feat(migrations): catalog measurements read functions (aggregate + paginated page)

supabase/migrations/20260707120000_catalog_measurements_read_functions.sql

@@ -0,0 +1,74 @@
+-- Read functions for GET /api/catalogs/measurements v2 (recoupable/chat#1850).
+-- The endpoint's aggregates must cover the ENTIRE scope in one SQL aggregate
+-- (the app-code loop-to-exhaustion approach was rejected 2026-07-07), and the
+-- latest-per-ISRC dedupe (DISTINCT ON) is not expressible through supabase-js,
+-- so both the aggregate and the paginated rows read live here as RPCs.
+--
+-- Scope = the catalog's songs, optionally restricted to those linked to one
+-- artist account via song_artists (catalog_songs ∩ song_artists). "Latest"
+-- = the newest spotify platform_displayed_play_count capture per ISRC.
+--
+-- SECURITY INVOKER (default): the api calls these with the service role
+-- (bypasses RLS); other callers are subject to the underlying tables' RLS,
+-- same as the claim_songstats_backfill_rows precedent.
+
+CREATE OR REPLACE FUNCTION get_catalog_measurements_aggregate(
+  p_catalog uuid,
+  p_artist uuid DEFAULT NULL
+)
+RETURNS TABLE (measured_song_count bigint, total_streams numeric)
+LANGUAGE sql
+STABLE
+AS $$
+  WITH latest AS (
+    SELECT DISTINCT ON (sm.song) sm.value
+    FROM song_measurements sm
+    JOIN catalog_songs cs ON cs.song = sm.song AND cs.catalog = p_catalog
+    WHERE sm.platform = 'spotify'
+      AND sm.metric = 'platform_displayed_play_count'
+      AND (
+        p_artist IS NULL
+        OR EXISTS (
+          SELECT 1 FROM song_artists sa
+          WHERE sa.song = sm.song AND sa.artist = p_artist
+        )
+      )
+    ORDER BY sm.song, sm.captured_at DESC
+  )
+  SELECT count(*)::bigint, COALESCE(sum(value), 0)::numeric FROM latest;
+$$;
+
+CREATE OR REPLACE FUNCTION get_catalog_measurements_page(
+  p_catalog uuid,
+  p_artist uuid DEFAULT NULL,
+  p_limit integer DEFAULT 50,
+  p_offset integer DEFAULT 0
+)
+RETURNS TABLE (isrc text, title text, playcount bigint, measured_at timestamptz)
+LANGUAGE sql
+STABLE
+AS $$
+  SELECT l.isrc, l.title, l.playcount, l.measured_at
+  FROM (
+    SELECT DISTINCT ON (sm.song)
+      sm.song AS isrc,
+      s.name AS title,
+      sm.value AS playcount,
+      sm.captured_at AS measured_at
+    FROM song_measurements sm
+    JOIN catalog_songs cs ON cs.song = sm.song AND cs.catalog = p_catalog
+    JOIN songs s ON s.isrc = sm.song
+    WHERE sm.platform = 'spotify'
+      AND sm.metric = 'platform_displayed_play_count'
+      AND (
+        p_artist IS NULL
+        OR EXISTS (
+          SELECT 1 FROM song_artists sa
+          WHERE sa.song = sm.song AND sa.artist = p_artist
+        )
+      )
+    ORDER BY sm.song, sm.captured_at DESC
+  ) l
+  ORDER BY l.playcount DESC, l.isrc ASC
+  LIMIT p_limit OFFSET p_offset;
+$$;