArtistsForUser :many
+-- M6a: artists liked >30 days ago AND none of their tracks played in the
+-- last 14 days, ordered by longest-since-last-play. cover_album_id is
+-- derived from a representative album (LEFT JOIN LATERAL).
+WITH eligible AS (
+    SELECT a.id        AS artist_id,
+           gla.liked_at,
+           max(pe.started_at) AS last_played
+    FROM general_likes_artists gla
+    JOIN artists a ON a.id = gla.artist_id
+    LEFT JOIN tracks t       ON t.artist_id = a.id
+    LEFT JOIN play_events pe ON pe.track_id = t.id AND pe.user_id = $1
+    WHERE gla.user_id = $1
+      AND gla.liked_at < now() - interval '30 days'
+    GROUP BY a.id, gla.liked_at
+    HAVING COALESCE(max(pe.started_at), '1970-01-01'::timestamptz)
+           < now() - interval '14 days'
+)
+SELECT sqlc.embed(artists),
+       cov.id AS cover_album_id,
+       cnt.album_count::bigint AS album_count
+FROM eligible e
+JOIN artists ON artists.id = e.artist_id
+LEFT JOIN LATERAL (
+    SELECT id FROM albums
+    WHERE artist_id = artists.id AND cover_art_path IS NOT NULL
+    ORDER BY created_at DESC LIMIT 1
+) cov ON true
+LEFT JOIN LATERAL (
+    SELECT count(*) AS album_count
+    FROM albums WHERE artist_id = artists.id
+) cnt ON true
+ORDER BY (now() - COALESCE(e.last_played, e.liked_at)) DESC, artists.id
+LIMIT $2;
+
+-- name: ListRediscoverArtistsFallbackForUser :many
+SELECT sqlc.embed(artists),
+       cov.id AS cover_album_id,
+       cnt.album_count::bigint AS album_count
+FROM general_likes_artists gla
+JOIN artists ON artists.id = gla.artist_id
+LEFT JOIN LATERAL (
+    SELECT id FROM albums
+    WHERE artist_id = artists.id AND cover_art_path IS NOT NULL
+    ORDER BY created_at DESC LIMIT 1
+) cov ON true
+LEFT JOIN LATERAL (
+    SELECT count(*) AS album_count
+    FROM albums WHERE artist_id = artists.id
+) cnt ON true
+WHERE gla.user_id = $1
+ORDER BY random()
+LIMIT $2;