Server changes/Sonarr

server/internal/recommend/engine.go

@@ -5,6 +5,7 @@ import (
 	"encoding/json"
 	"log/slog"
 	"net/url"
+	"sort"
 	"strconv"
 	"strings"
 	"sync"
@@ -33,6 +34,27 @@ type LibrarySource interface {
 	LibraryCandidates(ctx context.Context, genres []string, limit int) ([]json.RawMessage, error)
 }
 
+// CuratedLibrarySource is the optional richer catalogue query used for server-authored
+// collections. Keeping it separate preserves compatibility with simpler test sources.
+type CuratedLibrarySource interface {
+	CuratedCandidates(
+		ctx context.Context,
+		itemTypes, genres, studios []string,
+		limit int,
+	) ([]json.RawMessage, error)
+}
+
+// CuratedRow defines one reusable server-side shelf. Filtering determines membership;
+// the user's profile determines both item order and shelf order.
+type CuratedRow struct {
+	ID        string
+	Title     string
+	Kind      string
+	ItemTypes []string
+	Genres    []string
+	Studios   []string
+}
+
 type Engine struct {
 	source Source
 	log    *slog.Logger
@@ -47,6 +69,7 @@ type Engine struct {
 	// screen rather than a wall of near-duplicates.
 	MaxSimilarRows int
 	RowSize        int
+	CuratedRows    []CuratedRow
 }
 
 func NewEngine(source Source, log *slog.Logger) *Engine {
@@ -56,6 +79,29 @@ func NewEngine(source Source, log *slog.Logger) *Engine {
 		MinRowItems:    4,
 		MaxSimilarRows: 2,
 		RowSize:        20,
+		CuratedRows: []CuratedRow{
+			{
+				ID:        "curated:apple-tv",
+				Title:     "Apple TV+ Shows",
+				Kind:      "shows",
+				ItemTypes: []string{"Series"},
+				Studios:   []string{"Apple TV+", "Apple TV Plus", "Apple Studios"},
+			},
+			{
+				ID:        "curated:drama-shows",
+				Title:     "Drama TV Shows",
+				Kind:      "shows",
+				ItemTypes: []string{"Series"},
+				Genres:    []string{"Drama"},
+			},
+			{
+				ID:        "curated:comedy-shows",
+				Title:     "Comedy TV Shows",
+				Kind:      "shows",
+				ItemTypes: []string{"Series"},
+				Genres:    []string{"Comedy"},
+			},
+		},
 	}
 }
 
@@ -76,25 +122,77 @@ func (e *Engine) BuildRows(ctx context.Context, cred emby.Credentials) ([]Row, e
 	}
 
 	profile := BuildProfile(history, favorites)
-	if profile.IsEmpty() {
-		// A brand-new user has nothing to recommend from. No rows is the honest answer.
-		return nil, nil
-	}
 
-	rows := make([]Row, 0, e.MaxSimilarRows+1)
-	for _, seed := range e.seedsFor(profile) {
-		row, ok := e.similarRow(ctx, cred, profile, seed)
-		if ok {
+	rows := make([]Row, 0, e.MaxSimilarRows+1+len(e.CuratedRows))
+	if !profile.IsEmpty() {
+		for _, seed := range e.seedsFor(profile) {
+			row, ok := e.similarRow(ctx, cred, profile, seed)
+			if ok {
+				rows = append(rows, row)
+			}
+		}
+
+		if row, ok := e.historyRow(ctx, cred, profile); ok {
 			rows = append(rows, row)
 		}
 	}
-
-	if row, ok := e.historyRow(ctx, cred, profile); ok {
-		rows = append(rows, row)
-	}
+	rows = append(rows, e.buildCuratedRows(ctx, profile)...)
 	return rows, nil
 }
 
+func (e *Engine) buildCuratedRows(ctx context.Context, profile Profile) []Row {
+	library, ok := e.Library.(CuratedLibrarySource)
+	if !ok {
+		return nil
+	}
+	type rankedDefinition struct {
+		definition CuratedRow
+		affinity   float64
+		order      int
+	}
+	definitions := make([]rankedDefinition, 0, len(e.CuratedRows))
+	for order, definition := range e.CuratedRows {
+		definitions = append(definitions, rankedDefinition{
+			definition: definition,
+			affinity:   profile.CollectionAffinity(definition.Genres, definition.Studios),
+			order:      order,
+		})
+	}
+	sort.SliceStable(definitions, func(i, j int) bool {
+		if definitions[i].affinity != definitions[j].affinity {
+			return definitions[i].affinity > definitions[j].affinity
+		}
+		return definitions[i].order < definitions[j].order
+	})
+
+	rows := make([]Row, 0, len(definitions))
+	for _, ranked := range definitions {
+		definition := ranked.definition
+		raws, err := library.CuratedCandidates(
+			ctx,
+			definition.ItemTypes,
+			definition.Genres,
+			definition.Studios,
+			e.RowSize*6,
+		)
+		if err != nil {
+			e.log.Warn("curated row failed", "row", definition.ID, "error", err)
+			continue
+		}
+		items := RankCollection(profile, Decode(raws), e.RowSize)
+		if len(items) < e.MinRowItems {
+			continue
+		}
+		rows = append(rows, Row{
+			ID:    definition.ID,
+			Title: definition.Title,
+			Kind:  definition.Kind,
+			Items: Raws(items),
+		})
+	}
+	return rows
+}
+
 // gatherSignals reads what the user has watched and favourited, in parallel.
 func (e *Engine) gatherSignals(ctx context.Context, cred emby.Credentials) (history, favorites []Item, err error) {
 	var (