feat: vani of the day edit

internal/repository/vani_repo.go

@@ -217,6 +217,63 @@ func (r *VaniRepo) oneByHex(ctx context.Context, coll, hex string, out interface
 	return nil
 }
 
+// TranscriptBySlug loads a lecture by its URL slug.
+//
+// Search cannot do this: the slug is not an indexed field, so querying
+// "720720sb-london" matches on tokens like "london" and returns whatever else
+// mentions it. Resolving the slug directly is the only reliable way to pin a
+// specific item someone already has the URL for.
+func (r *VaniRepo) TranscriptBySlug(ctx context.Context, slug string) (*TranscriptionDoc, error) {
+	var t TranscriptionDoc
+	err := r.mongo.Collection("transcriptions").
+		FindOne(ctx, bson.D{{Key: "slug", Value: slug}}).Decode(&t)
+	if errors.Is(err, mongo.ErrNoDocuments) {
+		return nil, ErrVaniRefNotFound
+	}
+	if err != nil {
+		return nil, fmt.Errorf("transcript by slug: %w", err)
+	}
+	return &t, nil
+}
+
+// ProseBySlug loads a prose chapter by book and slug.
+func (r *VaniRepo) ProseBySlug(ctx context.Context, book, slug string) (*ProseChapterDoc, error) {
+	var p ProseChapterDoc
+	err := r.mongo.Collection("prose_chapters").FindOne(ctx, bson.D{
+		{Key: "book", Value: book},
+		{Key: "slug", Value: slug},
+	}).Decode(&p)
+	if errors.Is(err, mongo.ErrNoDocuments) {
+		return nil, ErrVaniRefNotFound
+	}
+	if err != nil {
+		return nil, fmt.Errorf("prose by slug: %w", err)
+	}
+	return &p, nil
+}
+
+// VerseByRef loads a verse by its book/division/chapter/verse coordinates,
+// which is what a verse URL carries.
+func (r *VaniRepo) VerseByRef(ctx context.Context, book string, division *string, chapter, verse int) (*VerseDoc, error) {
+	filter := bson.D{
+		{Key: "book", Value: book},
+		{Key: "chapter", Value: chapter},
+		{Key: "verse", Value: verse},
+	}
+	if division != nil && *division != "" {
+		filter = append(filter, bson.E{Key: "division", Value: *division})
+	}
+	var v VerseDoc
+	err := r.mongo.Collection("verses").FindOne(ctx, filter).Decode(&v)
+	if errors.Is(err, mongo.ErrNoDocuments) {
+		return nil, ErrVaniRefNotFound
+	}
+	if err != nil {
+		return nil, fmt.Errorf("verse by ref: %w", err)
+	}
+	return &v, nil
+}
+
 // VerseByHex / ProseByHex / TranscriptByHex load a specific item an admin has
 // chosen. The payload is then built by the same builders the random picker
 // uses, so a pinned pick renders identically to an automatic one.